Technical Questions and Discussions - V6 fuel pump in a 4 cyl car ??

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V6 fuel pump in a 4 cyl car ??

Printed From: West Coast Fieros
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Forum Name: Technical Questions and Discussions
Forum Description: Got a technical question about your fiero? ask it here.
URL: http://www.westcoastfieros.com/forum/forum_posts.asp?TID=1911
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Topic: V6 fuel pump in a 4 cyl car ??

Posted By: Capt Fiero
Subject: V6 fuel pump in a 4 cyl car ??
Date Posted: 19 June 2010 at 10:03pm

So after running through the list of issues with my new duke, I'd like to get it running, even if only on 3cyl.

I think I have narrowed it down to a flaky fuel pump. No real pressure at lines, car will sorta run with fuel being poured down the throttle body. I am now getting an odd sound coming from the fuel pump. I thought maybe low on gas so I went and got $10 in gas and put it in, even changed the fuel filter.

Question is what will happen if I put a V6 pump into a 4cyl car. Will it explode the regulator? Will the reg just not be able to keep up and run the injector at too high a pressure? If it was just a matter of buying a V6 or a 4 that would not be an issue, but I just happen to have 3 V6 pumps here to test with and I don't want to drop 100 bucks to replace the pump until frankly I know for a fact certain that is the problem.

Well if any of you have tried it let me know.

Thanks in advance.

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Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.

Replies:

Posted By: Matt
Date Posted: 19 June 2010 at 11:53pm

I dropped a V6 pump in mine, worked fine.

Also just try dumping some fuel into the TBI and see if she fires up. If you want to get really into it you could just slowly pour gas into the TBI to see if she'll keep running. (I've done this once when I was struggling with fuel pump issues)

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I wanna go fast.

Posted By: Capt Fiero
Date Posted: 21 June 2010 at 8:26am

Thank You Matt. Looks like it will be getting a V6 pump then.

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Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.

Posted By: Matt
Date Posted: 21 June 2010 at 8:42am

Np. Weren't you the one who told me to get a V6 pump, just in case I ever decided to do a V6 swap? I believe you also mentioned that the V6 pump wouldn't be sufficient if I were to get a V8, and in that case you recommended the Corvette pump?

You could probably dig up the old post where I was going through fuel pump issues to check what everyone said.

I bought a new pump from... Napa? for like $120.

I just found this doing some "googling"

"Has the fuel pump been changed? If so was it changed with the right one? The 4 cyl. fuel pump only puts out about 14 psi where the V6 fuel pump put out about 30 psi."

There is a VERY good chance that I'm remembering getting a this wrong. I changed the pump 2 weeks before I got married and was very distracted. I'd do some more research before going to all the work installing the V6 pump.

They also have different part no. at fiero store. So it doesn't look like the pumps are compatible as one is designed for fuel injection and the other TBI.

Sorry for the previous misinformation.

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I wanna go fast.

Posted By: Matt
Date Posted: 21 June 2010 at 10:17am

Here is my old post concerning fuel pump issues in a 4cyl.

V6 PUMP IS NOT COMPATIBLE!!

http://www.westcoastfieros.com/forum/forum_posts.asp?TID=673&KW=Matt - http://www.westcoastfieros.com/forum/forum_posts.asp?TID=673 &KW=Matt

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I wanna go fast.

Posted By: Capt Fiero
Date Posted: 25 June 2010 at 10:43pm

Ok wrap up, so I ran it by Dr.Fiero, Dawg, and several of the long time Fiero mechanics and everyone was kinda left scratching their respective heads. However they all leaned towards it "should" work. No one would say for sure or not. So I guess I am the guinea pig. Today 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 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.

P.S. side note, the reason it would not run, was someone used a rubber non fuel hose to replace the wobbler that goes from the fuel pump head to the feed line in the tank. It had corroded and turned to goo. I'll post pics up later. So I'll bet the pump is still fine.

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Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.