86 GL10 Turbo Modded, cold ECU issues, wont start COLD.

[AnotherGL10guy]

Hello, thanks in advance for any input. I tried searching relentlessly and found NOTHING.

sorry in advance for the long rump roast story. I NEED HELP!!!

 

 

I have an 86 turbo wagon, MPFI turbo with intercooler, boost control, lift and lotsa small mods. That said the fuel system and ECU are stock...

 

first off, the car has been rebuilt almost COMPLETEly, and for the last year has driven and run VERY nice for the ol EA82Turbo!

runs stock boost, and has been gently driven, not abused. car is super clean and has under 120k miles.

 

STORY,  PROBLEM and QUESTIONS........

Its has been very cold lately and I have found my car does not like to wake up early on cold mornings. Ill go to start it and.... nothing (crank no start issue). no fuel pump... I plug in the ECS green plug to trigger Ignition Switch and fuel pump relay while key is ON, and the ECS light starts to flutter/blink after about 5 minutes of warming up the ECS (under dash). I use a 12v heater thing bought from Harbor Freight to blow warm air on the ECS then it will start to blink the ECS light faster, then all the sudden it will start working and the fuel pump relay will start clicking and pump will work and car starts and runs fine all day, till the next morning that is!!

 

I have been having this issue for 2-3 weeks now and figured out the ECS wants to be warm my mistake one day. Without warming it up the car will NOT start. I can drain the battery trying (good strong charging system and Batt) to crank it and, NOTHING. I turn key on and off, hit fuel pump with screw driver, all that stuff LOL.

 

as soon as I start to warm up that ECS I see the ECS trouble light start to blink on. Mind you, its OFF before this and should come ON with ignition key in the ON position and does not untill warmed up.. This problem happen with the green plug connected or not, either way. Its just that plugged in I can sit there with the key on and listen for things to start working. The ECS light flickers the same as I warm it up either way.

 

Is this a Common ECS problem for these cars? I really dont think its the relay, seems to be the ECS. or maybe it is the relay? I buggered with the relay and found it seems to be fine. REALLY seems to be the ECS brain.

 

I tested the leads to the pump while it was having the issue and it gets no power to pump even while cranking. I also tested the pump on a cold morning and it fires fine.

 

I hope I was clear enough for some answers and help.

 

Possible Solutions..... Bypass ECS and run a toggle to fuel relay and pump? fix Computer? if any other please help. How? where? why?

 

thanks again to the awesome Subaru community!!

 

[l75eya]

Wow, that's an odd one. Maybe there is a cracked solder on the board in there and when it's cold it doesnt make contact but as it warms and the metal expands it does? Or a wire in the harness doing that?

[Gloyale]

I would remove the ECU......Check the condition of all the connectors.

 

Sounds like either the power or the ground to the ECU is not connected when cold.

 

I would inspect the grounding bolt on the intake....that's where the ECU gets all it's grounds.

 

Also....make sure that condesation isn't forming in the trunk and dripping down into the ECU.....I had that issue with an XT that sat outside for many winters and had the cloth on the rear shelf removed so it would condense water then drip through little holes down into the ECU.

[AnotherGL10guy]

you guys are great for replying thanks so much!!

 

175ya, I would think that could be, and I did take out the ECS (ECU) and un-screwed the cover from it to look inside, it looks very clean and I did not see any bad connections. Although this does not mean the plugs make good connection. I have tried wiggling all the plugs, wires and connections i can find related while having the KEY ON waiting for this ECS lite to pop on, NOTHING... only thing that seems to make any difference it warming it up a tiny bit.

 

Gloyale, (its a 86 GL10 turbo wagon, ECU is under the steering column and relays are mounted above the ECU)..... I have had the motor and trans out 3 times in the short time i have had the car, I have also re-arranged all said Grounds. Maybe this could be a problem. but because its cold? odd to me. It has run great and started fine every mornin except just recently when the temp dropped from 50 to 20 in a matter of a days time. as soon as it started being so cold in the mornin this starting happening.

 

 

on another note, I went to the parts store today and bought a so called fuel pump relay ($20.63 out the door) and put it in to see if it does the trick in the morning. with the way the ECS lite works tho i dont see how it can be this. Hope I didnt burn 20 bucks for nothing.

 

if i turn the key on after it is running during the day and all is well, the ECS lite is on (car not running just key is ON)... I then UNPLUG the relay and nothing different happens, lite stays on, car will not run without it plugged in. Same story for morning when the car will not start....Turn key ON, unplug the relay, nothing, plug it back in, nothing.

 

I would thing a connection but I have tried almost everything (except the grounds Gloyale Mentions!!!!)... I will give that a shot tomorrow in class. I am a student at BTC for the Master Auto tech Program!

 

Also, does anyone know if I can just BYPASS all this crap and run a toggle to the pump? maybe just flip it on when I start the car? or run it to an ignition Acc wire and toggle for safety?? I have done thius in the past but not with a FI turbo car, only on old 81-83 2 door Carby's..

 

I really thank you all for any further info and thoughts. ANYTHING helps at this point. Thanks!

 

Ryan

Edited November 19, 2014 by AnotherGL10guy

[AnotherGL10guy]

well it wasnt quite as cold this morning but still pretty darn bitter and it decided to start right up. Not 100% sure but it may have been just the relay not wanting to "click" on in the cold. strange but I wont know for sure for a couple days.