93FD3S

I'm running ported new motor with single setup. Fuel is 850cc promary and 1680cc secondary with Aeromotive FPR. What should the fuel pressure be at idle? Thanks.

Trexthe3rd

Uhmmmm, it would help a lot if you can start by stating the type of turbo and the target boost level. It would be totally different between a t04 at 12psi and a T78 at 25psi.

Wargasm

I would set the fuel pressure to about 36 PSI at 0 manifold pressure. (This will give you around 28-30 PSI at idle probably, depending on your port).

If the car runs well at idle (after tweaking your fuel injection maps in your EMS) and it also provides enough flow for your max boost at/near redline so you don't run out of fuel... you're good!

CCarlisi

The tuners I've dealt with use a pressure gradient of 40psi (meaning unplug the fpr vacuum line with the car running, dial in 40psi of pressure, and then reconnect the vacuum line). One of the benefits of using 40psi is that there is a large pool of people using this gradient to compare pfc settings with.

Higher fuel pressure will give you better atomization, but it also makes it more difficult to fine tune at low duty levels, because more fuel is metered in with each cycle. With that said, I'm using a gradient of 40psi with 871cc Siemans primaries, and I didn't have a problem getting a 14:1 AFR at idle.

93FD3S

Thanks for the help guys. I had my fuel pressure set at 40 psi at idle, but the FDs idle wasn't very smooth at all. I understand that the size of the engine port plays a part in determining the smoothness of the idle. I had to back the fuel pressure back down to about 33-34 psi, which helped. But I still have a idle surge when I first start the car for the first 5-6 minutes. I've tried to adjust the revs on the PFC and that helped some also. I checked the voltage of the TPS and its within spec. I also adjusted the idle screws. Dunno...

SPOautos

What fuel pump are you running? Are you using the stock fuel/return lines? I'm running 2 Walbros with a Aeromotive regulator and the stock return line and I'm worried that I wont have enough return. Are any of your guys running dual pumps with the stock return and still being able to run 40psi or less pressure? I hope so cause I've been worried that I wouldnt be able to get it that low.

Thanks for any info
STEPHEN

Jason

iTrader: (5)

Set the FP at 40psi and if you have to take some fuel out at idle.

Jason

package

I need some help just replaced my 1991 rx7 non turbo engine ran fine for about a month, now it stalls and will not run at all. replaced the air handler but it still doesn't run,whats next?

93FD3S

Jason, how do you take out the fuel at idle? I do have the commander with the PFC, so can I adjust the fuel at idle with the commander? Or do I need the data logit? Thanks..

Jason

iTrader: (5)

What does the car idle at?

93FD3S

The problem I'm having is that on start up the engine revs between 450rpms and about 950rpms for about 10 minutes. Then when I shut the car off and restart it it idles pretty steady 825-850 rpms. It almost seems to do it more when the motor isn't fully warmed up. I had adjusted the idle screws including the bleeder screw under the throttle body and that seemed to help. The other problem is that when I'm cruising say in 3rd gear and come to a stop at a stop sign (putting the car in neutral) the revs drop to about 500 rpms and almost wants to die but then rises right back up to about 825-850rpms. It does that everytime I come to a stop and put the car in neutral. I'm running only one belt (no AC, no power steerin, no airpump). I'm also using the ACT extreme lightweight flywheel with auto counterweight. It almost seems like theres too much fuel at idle. What do you think Jason? Thanks.

Jason

iTrader: (5)

My suggestion is bump the idle to 950 RPM and set the decel to about 1700RPM in the Power FC. The first thing is to get a steady idle then you can adjust the fuel. Once you have the idle steady then go into the commander and watch which cells the car is idling in. Go back into fuel adjustment and take out about 10% fuel.

Jason

cewrx7r1

iTrader: (2)

Are you still running: AWS, ISC, and or fast idle cam/hot wax rod?

The last one only affects cold starting idle speed after the AWS has disengaged.
It is adjustable but very often not mentioned.

You can also adjust the dash pot to slow down throttle closing; bump up fuel cut off to 1500.

93FD3S

Thanks....Chuck and Jason. I'll have to try in a bit. But no I'm not using AWS or the ISC anymore they are blocked off the plates. But I am still using the fast idle cam/hot wax rod. I've tried to adjust it screwing counter clock wise and it didn't seem to help the cold start idle at all. It just raised the rpms a bit. As far as the dash pot if I remember correctly it should barely make contact with the throttle arm at idle correct?

93FD3S

Jason
"My suggestion is bump the idle to 950 RPM and set the decel to about 1700RPM in the Power FC. The first thing is to get a steady idle then you can adjust the fuel. Once you have the idle steady then go into the commander and watch which cells the car is idling in. Go back into fuel adjustment and take out about 10% fuel".

When you say set the decel to about 1700rpm I'm assuming you are talking about the Rev-Limit menu? If so do I set both the F/C A-E (no electrical load) and the F/C E-L (with eletrical load) to 1700rpm? Or just one of them?
Also when you say "Once you have the idle steady then go into the commander and watch which cells the car is idling in. Go back into fuel adjustment and take out about 10% fuel" I'm assuming you mean go into the Map Trace Mode [Monitor] menu? And which menu do I use to take out the suggested 10% fuel? I really...really appreciate the help guys...!!! Thanks..!!

cewrx7r1

iTrader: (2)

Screw it in as far as possible but not enough that the throttle will not close all the way. This will slow down the throttle closing some and allow the ecu to try to regain idle control. But with your setup, you really do not have ECU idle control anymore except for fuel.

Kyle had the same problem as you. He ditched his ISC as you did, and set warm idle at 1000. Do not know what is fuel cutoff was at.

ONE unusual thing that he did that helped him alot was, set the fuel cells to the same value around the idle area.

Lets say your idle is in (P4.N3), he did something like set (P3-P5,N2-N4) the same as (P4,N3).