Popping and missing

[HOTSIX]

I have a popping / missing when I give her a lil gas to move it up and down the driveway.

Not too sure why - my idle is great...no problems....only under light to moderate throttle. The quicker the application of throttle - the quicker / more it happens.

What do I check guys ????

Could it be fuel pressure (what should it be - vac line off) ? Plugs not gapped properly ??

 

[HOTSIX]

Anyone got any thoughts ???

 

[Turtle TR]

There are about 3 of us on this section with the same problem. CRAP!! an none of us pinpointed it out. I'm still waiting on parts from John Pearcy because he has them on back-order, no biggy. I'm going to pick up my new plug wires this weekend and a new coil pack.

 

[Nocooler]

The Iac may be off a little. I see your using that Pitbull Chip I sent ya - becareful with that it has lots of timing!

Also check the fuel pressure - these cars don't need alot, mine ran best with 32 static. I watched Twins go 13.00 with 28 static. Lean it up a little and see what it does.

Jeremy

 

[mycarsucks]

Make that 3 into 4. I've been chasing this problem FOREVER!!!!!!!!

I'll be putting the finishing touches on my IC tommorrow, and would like to know what it is so I can actually drive the vehicle.

I dont think it's IAC I've got that set perfect. To me it seems like a fuel problem. If anyone finds out, please post the answer it's driving me mad.

 

[HOTSIX]

Hey Jeremy... I dont currently have that Pitbull chip in it - but thanks for the warning on the timing. Guess i'll need 93 octane gas when I use it and keep an eye on the boost huh ? Got the stocker in there 'till I get her airborne on the road.

I have turned my FP down a bit to 32 PSI with vac line off. I still have the problem.

It's a popping...but only when u accerlate light to moderately in gear - like to get up the driveway or over a curb. Seems like a miss...almost like timing is off or something....it gets worse with more throttle. No popping at idle.

My IAC seems ok (I think)...when the car heats up it drops the idle down where its supposed to be...(closed loop - or is it the other way round?).

Did a search and found most guys have it down to FP, O2 sensor and plugs.

I have a new GM 87 coil and module...new plugs and plug wires....but my O2 sensor is still stock and original.

Guys, i'm gonna try changing it (the O2 sensor) and see what that says. Since the O2 sensor sends messages to the ECM to assist with timing...i'll bet thats the problem. (or ill guess anyway)

Lets try to eliminate one thing at a time so we can enjoy our rides. I'm sure if we all work at it we will find the problem.

 

[mycarsucks]

I think O2 sensors do fuel not timing. I Replaced my sensor a few months ago so I dont think thats it. Ill try FP when I get everything running. Maybe its time for new plugs too.

 

[WFO]

well guys,i can eliminate the iac and the o2 sensor.i have a 16 position maxeffort(open loop chip,no o2 sensor and the iac is all the way closed)and i have the same problem.

it's a weird sound,hard to explain,more like a chirp or squeak,only at part throttle and increasing a bit depending on throttle position.that's the really weird thing,is it has to do more with throttle position than rpm,as i can get it to happen in any gear at the same throttle position.


i am going to pull the top end of my motor off pretty soon for ported heads/cam/timing chain and to weld my spearco adapter into the back of my intake.i'll keep an eye out for anything that could cause this funky sound and we'll see if it stops after it's put back together.


later,sean

 

[Boost231]

hey

i would personally think there is something worng with the chiop and how it is burned. my car had similar problems and it was a bad chip not burned correctly

brent

 

[Turtle TR]

I think mines could be fuel issues also. I hit about 23psi of boost on the stock fuel pressure regulator. it was after i put on my DIY ported elbow. I was like..."HOLY CRAP...23psi!" after that night..it started to run like crap!

 

[WFO]

Re: hey

Originally posted by Boost231
i would personally think there is something worng with the chiop and how it is burned. my car had similar problems and it was a bad chip not burned correctly

brent

probably an over-rich pop.mine did that when i had my m/e set too fat.

but this is a different thing(at least in my case)and it has happened with my old chip(mm)as well as my m/e.

 

[WFO]

Originally posted by Turtle TR
I think mines could be fuel issues also. I hit about 23psi of boost on the stock fuel pressure regulator. it was after i put on my DIY ported elbow. I was like..."HOLY CRAP...23psi!" after that night..it started to run like crap!

heh,we probably all have a blown headgasket

guess i'll find out shortly.


later,sean

 

[Turtle TR]

Originally posted by WFO



heh,we probably all have a blown headgasket

guess i'll find out shortly.


later,sean

I doubt it's my head gasket. I did a compression test and all are fine. No hints of coolant odor emitting from the exhaust either. But with the way I'm pushing the car...I wouldnt be suprised with having to change out my gaskets anytime soon.

 

[mycarsucks]

WFO my problem is exactly like yours. It appears to be more throttle dependant than rpm. What other than the TPS would be involved in part throttle acceleration? I wonder if it could be the TPS itself. I remember unplugging it, and If I'm correct things worked better then, but I was afraid to push it with the hard coded timing.

 

[HOTSIX]

Changed my O2 sensor guys.

No luck.

Checking plugs next....

 

[mycarsucks]

Try unplugging the tps once the car is started. I wouldn't push it hard, but I do believe it did cure my problem. If this is the case, then i would assume it has something to do with the chip programming. Do you happen to have more than one chip? and doesnt anyone have a stock 84-85 bin that I can burn to test it?

 

[84wh1]

I've got the exact same probleme guys, but it only happened to me after I swapped my ECM. I'm going to try adjusting the FP to see if that makes a difference if not I will try a stock 87 chip.

BTW, I had my chip burned for an 87ecm+87maf and when I put the 87 maf in, the car ran ten times worse than with the 84maf. I mean I coudn't give it ANY gas without poping, stumbling ect...
So i'm thinking that my chip could be my probleme.

Good luck!

 

[Turtle TR]

Originally posted by HOTSIX
Changed my O2 sensor guys.

No luck.

Checking plugs next....

I did that too...I changed the plugs and fuel filter as well. no luck. maybe my wires and coil and/or module are fried.

 

[84wh1]

Well, I had a little time to spare today, so I put my old ECM back in the car, and it ran perfect. No sputtering, no poping, nothing. It built boost fine. So that eleminates all possible fuel/coil/plug problems for myself.

I put the 87 ECM back in, and it ran like crap. It sputtered, made a poping sound and wouldnt build ANY boost.

My guess is that it might be a bad chip. Its a custome PTE chip. Maybee they burnt it wrong.

Has anyone ever had a chip burnt bad for them?

 

[HOTSIX]

Went to check the problem out again....with the intention of checking plugs...started it up...

...the problem has gone away. At least for now.

I cant explain it.