Fiero Domain Forum

I have had many GM cars, Vette's, T/A's, and small engine cars. This Fiero is kicking my butt! I have an 87 GT automatic. Bought the car from a guy for $500 had a bad fuel pump. Came to find out it had been sitting for like 4 years. Put a fuel pump and filter on it. fresh fuel of course... It will spin, start, shut off, in about that speed. It doesnt idle high; it goes right to 900-1000 and shuts off. I have 45 ish lbs of fuel pressure at the rail, no trouble codes, had the ignition module checked and it is good, it has power at the alternator, coil, distributor... Im out of ideas!! I really want this car up on the street again, but its driving me crazy trying to figure it out! Anyone have any ideas?

Anyone out there have any ideas? I love this little car and want to drive it!

Sorry for taking awhile, I'm thinking maybe you have an ecm issue. I've heard a few people say when the ecm fails it will fail to trigger your injectors. Your engine could possible start up off the cold start injector, which is mechanically activated but then stall when the injectors don't pulse.

Have you checked for spark at each of the wires?

Tried putting a small amount of fuel in the intake and see what happens?

Ive sprayed ether in the intake and it would burn it off. The guy i bought it from said the fuel pump was bad so i went ahead and changed it just because he had already bought one for it. I guess i could use a noid light and see if the injectors are firing?

Where is the best place to find an ECM?

Noid light is a good idea, and most auto stores should be able to order you an ECM should you need one.

When you first turn the key to run, before cranking it over, does the check engine light come on?

When I turn the key on, the check engine light does come on. I used a SnapOn Ethos to read all the sensor on the datastream mode, and i didnt see anything strange with any of the sensors other then the TPS. It was registering high like its bad, but it should start up with it unplugged under "limp" mode as other GM models right? It had a low MAP voltage code, but i had an extra MAP from the Vette and it cured that problem. I thought maybe the ignition module was causing the computer to not know the timing to fire the injectors, had it tested three times and they all came back good. The strangest thing is that if i use the jumper wire to make the engine light flash, instead of only flashing 3 times with the 1-2 flash it will continue without stopping then would show the bad MAP code then go back to the 1-2. I know that if its running and it flashes 1-2 then it has no communication with the ECM, but if its not running does it mean that the ECM is bad? On the other hand. I bought a cold air kit for it, you think it might actually give it a couple horses? If I can get it running I will do an engine swap. 3.8 is the easiest swap from what i understand.

The Fiero ECM will flash codes forever while in Diagnostic mode, what you're describing sounds like normal operation.

I cannot remember actually how dependent the computer is on the TPS sensor, though I think you can at least start the car without it. So you're ecm is at least booting, get a chance to test if the injectors are firing?

I haven't had a chance to get over to the car. Its in one town in my shop and i live over by the beach. Is there anyway to know for sure if the ECM is bad?

If its booting up I'm afraid not, an ECM can go bad with little or no indication. I spent a lot of money and time replacing components on my Formula only to find by chance the ECM was bad. I replaced it on a whim and my car suddenly ran perfect.

Advance auto parts has an updated ECM by Cardone for like $79 so even if its not bad im sure it would be a good upgrade.

Waiting on the ECM to come in.... (yawn)...time to work on my Bimmer...cant seem to get enough fuel to the webbers.... lots of fun tomorrow...

Alright... got the ECM put in the car, and picked up a new battery. Still the same problem. starts up runs a second or 2 then shuts off... im lost... anyone want a Fiero?

Sure :)

Ever verify if the injectors are firing?

I haven't been able to get the noid light from one of my friends. I am interested in selling the Fiero... im purchasing another Land Cruiser from a friend to help him through some tuff times... Will try to get the noid light this week someime though...

Alright tomorrow (wednesday) is the day. One of my friends from Caddilac is comming over and we are tearing into the Fiero. Ill post what we find tomorrow evening.

I'm not trying to hijack the thread, but I'm in a similar situation myself ... :-(
Just bought a 84 Fiero myself ... was told the fuel pump was bad ... and installed a new fuel pump in the last few days ...
Anybody want to buy a Fiero parts car in Canada ... Toronto actually ... :-(
The fuel pump was a pretty tough job in itself ... but I'm still having problems ...
Is there any additional information I should be researching for troubleshooting or for priming the fuel system?
I  attempted to prime the system without sucess ... at least 10 - 15 times ... so far ...
I hear the new pump start up in the tank for the 2 seconds each time  I turn the ignition switch on ... but no gas being pumped though ...
No pressure / gas in the line before the gas filter or at the carburator ...
On reassembly, the larger pipe was obvious, and I marked one of the smaller pipes to avoid confusion  ...
It doesn't appear that anyone has worked around the gas tank for years ...
As much as I'd like to be able to fix up this little Fiero ... its starting to be a very humbling experience ...
I've just about had it ... but still want to give it a shot to get this fuel pump problem taken care of ... and move on ... or just throw in the towel ...
This one has me stumped ...

Did you replace the hose that connects the fuel pump to the sending unit? That hose sometimes breaks and leaks all the fuel back out into the tank.

Yes ... I did ... the origional had been in for a very long time and was very swollen/distorted ... almost as if it the wrong tube was used,  that wasn't designed to be used with gas ...

I guess there is just no way around it ... I'll have to drop the tank again and inspect everything ... or just give up and sell it as scrap ... :-(

I hadn't thought of that hose before you mentioned it ... but I'm SURE it's OK ... I remember it as being very tight going on ...

If I can psych myself up to get under the car again ... I'll inspect everything ... and take a picture  when its out in the open ...

How about the wiring? Did you have to splice anything or was it direct plug in? Its a common-enough problem to accidentally wire it in backwards so it pumps the wrong way.

I think we're getting pretty close ...

I dropped the tank this morning ... had a look inside ... could be a combination of wiring or a defective replacement fuel pump?
Just ordered another fuel pump ... a Bosch 69237 ... it will be ready for pickup first thing in the morning ...
It should be quite a bit better than the Delphi I put on origionally ...
I did a bench test on the Delphi ... and a small gas stream flowed out ... very low in volume and pressure when running on a direct 12V source ...
The wiring seems quite a bit different on the 84 as well ... the Black single wire is the ground wire attached on the outside ... and the 2 (paired) light coloured wires going into the tank are for the 12V feed and the fuel gauge sender.
One wire from the pump will go to the 12V feed, with the other (ground) wire attached to the metal tube within the tank as it was origionally ...  ::)

I'll update you tomorrow after I pickup and install the pump ... at least I've now narrowed the problem down to pump itself, or within a few inches of it ...   ???

The 4cyl fuel pump is a relatively low pressure, I think 15psi or so but I would still think you'd get a decent amount of flow coming out of it when tested.

***Problem Solved***

I installed the new fuel pump ... there must of been something wrong with the origional replacement pump ...
I cycled the key 4-5 times to prime the system ... IT STARTED RIGHT AWAY ... no problem ...  ;D
That was a big plus ... since its been sitting in my garage since I bought it ... and god knows how long since it was running before I owned it ...

Now I'll have my work cut out for me ... trying to fix up everything else it needs ...  ::)

Thanks again to Xanth !!!!

My garage is getting pretty FULL now ... besides my daily driver ... I've got a 1954 Cadillac I've been restoring ... and now a 1984 Fiero 2M4 ...
Its the 1st time I'll be dealing with a composite body panels and a 'modern' electronics package ...  ::)
The picture of my Fiero ... was taken from the Craigslist Ad I bought it from ... $350 CAN
The picture of my Caddy ... the beginning of this summer ... I've been restoring it for the last 3 years ... this is the 2 summer on the road ... after it was sitting for 20 years or more ...

Congrats  8)

350 is pretty good for a Fiero just needing a fuel pump to get running, that's how I got mine. Previous owner left it sitting for 6 years or so, just needed the pump swapped.

Nice looking Caddy, have you finished working on it or is there yet more to be done?

Pretty well finished ..  roadworthy ... floats along the highway pretty nice ...  :)
Stitched  up a new interior for it ... usually wonky 50's colours ... kind of a olive & royal blue velvet like material ...  ::)
Did a quicky paint job on it myself ... but I hope to get around to spending some time and doing it again ...
Still a lot of work to do on the Fiero ... next step will be replacing some of the metal lines and a complete brake job ...
The garage is getting pretty crowded ...
One of them will have to be out in the SNOW this winter ... and it won't be the Caddy ...  ::)

I drove my Fiero last winter, and it did decently well. I only had all-season tires and still made it through. With some added weight and snow tires I think it would handle just fine. Front end is so light though its easy to lock up the front wheels.

Definitely don't want the Caddy going through winter after putting all that work into it  8)