Dodge Ramcharger

1985 Dodge Ramcharger Engine   

1985 ramcharger backfires on deceleration. I need to pin this problem down, what do i check and in what order? I would guess timing so i hooked up a timing light but could not see any marks, has a round cylinder to look thru a H.B. what is that for i am use to old pointer type. Truck start runs, but does not seem to have the power it should have. Took compression test, 2 have 130 6 have about 145 the two with 130 are on opisite sides. I do not want to just guess I need a pro to solve this. Blew my muffler.

Hello, Let me ask you about the timing mark on the harmonic balancer.

When you examine the balancer rim (engine stopped) do you see the groove cut into the pulley? If so, and you don't see it at all with the engine running and the timing light directed at the correct area it is possible the outer rim of the balancer has slipped.

Balancers are made of a wheel within a wheel and bonded together with rubber to absorb virations that are harmonic. If the inner wheel spins within the outer the timing reliability of the cut mark is lost.

The method to determine mark reliability is to remove #1 spark plug and bring the #1 piston to top dead center on the compression stroke. When that is done the timing mark should line up with "0" on the degree scale on the front of the engine.

If it isn't as described try a different harmonic balancer.

Roger

Roger,
Ok i will check this tonight after work. By the way if i go easy on the gas there is no back fire its only when i get on it a little bit which is normal does the backfires occur.

Bob

Thanks, lets see what you find.

Roger

Ok I found the mark on the damper, Smog sticker says 16 BTC The line on damper is at 0, It was not posable to see with out turing towards TDC, Than i tried turning to various position to see if i could eliminate backfire which i could not. It does seem to stumble some what at higher rpm but not bad. What do i try now?

You are now confident that the timing mark is at zero when #1 piston is at TDC? That is important to know. Can you achieve the 16 BTC timing setting?

Is the distributor mechanical advance working? Will the vacuum advance hold vacuum?

What does the intake manifold vacuum read? Does the EGR Valve close properly?

I'll be back. I'm going looking for more ideas.

Roger

Well i did not put my anything into the cylinder to see if it was exactly but it was defenatly on the commpression stroke. Be honest i do not understand all the componets that have to do with this year, more old school. Remind me how to check for advance, i would guees rev eng and see if it timing moves, by the way i do not think it did. or hook up a vacume to the advance and apply vacume. By the way how do i set timing at 16 it is hidden. Hmm maybe the advance is not working. I have the factory manual and could e-mail you a few pages on this. there are terms kie grounding the carb during test, and accumulator??
I will check vacume at manafold or close to it if nessasary, but it should be the same at the advance?
Also where do i hook up to switch crank the Truck.
I have a pic i could send of engine fender well.
Bob

At closed throttle there should not be vacuum to the distributor vacuum advance. If you want to check it here you'll have to open the throttle far enough for the vacuum supply port to open.

I have a timing light that allows me to dial in or preset 16 degrees advance. When preset I then set the timing on "0" (I can see the zero) knowing it actually has 16 degrees advance.

With the rotor removed from the distributor you can see the mechanical advance and determine if it will move or is frozen.

Look on the remote starter solenoid for a small gauge wire plugged onto a terminal labeled "I" for ignition or "S" for switch.

If you unplug this wire from the solenoid and apply 12 volts from the battery to the post left bare the starter should engage.

Do you have exhaust leaks anywhere besides the blown muffler?

Roger

Ok i will check the vacume and the mechanical advanced.(good idea). I will also buy a timing light with advance today if i can find one. I tried to locate the remote starter last night, ok i will follow the wire up from the solenoid, My eyes are getting old what is the best kind of light to see in these dark spaces,,, and thanks Bob

What engine do you have please?

We may well need to check into the Air Injection System if it has one. A defective Diverter Valve and/or Check valve can cause a deceleration backfire too.

If equiped you can check the Diverter Valve by accelerating the engine, and allowing the throttle to close rapidly. A momentary rush of air should be noted at diverter air outlet.

To check operation of the Check Valve, remove air supply hose from pump at distribution manifold. With engine operating, listen for exhaust leakage at check valve, which is connected to distribution manifold.

Roger

Did you get
mail from tuesday night?
Any way when i put a vacume guage on my distributer why would it not hold vacume,yet when i rev up engine the timing will retard? Good news is at my smog pump I disconected upstream line from pump and backfire went away, the funny thing is on the down stream side of pump when i disconnect it the backfire is still there? Anyway i belive the check valve you talking about is upstream of the pump about 1 foot away, how do i check that valve? blow air thru it? My factory serice book is junk, it does not explain how to check these things. Or how they work and why, very frustrating. Bob

Timing retards when the engine revs because there is less time in degrees of crankshaft rotation for maximum power to occur at ignition in the combustion chamber. The mechanical advance does this.

If ignition occurs too soon before TDC too much fuel mix is burned while the piston is still rising on the compression stroke. Performance suffers.

When a vacuum is pulled on the vacuum advance with a tester pump the advance should hold the vacuum.

To check operation of the Check Valve, remove air supply hose from pump at distribution manifold. With engine operating, listen for exhaust leakage at check valve, which is connected to distribution manifold.

If you don't hear exhaust leakage the valve is stuck.

Roger

Yes i apologise i did not see your message about check valve,I,m looking at my manual-switch relive valve which is on top of smog pump blows airboth down and up stream. So that valve must be bad also? As for the check valve? I guess what your saying is air would be blowing downstream which it should not. I do not think that is the case but i will check it,or it could be stuck and not allow air upstream? I pushed on that valve last night and it did not budge, Hmmm
I also was under the car and and the upstream pipe at exhaust has been crushed at least 3/4 of the way and i put vacume on that valve and it would not hold vacume Sounds like i have a varity of problems.
We are almost there. So i have a bad vacume at distributer.Buy new distributer? Bad relief valve, and probaly a bad check valve, and the valve down at the exhaust. Sound like the check valve failed and everyting downstream then failed. You know when i bought this truck the complete choke mechanism was missing,hmm they were probaly trying to fix this problem. So the vacume at the distributer does what? Pulls open the mechical advanceed? As you said earlyer the advance opens when engine is reved even though the vacume is not working? Please explain that!
You know your GOOD! When this is done which it sounds like we almost are, I have a AC problem on my wifes car. Do you understand ac problems? You don,t have to answer just think about it, it takes a charge but no cold air.
Thanks
Bob

You may find the vacuum advance can be replaced in your current distributor. Check that out before you replace the whole dist.

When the throttle is opened slightly there is a vacuum port that is uncovered and vacuum is applied to the distributor vacuum advance. At slower rpm's this allows the spark advance to occur as needed. If there is enough vacuum to outrun a small leak in the advance it will still work well.

Once the distributor spins fast enough the weights on the mechanical advance take over and their centrifical force actuates the distributor plate to advance when vacuum gets scarce.

Don't read anything into the tests for the Diverter Valve and the Check Valve. The test for each is specific. You hear air rushing or not and you hear exhaust leaking or not.

I do understand A/C systems. If you'd like to post a question concerning the wife's car you can request my help when you post the question for an answer. The process is the same for each question you need an answer for when the subject or the vehicle changes.

Roger

There is a new twist to this puzzel.The releife valve on top of the air pump was receiving intermintent vacume, off most the time, I applyed vacume to it and everthing was fine, i traced the hose back to an elctrical duel solenoid part of EGR system, unplug it there, applyed vacume,same thing problem went away,
electrician just stop by we checked the solenoid it works, so now tonight i will reinstall the solinoide
and find out why it is not opening on car or the soleniod insides are broken or the cts is not sending a signal to the solenode to open and send vacume to relive valve. Any way you did get me thinking about things that i have not thought about for thirty years and also how some parts work that i could not grasp by myself. So I belive i can solve this now. by the way I am constructon super, construction a bldg at a college and am a master carpenter. I always wanted to be a mecanic but never had the time or space to play, I now have a 2400 sf shop and a truck to play with that does not have be on the road every day. Thanks Bob

I want to see you win this one! Wish I had your building on my land. I'm retired and live in a gated community at a private lake. Platte restrictions will not allow out buildings. I try to help folks with this site and it keeps me thinking...

Roger

I can keep you informed if you like. tell me if my e-mail address shows up which i will add here.
[redacted] and how do we end this session. so you can get paid if you do in fact get paid.

Bob

All Parts will pay me when the customer accepts my answer. This is done by closing the question or clicking on a button that says ok to pay mechanic.

When the question is "released" it is opened up for any available technician to try to answer.

I do see your email address in your most recent reply. I cannot post mine on this site or I would have no peace. There is no way available to me to charge for my services through my personal email.

Roger

1980 Dodge Ramcharger All Part Groups   

Replacing with aftermarket carburetor ~ too many vaccuum hose holes. Can't seal no matter what tried. Are there some parts missing that should have been stripped off the old carb?

I do not think there are any parts off your old carb that require vacuum to be put on the new carb.. If all you vacuum hoses are connected properly under your hood, you prbably just need some rubber plugs/caps to cap off the remaining vacuum ports. Sometimes the new carb comes with some or remove any that might be on the old carb or you might have to pick some up from where you bought the carb. Good Luck