3500 (LX9) swap into a Fiero

If you run your 19's @ 55 PSI (22.5 lb/hr) they will work if the engine is stock.

the dipsticks are all the same for the gen3 engines, if you go to the yard grab a few because it's common for them to break.

FWIW, we ran 3.4 DOHC injectors in a 3400 with a cam and ported heads with no problems. Getting ready to put them in a stock 3500 in a few weeks.

True they work Superdave, I believe in this situation he's better off working with what he has instead of opting for what must be at least 10 yr old technology and parts for that matter if the last production year of the 3.4 DOHC is 1996. It's tough enough discouraging Fiero swappers from switching out aluminum heads for cast iron heads on roller cam blocks.

[Superdave]

If you run your 19's @ 55 PSI (22.5 lb/hr) they will work if the engine is stock.


the dipsticks are all the same for the gen3 engines, if you go to the yard grab a few because it's common for them to break.



FWIW, we ran 3.4 DOHC injectors in a 3400 with a cam and ported heads with no problems. Getting ready to put them in a stock 3500 in a few weeks.

[SappySE107]

Those won't fit the fuel rail. I sell one that replaces the stock unit.

http://wot-tech.com/shop/all/adjustable-fuel-pressure-regulator/prod_135.html

I also have the AN fittings for a remotely mounted AFPR setup.

http://wot-tech.com/shop/all/an-6-fittings-for-3x00-fuel-rails/prod_132.html

[flimbob]

Looks like there are several adjustable FPRs on EBay. Has anyone had any experience with any of these?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=200434481013&viewitem=&sspagename=STRK%3AMEWAX%3AIT

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=370234350106&viewitem=&sspagename=STRK%3AMEWAX%3AIT

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=370267283406&viewitem=&sspagename=STRK%3AMEWAX%3AIT

I also found that the head of my oil dipstick is broken. Does anyone know if the 3100 or 3400 dipsticks are compatable?

[IsaacHayes]

Ah yeah, forgot about the dual spray pattern.

If you got it figured out and the parts aren't that expensive go for it. Used 24# from a DOHC or something do show up every now and then for sale though.

The problem with DOHC injectors is that the spray pattern is specific for the DOHC valve design with a wider spray pattern instead of conical which is used on single intake valve ports. They will work with no problem however the spray pattern will result in more fuel being sprayed towards the walls of the intake runner. I forgot the degree of the angle but the DOHC injector was designed so that fuel would be sprayed evenly at each intake valve in an oval shape to hit both valves rather than the narrower conical pattern aimed at a single valve.

[IsaacHayes]

If you got it figured out and the parts aren't that expensive go for it. Used 24# from a DOHC or something do show up every now and then for sale though.

I have a 16lb set which is in my 2.8L, I have a 19lb set that came with the 3100 fuel rail. I also have a set that came with the 3500. I am under severe cost constraints and can not afford to purchase a set of 24lb injectors to use with the 3100 fuel rail. I need a solution that is around $50. I believe I can get a suitable adjustable FPR for around that price. Joseph Upton has already proven a modified returnless system can be done. I have also talked with a very knowledgable person from the 3800SC camp that has converted returnless systems on a regular basis with no drawbacks whatsoever. It also allows me to use the stock components from the 3500 that I already have in my possession.

Avoiding any changes that move backwards in technology is a good thing whenever possible. The newer the parts the better. The adjustable regulator is also an attribute and having the ability to attach an inexpensive pressure gauge to it is another plus if ever you have a starting problem and have to diagnose. It's not a complicated accomodation at all, you're basically attaching lines to the regulator instead of the rail and running one line instead of two to the engine.

[flimbob]

I have a 16lb set which is in my 2.8L, I have a 19lb set that came with the 3100 fuel rail. I also have a set that came with the 3500. I am under severe cost constraints and can not afford to purchase a set of 24lb injectors to use with the 3100 fuel rail. I need a solution that is around $50. I believe I can get a suitable adjustable FPR for around that price. Joseph Upson has already proven a modified returnless system can be done. I have also talked with a very knowledgable person from the 3800SC camp that has converted returnless systems on a regular basis with no drawbacks whatsoever. It also allows me to use the stock components from the 3500 that I already have in my possession.

[IsaacHayes]

Why go to returnless? Swapping injectors are easy. :P

Stock 3500 injectors are about 24 lb/hr from what I can remember the first time I looked them up. That's correct, at 380 Kpa (55 psi). Not sure if flex fuel injectors are the same in the event that was offered with the Uplander on the 3500. It's possible there's enough reserve so that a change in the stock code is all that was necessary at the factory to make up for the difference in that case although I believe they are still different in that circumstance.

[flimbob]

If I have to get different fuel injectors, I may look into the adjustable FPR/returnless mod Joseph Upson spoke of.

[IsaacHayes]

Yeah, you'll need larger. Not sure exactly what would be best, but 19#i s probably too small. Anyone recall what 3500 stock ones are?

[flimbob]

Removed the 3500 Plenum, fuel rail, and valve covers. Looks pretty clean. I need to swap valve covers so the oil spout is on the trunk side. While they're off, I'll paint them, along with the plenum. The Delphi injectors on the Malibu fuel rail are 19lbs. Do I need to use different injectors, such as 24lbers?

[flimbob]

Finally got the engine on the stand. So far I have only removed some mounts and the drive by wire TB. Looks like the exhaust manifolds connect and exit on the right hand side of the motor. I've read that it is possible to reuse the stock fiero catback system if using manifolds from a 3.1 turbo Grand Prix and fabrication of a crossover pipe. Anyone have any feedback on this or other exhaust methods? Cutting the trunk is not an option.

My 00+ Malibu fuel rail from Evil Bay arrived. It has Multec 2 injectors( 25322180 ) and the fuel regulator intact. Will start delving into updating the engine as soon as it gets a little warmer. I hate working in the cold.