98 gst wont start, no fuel, fuel pump is good.

[kidwiththelaser]

So my car isnt starting after a rebuild. Its sparking just fine. But not getting fuel into the cylinders.

I got it to run on carb cleaner.

I checked that everything was wired up, and its all good. Fuel is getting to the rail for sure. The injectors are getting 14v with the key on but not cranking.

I suspect either bad cam angles sensor, or maybe bad injector resistor pack?? I dont know how to test either one though...I know I should get a service manual but I just havent yet.

Can anyone help me real quick?

 

[kidwiththelaser]

injector resistances are around 2.5 ohms for each one. Also there are no CELS.

 

[cavillac]

If you have a 7 bolt it could be a faulty cam or crank sensor, I believe it has to have a crank ref. in order to enable the FP on.

 

[kidwiththelaser]

If you have a 7 bolt it could be a faulty cam or crank sensor, I believe it has to have a crank ref. in order to enable the FP on.

Fuel is being pumped to the rail.

Anyone know what exactly is needed to fire the injectors?

The injectors are getting 14v with the key on and engine not running, but they just arent firing for whatever reason.

 

[kidwiththelaser]

anyone at all?

 

[cavillac]

Ohh, you said you had no fuel. What you should've said is that you have no injector pulse.

Anyway there is constant power to the injectors and the ECU grounds them out to fire them, it is told when to do it by the cam/crank/cas, whichever you may have.

 

[kidwiththelaser]

Ohh, you said you had no fuel. What you should've said is that you have no injector pulse.

Anyway there is constant power to the injectors and the ECU grounds them out to fire them, it is told when to do it by the cam/crank/cas, whichever you may have.

yeah, thats kinda what I was thinking too, but I just dont know how to test the Cam position sensor. Or Crank angle sensor for that matter.

 

[kidwiththelaser]

But its getting spark and doesnt the ecu get the signal for the spark from the cps and cas too?

Couldnt it be a bad ect too? Anyone know how to test an ect?

 

[delta448]

It is somewhat likey that your ECU's injector driver circuits have been shorted somewhere. First, check the injectors to verify that the resistance is roughly 2-2.5 Ohms, if you find one that isn't -that's your problem.

After (if) the injectors all check out fine, check the driver circuit while cranking the engine over. To do this, use a test light to confirm that there is a pulsed continuity between the negative battery post and the ground lead for the injector. If the light either stays on constant or will not light, you will need to first check the injector wiring for shorts/wear and then (if none) replace the ECU.

 

[kidwiththelaser]

It is somewhat likey that your ECU's injector driver circuits have been shorted somewhere. First, check the injectors to verify that the resistance is roughly 2-2.5 Ohms, if you find one that isn't -that's your problem.

After (if) the injectors all check out fine, check the driver circuit while cranking the engine over. To do this, use a test light to confirm that there is a pulsed continuity between the negative battery post and the ground lead for the injector. If the light either stays on constant or will not light, you will need to first check the injector wiring for shorts/wear and then (if none) replace the ECU.

You are like my idol right now. I already tested the injector resistances and they all checked out, so ill check for continuity like you said.

 

[kidwiththelaser]

I just tested the injector wires for continuity, and there is definitely none when cranking.

A quick visual inspection of the wires leads me to believe that I probably need a new ecu......

thanks for all your help everybody!

Illl go throw in my eprom ecu probably a bit later and hope that it works! I will update this thread and see if that does it.

 

[kidwiththelaser]

Well I put my eprom ecu in and swapped the spark plug wires like this:

swapplugwires [ECMTuning - wiki]

BUT THE INJECTORS STILL ARENT FIRING!!

The eprom came out of a good running car, so thats for sure not the problem. I just cant think of what else it could be.

 

[kidwiththelaser]

im beginning to suspect its a bad resistor pack...I am not 100% sure because I dont know how to properly test it. But I tested the resistance between various pins on the resistor pack connector and all I ever got was either 0 or no continuity.

 

[kidwiththelaser]

ok, so I replaced the resistor pack with a good one. AND SHE RUNS!!!

But leaks a bunch of coolant, so time to continue the diagnosing!