Ok preface to the post. I got an 88 Coupe with 65,000 miles with unknown issues and am slowly taking the time to sort out all the bugs.


So today I went to town on the first major issue, lack of fuel. After putting $10 worth of gas in the tank, and still no fuel, then installing a new fuel filter and still no fuel, I knew the pump had to be the issue. If I poured gas down the TB it would run. So I went in search of finding out if one of my spare V6 pumps I had kicking around would work in a duke. I knew they physically they would fit, as people swap V6 pumps into dukes all the time when they are installing a V6 or a V8, just never installed a V6 pump and kept it a 4 banger. Even after talking to several knowledgeable Fiero mechanics no one knew for sure. everyone was kinda left scratching their respective heads. However they all leaned towards it "should" work. No one would say for sure or not.Biggest question is would the 4cyl fuel pressure regulator take it, or explode the first time I hit the key. So today I dropped and swapped pumps. I dropped out the tank, swapped in an entire 85V6 fuel pump+sender, and used the 85 harness and majority of the 85 hoses off of the tank. I took the time to photograph the differences between the smaller 84-86 10.3 gallon tank and the larger 87-88 11.9 gallon tank. You can clearly see in the front view some of the changes to the tank design. Well on to the pics.

88 Tank



85 Tank



88 on left 85 on right



88 on right





Side of 85 tank







Here is the best shot showing how much different they really are. The 88 tank is on the right





Now WHO THE HELL DID THIS, Ratchet, Zip Clips and what looks like rubber garden hose, or some other cheap hose that was NEVER meant for fuel to go through it. No wonder I was not getting fuel at the rail, the pump was basically just circulating fuel in the tank and doing nothing.





It was so nasty that when I touched it with my finger it just dissolved into a goo






I reached in turned the key and ZIP the pump came on perfect, I cycled it a few times, went around checked my fittings, actually first thing I checked was to see if it blew the fuel pressure regulator off of the Throttle Body and not even a leak.

So after carefully checking things again, I hit the key and Vroom the little 4 popper came to life. Idles smooth, revs up nice. There are still bugs to work out and I still need to find out if there is a mechanical issue with the head or not, but I was not going to go any further on the car until it would run.

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85GT Soon to be 87GT,93 Eldorado 4.9, 5spd Dual O2 Custom Chip, Custom Exhaust. MSD Everything Capt Fiero --- My Over View Cadero Pics Yellow 88GT 5spd Full Poly Suspension, Lowered 1/2" in front, Corner Carver.

Belive it or not those zip clips and 15+ year old rubber Garden hose connecting the fuel pump to te rest of it.... is....Factory!!

Switch to 87+ tank?
You also need a overflow tank in right 1/4 panel. See 22P. Overflow tank is protected for EVAP can. Wet fuel in Vent line is bad w/ or w/o EVAP. See cave, emissions

Bad pump? You sure? Measure with a gage? Or injector will not spay?
Injector will not spay is likely no signal from ECM.

Get a Noid Light. See cave, more scan tool in ECM section

No Injector signal mean:
ECM does see reference signal from ignition module.
ECM is bad

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

I have ran an 88 4 cyl and 2.8 for extended lenghts of time (6 months or greater) with the corvette TPI fuel pump. I rarely keep a stock engine for very long, so if I have to replace the fuel pump before the engine swap, the pump needed for the engine swap goes in first with the stock engine.

The V6 one will work just fine on the 2.5.

quote Originally posted by hobodude34: Believe it or not those zip clips and 15+ year old rubber Garden hose connecting the fuel pump to the rest of it.... is....Factory!!

quote WOW, how could GM be that far off their rocker. Were they trying to find ways to get customers back with problems so they could collect money. Well its all replaced now. Originally posted by theogre: Switch to 87+ tank? You also need a overflow tank in right 1/4 panel. See 22P. Overflow tank is protected for EVAP can. Wet fuel in Vent line is bad w/ or w/o EVAP. See cave, emissions Bad pump? You sure? Measure with a gage? Or injector will not spay? Injector will not spay is likely no signal from ECM. Get a Noid Light. See cave, more scan tool in ECM section No Injector signal mean: ECM does see reference signal from ignition module. ECM is bad

Ogre did you not get enough sleep? My problem was nothing to do with the injector everything else tested fine, and I was not putting an 88 tank in an 85 car. I was replacing the pump in an 88 coupe and using the 88 tank. I just happen to be stealing the pump and guts from my 85 Tank and found it a good time to photograph the differences between tanks. It was the hose on the fuel pump that was the real issue. I had a fuel pressure gage here however did not bother to even install it when I realized that during the prime sequence there was zero fuel coming up the feed line. I could have simply replaced the rubber hose, but the curiosity got the better of me and I wanted to see if the V6 pump would work. Besides I will, if I keep the car eventually change out the duke for something, anything else.

quote Originally posted by fieroguru: I have ran an 88 4 cyl and 2.8 for extended lengths of time (6 months or greater) with the corvette TPI fuel pump. I rarely keep a stock engine for very long, so if I have to replace the fuel pump before the engine swap, the pump needed for the engine swap goes in first with the stock engine. The V6 one will work just fine on the 2.5.

That makes me feel a lot better, knowing that I shouldn't have any issues running it like this, and like you, I doubt this 4 banger is going to stay for any length of time. If I keep the car, I will have to change out the duke. I have my 88GT with modded V6 and my 4.9 5spd car, which I know is going to make this car feel like a snail on the road. If the car was not so lo miles and eligible for collector plates, I'd already be looking for a good swap motor. I've got 2 spare 2.8's just sitting here not doing anything, but what I would really want is a 3.4 TDC. I've got a low reving torque motor, and a 2.8 why not go to the other extreme.

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85GT Soon to be 87GT,93 Eldorado 4.9, 5spd Dual O2 Custom Chip, Custom Exhaust. MSD Everything Capt Fiero --- My Over View Cadero Pics Yellow 88GT 5spd Full Poly Suspension, Lowered 1/2" in front, Corner Carver.

Boostdreamer in looking for a fuel pump found one manufacturer knowingly only supplied the 2.8 pump but listed it for both engines. When asked the manufacturer said yes - the higher pressure pump will work with no problems in the 2.5. The excess fuel pressure is just bled back to the tank. His thread is on here somewhere. Three pumps before he got things to stay working - He had an electrical problem that was overheating the pumps (he thinks). I think the problem got cured so that is the apparent solution to what was happening to his Fiero.

So extrapolating from what that manufacturer said - It should be just fine.