TPI ME

Let me start by saying this is my first TPI, and I have learned a lot from reading all of your posts. I am hunting down a problem.
The problem is intermittent, almost like the computer corrects it temporarily.


87 305 TPI, 5 speed.

When I start it up it runs like a champ for a few minutes, then just shuts itself off. Sometimes if I restart it it is fine for another few minutes. Sometimes it is boggy and smokes out the tail pipes rich. If I let off the gas it will just die. It then starts hard like its flooded. If I get on the throttle hard to keepit from dying it smokes black out the tailpipes and sounds like its missing. Probably choking on the amount of gas. 30 seconds later it revs up and all is well for a while. If it happens while cruising it kind of bogsbut is hard to describe. If not on the throttle it sounds like it isn’t runningat all and will die. If it hit the throttle again fairly soon it keeps running.


This seems to be set off when the engine gets warm.


If I screw open the throttle plates on the TB to raise theidle to 1800-2000 or so then when it wants to stall it doesn’t, it just almost stalls, and comes back. I tested last night and it was sitting and idling andwhen it stuttered I checked and bothradiator hoses were warm, indicating the thermostat had just opened.


New cap and rotor, plugs, wires, CTS, ICM tested good, problem remains.


Getting codes 33, 34, and 42.
Thinking new MAF relays as the next step.
Can a pick up coil do this?
Something else to add, this is an 87 305 TPI from a Firebird, and the ECM and harness from that car as well. However this is all installed in an 87 Fiero GT with a 5 speed getrag. The only things modified on the engine are headers, CAI, and the tune was done by Sinister Performance and is set up to exclude the CSI. The problem existed before and after the tune. I have a 1 wire 02 sensor in the header collector.
Any advice helpful. I am hoping to make it to a show/meet next weekend without "the bog".


It feels like If I just got on the highway and drove 60 mph constant the problem would never present itself, until I let off down to idle.

TPI ME

Don't be afraid to throw me ideas, the fact that the engine is transplanted I don't think changes much.

TPI ME

I will be ohm testing the pickup coil tonight.


I plan to install new MAF and fuel pump relays this weekend.

RBob

iTrader: (1)

The codes show two different things: MAF hi/lo malfunction (33/34), and an EST malfunction (42). It is important to know whether the code 42 occurred on it's own, or did it occur with an unplugged EST/BYPASS connector.

If the EST code was from opening the EST/BYPASS connector with the engine running, then can concentrate on the MAF codes. A scan tool can be helpful as it will show the MAF airflow.

If code 42 occurred on it's own then the possibilities open up. ECM needs to be mounted such that it is insulated from the chassis. Check the battery cables (tight/corrosion), same for alternator cables. Then the ECM grounds to the engine block.

RBob.

TPI ME

Thanks. The ECM is mounted in the cabin in the stock Fiero location surrounded by plastic so it is secure.


I checked the pick up coil last night, 752 ohms, so since I have read 500-1500 is good, it must be good.


I will unhook the battery for 30 minutes tonight to clear codes and run it again and see if the 42 comes back.


If it comes to getting a MAF, I have a few available locally. Is the autozone "duralast" one junk? Has a lifetime warrantee and is $128, #DL-6014. Otherwise Cardone for $153.


But I suspect / hope its just relay issues. I was fuzzy on what were good ones for that as well. I picked up BWD relays from Oreillys.

TPI ME

Does the symptom of the bog, and dying fit as what the the MAF would cause? Everything I have read peoples experiences were hard starting when there are MAF issues. Mine starts great, only has issues "when it decides to".

TPI ME

Just code 33 now. After replacing the maf power and burning relays, and resetting the codes. So...maf or maf connector then?

Fire"Dutch"Bird

iTrader: (1)

I had similar problems, due to a bad (ground)connetion at the fuel pump relay...

TPI ME

I can for sure check it out, just the black wire off the fp relay, could replace that relay too. I suppose there is no code for an fp or fp relay...

TPI ME

Well, after both maf and fp relays didn't help, I bought the cardone reman maf, and..success! Runs like a dream.

One question, how can I know if the maf does its burn off or not. Would a code come up if it didn't?

Fire"Dutch"Bird

iTrader: (1)

Yes, code 36.

TPI ME

Thanks.

TPI ME

Just for anyone else chasing MAF problems. The car ran great quite a few times. Started it up to head home yesterday after it sat for 7 hours, ran pig rich smoking black had to keep on the throttle for it to run. Constant SES light. I shut it off and checked the code, 34, related to maf power.

So I unplugged and replugged in the maf connector at the maf. That's it. Good to go fired right up and idled perfect and drove home.


Watch those connector contacts! Quick fix. Mine were clean too.