First of all. Car is 87 IROC 305 TPI with auto tranny. Wires, cap, rotor & coil are all within 2 years old. This is a fairly recent problem I believe.


I'm having issues with my car at the moment, or maybe it's having issues with me?

Problem is this. If I'm driving along at say 25-30mph and put the foot down, the engine RPM will go down and the car will almost stall. Indeed it has stalled once from this. Sometimes you do it and it hesitates for a few seconds then accelerates, while others it hesitates for a slightly longer period, drops the RPM and I end up lifting off the gas to get the RPMs back up.

However, tonight, I also had a backfire. My friend who was behind me said he heard one earlier in the evening too. With regards to the one I heard, I was going round a corner, low on gas which caused the car to lose power momentarily as it wasn't getting fuel. Straightened up, car got gas, car went very fast and also backfired.

I'm wondering if this could be caused from running VERY rich? Foot goes down, fuel gets dumped in, not enough air to burn it off etc?

I was out one night and someone said they could smell gas from the car when I put the foot down-they were in a car behind me. Tonight I had the car idling on the driveway and a wet patch formed on the ground where the exhaust exits-the pipes point downwards.

Basically, I'm at a loss here. I disconnected the MSD box and it made no difference, so I've ruled that out. Any other ideas as to what it could be?

I can run the scan tool if that would help shine some light on the situation?

Thanks for the help


Robert

 

After doing some reading I'm starting to wonder if one of the plug wires has come in contact with the headers that is to blame for this. The back fire could just be unburnt fuel in the exhaust. One of the wires was actually smoking a few weeks ago because it was too close to the header. I moved it out of the way, but I'm wondering if this could be the cause? I can't remember when this problem started though.

I'll look at the wires tomorrow.

Still looking for other ideas.

Thanks

 

What you are describing is afterfire, not backfire (which pops through the intake tract). Afterfire can be from intermittent ignition, overall highly rich condition, or incomplete combustion.

A two year old cap, rotor, and wires is suspect. It's at least worth checking the cap and rotor for corrosion, wear, and cracks or carbon streaks. Make sure you inspect the coil secondary terminal insulating washer between the coil and cap.

Plug gap is also important, as is wire continuity and insulation condition (which you already alluded to).

 

Vader,

Thanks for the reply. The plugs were just changed, and the new plugs made no difference to the problem.

I will report my findings on the wires tomorrow.

Thanks again

 

Ended up taking the distributer cap off and found that the contacts inside it were slightly coroded. I cleaned them up with some fine sand paper. I also too off the rotor and cleaned the contact of that too. Installed everything and went to start the car, and it wouldn't start. took off the cap and the little notch in the rotor that holds it in place on the distributer had broken. Put in an old rotor and the car started but wouldn't go above 500rpm and ran very badly. I'm wondering now if I didn't push the rotor all the way down when I put it back in and when it turned it came into contact with the cap? If this is the case, will I have to mark the timing mark at 0* and reset the distributer by then pointing the rotor at the #1 contact on the cap? I've ordered a new cap and rotor and should hopefully have it tomorrow.

Thanks for any help. I'm worried I've now made things worse

 

I just posted over in TPI section but I've been reading all night long it's 4 something in the morning right now but my car has the same symptoms but worse....I can barely get it moving cause if I push the gas the car hesitates or afterfires so I have to get the rpms up high enough by pushing and releasing the gas a bunch of times till it hits 3000 or so rpms and the just drop the clutch...if I keep it between 2700 and 3300 it runs fairly smoothly .... if I try to increase speed it stalls and hesitates and if I decrease speed ...rpms get to low same thing happens. I don't know if you've checked your codes but I've got 33,34 and 42 so hopefully someone will have a solution....

 

33 and 34 are MAF error codes. Make sure you have power to the MAF (both 12V and 5V), and that you are not getting power through the burn off circuit. 12V applied to the burn off curcuit during operation will render the MAF signal useless.

 

Thanks Vader...I just printed that out...I'll check it out and yak at y'all later...I'll try anything at this point.