TGP now runs like junk and the check engine and coolant lights flash rapidly

[jongrappin]

I swaped the computer out with another one with shit the same problems. The car will sometimes run but rought.

Both of the lights flash rapidly while the car is running on not?

 

Where do i start looking to find this like monster!

[digitaloutsider]

The MEMCAL has failed. If by "computer" you swapped the whole ECM, it's the chip. If by "computer" you swapped the chip, it's the whole ECM.

 

Willing to bet it being the MEMCAL.

[jongrappin]

I tried swapping the Chip at first and the car had the same issues. I then swapped out the whole ECM, this still changed nothing. Also i tried swapping the chip and ECM combinations.

 

Other thoughts. The car wont even start unless i turn it over for a while and push the gas pedal to the floor..... its not carburated but pumping the pedal seems to get her started? does this help ?

 

I think i will start by checking the coil pack and compression

The MEMCAL has failed. If by "computer" you swapped the whole ECM, it's the chip. If by "computer" you swapped the chip, it's the whole ECM.

 

Willing to bet it being the MEMCAL.

[jongrappin]

The fuel pump does not turn on when the key is turned forward. If i use the fuel pump test connector wire the pump comes right on. I looked at a wiring diagram and now i wonder if its the Fuel Pump Pressure Switch.... any help?

[Addicted To Boost]

Check your fuel pump relay.

[tornado_735]

I am shocked it will start with the pedal to the floor. If you hold the accelerator to the floor white starting, it enters 'Flood Clear Mode' and doesn't pulse the injectors. I don't know, maybe the TGPs were different.

[RobertISaar]

I am shocked it will start with the pedal to the floor. If you hold the accelerator to the floor white starting, it enters 'Flood Clear Mode' and doesn't pulse the injectors. I don't know, maybe the TGPs were different.

 

this is mostly correct. beyond a certain TPS%, there is a cranking fuel multiplier that ALMOST zeroes out the pulses. up to i think ~25% though, it increases the pulsewidth, though it's a very easy table to mess with, so you could set it up to continue increasing fuel all the way up to 100% TPS if you wanted to.

[jongrappin]

Robert I dont understand what you are taking about really.. heres an update...

 

1990 Turbo Grand Prix - Wont Start - Need Help

the car ran perfect, then ran like crap for a little while, now wont start. Definately a electrical problem.

 

More info.... after digging deeper into the fuel pump relay, wiring, oil pressure sensor, etc... I found the orange wire(480) going into the relay providing 12.2 volts thus this should mean the oil pressure sensor switch is working, The Green/white wire(D7) from the ECM called "12 Volt pump relay drive" has no volts.

After doing this i noticed that my dash lights are not turning on properly! The Service Engine Soon Light does not come on, nor does the low coolant light. These lights should turn on when the key is forward as they do in my other TGP and as they did prior in this car as well. The check gauges light is on when key forward, as it always has been..

Other thoughts... When I was swapping out the ECM one of the times I may have forgot to disconnect the battery cable!, if i did this would it fry a relay or a fusible link?? I have tested both ECMs on the other car and both run flawlessly. I have checked all fuses and tried swapping some of the relays to test them, which ones should i test? Also where should i test fusable links?

 

Where do I start to diagnose the problem with the Service engine soon light not coming on when key turn forward.

 

...This is starting to piss me off, I think I may just pull the front clip off this one and but it on the 2nd TGP as thats all it needs!

[RobertISaar]

i've connected and disconnected MANY ECM/PCMs with everything else otherwise powered up and never had an issue...

 

the only fusible links i can think of on a TGP would be the ones down near the starter...

 

but the "pump relay drive" is what the ECM uses to power up the fuel pump(via the relay). you'll only get power on that circuit when the vehicle is running, or during the first few seconds when you roll the key forward.

 

can you communicate with the ECM in that car?

[jongrappin]

After looking at every, fuse, relay and fusable link, i come to find out that the orange wire that powers the ECM was repair in a couple spots! I replaced the whole wire, car now runs and drives like a charm again...