Pontiac Trans Am

2002 Pontiac Trans Am Electrical / Lighting Systems Making Noise  Always

pontiac trans am automatic headlight problem. all of a sudden wthis started happening. When I click to set my alarm it makes my automatic headlights go up and down and then the driver side lights motor makes a loud noise. It will also make the loud noise when I turn it off from the inside?

The noise is only on the drivers side light but both headlamps go up and down when I arm or disarm my alarm. When I turn my lights off from the inside of the car the drivers side headlamp motor makes a loud noise. Coming from the manual control to operate the headlamps.

Sounds like the mechanism is going bad. You will either need to replace it, or disassemble and repair. It is possible that lubrication will resolve it, but most likely will need something more involved than that.

2002 Pontiac Trans Am Electrical / Lighting Systems   

The front right-hand turn signal and running light have stopped working on my 2002 TransAm. The rear right light works but does not blink. Should I change the front lights, or could there be a different problem. Left-hand lights work fine.

I am quite sure the rf turn signal bulb has failed. When you replace it, try to use a quality bulb as there is lots of cheap offshore parts out there!~

Thanks for the reply? True for the running light too then? Sure seems coinicidental that they failed at the same time.

2001 Pontiac Trans Am Heating / Cooling System   

01 trans am heats up really quick. has new thermostat and cooling sensor, radiator has been back flushed. no water in exhaust and no water in oil. fans work but don't come on till it over heats. not losing any water except when it over heats and bubbles out of resivor. any ideas? thank you

also the heat blows out hot air till it starts to over heat then blows out cold air.

If you know someone with an emission type exhaust tester to check for C02 at the rad filler area with cap off.
You might also look at the fan thermostatic switch, by the thermostat housing.It is what turns on and off the rad fans at a predetermined temp.
Even if rad was backflushed, it might have some blockage.See if you can check the temp of the cooling fins in several locations when rad warm.You might be able to use the palm of your hand for the test.I use an infrared temp gun.

1999 Pontiac Trans Am Electrical / Lighting Systems   

when headlights are turned on the doors raise normally however all four lights, both high and low illuminate dimmly when high beams are selected the drivers side light set goes out and the passenger side both low and high are lit brightly all other exterior lights operate normally.

Carefully check the wiring from therear of the bulbs to the ground circuit.Typically a black wire, terminating at an eyelet which is screwed to the radiator support, it commonly gets a little corrosion and you have that problem.If you have a volt/ohm meter handy, you can check the circuits individually , especially the ground or negative circuits.It would not hurt to test each bulb individually also.
I will be here for the rest of the afternoon
and evening, for updates.
Bruce

I do not have access to the car right now it belongs to my grandson and he has it at work. Do you think the DRL module could be involved. Have you seen this problem before?

Have you seen this problem before and are you sure the crooded ground is the problem ?

With wiring, nothing is written in stone, but the unusual light issues seem to lead that way.
1)A bad gnd will give you dim lights.
2)A bad gnd will give you unusual operation
(the voltage trys to ground elsewhere)

Daytime Running Light Modules certainly have their share of faults.
I always try to fix the most economical
methood first...the DRL is not cheap!
GM does have a reoccuring DRL mod. problem that can be repaired.You have to dismantle the case and very carefully examine the soldered connections for cold solder joints.(they look kinda pastey white instead of silver) If you can solder connections reasonably, it is possible to re-solder them.

According to the gm f body shop manual vol 3 pg 8-47 and 8-51 the headlights and the fog lights use the same grounds G105 and G106 and the fog lights work normaqlly.

Then you might want to find a magnafying glass, bright light and soldering iron.

Might also want to examine the gnd wires also, even they terminate at the same location, the wire to it may be a problem.

1997 Pontiac Trans Am Engine   

while driving my car at steady speed engine suddenlt stops... electrics are on and a "check guages" light comes on and "abs inop" lights up...this has happen 3 times... the 1st time i was able to drive the car for another 10 months before it happened again,,, the 2nd time it woud not start and eventually I had fuel pump replaced and tuneup... the 3rd is my present question...

Does it shut off just as if someone flipped a switch or does it cough/sputter to a stop?

Also let me know which engine you have & if you will be troubleshooting and repairing yourself.

Yes it shuts off as if someone flipped a switch... My engine is the 5.7 liter, 8 cylinder... I will be taking it to service but wanted some advice before doing so...

Okay, your engine likely has the optispark distributor (the 8th character of your VIN will be 'P') that is prone to failure. If this is the problem it is expensive, so very important to shop around for parts (sometimes ebay has the best price.)

You should visit an Autozone or Advance Auto store and have them check the trouble codes (free service.) Note-- they may tell you they can't check the codes unless the engine light is on. This is not true (they are incorrectly trained), there may be pending codes that have yet to turn on the light, or a trouble code that does not command the check engine light on.

If they do find codes make sure they do not erase them (make this clear.) If you take the car in the service department will want to see the information for themselves. Let me the alphanumeric designation of the trouble codes, EG- P0300, P0501, etc.

OK.. also like I said initially I just had a tuneup done and the distributor was replaced... I have a Car MD device for checking codes... and it does not show any codes perhaps I could get a diagnostic readout and take it back to where I got the tuneup...

I think your device is the same as the parts store (from a functionality standpoint.)

If the distributor was replaced and the problem repeated, it could be the module, coil, pcm, or igntion switch. All tough to catch if intermittent with out codes. Is the car running now?

Yes... It is running.. I just went out for some food and just as I got into my complex... it stopped again... I tried 3 times to start it but ut wouldn't start... so I walked to my condo dropped some stuff off, walked back to the car and it started... I'm also suspecting perhaps and electrical problem...

Did you send another update? I just got a new email notification but it says waiting for mechanic...

Ignition module is probably the most likely. You could try using electronics component cooler when it won't start. If this consistently gets it starting again, the you have pretty much confirmed the problem.

Or perhaps a hair dryer to heat the module. If you could recreate the no start (when it otherwise would start) by heating the individual component, you'd also confirm the problem. Be careful with potentially flammable substances under-hood.

As for the emails you receive, I'm oblivious.

Thanks for hanging in there for me... But remember its not really a starting problem, because when the problem comes up the car is already in motion and then the engines just cuts off like a light switch,,, it only had problems starting the last time, after it suddenly stopped an hour ago, but within 5 minutes it started up fine... you mentioned the ignition coil,, but isnt that just for starting and once the car is started it is no longer a factor... or am I wrong in my thinking...

The coil is what actually produces the spark, everything else simply supplies voltage to the coil and/or the negative voltage trigger (precisely timed) which causes the coil to fire. The coil fires during engine cranking (starting & running.)

Right, so it's never been a starting problem... just that after it has started normally and been running as long as a 1/2 hour it stops suddenly... I pull over and put it in park and it starts right away... what about the electrical system... if there is some kind of intermittant break in the circuitry wouldnt that possiby account for what happening... or what about an alternator thats' on its way out... I've got 120,000 miles on this car...

Excuse me, I missed what you said about starting and "running"... ok thats something to go on.... Is that expensive to replace...?

The coil is possible but not as probable as the ignition module, not even close. I just wanted you to understand the importance of the coils role. Copy and paste the following links into your address bar--

http://www.autozone.com/az/cds/en_us/[redacted] d/80/1c/e3/4[redacted] d801ce348/repairInfoPages.htm

http://www.autozone.com/az/cds/en_us/[redacted] d/80/1c/e3/9[redacted] d801ce399/repairInfoPages.htm


You'll notice more internal links at the site to explore components of your car. Next link is for Aftermarket Parts (Original Equipment is recommended)--

http://www.partsamerica.com/ProductDetail.aspx?MfrCode=GPS&MfrPartNumber=EL389&PartType=194&PTSet=A

If you were going to take a chance, I'd take one on the module (if you wish to change it yourself without diagnosis.) By the way, most shops will not be able to confirm a problem with the module UNLESS it fails when they are monitoring the system with their test equipment.

Just one more thing would it make any sense to have the whole electrical system checked out 1st by a specialist which might also include testing those components...?

Yes, it does... but-- you will be paying for diagnostics that have already been done. They will check the PCM for trouble codes. Their expensive scan tool will not see anything more than your code reader, assuming your code reader works. If you did have trouble codes then the capabilities of their scan tool begins to justify the cost.

If you pay a specialist, make sure you get one that is qualified to check the whole system. This means having a lab scope to to attempt to test the health of the module, coil, etc.

I'm not saying they won't be able to find the problem. Just that if they are honest, you may be paying them to say they can't find the problem. If they are 'salesmen' at heart you may end up paying for their guess.

If it fails while they have the car my concerns no longer apply, or shouldn't.

Let me know what you find or if you have any more questions.

1996 Pontiac Trans Am Electrical / Lighting Systems   

my airbag light is on and my steering wheel radio control don't work either this started yesterday.

It sounds like your clockspring has gone bad. This is a component that allows for continous electrical current to the items in the steering wheel and column assy. To replace you have to disassemble the steering wheel and remove the wheel. Not complecated but you must disconnect the Neg wire from the battery and leave it disconnected at least 10 minutes before starting work to prevent airbag from going off due to stored power. The clockspring can cost between 150 and 300 depending upon where you purchase it. Let me know if I can be of more assistance. Al
PS the next components to fail will be the turn signals and the horn. This is a safety issue because the SAS can get a false deployment signal and deploy the air bag.

THis is a follow up response to the potential problem you were having with your Trans Am. Was the problem actually with the clockspring or was the problem elsewhere? Hope you have a great holiday season.

1995 Pontiac Trans Am Engine Lagging When accelerating Always

Engine lagging on all(6 speed)accelerations, (rpms at 1500 or below) heavy engine vibrations and loss of power, constantly down shifting to bring rpm up to 2000 prior to progressive gear change. Replaced distributor, cap and rotor, spark plugs, fuel filter, in-tank fuel pump, starter, dealer technician inspected all engine fuse box electrical relays which tested good, elbow between throttle body and MAF sensor to ensure no leak, replaced both
Oxy sensors about 2 years ago, knock sensor has not been replaced, connectors have not been replaced, solenoid replaced about three years ago, now heavy exhaust odor - no billowing smoke. Costed me alot of money. Contemplated on a dealership computor diagnosis to identify the problem but running out of funds. I need help!

You need to replace your catalytic converter and possibly your muffler.

The vehicle has a two chamber Ravin muffler, headers with three inch exhaust and tail pipes, when purchased this used vehicle in 1998 no catalytic converter observed,combination worked well with 20-25 mpg highway, 65 mph in 6th gear @ 1500 rpms and no hesitation for hard acceleration from that point. Why now the problems? Your suggestion lean toward a flow restriction?

What's causing the engine vibration while acceleration? What causes the engine lag while accelerating and shifting into a higher gear?

Waiting for answer.

The performance issues could be caused by a lean fuel mixture or an excessively rich one.

How is idle?

Have you taken a look at the spark plugs? Black sooty deposits is to much fuel. A white blistery appearance is a sign of lean fuel mixture.

Does the check engine come on when the engine is running?

What does the exhaust smell like, unburnt gasoline or a sulfur-like (rotten egg) smell, or?

The spark plugs were recently replaced, there was black soot on the old spark plugs, The check engine came on and the odor smells like unburnt gasoline.

Use the following link to access a repair guide for your car. Hopefully you are fully OBD1 and not partially OBD2 compliant. If you are OBD1 you can access the trouble codes yourself, while OBD2 requires a scan tool. You can tell by observing the diagnostic connector, if there is a terminal for A & B you can check the codes.

When you access the following site and load the repair guide- go to "Emissions" to get instructions on pulling diagnostic codes. Let me know what codes you find.

http://autozone.com/servlet/UiBroker?UseCase=RG001&UserAction=viewRepairGuideYMMEYear

1995 Pontiac Trans Am Engine Overheating When idling When warm 

coolant boils out through filler tube while car idles; fan kicks on between 240 - 245 degrees; when MAF sensor is unplugged, both fans come on and car idles at approx 185 degrees and everything seems fine; same if coolant sensor switch is unplugged; coolant sensor switch, radiator cap, and thermostat have been changed; while driving, temp stays at 185 and car runs fine

Hello, What engine please?

From what you describe I doubt the water pump is doing it's job. I believe the cooling fan is coming on too late.

How clean is the radiator? How many miles on the engine please?

Roger

the engine is an L1 WITH 123,000 MILES. WITH THE RADIATOR cap off collant is circulating.

Are you confident the radiator is not stopped up below the circulation you see?

If when the system is warmed up and under pressure the cooling fan should come on about 208 degrees F.

Have you pressure tested the radiator cap? I know you said it is new but does it work properly?

Do you have coolant mixing with the engine oil? Are you having to add coolant. I'm wondering about possibilities of an intake manifold or head gasket leak...

Roger

no coolant with oil. not confident about radiator.

coolant is being lost through plastic filler tube.no collant in oil,not confident about radiator.

Are you saying you see coolant backs up into the overflow reservoir and boils when the system is sealed and the engine idles?

That would call for a compression test to determine head gasket integrity.

The cooling system maintenance chart calls for a system drain, flush and refill every 30,000 miles or two years. This is to be done while the engine is cool. Any idea how current the system maintenance is?

Roger

i flushed the system but i don't think i did it properly.this all happend after i flushed it.

i didn't mean to push the release button.i want to talk to the same mechanic

Well hey, If this all came about after you flushed the engine cooling system...

Were you performing maintenance or trying to fix a problem?

If you didn't have a problem before it's possible the trouble now is just air trapped in the system. Bleeding the air out can be a pain.

Roger

just performing maintenance.would air lock cause the fans to come on to late.

Yes, because of steam. Is there a bleeder valve on top of the thermostat housing? It is never going to behave until the air is out.

Roger

yes there is a bleeder on the hose going into the it.

Fill the system with 50/50 coolant/water and fill the overflow bottle to the cold line.

When you install the radiator cap turn it far enough that it cannot be removed without pressing downward but don't turn it to line up the arrows with the overflow tube.

Start and run the engine with the car's heater on high. Raise and hold the RPM to about 1500. Watch in the overflow reservoir and you will see bubbles of air escaping. You will also see the coolant level rise as the engine warms up.

After the air escapes you will see the coolant level go down. If it drops below the cold line top off to the cold line and wait for it repeat this cycle.

Allow the engine to idle. Lock the radiator cap on. Check to see if the heater is blowing hot. Service the overflow reservoir to the FULL HOT line and tighten the cap.

Carefully and slowly open the bleeder screw above the thermostat just enough for air to escape and wait for constant coolant flow. It's hot so watch it!!! Lock the bleeder screw. You may wish to have a rag over the bleeder screw to help control the flow from the bleeder screw.

Road test the car, check the heater air outlet temp for satisfactory temperature. Top off the coolant in the overflow reservoir to the FULL HOT line.

If necessary you can open the bleeder to check for any remaining trapped air. Just be careful. Coolant under radiator cap pressure will come out hot (215 degrees) and fast.

Let me know how it goes,

Roger

thanks alot. i'll do that.

with the radiator cap off.i see coolant coming through tha recovery tube back into the radiator is that normal or does it indicate a pluged radiator?

Are there two tubes connected to the overflow reservoir...an inlet from the engine and an outlet to the radiator?

I may have to switch data bases to get a more definative answer. I won't have access to the data base I have in mind until tomorrow afternoon.

Roger

What is your email address, please? I'll send you a cooling system bleeding procedure I found in the Mitchell 1 Auto Repair Data Base.

Thanks,

Roger

[redacted]

Thank you, I'll send it along.

Roger

Hi, Any news here? Just checking in with you...

Roger

haven't had time yet.been on the road getting jobs done.

Thank you for the update.

Roger

the bleeder valve sets higher than the radiator,so i cant get coolant to reach that point while filling the radiator.i'm going to try pulling it on ramps than filling with coolant,maybe i can get the air out like that.if that does'nt work than i don't know.it's driving me crazy.perhaps a very large hammer??

Perhaps when the cooling systems begins to build pressure during warm up you can vent some air out of the bleeder.

I remember being so upset with one GM car I was working on that I took the thermostat out, left the thermostat housing off, and poured coolant in the thermostat opening until the level came up to just short of overflowing. Then I put the thermostat in and put it all back together, checked the radiator level and tried it again.

It worked.

Roger

1989 Pontiac Trans Am Electrical / Lighting Systems   

I am in the uk and have had to change my rear lights on my 89 trans am so that I have an amber turn signals at the rear. I acomplished by rewiring the rear lamps and adding a amber lens. Now my turn signal do not flash they just stay on! I am told I now need to fit a different relay, which is the relay for the turn signal, i know its in the convenience centre, there is a round one and a square one? and do you know which one i could get to activate the flashing?

thanks

sorry it is a 89 Pace car like the GTA

A Pace Car in England? Not many out there! The European requirement for The amber turn light is a pain! Changing the flasher (round one) to fix the problem might not be the fix.Grab a Haynes manual (they are printed in England?) They have detailed wiring diagrams.
There is a small light box available in North America that is sometimes used when wiring cars to tow trailers (I believe they are called caravans there?)The trailers have a common red turn/brakelight. The cars sometimes have a separate amber turn and red brake light, making it incompatable with the trailer lighting. A small box is available to cure this problem.It is wired into the taillight wiring. It might solve your problem.
How did you solve the amber problem? I own an Camaro IROC Z Convertible, and I believe some years had red and some had red/amber lens.They were quite interchangeabe from '82-'92 and that would be a clean looking fix if you found the same for Firebirds and Trans Am's. If there are other years 'Birds with red/Amber taillight lens, EBay probably a good place to start looking.
The Haynes would be a good start.

I cut out a piece of the red lens and glued in a clear piece and painted it amber. I can email you a pic if you would like to see them. The Gta pace car has different light clusters to the ordinary Trans am/firebird, they doo indeed have an amber turn but it is completely different looking. I am told i only need to upgrade the flasher unit, but unable to firstly locate it, some people say there is one for the turn and one for the hazard lights, the hazard lights currently flash correctly, pulling my hair out over the turns though, ps there is 4 89 Pace cars in the uk! mine is no 448

Yes the turn and hazard lights often use separate flashers, wich are round. They are sometimes 'hiding' directly above the steering column (LHD) above the footpedals, and yes, hard to find!
I like my lens solution better,but if they are different, replace your clear amber painted part with an amber one from a damaged UK car taillight. Trimming the amber piece will probably give you a brighter, easier to see light that might prevent an accident!
My email is [redacted] if you would like to send photos.

thanks i'll have another look under the dash.
i have sent you some pics

Colin

ok

1989 Pontiac Trans Am Ignition System   

i don't have spark coming out of coil. replice ignition module and coil. didn't solve. help me please. chuck

Make sure you have key on battery positive to the coil (one end of test light to a known good ground and the other to the coil electrical connector).

Make sure rotor is turning inside the distributor. Next check the pick-coil inside the distributor. Most auto parts stores will test this free of charge off the car. If they don't have a test have them check the ohms of yours and compare it to a new one (shorted or open is surely bad).

This assume you have a distributor on your engine.

1988 Pontiac Trans Am Engine Malfunction When idling When warm 

I have a Trans AM 5.0L 305 TRI, After its warm the oil pressure dropes to 30, when I stop it dropes to 0. If I put the car in N instead of D it seems to be OK otherwise it starts beeping. I have replaced the oil sending unit already. can you help

thats TPI not TRI

TPI not TRI

Hear any ticking when the pressure is at zero?

If not check your idle speed, could be to low.

no ticking, how do i check the idle speed?

You'd need a tachometer to check idle speed.

If you turn the wheel- while stopped in drive- does the idle speed increase slightly? An alternative test would be to turn on the A/C (if applicable) under the same circumstances.

At a shop they'd install a mechanical gauge to check the oil pressure with, this ensures an accurate reading.

You could have worn engine bearings causing the pressure to drop. While this is very possible, some mechanics jump to this conclusion without verifying proper idle speed.

Another problem can be a dirty pick-up screen on the oil pump.

1987 Pontiac Trans Am All Part Groups   

Today when I left for work I noticed a repetitive clicking sound coming from the front passenger side. I unscrewed the bottom dash panel and found that it was a relay clicking wildly. There are three components in there and it is the one in the middle (a white plug fits into it). Do you know what this is?

from left to right
blower motor high
cruise control
blower motor low

Any idea why the cruise control relay would click so much while driving?

1986 Pontiac Trans Am Engine Hesitating When accelerating When warm 

I have an 86 Pontiac TA 305 Fuel Injected. When cold, it starts fine, accelerates smoothly and runs great. As soon as it warms up, it hesitates on acceleration sometimes to the point of stalling. If I manage to keep it running, once the rpm's get above around 2000 it then accelerates ok up to highway speeds and runs pretty good but with an occassional miss. I have replaced plugs, wires, cap, rotor, fuel filter, air filter, o2 sensor. No check engine light and no trouble codes showing up on scan tool. Warm, it still starts ok and idles smoothly at 900 rpm. Checked timing and it is ok.

Take a close look at the throttle position sensor. Also do a road test with the egr disconnencted, to make sure it is not opening prematurely. GM mass airflow sensors were troublesome in this era, as were fuel injectors. Make sure the new plug wires are good.

Hi, wondering how you are coming with the car. Any questions?

1986 Pontiac Trans Am Ignition System Chugging When driving Always

I was diving today and mashed the pedal to the floor. My car stalled and then started running again, but now it sounds like its missing a cylinder and doen't run nearly as stong. This is just a bad plug right? Is there any easier way than putting the car on a lift and maybe taking off the headers to remove the spark plugs? Thanks

It does sound like a spark plug fouled out or a wire failed. Have you attempted to pull the plugs from the fender well? A little time consuming, but easier than getting under the car if you dont have a life. Let me know .. Al

1986 Pontiac Trans Am Engine  When driving When warm 

When driving at above 60MPH, my temperature gauge pegs right to the end, then when I slow down it goes back to normal. There is no coolant leaking, the heater core is a year old. Is this just a sending unit problem or is the thermostat wacky? Thanx

I would try a new thermostat, just to be safe.
If the engine shows no signs of overheating it's likely a problem with the sending unit. Especially if the gauge moves faster than you'd expect the temperature to change.

1986 Pontiac Trans Am Engine Malfunction Happens always No pattern

86 Trans Am with a 305 TPI. When I turn the car on the temperature gauge is fine then it goes off the scale past the overheat point. The engine is not overheating, the thermostat has been replaced as has the temp sending unit. Still the problem persists. Could it just be the gauge itself? Thanx

The guage could be malfunctioning. Pull it out and test it with an OHM meter for resistance, not sure what the particular specs should be but it should stay constant. I myself would have replaced the guage first - they are a little known for not functioning properly.

1983 Pontiac Trans Am Electrical / Lighting Systems Malfunction Happens always Always

Hello, My rear window defroster quit defrosting. Fuse is good, switch seems good. Bought a new relay but can't find where it is under the dash to replace it. I have pulled dash apart as far as possible, and still be able to drive it. Nothing in site. Do you know where the thing is located? thanks Flash

Have you looked in the LH kick panel, to the left of the dash? Or just following the wire from the switch?

Can't follow the wire to far. after a couple inches it all disapears into the wiring harness which is pretty well inclosed. took off the kick panel on the driver side and nothing there. Any other ideas let Me know.. thanks
Flash

Behind RH Side Of instrument cluster looks like a module has a heating element built in

Pulled off the instrument cluster and its not back there.
Will release the question and see if someone else might now its location.
thanks for trying
Flash

doesnt look like a normal relay looks like a box not directly on inst. clst. is loocated up in dash behind ic

Hello, I will look again.. I have the a new relay. A rectangular silver shape with a angle bracket already attached. It came through vintage parts so I am assuming the original one looks much like the new one. I have layed down looking up behind the instrument panel with a flash light and don't see it. As it is My transportation car I hesitate to take more of the dash apart when its not the weekend. Maybe there is a way to take the "top" of the dash off??
thanks
Flash

took another look. Nothing. Will take the "top" of the dash of when weather allows. I don't even see the relay in the wiring diagrams!!
thanks
Flash

unfortunaly you are wrong at least on this car. I found it on the passenger side. If you take off the plastic piece below the funny glove box (it looks more like a leather folder than a glove box) there is an opening. The relay is held in place there with two screws.. Thanks for trying
all the best
Flash

all cars are different even went on all data and it didnt even mention there

yeah I know.. Thanks for the effort is much appreciated.. Just in case someone asks you again a fellow with an 89 trans am said he found his in a similar location (to mine)
have a great thanksgiving!
Flash

ok

1982 Pontiac Trans Am Electrical / Lighting Systems   

require info for headlight motor wiring , mainly referring to relay set-up and operations. Cheers Carl

Hi, I'll sure get to looking for the wiring diagram for you.

May I have your email address please?

Roger

I have a wiring diagram to send to you. May I have your email address?

Roger

Are you there??? Please advise your email address and I'll send you the wiring diagram you requested.

Roger

1978 Pontiac Trans Am Brake System Malfunction When troubleshooting Always

all new lines,master cylinder,perportion valve,calipers,wheel cylinders,the only thing original is the booster,fronts are strong,but I keep losing the pedal and the rear bakes are weak.I even tried a vacuum bleader.

When the brakes become spongy do they stay spongy? Also how long does it take for them to become spongy? I'll assume the master cylinder was filled and bled upon installation.

Sometime air can become trapped (in places like the calipers). One 'trick' is to hit suspect areas with a rubber mallet to dislodge the air. Another thing is to wait about about half a minute between bleeding attempts, this allows trapped air to accumulate so it can be removed.

If you keep pumping the brakes do you lose fluid? This may take a lot of pumps to confirm.

The master cylinder itself may be bad. You may need to obtain plugs for the master cylinder output ports. Insert the plugs (say for one or two of the back brakes to start with) and pump the brakes up. Any change?