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88 spfi trouble


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199 replies to this topic

#101 eulogious

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Posted 18 October 2011 - 07:20 AM

Wow. Did that happen with the first one?

If you are smoking it, then there is something wrong most likely with the power to the ecu. I don't think that there is enough voltage else where to make it "smoke". I would check all your grounds, and then start my checking the main power wires and ground wires going to the ecu. You got something bad going on.

Or you could just remove the computer and carb it like McBrat said :)

#102 bheinen74

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Posted 18 October 2011 - 10:35 AM

Iv'e got harness for spfi he can pull for 15 bucks. Will onnly have the car for 2 more weeks then its off my yard due to city violation of junk cars.

#103 GeneralDisorder

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Posted 19 October 2011 - 01:09 AM

Check for power where it ought not to be. That's what will smoke the ECU. Power where it should be wouldn't be a problem. Power to a ground wire would blow a fuse or burn wireing. What you have is a short from a power lead to a sensor lead, etc. Thus you have 12v on a signal line, etc from a sensor. Pull the ECU connectors and start figuring out which one's should have power, and which one's should have ground, and which one's shouldn't - check all the wires that shouldn't have power with whatever they go to - when you find something disconnect the sensor, etc and see if the problem goes aways - could be a short in a device rather than in the wireing itself.

Too bad you aren't closer - this is the kind of problem I live for :-p. I solve stuff like this when no one else can. It's just a matter of patience, consistency, and deductive reasoning. I also have the benefit of having stripped and rewired a dozen or more SPFI harnesses. I know their weaknesses and how they are built. Again I wish I were closer to help you hands-on.

GD

Edited by GeneralDisorder, 19 October 2011 - 01:11 AM.


#104 The Dude Abides

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Posted 20 October 2011 - 11:42 AM

GD is there any type of write up on how to pull the harness. Ive seen some people take off the fender, i dont know what all is involved. I dont know how much of the harness needs taken out.

#105 GeneralDisorder

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Posted 20 October 2011 - 12:17 PM

GD is there any type of write up on how to pull the harness. Ive seen some people take off the fender, i dont know what all is involved. I dont know how much of the harness needs taken out.


Sounds like your trouble started after messing with something in the engine bay - I would pull the drivers side fender and you will see where the harness goes into the engine bay and into the firewall to meet the dash harness. The ECU connectors are on the engine bay side of the harness so I would just replace that. It disconnects from the dash harness near the driver's left foot area.

GD

#106 The Dude Abides

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Posted 20 October 2011 - 12:21 PM

Do i need to pull the dash.

#107 GeneralDisorder

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Posted 20 October 2011 - 01:10 PM

Do i need to pull the dash.


Nope. Definitely not.

GD

#108 The Dude Abides

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Posted 21 October 2011 - 05:43 AM

Will any harness do or is i tlike the ECU i need to find something specific. I need to replace the ECU as well as the harness.

#109 Petersubaru

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Posted 21 October 2011 - 07:45 AM

Will any harness do or is i tlike the ECU i need to find something specific. I need to replace the ECU as well as the harness.

..I "think" all ECU's are interchangeable, but the wires leading out of the ecu end up in different locations within the connectors..for example I have a '90 spfi conversion I did, but my spare harness (1992)from the intake will not fit the connectors '90 at the harness leading from the ecu..then again when looking at the spfi conversion pin-out info , it is altogether different from the '90 and '92..maybe it is a little more streamlined in the US...

#110 The Dude Abides

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Posted 02 November 2011 - 04:45 AM

GD are all harness interchangeable. Do i need to change out the wires in the engine as well . I thought all wires in the wireharness needed changed.

Ben

#111 uss_essess

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Posted 10 November 2011 - 10:18 PM

GD are all harness interchangeable. Do i need to change out the wires in the engine as well . I thought all wires in the wireharness needed changed.

Ben

Did you ever get an answer for this? Looking into swapping mine out.

#112 The Dude Abides

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Posted 11 November 2011 - 03:59 AM

Nope, not yet.

#113 subynut

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Posted 16 November 2011 - 03:02 PM

There are differences in both wiring and ECU:
AT or MT?
get the harness from as close to your year as possible.
87 and older are different from 88
I think they changed it again sometime after 90, but I am not completely sure. If there is a difference, GD would know.

#114 VaporTrail

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Posted 18 December 2011 - 12:28 AM

my wife saw Guido in the garage today for the first time... she said it looks like it's been shot... :)

#115 bheinen74

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Posted 18 December 2011 - 12:39 AM

Better Milk that cow is what i would be saying.

#116 The Dude Abides

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Posted 18 December 2011 - 01:39 AM

Work that McBrat magic man.

#117 GeneralDisorder

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Posted 18 December 2011 - 12:26 PM

SPFI harnesses come in about 4 flavors over the years. Suffice to say you want an 88 or 89 harness and you shouldn't have much problem swapping it over. A 90 to 94 harness would probably work as well but might have a few more differences.

All the SPFI ECU's are interchangeable. But the 86 and 87 ECU's have two wires swapped for the distributor signals. You have to swap the wires at the distributor plug - but they will work. Also 90 and newer ECU's are looking for an additional switch on the clutch pedal assembly. But other than the distributor wiring - I don't know of any differences between ECU's that will result in a no-start condition. They will all start the engine and run it - sometimes spewing codes as they look for sensors or switches that aren't present.

Sounds like Mick is on the job now. I'm sure he'll come up with something.

If a harness is needed - I could most likely source the exact year and match it up from my yards around here. EA82's are still fairly plentiful around here.

GD

Edited by GeneralDisorder, 18 December 2011 - 12:33 PM.


#118 VaporTrail

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Posted 25 January 2012 - 02:16 AM

ok. after taking the ECU board out of the case, I can trace the circuit from the resistor that was cooked (R1) to pins B11 and B23. I've got Ben's '87 FSM, and not sure if it translates the same for the '88, but those pins correlate to the 2 white wires that feed the Ignition Relay.

there's also roundish blue/white diodes that are fried on both bad ECUs. They are fed of of A16 and A18. A18 goes back to the fuse panel, and A16 goes to the check connector.

#119 bheinen74

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Posted 25 January 2012 - 02:21 AM

well check for what isnt supposed to be hooked up under hood.


I still have a few of these under my watch at junkyards, although one has a dual range spd and it has a tach :)


I am tired of nothing.

infact, I am getting 2 D/R this week to replace my one GT wagon

the Ben car was fine until what. he had
- a bad alternator
-he changed the valve covers and

-then the problem


GET A GOOD ALTERNATOR ON IT, the one he has IS JUNK. then replace the ECU omg I am pissed, we know he has a bad alternator, it fried stuff so relplace the ecu it fried, and get aknow good alt on it.

I can drive the 60 miles one way, throw in a ecu,AND "good "Alternator, and, likely, drive it home. YES PISSED OFF AT THOSE WHO DONT CHANGE THE ALTERNATOR FIrst to known good. go ahead fry some mre ecu and not check the connectors under hood too

Edited by bheinen74, 25 January 2012 - 02:29 AM.


#120 VaporTrail

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Posted 25 January 2012 - 07:06 AM

well check for what isnt supposed to be hooked up under hood.


I still have a few of these under my watch at junkyards, although one has a dual range spd and it has a tach :)


I am tired of nothing.

infact, I am getting 2 D/R this week to replace my one GT wagon

the Ben car was fine until what. he had
- a bad alternator
-he changed the valve covers and

-then the problem


GET A GOOD ALTERNATOR ON IT, the one he has IS JUNK. then replace the ECU omg I am pissed, we know he has a bad alternator, it fried stuff so relplace the ecu it fried, and get aknow good alt on it.

I can drive the 60 miles one way, throw in a ecu,AND "good "Alternator, and, likely, drive it home. YES PISSED OFF AT THOSE WHO DONT CHANGE THE ALTERNATOR FIrst to known good. go ahead fry some mre ecu and not check the connectors under hood too


Denis put on a good alt when he had it... I'll most likely replace it with one of mine after I go thru the wiring. this was just my first 5 minute look into the toasty ECU...

#121 The Dude Abides

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Posted 25 January 2012 - 07:31 AM

well check for what isnt supposed to be hooked up under hood.


I still have a few of these under my watch at junkyards, although one has a dual range spd and it has a tach :)


I am tired of nothing.

infact, I am getting 2 D/R this week to replace my one GT wagon

the Ben car was fine until what. he had
- a bad alternator
-he changed the valve covers and

-then the problem


GET A GOOD ALTERNATOR ON IT, the one he has IS JUNK. then replace the ECU omg I am pissed, we know he has a bad alternator, it fried stuff so relplace the ecu it fried, and get aknow good alt on it.

I can drive the 60 miles one way, throw in a ecu,AND "good "Alternator, and, likely, drive it home. YES PISSED OFF AT THOSE WHO DONT CHANGE THE ALTERNATOR FIrst to known good. go ahead fry some mre ecu and not check the connectors under hood too


Oh brent. After dennis put on a known good alternator on and fixed the bad relay on the computer it still refried. It had the known good alternator on it when i got a brand new ecu from someone on here and it promptly refried when i tried to start it after i got it back from dennis. The alternator problem is fixed it is beyond that.
I will admit that some of my mechanical skills are limited which is why i ask for help. But i have had the upper PVC system and snorkle off many times cleaning things and rehooking things up. I know how to put that back together. I combed over that car 6 times atleast when the weather was warm. 5 more when it was cold. Ive had 3 independent mechanics come look at it as well as Dennis and now Mick.

I will admit, i messed up not replacing the alternator. I never had the money, i tried to milk it. I didnt really have much of a choice in the matter and now were here. If i would of replaced the alternator when the regulator failed none of this would of happened but i cant go back and change anything now. It is what it is and this is the last stand for guido. Believe me brent, i have combed over that car many many times. Unless the alternator is bad that Dennis gave me i cant possibly think of anything else other then electrical it could be.

On a side note mick, i have been told that the same electrical system they started useing in 87 is in the 88 as well so it should translate over.

Not busting your balls on here for calling me out brent but believe me, if anyone was proactive in trying to figure out what happened and who screwed up its this guy right here.

Good Luck Mick.

#122 bheinen74

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Posted 25 January 2012 - 11:37 AM

Me Yelling at GUIDO again.

#123 bheinen74

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Posted 25 January 2012 - 02:23 PM

Me, thinking alternator Dennis put on is bad.

#124 The Dude Abides

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Posted 11 March 2012 - 10:43 PM

Will Guido ever run again. Tune in

#125 AKghandi

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Posted 12 March 2012 - 01:55 AM

Well ive been reading over this and I have an idea, the Maf could be shorting out the ecu the Maf has a system that heats the wires up to clean them it could be stuck on causing the computer to fry.(I don't remember exactly what it's called it's in my chiltons book tho) and there is a relay for it iirc

My 87 turbo had all kinds of problems like yours mine never got that bad but it still made my head hurt for a few weeks, it was the Maf ...and this all started after I sprayed the Maf out... And I bet the over charging doesn't help..

Just out of curiosity have you tried it with the alt unhooked? It should run without the Main wire hooked up

Just a few ideas, it pains me to see a Subaru in a coma like that.




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