We are working on a project 1990. The car had been in a fire. All the engine harnesses were replaced. Found out recently the harness was from a 1991; hoping that is not going to make a difference. New engine is in, wires and hoses all connected. We are ready to go. Foot on the clutch, turn key, and the car begins to crank, however it does not start. Checked for Spark using HEI spark tester. Got a nice bright spark. We have air. Fuel pump is on, and we have fuel pressure. Pulled a plug and the plugs are dry. Decided to tease the engine by pouring a little fuel into the TPIS miniram. Car turned over for a second the died. What could be causing the fuel injectors not to spray fuel? I must be missing a wire, or sensor or something. How do I trouble shoot this???

Dan

Did all injectors go bad at the same time. Now another big contributor to NO SPRAY would be a blocked fuel filter, blocked fuel lines, a fuel pump that is not running or a fuel feed system in the tank that leaks (such as a deteriorated hose connection between the fuel pump motor and the hard line inside the fuel tank). Another possible is that the fuel injectors are not being told to fire by the ECM
Unplug the injector harness and put a noid light or a test light to check for injector pulse. If there is none, it can be caused by a VATS issue or a bad ignition module, among other things
If you don't have a noid light from Harbor freight you can use a multi meter to test the injectors.

On my 87 I had one bank fail and it was caused by broken wire in the loom.

On my '91 if the airbag fuse is not live there will be no fuel to the injectors...

Injector pulse should come from the ECM.

As stated above, check with a noid light.

VATS normally also takes out the starter in addition to the injector pulses. It could, however, be a faulty VATS module if that was damaged in the fire.

I like Joseph's idea, I have heard that before. If not, I think Andy has the troubleshooting charts for your year.

I have good fuel pressure that I can tell you. I agree it could be a vats issue. What is the location of the vats module? Are there any specific wires (ground wires) or disconnected sensors I should check that would keep the injectors from firing. I feel like that could also be a problem.

If anyone has a flow chart or a link to one it would be greatly appreciated if you posted it. Thanks as always.

How 'bout the clutch start switch?

Does an open clutch switch disable the starter, same as [normal] VATS does?

Andy has the CD with all the charts.

Are the injectors new?

If you run it on starting fluid, will it continue to run by itself once it catches?

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No, but they are lightly used. I think they might be a little larger than the factory ones, however TPIS has no information relating to retuning. I expect the car to run like crap... but I expect it to run.

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No

I think a brain storm of a list of things that are required in order for the injectors to fire would be a good place to start.

I was reading that oil pressure must be at 4psi at the sensor in order for the injectors to fire. I have to get a mechanical oil pressure gauge on this thing and check that as well.

DG

Yes, once the car sees 4 psi it will allow the injectors to fire. But I doubt your new motor has zero oil pressure.

I will have to look at the troubleshooting tree in my FSM tonight for the 89.

http://www.digitalcorvettes.com/forum ... msite/20714/topics/101921

Read through this, should have some charts.

Do you have 12v constant on the fuel injection harness?

From the 89 FSM, sorry it took so long:

This is interesting. Used a Noid tester to check for pulse at fuel injectors. Light is flashing indicating its ok. Fuel Pump turns on and I have fuel at the fuel rail. HEI spark tester shows spark. Checked TPIS minram system. It had ford Injectors. So we ordered new stock injectors. Installed them. Plugs are still dry... does not appear that the injectors are opening. Poured gas into the intake. It ran for 2 seconds and then shut off. I don't have any idea what I am missing here. I have power at the injectors, fuel, and spark....

DG

Something I noticed. Tach is connected however the needle moves down on turn of key, and does not indicate RPM.

Since it is a miniram, pull the injector rail off and put cups under the injectors and then crank to see if you get fuel.

Otherwise I wonder if you have a wiring issue based on the tach not showing cranking rpm.

Its definitely getting fuel to the fuel rail now. I don't have a fuel pressure tester, but will buy one this week. My question is at this point, would low fuel pressure lead to a complete no start situation or just cause the car to run like crap?

DG

I can't say for certain, it would probably depend on how much fuel pressure. How do you know how much pressure there is? Is it shooting out when you depress the schrader valve or just bubbling out?

I recommended pulling the injector rail off to see if there is spray from the injectors themselves, not pressure.

A decent quantity of fuel comes out however it doesn't spray out.

It should spray out. Get a fuel pressure gauge on it and get some real numbers.

Great News!!! She runs. Not very well but I managed to get it to idle tonight. Purchased a fuel pressure gauge and put it on the engine. It produced 1 psi of fuel pressure. Pump was running so I checked all the lines and they seemed OK. figured it might be a weak pump so I ran over to advance auto and picked up a new stock one, installed it, and had 46 psi of fuel pressure instantly. Turned the key and it sounded like it wanted to kick over. It did take a few minutes but I finally got it to start. Had to keep playing with the distributor to get it to start and the gas pedal to get it to finally run. When everything is all said and done I manged to get enough advance to keep it running. It ran really rough but its not tuned and I don't think my distributor is advanced enough because it is contacting the TPIS intake and has very limited movement. So my plan is to replace the distributor with a smaller one that is more manageable, drain the fuel and replace with fresh fuel because I have a feeling the gas is bad as well, and have the car tuned.

One thing I noticed that is interesting. I am getting oil pressure, however it seems very high. I am running Joe Gibbs BR30, and I have 80lbs of oil pressure cold. This seems kind of high. Any concerns with this?

Dan

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I don't know that specific pump. Is it high pressure/high volume?

I know it's not uncommon to see 80 psi with a cold motor that's new, but you should put a mechanical gauge on it to be sure.