is my ecm dead?

[novaderrik]

a couple of months back, my fuel pump died. since i was low on cash, it had to sit and wait.
well, i just got done putting a new pump in it- got Rockauto.com's last stock replacement Carter pump for $40- i want to get a Walbro 340, but $$$ and their recent problems made me decide to just get the cheap pump for now. i also put in a Racetronix hotwire kit (very nice stuff).
now it won't prime the pump by just turning on the key- but if i pull the stock relay out and jump the wires, the pressure goes straight up to 45. try to start it like that, and nothing- all it does is crank with no fire at all. all my fuses are good, and there is power at least to the little weatherpack connector by the battery. there is no CEL at all with the key on/engine off, but my other idiot lights do come on. it got dark out and i'm working without a garage and those pesky MN mosquitos started coming out, so it was time to quit.
if the ecm is bad, i know of a brand new in the box ecm for an 87 GN that i can get for $40, and then all i'd need is a different chip and the IAT sensor to add in.

 

[Jerryl]

Are you getting spark and injector pulse?
Did this start suddenly?
Check the sticky on top. There is a link to a "Crank but no start" flowchart.

FWIW;
If the relay is bad, AND, the oil pressure sender is installed, it should run after it starts. The oil pressure sender is connected in parallel with the FP relay and will pwer the pump if oil pressure is above 5 psi.
Could very well be the ECM as well if you get power to the ECM pin and still no prime/start.

 

[novaderrik]

there is no oil pressure sender- it was long ago ditched for a pressure gauge.
and, yes, it started suddenly- yesterday, just for kicks, i tried to start it even tho i knew the fuel pump was dead- it would fire a few times but not run. and the check engine light was working yesterday, too.
now there is no check engine light- but just now i unplugged the ecm and the connections were all corroded up. i cleaned the connections as well as i could using the tip cleaner for my cutting torch- need to get some contact cleaner tomorrow. plugged the ecm back in, and it started- but i forgot that i had taken the fuel pump relay out, so it died in about 5 seconds. still no check engine light, tho.
plugged the relay in and did nothing else, and it's back to no fire or gas again.

 

[Jerryl]

there is no oil pressure sender- it was long ago ditched for a pressure gauge.
and, yes, it started suddenly- yesterday, just for kicks, i tried to start it even tho i knew the fuel pump was dead- it would fire a few times but not run. and the check engine light was working yesterday, too.
now there is no check engine light- but just now i unplugged the ecm and the connections were all corroded up. i cleaned the connections as well as i could using the tip cleaner for my cutting torch- need to get some contact cleaner tomorrow. plugged the ecm back in, and it started- but i forgot that i had taken the fuel pump relay out, so it died in about 5 seconds. still no check engine light, tho.
plugged the relay in and did nothing else, and it's back to no fire or gas again.

Sounds like (at a minimum), you need a new set of ECM connectors. (see link)
Corroded connectors will cause all kinds of problems with the car.
Casper's Electronics, Inc.: ECM Splice Harness Side 1984 / 1989

 

[novaderrik]

figured it out- the pin in the ecm on the wire that goes directly to the battery broke off. might be corrosion related, might just be one of those random things that happens- but either way, it's a good time to upgrade to an 87 ecm and a turbo tweak chip..

 

[novaderrik]

i kinda sort of halfway fixed my problem.. i went and got an ecm from a junkyard thatwas pulled from an 86 Electra for $40. i plugged it in and it started right up- it started faster and idles smoother than it ever has. the CEL was on, so i grabbed the wire and IAT sensor from a harness i have laying around from a 92 Caprice, and now the CEL is off, but the idle is now up at 1200 in park, 800 in gear.
i still plan on getting a different chip- and maybe a MAF translater so i can use that LT1 Caprice MAF that is just sitting there. i'm not going to go out and do any 15psi WOT blasts, but at least the car is movable now so i don't have to mow around it any more..