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backfiring. check engine light, etc.


Zeptoplix

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So today I finally "finished" the lower intake gasket problem i started in july.

 

After much messing around, and redoing some work (fuel line o-ring cracked on reinstallation s.o.b.) Got the firing order finalized, and got the car running.

 

It however, does not run like i would like.

 

It doesn't really start that great, but it does not turn over excessively or anything before firing.

 

When it is running, the idle doesn't bounce around by the sound of the engine, but the engine is definitely not running smooth. When i open the throttle, it rattles a bit, almost sounds like a knock. When I open it more, it backfires through the exhaust. If I put the car in gear, it will not move. I have to press the gas quite a bit, and it backfires through the exhaust like crazy. If I just put it in gear, and not push the gas, it will stall the car.

 

Unfortuneatly, I know NOTHING about the previous history of the car. The only thing I do know, is I found the emissions test paper and the numbers seemed high, close to the maximum allowed in some cases. The N0 and the HC readings were high. The friend of ours who gave us the car said a mechanic told him it needed a headgasket, and a fuel injector. I tested the fuel injectors, and all metred out at 12.7 ohms. I replaced the intake gaskets, reinstalled the pushrods, torqued them to 25 ft/lbs, torqued the lower intake vertical bolts and then diagonals, reinstalled all the miscellaneous plugs, and got the vaccuum lines reattached. Alll except one. The "t" by the battery, well I can't find ANY nylon tubing or what not to plug into the front port of it. I have looked high and low, and cannot find anywhere that is missing a line. (yes the heater works in all positions) Also in this area, there is a single pronged plug with a red wire. I can also not find the home for this plug.

 

Sorry for the long post, just wanted to put some info out there and maybe get some answers... Thanks.

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what kind of car/engine? The "T" by the battery should go to the vacuum canister. Driver's side fender is where it sits. Should look like a black plastic ball. If its not that, should be the cruise. That vacuum issue should not cause a miss like you describe, though.

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It sure sounds like you messed up the firing order, what was the code the ECM gave you?

 

oh, btw, the red plug is to check the fuel pump in the assembly line, it's also in the FAQ

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Okay perhaps the vaccuum canister is mising, i cannot seem to find it in there.

 

this is a 95 Lumina with a 3100 engine.

 

I can double check the firing order again, but we were careful when we did it. Any other ideas to go along with the timing one? might as well have a bunch wh4en i start messing around with it.

thanks.

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Sorry. Im not experienced with these cars. How do I pull the codes? Where would i find the connector for the PCM to tell what version OBD it has?

 

btw. checked the firing order, and it was correct.

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When all else fails.... go back to the basics...

 

Do a compression test.

 

You metered the injectors, but did you actually pressure test them to make sure they're all squirting and not leaking?

 

Stick a vaccum gauge on it, and see what it's doing when it's idling. Make sure it's high (above 18") and steady.

 

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WHAT CAR? WHAT YEAR? WHAT MOTOR? Answer we these questions three before ye shall be answered.

wait! thats been done. NVRMND.

Your car has the OBD 1.5, it is almost impossible to get the info from it. All the info I see says the car requires an obd 1 full fledged computer reader, and not the jumper key.

 

 

The vacuum ball is hidden under the drivers side fender, behind the bumper, beneath were the battery is located, if you have a gen 1 or gen 1.5 car.

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I'd do the following:

 

1. check the firing order and make sure all wires are securely connected to the plug/terminal

2. do an idle relearn

3. Check the vac ball located lower driver side fender

 

Let us know what you find. Yea I hate the OBD 1.5 too...i'm fucked with it aswell...

 

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Well all the pushrods I removed were the same length if i recall, and when I did remove them, I was careful to make sure that I put them back in the right spot.

 

I have double checked the firing order several times. I can make sure the wires are on tight though.

 

As for pushrods. When I re-installed the rocker arms, was I supposed to rotate the engine and then torque them so they would be seated properly? If that is the case, hopefully i can still take the valve covers off with the upper intake assembled.. There is no vaccuum canister that I can find. I will check again, but I have looked what seems endlessly for it. If i do find it, I have some new nylon tubing to run to it. But it seems to be non existant, as in someone removed it. How crucial is it for the engine to have this piece?

 

I am getting another car tomorrow, I will park this car somewhere else and work on it still. I am going to get a compression tester this week, Might as well, that way i can check my taurus too just to see where it stands.

 

I know i am a noob on this board, but is there an FAQ on the idle re-learn?

 

If i check the build date, will that tell me which OBD I have? was it mid year they had obd 1.5? anyways, sorry for the long post.

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Well all the pushrods I removed were the same length if i recall

 

Did we ever get to find out what engine it was? Yes I'm too lazy to scroll up. :D

 

Anyhow - I was thinking it was a 3.1L. Aluminum heads, splayed valves. Those - the intake and exhaust push rods are different lengths.

I already killed a couple valves to discover this. Once. :redface:

 

 

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well for anyone who starts reading now, it is a 95 Lumina with a 3100 engine.

 

that said.

 

I am confident i did not mis-install any of the rods. and upon start up i did not hear any mechanical noise other than the engine running.

 

I will try the "idle relearn" that i read in the FAQ

 

 

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This sounds quite a bit like when my buddy ran the plug wires from the distributor on his car the wrong direction and had the firing order SEVERLY messed up.

 

Granted the w's have coil packs, but still sounds like the same problem.

 

Unless it's mechanical inside the motor, I'm leaning towards a firing order issue.

 

I'm no 3100 expert, but can someone post a diagram to the topic starter showing which plug wires go where and from which coils? Not to doubt your ability, but just to verify.

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The coils should be labelled what cylinder they go to. The cylinders in the front of the engine bay ( from left to right looking at the engine from the front bumper ) are #1, #3, #5. The cylinders in the rear of the engine bay ( from left to right looking at the engine from the front bumper ) are #2, #4, #6. Someone else can pickup on the coils, if they arent labelled. Im not exactly sure.

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