Chev Tahoe

2003 Chev Tahoe Engine Stalling When accelerating No pattern

Diagnostic by dealership took three analyses plus driving it to call it a computer malfunction. That while driving the vehicle engine shuts off. Recommendation: replace the computer. I believe that it could be a sensor fuel related.

You are right, the symptom you describe "could" be coming from a sensor. It "could" be the computer. It "could" be a loose wire somewhere. It "could" be......

To find this fault, will take some time, and MUST involve live testing at a time when the engine shuts off.

I hope the dealership did that. If they did, and the tests pointed to the computer, that would be the obvious place to start.

Hope this helps,
Dale

2001 Chev Tahoe All Part Groups   

ac compressor hose high and low side lines to dryer

I'm not sure I understand your question.Do you need to know whitch is the high and low side lines?

i need a price on these parts,the high side line and the low side line.

If your looking for used parts,check the parts section of this site.wise,check online with NAPA.com,Car Quest.com or maybe even EBay

1999 Chev Tahoe Drive Train / Driveline  When shifting No pattern

With the automatic transmission set to D or 3, when coming out of a full stop, there is a "thunk" as if something were engaging, as if the gearing is coming in at the wrong time, as if power were being applied too abruptly. It works something like earthquakes: I either get two small "thunks" or one bigger one. Sometimes I get no thunk at all. The "thunk" is not quite a sound as much as it is felt.

When coming into a full stop I also get a "thunk," usually a single "thunk."

need more info 2 wheel 0r 4 wheel drive

4wd. It does this regardless of what 4wd mode I am in... whether I'm in "2 Hi" or "Auto"

check front drive shaft

1. What do you mean by, or what is, a "front drive shaft"? Does this have something to do with 4wd system? I ask because by setting it to 2Hi it effectively is only running rear wheel drive.

2. The "thunk" seems to be coming from the back of the vehicle. I should have mentioned this earlier. Does this change your thinking that I need to check the "front drive shaft"?

front axles turn regardless of what gear you have it in and yes coming from rear matters does your vehicle have a spare tire mounted under the rear

Spare tire is not mounted underneath.

This might help: I first noticed the thunk after asking my mechanic to change the transmission fluid. The thunk was most prominent right after changing the fluid.

This might also help: The fluid change was prompted by an odd event with the transmission. I put the vehicle in reverse and there was a delay, it didn't go into gear until after I had started accelerating and so it came in very abruptly.

GM has had there fair share of problems with shift solenoids. Have a qualified mechanic check these.

1999 Chev Tahoe Engine Overheating When driving Always

As preventative maintenance, I recently had my thermostat and water pump replaced because I have about 140,000 mi on this 99 Tahoe and because the temperature guage was showing the temp to go too close to boiling before the thermostat allowed the "water" to start flowing. This behavior always happened while starting from cold. But once the temp guage started to go down it stayed down, presumably because the thermostat kicked it. After replacing these items, the problem appeared to go away. Anyway, now, after the thermostat and pump change, last night, my truck started to overheat and by this I mean past boiling point of water which had never happened before. Luckily I glanced at the meter and cought it before it went all the way toward the red. So I pulled the truck over and allowed things to cool off. It cooled down relatively quickly, and I'd start to go again and it would start heating up. etc. Found myself at a gas station and I topped off the antifreeze, it was about half gallon low. Hoping that was it, but knowing better, I headed home along back roads so i could keep a low speed. I didn't make it home. It did run for about 10 minutes and in that time the temp was flutuating greatly between normal and boiling (140 - 210) as if the thermostat was turning on and off. Eventually the temp started running away toward 260 so I stopped the engine before it got to the red. What's going on?

The first thing you need to do is determine that the system is full of coolant (no air). The best way to do this is by inserting an aspirin to hold the thermostat open so you can top off the coolant. The aspirin will dissolve quickly and the thermostat should work fine.

My first guess is that the new thermostat is faulty- this happens more than you'd probably think.

Also check to see if fan is operating properly (especially if it only overheats at idle or low speeds= no cooling airflow from wind-speed).

There are other possibilities but start here and let me know if you need further assistance.

1. Looking into the radiator from the cap, the coolant level is about 5 inches from the top. I can see about an inch or two of the radiator block --the silvery metalic block inside the radiator. I realize this doesn't tell me if there is any air in the engine.
2. Where would I insert the aspirin? How does this insure that the thermostat stays open?
3. Can't just take the thermostat out? Car runs fine cold. It'll eventually warm up. Would it damage the car to operate without a thermostat?
4. Please try to answer this one irrespectively of your affiliation to all-parts: my mechanic uses Delphi claiming it is the same as GM for parts; I've been through three delphi alternators in three weeks and now this thermostat is less than 3 mo. old. Is Delphi having problems or do they just plain suck?

You manually open the thermostat (removed from engine) and insert the aspirin so it cannot close completely. An interenet buddy won an award from a technical magazine for this 'Tech Tip'.

The engine may not reach proper operating temperature with the thermostat out. This is not good for efficiency. There is also the possibility of engine damage- I've never seen it happen and honestly don't remember how.

Delphi is an original equipment supplier for GM. GM Dealer parts have suffered in quality since their 'glory days'. Your experience with alternator failures points closer to "sucks" than having problems.

As I said it may be something else- plugged radiator, combustion gases, etc. Let's rule out simpler less pricey problems first.

I've never done much more than change the oil/spark plugs in my vehicles. I don't want to attempt taking the truck apart to pull out the thermostat, etc. Is there another way to tell if there is any air in the system? As I said, after adding half gallon last night to the resorvoir, the coolant level this morning is not all the way to the top. It's about 1" or 2" down from the internal radiator block. Is that normal?
Why would the temp meander back and forth between 140 - 210 degrees and then eventually head toward 260?
At one point I didn't believe my temp guage because the car didn't seem that hot when i went to fill the reservoir.
My battery is low also... I don't know how many more starts I have left.

Keep topping the radiator off and the reservoir. Start with a cold engine and the radiator cap off. Observe coolant flow- if you start to see excessive bubbling/gurgling let me know. You problem may not be air in the system, but this is the first thing that must be ruled out after the system was 'opened up'.

By all means replace your battery right away, you don't to be stranded. Some chain autoparts stores (Advance) offer free installation.

-Can I start it and look for bubbling/gurgling without filling it any further? And then report back to you what I see?
-The reason I don't want to top it off is because, since I just had the water pump and thermostat changed out and since I think the mechanic will make good if it is either of these two items, I want to tow the car to him Monday morning in the same condition as when the problem occured so he can reproduce and observe the problem. The info you are helping me with is to give me an idea of what it could be, kind of an informed opinion, and to suggest that to my mechanic as a possibility (or even as an instruction). He's a good guy, it's the parts I don't trust.
- So is observation of bubbling/gurgling good enough?

I don't think your mechanic will have any trouble diagnosing the problem.

To answer your questions, if you are curious what to try...

Yes, certainly. Although do not allow the engine to run-

1. If the level drops to low
2. Coolant starts to gurgle over
3. The temp gauge climbs to high.

If you had a thermometer you could monitor the temp in the radiator and compare it to the gauge reading. In this case it would only be relevant after the thermostat opened (this is evident by a slight drop in temp at the gauge and you'll notice coolant flowing through the radiator). If coolant doesn't begin to flow because the thermostat never opens do not allow the engine to continue to run as I said before (in worse case scenario it could become a hazard to you as well as the engine at high temps- ask for more detail if you need it).

Be sure to use extreme caution around moving engine parts.

With the luck you have been having with parts, a bad water pump is possible too (albeit rare).

-With regard to 'dont let it go too low', how low is too low? And speaking of coolant levels, if I want to top it off at the radiator cap, how far do I fill it?

-about Delphi.. ok Delphi is an oem to GM.. but does that mean that delphi parts are identical to the parts I can order from my Chevy dealer? Ok not identical since the logo will not say Delco, but what I mean is: same design, same quality, same function, same failure rate, etc.

-ok, so, while making sure the temp doesn't get too high, I'm checking to make sure the coolant starts flowing, not too low on level, and no gurgling.

If you can't see the coolant consider it to low.

If Delco tagged parts are available, I'd choose these.

-So really Delco is better than Delphi. Yes? Assuming it actually is labelled Delco and not Delphi.
- I couldn't contain myself. I went out and topped it off after watching it for a while. This time I added it to the radiator (last time the reservoir). To top it off at first, I added just under a quart. Then I watched. There was a bubble about every five seconds. When the car reached normal operating temp the level started to drop. It dropped way down, beyond where it was before I added more this morning. So I topped it off some more. i'm adding water now. The amount I've added today is about one half galon. Add that to the half gallon I added to the reservoir last night (although clearly not all that was added to the resveroir made it to the radiator last night). So figuire, in total, I've added almost one galon.
-The bubling is down to about one per minute, sometimes two bubles right after each other.
-What's next?

Douglas?

Small bubbles periodically is normal. If the coolant level is no longer dropping test drive. Don't allow the engine to overheat.

I already filled it and I already test drove it. It does not overheat, although i only drove it 10minutes. There is a leak. It is toward the front of the engine block. The drips are coming from underneath the lowest part of the engine just behind the lowest pully on the belt. It drips when warm, and when cold it eventually stops dripping.

That would explain why it overheats, as the coolant level will drop to low when you have a leak.

Has you mechanic checked his work to see if he caused the problem?

No. I need the vehicle right now. I loose about a cup for every 20 minutes I drive (commute time). I'll take it to him next week. Is there anything I can try between now and then?

You could use a sealer, but to much sealer is not good.

Does the engine overheat when you keep the coolant full?

No. It does not overheat as long as I keep topping off the radiator. I do this every morning and I carry a gallon of water in the car in case.

SECOND REPLY IN A ROW
Oh, also, about the sealers, I thought the sealers were for when it was leaking from the radiator. I'm leaking in the engine somewhere. Can I still use the sealer?

It is your choice, from a debatable issue.

Many techs cringe at the idea because it is possible to clog things like heaters cores especially with excessive leaks. Most of these people are oblivious to the fact that GM uses sealer in their engines (some anyway, not sure about all) from the the factory.

If the leak is to great sealer will not work.

How far are you driving? A cup every 20 minutes is not a terrible leak, at least not yet.

Just commuting to work and back. 20 minutes each way. Then I refill in the morning. Sometimes I check before I leave work if the engine is cold.

Tough call then, you want to be sure your mechanic can accurately identify the leak so it can be properly repaired.

BTW- Is this from an engine gasket, hose, or you can't tell?

I can't tell.

I'd probably keep adding coolant. In worse case scenario the leak sealer could stop the leak and your mechanic wouldn't be able to find where it was leaking (or misdiagnose the leak).

OK, Thanks.

1999 Chev Tahoe Drive Train / Driveline   

Light comes flikking on, but dont engage front wheels.

Hello,

Are you talking about the 4WD light? Does it turn on normally or continually flicker?

it turns on normaly

Hello,

I've re-opened this question at the customer's request.

Mark,
Site Admin.

It turns on normally.

1998 Chev Tahoe Windows / Glass  When accelerating No pattern

When I accellerate or start up a hill I can hear water sloshing around. It seems to be coming from in front of the dash. With my ears it could be anywhere. I keep looking for a stopped up drain, but no luck so far.

Hello, Does your a/c condensation drain for the HVAC case work? If the drain is blocked and you have been using the a/c the condensation will back up in the case. It can overflow onto your carpet.

Is the vehicle low on coolant and you may be hearing coolant circulate through the heater core?

Roger

I ran the car with the a/c going for 15 minutes and didn't see any condensate under the car. This makes me think that must be it. Next problem is that I crawled around under the car and couldn't find the drain. I am looking primarily just inside the right front wheel. Are there any diagrams available to show me where the drain is?

I may have trouble finding a pic of the drain location.

It is located at the bottom of the HVAC case and is routed through the firewall at the lowest point of the HVAC case. You'll find the drain on the base of the firewall passenger side. Not in the wheel inner fender.

The drain can be a 90 degree angle rubber boot or even a quarter sized round stopper looking plug with a split in the bottom to allow water to drain and help keep bugs out.

A 90 degree boot type drain can be pushed on too far and hinder drainage. It can be rotated up and not drain.

When you locate the drain be ready to get out of the way when you clear the blockage. You will get wet. If you should find the round quarter size diameter plug with the cross split in the bottom just pull the whole plug out and leave it out.

Please advise,

Roger

Have you located the HVAC case condensation drain? Was it plugged up?

Thanks,

Roger

I never did find it. I sold the car. The new owner didn't seem to be too concerned about it. I knocked a few bucks off the price because of it and seemed happy. I guess we can forget this one.

Okay, to obtain a refund write to All-Parts.com, Site Administrator, All-Parts.com.

Or, to accept my answer so that I may be paid please click on th "OK TO PAY MECHANIC" button.

Thanks,

Roger

1997 Chev Tahoe Electrical / Lighting Systems  Happens always Always

The daytime running lights on my '97 Tahoe were disabled by the prior owner (I assume). How do I correct this? The daytime running light indicator on the instrument panel works as it should, that is, during the period when the headlight switch is in the off position, which would indicate that the daytime lights should be on.

Do you have an Owner's Manual that lists the Fuse and Relay locations and purpose?

It could be as simple as burned out bulbs, or a relay removed. Remove one of the lights and check for voltage at it's connector when the key is ON and your DTRL indicator is lit-up. Do you have voltage?

Please advise,

Roger

I'll check, but everything works except the daytime running lights which are, in effect, the headlamps which function properly when the switch is on.

Okay, I'll get a wiring schematic tomorrow and see what suggestion would help.

If the DTRLs are indeed the headlamps themselves, then a relay or fuse could easily be at fault because the voltage would be split from one feed, and put the lamps in series. Wired in series causes the headlamps to come on at half power/brightness.

Do you want me to FAX what I find?

Roger

Do you have Quad Headlamps, or Sealed Beam Headlamps?

If you have a FAX number I can send you schematic and graphic maping for the Convenience Center. Would a FAX need a cover sheet?

Please advise,

Roger

Hello, I'm trying to help you. Is this question still active?

Thanks,

Roger

Quad Headlamps. Fax [redacted] . No cover needed.

Thank you.

A FAX has been sent. My source is The Mitchell 1 Auto Repair Data Base.

The DTRL Module is stated to be found under the left side of the dash and is taped to the wiring harness.

Roger

1997 Chev Tahoe Ignition System Malfunction When accelerating When warm 

Runs good cold but gets worse as it warms up. It feels like it not getting fuel but I have elimiated it being a fuel problem or plugged cats. It is a sensor that controls the spark timming. The timming retards when I rev it up to the point that it won't rev past 2000 rpm in nuetral warm. When I uplug the knock sensor it runs bad cold instead of the normal good. Need help to determin if the problem is:
1. Knock sensor
2. Distributer sensor
3. Crank sensor
4. Ingnition module
5. ECM computor

If it has no power and won't rev, the check engine light should be on. Visit Advance Auto or Autozone and they will read the trouble codes free of charge. Let me know the exact alphanumeric codes they find, IE- P0300, P0401, etc.

For further troubleshooting beyond computer (PCM) codes- please include the engine size. Also let me know if the idle is okay or not.

I don't get the check engine light so no codes. The olny time I get a code is when I unplug a sensor like the mass air or ox sensor. The strange thing is when I unpluged the knock sensor I didnt get a fault. Any other sensor I unplug I get the check engine light. I don't have a reader so I disconnect the battery to cancel the fault I caused by unpluging a sensor. If the check engine light would have come on it would be much easier. I was hopeing for your best guess. The engine always idels good and starts good

Because I did not get a fault code I removed the cats thinking they were plugged had 5 psi back pressure. This did not solve the problem.
The fuel pump and filter have been changed along with cap, rotor, air cleaner, plugs, plug wires and TPS sensor. I know it is a ingnition problem because the engine won't rev up when I step on the gas and then squirt gas into the air intake. right to the floor it just sits at 2000 rpm no matter how much gas I squirt into the air intake.

I forgot to give engine size 5.7 liter.

waiting for a replie, I need to sort this out now. I suspect a faultly ecm (computor) the big question I have is "by unplugging the Knock sensor should the check engine light come on. It did not, what does this mean?

I assume you do not have a problem with back pressure now.

You should get a code or at least a pending code with the knock sensor unplugged. If you don't there has to be a computer problem.

If you unplug the temperature sensors does the engine run any better?

YOu can heat (or cool) the distributor/ig mod with say a hair dryer while the engine is cold. Does this make the problem appear right away? This is not a very technical test, but actual testing requires expensive scan tools and lab scopes.

Thanks for your help. I have no back pressure now, I was disapointed that by removing the cats did'nt solve the problem, thought the cats were the problem for sure. I unplugged the temperature sensor and the check engine came on, but it didn't run better. The knock sensor seems to make the most sense, seeing that it ran bad cold with the knock sensor unpluged (open circuit) would it be OK to try and ground out the Knock sensor (closed circuit) and see what happens?

One more question, does a 97 Tahoe have a (Limp home mode)? This is exactly what it seems like is happening. On the highway I keep hearing a click like the air conditioning clutch kicking in and out. At the same time the truck feels like it shifted gears. To me it seems like the computor thinks the engine is overheating or pinging and is then switching to "limp home mode" The dash temperature gauge shows the temperature guite low.

Limp mode or limp home mode, yes, but the check engine light should turn on.

I'm not certain on the knock sensor turning on the check engine light right away. Some vehicle do and some don't. You can borrow a code reader from most Autozone storers (for a fully refundable deposit).

I want you to use the following link-

http://www.bedlib.org/ebsco.html

From the link click on the ARRC banner. From there access the repair guide for your vehicle. Then click on TSB's and Recalls. See if there is anything that relates to this problem- especially under PCM, Sensors, Etc.

I bought AutoTap scan software and got the following codes when I connected.
PO141
PO171
PO174
PO338
I didn't think codes were avalible unless the check engine light was on. Hope the codes will point me in the right direction.

Okay, were these codes pending codes? If you erase them, which one(s) come back right away?

They were codes, not pending codes. I cleared them and drove for 15 minutes (it was running bad) Reconnected the code reader and no codes at all. The code that seemed the most likly was the crank sensor code. Don't know why it wouldn't come back

If the problem is not present the check engine light will go off. If the cats are still removed you should definitely get the 02 codes back- this should turn on the check engine light before the drive cycles complete.

Crank sensor codes usually don't set when the crank sensor is bad. If a crank sensor code sets there is usually a problem with the crank sensor or its electrical connector.

ya I know I should get the codes again but no luck. The problems I'm having have been going on for months. With no codes except for the other day, they are the ones I gave you and the check engine light was not on. Two weeks ago I had it in a shop and they couldn't get any codes either. They said to take it to a dealer. I'm putting in a new crank sensor tonight and if this does'nt solve the problem I guess I will need to take it to a dealer. Alot of people have had a quick listen to it when I put it to the floor and they all say it can't be a sensor because of how poor it's running with no check engine light. What buggs me is it runs very good cold so it can't be mechanical.

Did the other shop rule out the map/maf sensor?

It is really looking like a computer problem, but looks can be deceiving.

I figured right from the start the problem would end up being something stupid. As it turns out the Carter fuel pump I installed didn't have a barb on the hose connection like the AC delco pump. The hose pushed of the pump just enough to cause a fuel leak inside the tank. So the fuel pressure was good cold until the bypassing fuel warmed up the rubber hose causing it to leak more fuel. I checked the pressure a number of times and it was in the acceptable range 56 psi to 60 psi. The pump would move just enough in driving to cause the rate of the leak to change making it a hard problem to find. I replaced the Carter pump with an AC Delco problem solved. I did a test on the Carter pump after I removed it an it was putting out 100 psi. The the shortfall of the Carter pump wasn't low pressure but a poor design on the pressure tube (no barb). The gauge I had clamped onto the pump for the pressure test blew off no matter how tight I clamped it. It makes me wonder how many others have had this problem.

Interesting, I wonder if the carter pump was the wrong one for your application or simply may cause the problem you experienced by design.

I'm trying to speculate how lack of fuel could not be remedied by adding fuel directly. I suppose the fuel could to liquid by adding it to the intake-- but don't buy into that theory.

I had the same question and was told that a liquid like gas is not a good test, I should have used butane. I was convinced it was an ingnition problem because the gas didn't work and it ran good cold. I didn't concider a internil fuel leak.

1997 Chev Tahoe Engine   

I am not sure if it is engine or ? I am hearing a slight beeping sound when the Tahoe is running and I am standing next to it. It sounds like it is coming from drivers side toward the middle of the Tahoe. Karen

Do any warning lights come on when you hear the sound?

Does the engine have to be running or will it make the sound with the key on & engine off?

No lights are on or come on and yes it needs to be running.

It sounds like a faint back up beeping sound, and no noise with just key turned on.

Okay, I'll do a bulletin search to see what comes up for this unusual problem.

BTW- Did it ever have a back-up sensor/beeper intalled, to your knowledge?

We bought the tahoe used, so no we did not.

1996 Chev Tahoe Drive Train / Driveline Making Noise When accelerating Always

I am hearing a mild "grinding or clicking" noise when under moderate acceleration. It does not make the noise when in reverse or when in 4-wheel drive. Nor does it make the noise when not or only slightly accelerating. The noise seems to be coming from the transfer case or the drive shaft to the front axle. Fluids and u-joints seem ok. The vehicle has 185,000 miles. Any ideas?

The factory may have a repair bulletin for this problem. If you leave your engine size I'll check the database.

It has a 350 CI (5.7L) V-8 with automatic transmission and air conditioning

There are numerous bulletins. I think it would be more beneficial for you to review the bulletins and get back to me.

To view the bulletins use the following link-

http://www.bedlib.org/ebsco.html

From this link click on the ARRC banner then enter Year, Make, Model, etc. Once you access the repair guide click on TSB's and Recalls.

I have reviewed all of the applicable service bulletins but none seem to address my problem.

1996 Chev Tahoe Drive Train / Driveline   

when shifting into reverse it immediately makes a screaching noise an will not move i put it back in park then back into reverse an it goes or just an sometimes ill get that noise when shifting into drive this is all happening in 2hi mode

check engine light is on as well

Because the check engine light is on you should always start with that.There are some solenoids and sensors in transmission
that might be turning on that light.
Many auto parts stores are now offering a free scan for codes...let me know what comes up.

i can go to say a Pep Boys and they offer a free code scan

also horns dont work where do you suggest i start troubleshooting

With A horn, I check the obvious, your fuse,I would then run a temporary wire from battery positive to horn, and see if horn is dead. If it beeps, I would then test horn relay, and if it checks out, then the horn button.If the wire to horn does not work, check the ground wire if it has one.Some are grounded by the mounting screw and do not have a wire.