When it started

I had a misfire in the 5th cylinder.i fixed it because the original spark plug was cracked but when i got on the highway that day i got my car cruising around 55-65mph but when i accelerated up around 80-87mph. Then all of yhe sudden no power to the throttle so i pulled over an then at idle violent vibrations i popped the hood and there was no smoke at all or nothing strange just the engine
shaking from side to side like more then one misfire. But when
i turned it off for 10mins then cranked it right up it idled fine and ran fine. then when i got off the expressway an road a couple of miles to the street my it did it again. but this time i i roled off from the light an around 2000 rpm it started losing power all the way down to 500rpm then at a stand still it idled form 500-1000rpm back an forth but when i turn it off for like 8mins an cranked it again it ran fine all the way back home another 4miles. progessively it started happening more often. but now 3weeks ago at start up the gauge would bounce from 500rpm to 1000rpm. When i press the throttle it would just sputter then stall.
im getting Code 33 & 35.

i checked all my vacum lines an there good i checked my wiring coming from my map sensor and i replaced 02 sensor, Tps, Iac, EGR valve, Ignition coil, Ignition module, Spark Plugs and spark Cables and i apprently had two arks from two different cables. I cleaned my distributor i cleaned my throttle body i put in a new air filter a new temp sensor. But when i started to sea foam my intake the brake booster vacumm line would pop some kind of smoke or vaper almost like my cars choking? but when i got a consistant path of sea foam going the idle would pick up then i would connect the vacum back to the brake booster the car would idle fine intill i press the throttle then the idle drops an then bounces again sometimes to a stall eventually!!!!? and my oil pressure always stays up on the gauge! and i can here the pump working fine.

honestly im really frustrated because i always dreamed of having a third Gen to keep forever but this is sooo confusing! i need ideas

 

sorry for making this so big i just wanted to give u as much detail as if u were there

 

For now ignore the error codes, they are likely from the engine not running correctly. Code 33 is MAP high, and code 35 is IAC error (can't hold an idle).

If the injectors are the OEM Multecs the coils in them are most likely shorting out. This is why the issue is intermittent in nature. Will need to pull the plenum to check the resistance, do this while the engine is hot, each one should be about 12 ohms.

Also, check the wiring harness in and around the coil bracket for chaffing. There is a TSB out for this as some cars were built with the harness routed incorrectly.

RBob.

 

sorry im kinda new but what coils are you talking about for the injector if i ohm the injectors out an im getting all 12s then what?

and my other question is what coils are u talking about i thought the only had an ignition coil and relays?

 

oh actually i see what u mean by coils but if i ohm them what should llok for? injectors that arent reading 12 should be replaced or something or should follow those wires to something? to look for any additional problems?

 

The injectors should all be about 12-13 ohms. If any are not then replace them all. About $125 from Southbay. At least then you can be sure you are starting from a good base.

 

ok ill see if they are all good but even though pressures good u think its just an injection problem?

 

Injectors have a coil of wire in them. When activated (power to them) they pull the injector open to spray fuel. The OEM Multec injectors that were factory installed in that engine have issues with the coils shorting out (actually, all 3rd gen PFI engines from '89 - '92). When they do the ECM has trouble pulsing all of the injectors.

This is because it is batch fire and the ECM fires all 6 at the same time from the one driver. As the injectors heat up the coils short more often and worse. As the injector PW gets larger, the ECM has additional trouble pulsing the injectors.

If they are the original injectors I wouldn't even bother to test them. They would get replaced at the same time the plenum was off to test them. The only testing that would get done is to either: see how far one can throw them, or how much weight they add to the nearest trash can.

RBob.

 

haha ya someone else said that in a different but i think im gonna replace them anyway and go from there but anotjer question if u can answer, so here it is i took off my braces and monts from my catalytic because i thought it was clogged but now since i cant find a torch to remove the other end of the catalytic from the exhaust pipes from the engine. so its kinda hanging off a lil but do u think that will effect the engines idle?

 

The open exhaust after the cat-con most likely won't affect the idle.

If you have disconnected the battery then an idle learn is required. This is for the '90-'92 MPFI cars. Here is a decent thread on this:

https://www.thirdgen.org/forums/v6/1...dle-learn.html

RBob.

 

so i started my car up to go through the idle relearn prosedure an immediately i had smoke coming form the exhaust before i started to the car i clean the throttle body so is that why?

 

What did you clean it with and did the smoke stop?

 

i sprayed the throttle with B-12 an no it the smoke didnt stop also i think im gonna need to replace the battery beacuse its 5 years old an its been sitting for like 4 years untill now just a hunch.
also for an update I put the sensors that were still working back on my car an when i got it to crank over it held a consistant idle.I put the TPS, Map and the IAC back on. so im guessing i cant do any work to the car till i get a new battery with better Ampage

 

alright so this was the situation i had 3 bad injectors an a loose distributor cap i replaced them an now she basically a brand new car she runs like a dream but..? is the idle supposed to be as low as almost 700Rpm or do i have to retime it

 

The injectors should all be about 12-13 ohms.

 

For a stick in neutral and an auto in gear the idle speed is 650 RPM. An auto in P/N is 700 RPM.

RBob.

 

oh really thank then imma advance it appreciate the help an where is the pcv valve

 

Actually the problem was i had 2 wrong injectors an so they were putting out the wrong olms from the other 4! i replaced them an she ran like a dream thanks for the help!!!!

 

I have a problem with my 1991 Firebird 3.1 V6. I rebuilt the engine and replaced every electronic switch under the hood. IAC, MAP, TPS, OIL sending unit, Knock sensor, Coil, Plugs, Wires, Fuel injectors, Fuel pressure regulator, Fuel pump, oxygen sensor, Smog pump, and Catalytic Converter. The car run great when I got everything back together. That was 3 years ago. I have put about 350 miles on the car and now when I start it up it might run and it might not. When I start the engine and it starts, it purrs like a kitten. Then all of a sudden it will just die like the ignition switch was turned off. When I go to start it back I have to hold the accelerator peddle down to get it to start. When it starts the check engine light will flash continually and the engine sputters. The exhaust is black and smells like raw fuel. I have to keep the engine RPM above 2000 to keep the engine running. Then sometimes the check engine light goes out and the engine smooth's out and runs like nothing was ever wrong. I can hook my Elite AutoScanner Pro up and there are no codes stored in the computer after a episode. I had it hooked it up one time when a episode happened and there was many codes showing, non that I wrote down but ECM Error was one of them. Any idea where to start the trouble shooting process?

 

The ECM is bad, replace it. Be sure to swap the MEMCAL over to the new ECM.

RBob.

 

When you say MEMCAL your talking about swapping the PROM chip from the old ECM to the new ECM?

 

It is more then just the PROM:

https://www.thirdgen.org/forums/dfi-...om-calpak.html

But still just a single piece.

RBob.

 

I finally got me a rebuilt computer for the car. That fixed the problem I was having. Thanks for the info.