LS3 - first start - no fuel

[Zachalanche]

Hi,
Just looking for some advice in case I missed anything obvious.

I'm trying to fire up my ls3 with GMPP harness and computer for the first time, and I'm not getting any signs of fire. I pulled a spark plug and it is bone dry...doesn't even smell like fuel. I checked one of the injector plugs and it is pulsing. I also checked the fuel rail for fuel and the first time I cracked it I got a rush of air, but its safe to say at this point I have all the air worked out.

I've triple checked the fuel system and everything is plumbed in the correct direction. Pump is running, and the only thing left to check is fuel pressure (I need a tee fitting and a gauge to do this, so it hasn't been done yet.)

My fuel system is an aeromotive 340 pump, corvette regulator/filter from tanks inc., and a single line up to the engine.


Still when I check the spark plug on the cylinder that I verified injector pulse, I see no signs of fuel whatsoever.

I plan to confirm the fuel pressure, but is there anything else I can check in the mean time?

[dhutton]

Does fuel squirt out the Schraeder valve on the fuel fuel rail when you depress it? If it doesn't it will not fire.

Don

[Schwartz Performance]

One common mistake is to swap the feed and return on your regulator. It will provide some pressure to the rail but not enough. The return is the small tube. Double check that. I've had the same thing happen lol.

Also make sure the direction of your maf is correct.

-Dale

[Zachalanche]

Does fuel squirt out the Schraeder valve on the fuel fuel rail when you depress it? If it doesn't it will not fire.

Don

no schraeder valve. has different fuel rails. but I did crack one of the fittings looking for what you just explained. and there didn't seem to be as much pressure as I would have expected.

[Zachalanche]

One common mistake is to swap the feed and return on your regulator. It will provide some pressure to the rail but not enough. The return is the small tube. Double check that. I've had the same thing happen lol.

Also make sure the direction of your maf is correct.

-Dale

that is the exact symptom I am seeing, but I think my regulator is right....unless the sticker is wrong. Maf is correct. If you look closely you can see where I have written return and supply on the lines. I Unhooked the supply where it passes through the trunk floor, and turned the pump on, and it flowed like crazy. so I know That I didn't mix up the lines in the tank either.

[Schwartz Performance]

Darn, you do have them correct lol.

[1989GTA]

The problem I had was the ground wire on the injectors was not hooked up. I would check to see how much fuel pressure you have. I assume you can hear the fuel pump running?

[Zachalanche]

I can hear the pump run, and feel fuel flowing through the supply and return lines. double checked all grounds, and even hooked up a light to one of the injector plugs to verify the injector was being triggered on and off.

need to get a gauge installed to check pressure - working on ordering that.

thinking about pulling the regulator and trying to test it somehow.

I've disconnected lines under pressure before (replacing a fuel filter on a pickup and didn't get the system depressurized enough) and with only 40psi, you take a gas bath. Like I said before I cracked one of the fittings on the fuel rail (very carefully) expecting to hose half of the garage down. to my surprise I didn't make much of a mess at all. there was some pressure, but didn't seem like 60 PSI. this leads me to believe the regulator is opening prematurely.

the regulator is brand new, are there bad brands out there or is it common to have a faulty one here or there?

[1989GTA]

I have never had a problem with the Corvette fuel pressure regulator/filter. Not to say one cannot be bad. May sound odd but is your fuel pump hooked up correctly with the +12v where it should be? The pump could be running backwards. By the way just thinking out loud.

[csouth]

It's going to be messy, but you need to troubleshoot from the fuel pump out now. Get a bucket and disconnect the supply line before the fuel filter/reg, have someone turn the key on for a single pulse only to see of its pumping correctly. I know you said you feel the gas in both lines, but could be the wrong direction. If that works right, I'd move to the supply line and disconnect at the rail. Prep for mess, if it dribbles then you can factor in a possible bad regulator.

[marolf101x]

Check the pressure. I had one of those pressure regulators not providing enough pressure once. Brand new, right out of the box.
Picked up a brand name unit from the parts store, and had it running in 10 minutes.

[stinger67]

When we started mine, our issue was not enough fuel pressure. Turned out to be a bad filter/regulator. We went back and specifically bought the fuel filter/regulator for a new Vette, cured the problem.

[rustomatic]

This just sounds like what happened when I reversed the fuel lines on the Exploder 5.0 swap I did last summer. I thought the inlet line was the big one, but was wrong . . .

[dhutton]

The Wix filters are one of the better ones.

Don

[Rucumn]

Double check the simple stuff too.....such as, do you have enough fuel in the tank to submerse the pick-up? I left my project sitting for quite some time and enough fuel evaporated or stagnated that I could not get it started.

Also, probably not the issue, but is your fuel tank vented? This is normally not the problem until you are up on the road in the middle of no where:0

[Zachalanche]

Double check the simple stuff too.....such as, do you have enough fuel in the tank to submerse the pick-up? I left my project sitting for quite some time and enough fuel evaporated or stagnated that I could not get it started.

Also, probably not the issue, but is your fuel tank vented? This is normally not the problem until you are up on the road in the middle of no where:0

good point, the tank was bone dry when I started. I did put 5 gal in (tank holds 22). I certainly hope I'm not hauling 5 gal of unusable fuel around.

Tank is vented.

When I verified the supply line was actually the supply line (not accidentally crossed inside the tanks, and pump not running in reverse), All I did was bump the pump for a split second, and about a pint of fuel came out. So it appears that this pump can really move some fuel.

[Zachalanche]

Based on your comments, and some of the reviews on the summit website:
https://www.summitracing.com/parts/t...4-kit/reviews/

-I am leaning heavily toward the regulator being the issue. So do I take a chance and just spend $40 and get a Wix filter/reg? or do I purchase the fittings and pressure gauge that I need to properly troubleshoot the issue.......and then likely spend $40 on a Wix filter/reg.

[Zachalanche]

Arrgg. Well, as murphy's law would have it, jumping to conclusion on the filter reg being the culprit did not result in a running engine. I decided to bench test one of the injectors to see if it was opening when triggered......it was not. one by one I pulled the injectors out to find that every one of them was stuck in the closed state. I was able get 6 of them working again in pretty short order, 2 of them would not budge. Once I finished that I went back and tried to cycle the first one again, and it was already a bit sticky compared to 30 minutes prior when I had it functioning fairly well. So I gave up at that point and tossed them all in a cup of Seafoam.

hopefully this is the smoking gun......and hopefully I don't have to buy a set of injectors. these things have never been used.

[andrewb70]

Did you ever verify that you are getting spark? There are two grounds that need to be bolted to the back of the heads. They are direct grounds for the coil packs.



Andrew

[Zachalanche]

Did you ever verify that you are getting spark? There are two grounds that need to be bolted to the back of the heads. They are direct grounds for the coil packs.

Andrew

grounds are good. and I have verified there is power to the coils. I haven't verified the plugs are actually sparking, but there is fore sure zero gas entering the cylinder.