2010 Camaro FPCM

[E85 LSX]

I'm tuning a ls3 Camaro and need to increase my rail pressure under WOT as my injectors are going static. I changed the desire pressure for high flow but it seems to have no effect. In my log i can see the requested fuel pressure is raised when I do a wot run but the delta across the injector is unchanged.
I am thinking that either these FPCM settings do not do anything on these new camaros or my fuel pump can't keep up.

Either way I am installing a BAP this weekend to hopefully solve this problem.

[RWTD]

I don't think the BAP will work. Read this:

http://www.hptuners.com/forum/showth...358#post170358

Also, please post up your *factory* tune, if you don't mind.

[E85 LSX]

RWTD,

I read that and was also concerned about the BAP working in this situation. Several companies are making supercharger kits for this car, Ligenfelter being one of them. The BAP is listed as one of the items installed for the supercharger kits so I called Ligenfelter and asked them how to wire it up. They said they wire it in before the FPCM, told me what wire and where in the trunk and sure enough in my fuse panel in the trunk there is a 20A fuse for the FPCM.

After reading the post you have referred to I am still concerned that this might not work but we will soon find out, my BAP will be here tomorrow. I am sure other people are interested in this issue so I will continue to update with my progress.

[lito]

Will be nice if you can share your findings regarding the BAP

[RWTD]

Okay, I think I may see your problem. Your Low and Hi Flow Upper and Lower tables need modifying in order to tell the pcm to switch from the normal and Low Flow tables. You need to log "Fuel Flow" (hopefully Chris has added this pid into the Scanner), and then come to an idea of where to set this table to. As a test, raise your "Normal" scalar from the stock 58 psi to say 70 psi, and see what happens.

If that's not it, then there is an additional parameter somewhere preventing this from happening. Curious, what are you using to determine that the delta is not being raised?

[E85 LSX]

I requested a higher fuel pressure for the high flow values and at WOT the requested pressure did switch to the high flow psi I requested but the delta across the injectors did not chage at all. I am using the scanner to determine this, I log fuel pressure requested and injector delta psi. Also if my rail pressure did change the injector duty cycle would have been decreased and if it didn't I would have gone rich. So I am sure my rail pressure did not increase even though my requested pressure increased.

At part throttle though when I requested a higher pressure the injector delta psi did increase. This leads me to believe the fuel pump is not keeping up at WOT.

[E85 LSX]

I don't have the solution yet but I learned alot over the weekend. Splicing the BAP before the FPCM will not increase the rail pressure. It looks like the FPCM does regulate the voltage out regardless of the input voltage, which is what people have seen with other FPCM's. I'm still working on this though as I have a few more ideas.

Another thing that is weird is that I can request a higher rail pressure in the PCM and get it at idle and part throttle conditions but at WOT my injector delta is always the same no matter what I command in the PCM. I think there might be a parameter we do not have access to or I just haven't found yet that is setting the rail pressure at WOT

[BoostedYards86]

ok what is FPCM...sorry i just trying to gather info on the 2010 camaro's...just purchased one last week.

[lito]

ok what is FPCM...sorry i just trying to gather info on the 2010 camaro's...just purchased one last week.

Fuel Pump Control Module, it is a variable DC/DC converter that outputs different voltage levels for the pump depending on fuel flow and pressure requirements.

[BoostedYards86]

ok i figured it was like a fuel pump command module...so i was close enough. just had the wrong name.

[E85 LSX]

After trying different settings in the ECM the fuel pressure still falls at WOT. Attached is a log with the BAP installed before the FPCM. Also, I command a higher pressure during the WOT run when the high fuel flow is met. The requested pressure goes from 58 to 70 and this has absolutly no effect on the rail pressure.

I want to install larger injectors but know that the pressure will still drop untill I figure out how to increase the voltage to the fuel pump. I might try wireing the BAP directly to the fuel pump and bypassing the FPCM but am not sure if thats the best idea.

Anyway I am trying to figure this out ASAP so I can install my cam!!

[RWTD]

Will the ZR1 fuel pump fit in your car without heavy modification, is the question?!

As for Commanded FP going to 70, if it's not having an effect it makes me believe there is something in the tune that is preventing this. Maybe Chris can chime in and give his thoughts? Do you see ANY change in the FP once you go WOT? Does FP fall below 58 psi at all during the pull? If it doesn't, it would seem to me that you have enough fuel pump to run at least some higher FP than factory.

[icicleboy]

again, I've looked at the pump at wot with a scope, and seen the duty cycle go to 100% which means the pump is not keeping up. The same problem still exists... the pwm output is 12.0V EXACTLY and never changes in voltage. It's the DC (duty cycle) that constantly changes with demand while watching the fp sensor. The pump is not too small, 12V is too little. One option is to create a circuit that will lower ground to something like -2V (referenced to ground) or even lower. Still allowing the PWM to vary as needed. Another option is to make another driver circuit like a bap that will output in pwm at a higher voltage and basically copy the output of the fpcm. The vette pump is not compatible at all as it's a 5 wire stepper style motor.

If we're stuck with this fpcm, and it can handle more 2x the current reliably, the other option is to do a double pumper in tank and let the fpcm figure out the lower pwm duty cycle since it's closed loop. Or what about an inline pump that is mounted on the rail that is also duty cycle controlled by the fpcm?

[E85 LSX]

icicleboy, thanks for chiming in. I read your post before the BAP install but I guess I just wanted to test it myself. Can the BAP be installed after the FPCM or can it not handle the pwm? I'm assuming it will not work.

Another idea I have is to study the FPCM itself and see if its possible to "jump" the part of it that is regulating the voltage to 12v and just let it control the PWM. If this is possible the BAP can be installed before it to control the voltage. As soon as I locate the FPCM I will look further into this solution, I still can't get my hands on the service manual for this car though.

I like the idea of installing another pump in the tank and letting the FPCM control them both, as long as drawing twice the current doesn't hurt it. If this works we should be able to deliver twice as much fuel. Do you know what type of pump I would need, just order the OEM pump for my car or go with one of the walros? I'm sure I could custom make a dual in tank pump setup. Maybe I'll be the guinea pig for this experiment.

RWTD, the psi is always around 50 at WOT, in the attached log it is dropping as the RPM is increasing. . . definitely need more pump.

[RWTD]

On a Ford you can install the BAP pre or post-FPDM, tho you will have drivability issues if you wire it in post-FPDM. I have no idea if wiring it in post-FPCM on GM would work or not.

In regards to installing an additional pump, why not just install a 2nd FPCM to run the additional pump, just like we do with installing an addtional FPDM on the Fords when we use 2 GT40 pumps in the same tank (the factory FPDM will go into thermal overload on 2 GT40 pumps). mjchip makes a modded FPDM that will handle the current of two GT40 pumps, but the ideal method is to do like Ford did on the factory GT40, which is 2 GT40 pumps and 2 FPDMs (one for each pump).

RWTD, the psi is always around 50 at WOT, in the attached log it is dropping as the RPM is increasing. . . definitely need more pump.

Yeup, that tells the answer right there! Thanks for chiming in with that info.

[Chris@HPTuners]

guys do i need to do anything here or have you got things sorted? If the DC is at 100% it sounds like the pump just can't go any faster

it doesn't surprise me as generally the functionality is used for emmisions and NVH at idle and low throttle not performance.

Chris...

[E85 LSX]

Installing a 2nd pump and maybe even a second FPCM sounds like one of the best ideas to me, but maybe theirs an easier solution.

What do you guys think about wiring the BAP directly to the fuel pump which would essentially take the FPCM out of the picture. In this situation the pump would be seeing 14v all the time and we could boost that to 17v with the BAP. We know right now that the pump never sees more than 12v so this would really increase output. The only problems I could imagine would be with pump life and heating the fuel to much by running the pump at 14v while just idleing or cruising. I'm also not sure how the FPCM would effect the PCM if I just disconnected it.

[icicleboy]

I have an MSD BAP here, and a signal generator.... I'll see if a PWM input equals a PWM output and report back.

[RWTD]

It sounds plausible, but I just do not like the problems that can happen with drivability quirks, like spiked fuel pressure when the demand comes in (if you put it on a switch of some kind, whether rpm operated, or boost operated for those with blowers). I've seen this so much on the Fords where everyone complains, so they go back with the BAP before the FPDM, and the FPDM determines if it wants to let the voltage through or not. Sadly, as we know, the FPCM on the GM won't allow for this.

icicleboy, did mjchip ever get back with you at all?

[EC_Tune]

Has anyone looked at the ZR1 pump as a re-fit for the Camaro? ZR1 has FPCM as well.