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Forum namePerformance/Engine
Topic subjecthigh rev killed my ecu?
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=108947
108947, high rev killed my ecu?
Posted by Kmonster, Jun-11-08 04:45 PM
95 eclipse RS stock except cold air intake.

may have been a coincidence, but my engine died one night right as maxed the rev limiter. trying to go fast and not paying attention to the rpms it went all the way up and then the engine just stopped and wouldnt start back up. well, 2 times out of 50 tries it will start but you get the idea.

well here's the thing this should be so simple because the fuel pump just isnt getting power. i tested it with direct power, starts and runs just fine. tested the power at the connecter and no power. traced the wire back to the fuel pump relay and mfi relay. the mfi relay wasnt sending the power. replaced both relays for the hell of it since i learned the relays could be got at autozone for under 10 bucks each (thank you search function)assuming that both relays are good, the fuel pump is good, and there is no short in the wiring(/me says prayer)what would cause the fuel pump to still not turn on or even prime when i turn the key? thanks guys.

p.s. never had too much trouble before this... the idle was a bit odd sometimes jumping and falling at its own will, but i wrote it off as maybe a fuel filter issue.

p.s.s. check engine light wont stop flashing now even after finding no codes on the odb2 reader.
108952, RE: high rev killed my ecu?
Posted by DarkOne, Jun-12-08 03:08 AM
95 ECUs tend to die from age causing the ground traces on the board to lift.
108953, RE: high rev killed my ecu?
Posted by DR1665, Jun-12-08 07:03 AM
Originally posted by DarkOne
95 ECUs tend to die from age causing the ground traces on the board to lift.


How random is that? (I knew they had the reputation for failure, but damn.)

I'd say you've done some good trouble shooting. Looks like it's time to hit up the j-yards and find yourself a new ECU (or Ebay). Good luck!
108958, RE: high rev killed my ecu?
Posted by RoninEclipse2G, Jun-12-08 07:43 AM
Originally posted by Kmonster
replaced both relays for the hell of it since i learned the relays could be got at autozone for under 10 bucks each (thank you search function)


A smart new guy that can use the search function! Sweet! perhaps the world isn't coming to an end!

rebuilt ECU's here for not too expensive https://www.mitsubishiparts.com/oe_parts_catalog.html
109004, RE: high rev killed my ecu?
Posted by Kmonster, Jun-16-08 03:07 PM
Thank you for the replies. DarkOne pretty much nailed it I think. While I haven’t gotten my ECU yet due to low funds, I have learned a few things.

The fuel pump relay is not sending power to the pump only because of a lack of ground at the relay. The wire seems to trace back directly to the ECU suggesting DarkOne is right. I notice though that by supplying the fuel pump relay with a proper ground the car will start consistently where before it would only crank. It leads me to believe with one or two more redundant ground wires installed I might be able to drive it at least until payday. In the meantime it continues to die under load.

Now bare with me here for a minute. When the engine is in gear I have to keep the rpm under 3k or it dies. When not in gear I can mash the throttle and it climbs rpm all the way to redline with no problem. My thinking was the injectors would output the same amount of fuel flow in and out of gear when full throttle. The voltage and ground required to the injectors being the same in both cases too right?

If my thinking there was correct then there must be sensors to indicate gearing and such and this is all way more complicated then I could imagine, and I’m doomed to immobility and weeks more of dependency. In any case i appreciate any helpful information.
109008, RE: high rev killed my ecu?
Posted by justins71, Jun-17-08 10:40 AM
Originally posted by Kmonster
My thinking was the injectors would output the same amount of fuel flow in and out of gear when full throttle.


Yes, but no. For the brief second your MAP is at 0"Hg until you hit redline they're similar (load to no-load), but for sustained load (in gear) it requires MUCH more fueling. Usually a good test for clogged fuel systems, it'll rev great in neutral, but under load it'll rev up for a short while, then power will taper pretty quickly until it starves the system.
109122, RE: high rev killed my ecu?
Posted by Kmonster, Jun-24-08 04:27 PM


ARRRGHH!

Well i got the replacement ECU today and it didnt help one bit. The one and only perceivable difference is the ocassional check engine light. (code p1390)

I did some more reading though seems the crank position sensor cured a very similar sounding problem that a member here had

http://forums.2gnt.com/dcboard.php?az=show_topic&forum=4&topic_id=89340&mesg_id=89340&page=&topic_page=2

so thats next i guess.
109006, RE: high rev killed my ecu?
Posted by spooled420, Jun-16-08 06:48 PM
i have a jet performance ecu for a 95 if your interested.jet claims 8-10 hp gain but I had to take it out when I turboed because the ecu adds advanced timing,so for non turbo application only.
109139, RE: high rev killed my ecu?
Posted by DarkOne, Jun-25-08 06:08 PM
Originally posted by spooled420
i have a jet performance ecu for a 95 if your interested.jet claims 8-10 hp gain but I had to take it out when I turboed because the ecu adds advanced timing,so for non turbo application only.


...and jet's claims are flat out lies anyway.
109697, RE: high rev killed my ecu?
Posted by Kmonster, Aug-13-08 03:26 PM
i hate finding threads that are left unresolved so let me bring this one home... the problem was nothing more then overheated wiring creating a short. wish i had a shortcut for finding it but it was pure luck. thanks for the input everyone i love this forum already.
109725, RE: high rev killed my ecu?
Posted by bullettdsm, Aug-14-08 03:05 PM
Points to you sir for doing the right thing for future searchers.

Gracias,

MB