555

Ok.... finally got my tbi fitting for my fuel pressure gauge. I'm reading around 11-12. I was told this was normal. However when I pinch off my return line it jumps up to around 18 and runs great. The problems I've been having is my car dies after it warms up and when I push the clutch in unless I feather the gas. This is all recent due to my 305 to 350 conversion.... Sound like a pressure regulator?

Damon

Nope, your fuel pressure it totally normal. 10-12 running and 18 when dead-headed is exactly what you should expect from a stock TBI setup. Sounds like a tuning issue or a vacuum leak.

irishhockey34

iTrader: (12)

+1 on the tuning. my car did the same thing after my 305 to 350 swap. get a chip. i recommend www.tbichips.com

555

I got a "tbichip"......... any reason it runs great after its deadheaded?........

irishhockey34

iTrader: (12)

maybe idle speed is set too low? or as stated above a vacuum leak. Doesnt really sound like a fueling problem if the car runs fine when you put your foot into it. If it was a fueling issue, the car would be running lean in the upper RPM range, not down low.

555

upped my idle... now it stays running, just surges a little. If I disconnect my map sensor it seems to idle better.....?

irishhockey34

iTrader: (12)

surging usually has to do with the tune, hopefully someone else can chime in on this?

morepowerjoe

I had the same problem for a while. Come to find out I was never getting the engine temp high enough to go in to closed loop before I was tuning everything. So when it went into closed loop it just got worse. I still have a little of the same issue with a slight surge, but it's because I still have a stock chip with 10.1 and a aftermarket cam.

xch3no2

I would next recommend a boost in fuel pressure to 15psi, most run better that way, and that will allow you to lower the idle adjustment back down where it belongs. When you unplug the MAP sensor and it runs better I would replace the MAP. Your conversion will need some work getting the right tune in the ECM, time to start a little monitoring & logging.

555

I found some "JET" adjustable regulators @ Jegs... any good or bad reviews, thats about all I could think of to boost my pressure, right? I'm hoping it helps with my high rpms, it almost acts like it governs at 4500-5000 rpms running lean as hell.

Ronny

iTrader: (1)

Unlikely a "stock" fuel pump can sustain, under load, much more than 12 lbs FP. As they age they become less efficient. If you update to a GM TPI or aftermarket large increases in FP can be sustained under load. I believe Jet offers a good product for reg. Is Jet a stock replacement? Turbo City also offers same. Aeromotive is the best you can buy but not a stock replacement. Aeromotive requires plumbing and capping the stock location.

irishhockey34

iTrader: (12)

Jet is a direct stock replacement of the FPR. It is fully adjustable, but then again so is the stock one with little modification.

Ninety-One

If it's running better with the map disconnected, make sure the map sensor is hooked up to manifold vacuum, not ported vacuum, check your under hood vacuum line routing sticker.