3900 swap into Fiero

[Joseph Upson]

Why fuel rail and injectors are you using?

Stock 3900 fuel rail with 30 lb/hr injectors from the 8100 big block. They are the proper size to fit underneath the intake manifold. The 3400 rail requires clearancing the runners for the long narrow injectors to fit properly. I wanted to use the 36 lb/hr 3800SC injectors but that was the problem I ran into so I'll keep a look out for the short 42 lb/hr injectors that also work with the stock fuel rail.

[Blackrider]

Stock 3900 fuel rail with 30 lb/hr injectors from the 8100 big block. They are the proper size to fit underneath the intake manifold. The 3400 rail requires clearancing the runners for the long narrow injectors to fit properly. I wanted to use the 36 lb/hr 3800SC injectors but that was the problem I ran into so I'll keep a look out for the short 42 lb/hr injectors that also work with the stock fuel rail.

Are your running a returnless system?

Do you think the 8.1L injectors will work on the LZ9? The question came up a few days ago on the G6 forums about larger injectors, and I'm still searching.

[Joseph Upson]

Are your running a returnless system?

Do you think the 8.1L injectors will work on the LZ9? The question came up a few days ago on the G6 forums about larger injectors, and I'm still searching.

Yes I'm running a returnless system, you can see the method I used towards the end in the link to the pictures. The injector plugs are different and you would need to tune the injectors in since the flow rating is at a different and lower pressure than the stock 3900 injectors. I'm not sure how much benefit going to a larger size injector in a naturally aspirated engine would offer when there is reserve in the stock injectors and increasing the pulse width would offer the same effect. The injectors are also Multec I vs II or III for the 3900 but the pintle end is the same, the 3900 injectors I recall are a little heavier.

My engine is from an 07 Uplander which I believe was E85 compatible so they may be a different version than those used on the non E85 engine which will not need the extra fuel flow capacity required by the lower energy fuel unless the E85 compatibile injectors were used in all of the engines.

[Blackrider]

Yes I'm running a returnless system, you can see the method I used towards the end in the link to the pictures. The injector plugs are different and you would need to tune the injectors in since the flow rating is at a different and lower pressure than the stock 3900 injectors. I'm not sure how much benefit going to a larger size injector in a naturally aspirated engine would offer when there is reserve in the stock injectors and increasing the pulse width would offer the same effect. The injectors are also Multec I vs II or III for the 3900 but the pintle end is the same, the 3900 injectors I recall are a little heavier.

My engine is from an 07 Uplander which I believe was E85 compatible so they may be a different version than those used on the non E85 engine which will not need the extra fuel flow capacity required by the lower energy fuel unless the E85 compatibile injectors were used in all of the engines.

I don't think they where.

I don't need injectors right now, however people running Nitrous are running into issues around the 75 shot mark, so my research is for them. (:

[Joseph Upson]

Back at it. Corrected two oil leaks I hope, bled the brakes, added a central oil restrictor for the oil feed to the turbos and finally installed air filters, Advance auto had the right size for the job.

My oil pressure gauge shows an oil pressure of about 45psi however I'm not sure how accurate it is, it's also a little erratic. I curious because I have not had problems with oil pressure to a single turbo setup and a twin setup should reduce oil pressure a little more. Both turbos started to smoke out the exhaust after a little revving, the rebuild before the brand new turbo so I'm wondering if the pressure is up around 80 psi as found in a fresh 2.8L. The oil pump is larger than previous pumps and I imagine there is some compensation incorporated since the squirters are activated at a certain pressure so maybe high rpm really pushes the oil causing the problem at the turbos. I have 5/8" drain hose from the turbo so it shouldn't have a problem there.

I hope to be making a second attempt at a test drive some time today.

[IsaacHayes]

Cool I was waiting for some updates! Looks like your TB coupler clamp isn't on too straight! Wow not much room for the filter on the rear turbo! I see you are using a filter on the BOV, most people don't which isn't a good idea.

[Joseph Upson]

Cool I was waiting for some updates! Looks like your TB coupler clamp isn't on too straight! Wow not much room for the filter on the rear turbo! I see you are using a filter on the BOV, most people don't which isn't a good idea.

Yes, it's not wise to run the blow-off valve without a filter unless you have one that somehow remains closed when not relieving pressure and has an air tight seal, otherwise you'll be sucking junk into the engine. In Atlanta the in the Spring the pollen count is rediculous and all over the engine.

Actually the forward filter sits the way it does because of a clearance issue, the aft has some more room available the way it is. I saw the TB coupler clamp when I posted the picture.


So far the corrections appear to be working fine, I thought I had a turbo problem but it looks like I was just burning off excess oil after the restrictor was installed since the remaned turbo appears to have stopped smoking.

Right now I'm have a problem with achieving a smooth acceleration; when the pedal is pressed the engine revs to about 3000rpm and cuts out to full lean on Zeitronix WBO2 data logger, if I pump the pedal it will rev so I have to find he table that's causing the problem and add fuel to it at that point.

[IsaacHayes]

AE table messed up maybe? Or are you saying when you hit it hard it's fine but if you come up slowly then it goes lean?

[Joseph Upson]

AE table messed up maybe? Or are you saying when you hit it hard it's fine but if you come up slowly then it goes lean?

You have it right, when the accelerator is pressed it revs properly up to about 2500 rpm and then immediately goes lean and nearly stalls unless I release or pump the pedal. It can be manipulated up to higher rpm but not in one continuous press of the pedal.

[IsaacHayes]

Ah well that should be easier to fix it's just running lean in certain tables. Just need to go through the normal tuning procedure. I take it you have not done much other than compensate for injector rates as far as tuning yet?

[Joseph Upson]

The injector rate was changed but I took a look at the "AE Async Pulse Multiplier Vs. Delta TPS" and I had changed it by considerably lowering the first half of it and considering it addresses the first 50% of acceleration I believe that's where the problem is since another table starts at 60% on representing WOT. I'll also have to lower the base pulse width to get rid of the tip in rich pump shot.

I didn't drive it up the road due to the acceleration problem but hopefully tomorrow will be able to get it to perform properly. It idles right at about 950 as programmed and the exhaust temperature never reached 800 deg F hoovering around 650 F going up to the 700 range when revving.

Still can't get that stupid Moates APU-1 emulator to datalog although it emulates but what good is that without being able to read the BLM.

[IsaacHayes]

The way I understand it PE is when you are in WOT, and AE is when you snap open the throttle quickly, it squirts more fuel so it doesn't go lean from the quick throttle opening.... But I'm no tuning guru.

Can you just run an ALDL cable and use that to data log??? That would require another serial port but you could use a USB adapter on one. If you do on the ALDL cable I'd advise a USB one or a powered aldl cable if using USB adapter as I'm not sure if the problems people have with the adapters is cause many of the cables steal power from the serial port to power the chip and the USB adapters likely don't work that way.

[Joseph Upson]

The way I understand it PE is when you are in WOT, and AE is when you snap open the throttle quickly, it squirts more fuel so it doesn't go lean from the quick throttle opening.... But I'm no tuning guru.

Can you just run an ALDL cable and use that to data log??? That would require another serial port but you could use a USB adapter on one. If you do on the ALDL cable I'd advise a USB one or a powered aldl cable if using USB adapter as I'm not sure if the problems people have with the adapters is cause many of the cables steal power from the serial port to power the chip and the USB adapters likely don't work that way.

That's the problem I mentioned earlier, I have all of that in the Moates emulator, it just refuses to connect and datalog with the 8F code so I have to rely on the back up Zeitronix WBO2 datalogger to monitor A/F

[Joseph Upson]

I finally solved the emulator problem at least most of it anyway, poor connection at the ALDL plug, driver was not updated although the computer said it was.

As mentioned under the computer section it appears I have a bad MAP sensor according to the datalog and finding that out at the last moment as was with the CPS sensor on a previous excursion I ran out of time again.
Hopefully the next trip months from now will be the charm

[JohnnyReb]

How are you doing with Moats? I always had good dealings with him. Seems unusual not to receive any support. When I 1st got my AutoProm USB I had all kinds of issues, all my fault but got plenty of help. I'm gonna blame my problems on a crappy users guide, LOL.