Hey y'all,
Got a 1990 Camaro Iroc 5.7l tpi. Car turns and starts for a few seconds with some starter spray. Changed fuse near battery for fuel pump, changed out fuse 1,6 and 10 under dash. Changed left and middle relay on firewall (fuel pump relay). In on position security light goes out as it should. SES light stays on like it should. Valve on fuel rail has no pressure and nothing coming out, I'm stumped. Still cannot get a whine from the fuel pump. I am dreading dropping rear end to change pump. Anything else I should check prior? Thanks in advance!

 

Have you physically checked power at the fp relay ?

 

I have not, how would I do that? I'm sorry I'm a beginner.

 

Cavity E on the pump relay by the master cylinder is pump feed. Power for 2 sec prime or while cranking.

 

check voltage at the fuel pump connector clipped to the under pan just above the rear diff. Unplug it and put a meter on the pin and have a bud turn the key. If you see 12v then your problem is likely the fuel pump (though still could be a bad electrical connection on underside of sending unit). If no power, then trace it up to the fuel pump relay ... one of 3 bolted to the top firewall on driver side (most likely), probably the one with the fuel pump pigtail test connector hanging off it. An electrical diagram would help and should be able to find one on this forum.

better yet, just go here:
https://www.thirdgen.org/forums/tech...-no-prime.html

 

^^^^THIS

 

...

 

Hi everyone and thanks for the help. I know its been a year since I posted. I put in a new fuel pump, tank, fuel filter, the whole sending unit. I now have fuel at the rail. Still wont start! Im going to repost this so I can get some traction. Any ideas on what to try next? Also, it doesn't seem to do anything with starter fluid now, just turns over. Thanks

 

Still have old injectors? Can you see pulse signal with a noid light ?

 

The original injectors are in it. Arent removing these a PITA? I wish I could start somewhere else with diagnosing. Thanks.

 

read the previous post, good luck

 

How much pressure at the rail valve?

 

Hi I will check pressure amount at rail soon. SIR I apologize ans misread about the injectors. I checked with noid light at the connectors and all got a consistent pulse. So I guess I can rule out a VATS issue.

 

Seems like all the injectors are varnished shut . Not to uncommon for sitting for years.

 

Strange, today im getting no pressure at the rail. Primed a few times.. all zeros on the test guage. Poked the valve, not a drop of fuel. New tank with only 4 gallons of fuel put in it but it never started. I can still hear pump priming. Very confused now.. thanks all

 

Welp....start moving back through the system. I'd remove the fuel filter, put a bucket under it and energize the pump again...see if you got fuel there.

 

Was the pulsator put back on the new pump
?

 

No the pulsator was old and messed up. They provide a little tube instead. Thought it wasnt really necessary anyways.

 

I personally don’t like the tubes or a pulsator and use a high pressure rated hose and clamps. You might pinch the return line by the drivers side fender well. See if pressure rises at prime.

 

Since there is evidently no fuel rail pressure, be sure that the test gauge fitting is fully seated and depressing the core of the Schrader valve when it is connected. Don't bother asking why I suggest that, other than to learn that some of the offshore equipment from budget importers like "Port & Crate" are not necessarily fully correct and functional.

 

I don’t exactly recall what VATS disables, but I would try bypassing it with resistors to eliminate that as a possibility. When VATS went bad on my 1990 I bypassed it and it’s been great since. The ignition key can become worn and cause intermittent VATS issues.

 

Nothing to be stumped about. Your fuel pump isn't running.

Disconnect the 3 pin connector from the car to the fuel pump at the rear bulkhead. 1 pin is 12+, 1 pin is the fuel sending unit, and 1 pin is ground. As best as I can remember the two pins on the outside are 12+ & ground with the sending unit pin in the middle. Connect a DMM to the 12+ and ground pins and watch the meter as someone else turns the ignition key from the Key Off position to the Key On, Engine Off position and the fuel pump primes for 2 to 3 seconds and see what the voltage is if it has any voltage at all. There is not an unlimited number of fuel system primes. After so many cycles of Key Off to Key On, Engine Off it quits priming the fuel system. You will have to wait awhile before it will prime the fuel system again. There are more than enough fuel system primes before it quits for you to see if it's getting voltage at the connector though.

If you have proper voltage at the rear bulkhead connector but the fuel pump doesn't run then your problem is between or including the connector on the fuel pump wiring harness to the fuel pump itself.

 

VATS won't enable the starter enable relay in the driver's side kick panel and it won't send the special signal to the VATS pin on the ECM.

VATS doesn't do anything to the fuel pump circuit or the ignition system.

If the VATS PASSkey module doesn't see the correct resistance from the pellet resistor on the key the car won't crank and if the ECM doesn't get the special signal on the VATS pin within 2 to 3 seconds it disables the fuel injector driver and won't pulse the fuel injectors.

His car cranks over but won't start because his car has a fuel system problem.

Your car doesn't have the VATS PASSkey module system bypassed. It has the VATS PASSkey module system tricked. Your car has the steering column resistor system bypassed. If your VATS PASSkey module fails your car won't crank or run.

What you have actually done is made your car easier to steal and left in place the system that leaves you in the parking lot or garage with a car that won't crank over and run.

 

You are hearing your fuel pump prime, but getting zero pressure at the rail.

This is what I would do:
1. Check voltage at pump connector above rear diff at key-on as previously described. Should get 12v min for a couple seconds. If you don't get 12v then your problem is upstream.

2. If getting 12v, it's time to pull out your fuel pump and investigate.
A. Look for any obvious issues. Fuel hose could have slip off or have blown out. Non submersible grade fuel hose will fail quickly. Make sure fuel inlet cap was removed on fuel pump.

B. Test electrical continuity using multimeter between sending unit connector and fuel pump connector (power pin, ground) and sending unit ground point and fuel level wire (purple on mine). In other words check any and all wire terminal points. If connection test fails, pull the connector off the bottom of sending unit round plate and run same electric test between the 3 exposed pins and same points as before. If test still fails get a wire brush and clean the 3 pins under sending unit plate and the pins in the female connector (use mini needle files). Could also get some electrical contact cleaner spray. Don't take off too much metal, just scratch up the surface.

C. If none of A or B, then very possibly your fuel pump is bad or your sending unit isn't getting enough current. May have a poor connection from battery or your power wire needs to be upgraded to work with the newer model sending unit and pump assembly.

 

From my last test of priming, I had disconnected the rubber fuel line and metal fuel line drivers side engine bay and it spewed fuel each time.. when reconnected, still nothing to the rail. A friend of mine suggested the fuel regulator because it can get stuck. Any thoughts? Thanks everyone.

 

What was the pressure at the rail ? Did you ever check injector pulse ?
you can hook back up the rail crossover lines and pinch the return and see if pressure is higher at the rail.

 

All ^those^ questions...find the answers to them.

The regulator cannot really get "stuck". It could tear a diaphragm, but then it would flood the plenum with gas....and that wouldn't kill fuel pressure in the rail, anyway.

I question your testing of "no fuel at the rail"....when you have fuel at the rubber line that screws on to the....rail. I would use a gauge to check pressure at the rail, as TP said/asked a couple times, now.