HELP PLEASE!!!

F

fstfoon

New member
I have a 91 ty that will not start! I checked fuel pressure and it was low and bleeding off so I just did a fuel pump. Pressure is rock solid at 58psi now. Cap and rotor are new and I have spark at the plugs. But...It wont start! Any suggestions or advice is greatly appreciated!
Thanks
 
J_SULLIVAN

J_SULLIVAN

A&P slave monkey
Starter okay? All your electrical in the right places? And if you have a "91" Ty, I have to meet you!
 
F

fstfoon

New member
ECM?

ECM?

Fuel pump is running. I can hear it and see it pressure up the fuel guage I have connected. The B fuse is OK. I just checked injector pulse and it has none! Has power to injector but no pulse. I was going to check and make sure comp was getting power, do you know what pin on the comp is the power in?
Thank you so much for you help guys
 
F

fstfoon

New member
ECM

ECM

I haved messed with the ecm in the past but I have it hangin down right now and all connections seem to be tight. No one knows what pin is power in?
 
F

fstfoon

New member
Well bad news, I tested the power ins and both are good, so is ground and fuel pump relay control. Still no injector pulse though. I figured I would see if the tps had 5v with the key on to see if the ecm was alive and it does have the reference voltage. So I dont know were to go now? Is it probable that the ecm is bad and only not giving injector pulse? Does anyone know what pin the injector pulse is on the ecm?
 
G

GM TURBO

Sell Out
A4 = 5V MAP
A5 = 5V TPS
A6 = 12V IGNITION
A9 = ALDL SERIAL DATA
A11 = FUEL PUMP RELAY CONTROL
A12 = GROUND

B1 = 12V
B5 = MAT AND TPS GROUND
B6 = COOLANT TEMP SENSOR AND MAP GROUND

That's all I've got. On the chart I have the ones that aren't listed and unused.

Is the truck turning over and just not firing?

Ignition control module maybe? Are you getting spark?
 
F

fstfoon

New member
Thanks again for all your help and info!

I do have spark, then engine cranks but doesnt start. Never even tries to start. I figure there is only two things that can cause the injectors to not fire and that would be the ECM or the Trigger <--which I think is in the distributor :-? . So Really I guess I have to try and find if the ECM is getting that "cam signal" and if it is buy a new ECM. One more thing, what should I set my fp at?
Thank you for you help/advise!
 
G

GM TURBO

Sell Out
Well, there are a few ways to set fuel pressure. The way I do it which has proven useful.

There is a power dist. block on the firewall right above the FPR. There should be a white wire with a female connector that goes into a wire loom. Jumper those together with the truck off - no need to pull the vac line if the truck isn't running. If you have an Ultimate chip - the base FPR is 50#. If you are running a stock chip - maybe 43-45#. I've heard both numbers - either one will get you in the ball park.

Have you checked to see if the chip is properly seated in the ECM?

Anyone local to try swapping ECMs with?
 
F

fstfoon

New member
I dont know if there is anyone local, kinda new in the syty community.

I had a "street strip" chip in the ECM but I replace it with the stock chip to see if it was causing my problems. The chip is seated correctly, I have made sure of that many times.

My check engine light though just blinks once very briefly when I turn the key on and doesnt stay illuminated. Aren't they suppose to stay on with key on engine off? This might be an indicator of a bad ECM.

I checked all the pins you gave me and they seem to be working fine. Just gotta find out which one sends out injector pulse signal.

Thanks
 
G

GM TURBO

Sell Out
Yeah - it should stay on for sometime - I think it will stay on for fuel pump prime and then it'll blink. I think.
 
A

AZTY

New member
Still need some help? If you do there is a couple of guys locally... Brandon, Nick, Ryan, and myself that could probably take a look and see what we could do to help. I am PMing you right now with my phone number.

Robbie
 
F

fstfoon

New member
Thanks for all of your help/info on this subject. I figured it out this morning. I got a little :evil: and hit my ECM and then my check engine light illuminated...and the truck started and ran good. Then I hit it again and the light went off and the truck wouldn't start! So my brilliant diagnostic technics have led me to the conclusion that I need a new ECM.

Thanks for all the help everyone! Hopefully she will be back on the road soon!
 
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