fuel pressure advise

[carbed 85 gt]

Hey I have my 93 lx with the following: Trickflow heads, TF stage 1 cam and the track heat intake,also 24 lb injectors with C&L 73 mm meter cal'd for 24 lbers. Not tooo sure what pump is in the tank. I was told witha stock pump to run more fuel pressure around 40psi, when I bring it up this high the car runs poorly at idle but great at WOT. If I back off the fuel to about 32-35 it idles great but not good for any WOT pulls. THe car doesnt have a tune yet and I am just looking for a good point to start off.

 

[sorrell]

35-40 with vaccum off

 

[95opal]

32-35 seems pretty low i would start around 37-39 and see how she runs

 

[Michael Yount]

The pressure should be set at the stock setting - measure it at warm idle with the vacuum off the regulator and plugged - 38-39 psig. If it's misbehaving it's likely because the calibration on the C&L isn't the most accurate in the world. Someone who knows what they're doing in the tune department can help you with that - but your money might be better spent on a better maf. You might also try clocking (rotating) the maf so the air hits the wire differently. Make small changes, and drive it for a day or two before making the next change. Keep records so if you move it into a position that's really crappy, you can back to something that works better. And remember - the computer 'learns' about new operating conditions and adjusts. So drive it for a while before drawing any conclusions about how your clocking change is working.

If you have the stock pump -- well, it's barely adequate to keep up with the stock motor, let alone with a HCI set up like yours. Find out what pump you have. If it's stock you need to move up in size.

 

[carbed 85 gt]

So my problem with higher pressures is probably a lack of fuel vloume whe running the stock(?) pump that high? makes it run bad without the volume needed I guess

 

[carbed 85 gt]

So could fuel pump going bad would cause idle problems?

 

[carbed 85 gt]

Well I still need a pump but found my culprit to my idling issues, it has been my C&L the whole time. I rotated it 90 degrees with the sampling tube away from the motor and it runs a lot better. It will start without giving it throttle to keep it going and surging is only about 50 to 100 rpm now without any stalling at lights. I thought it would be ok as it ran great with a 19lb tube and bolt ons, now with a 24 lb and H,C,I it needs some help. figures huh