zrracer

I have a 90 ZR-1.

I am trying to run down a VERY rich fuel problem with no check engine light. The pumps are new. the plugs are very fouled. The car will idle and run very rough. Looks like a mosqueto fogger car. The fuel pressure is at 55ish psi. It will only hold for 2 seconds and then drop to 0. Is the fuel pressure gage doing this?. I would think the system would hold pressure?. Could all the injectors be leaking?. All the plugs look the same.

Thanks in advance for suggestions.

gbrtng

One or more leaking injectors - fuel pressure will hold for 10-20 minutes with good ones.

Dandy97

Could be a bad fuel pressure regulator. When they go bad they leak fuel into the plenum.

Aurora40

Man, I'd have to think they'd leak like hell to bleed off all the pressure in 2 seconds! Though I guess the "mosquito fogger" description might fit a car with injectors that leak like hell?

Like was said though, some FPRs will leak fuel through the vacuum hose when they go bad, so this also could account for it. Try removing the vacuum line from the FPR while the pumps are energized. See if fuel comes out the vacuum fitting. This is a common failure mode on Northstar motors, don't know if LT5 FPRs fail in the same way, but it's a very easy check.

zrracer

I have dicided to pretend that the injectors are good and check the FPR. I will try Aurora40ies idea. Of the thousands of pages in the manual of course the FPR page is gone.

glass slipper

What color is the smoke coming out the exhaust?

Crabs

If he's running "mosquito fogger" rich, then the color of the exhaust is probably BRIGHT RED!!!

Goldcylon

I think this is what is going on here 20-30mins is a good indication of how long they should hold pressure for at the rail. If I may suggest some RC injectors or Accels should be considered at this point. Whatever you do dont reinstall GM OEM brand. GC

zrracer

HA HA !!!!

Its actually a light gray color. I can put my hand if front of the exhaust tips and feel moisture that smells like gas.

Goldcylon

Damn just add a spark controller and you would have a James Bond anti tailgater device

djpatrick35

That'll keep 'em off your tail! BOOM!