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symptoms of dead or dying ecu / ecm - 1984 ea81t


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88 replies to this topic

#76 lastchance

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Posted 06 November 2013 - 01:24 PM

 No,it is on the other side by the coil.Altitude connector is seperate.You are supposed to disconnect it w/setting timing so that it does not interfere.

Compression,vacuum and fuel pressure checks are all good ideas.

Miss at hot idle sounds most likely like an unmetered air or vacuum leak, though.
I would try injecting some propane into the intake.If the idle smoothes,you can eliminate mechanical problems.

Carefully inspect the large rubber intake tube and all associated plumbing for cracks or leaks.
PCV hoses too.
I had to add a few clamps.

 

good deal. i have a propane torch that'll do the job. 

 

i've actually noticed some excess oil seepage around the intake plenum and had recently replaced the PCV valve, i seem to remember the hose being really fragile and/or cracked back in that area. 

 

inside diameter on the PCV valve hose should be 3/8" or is it 3/4"? 



#77 lastchance

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Posted 06 November 2013 - 02:00 PM

and as for the miss/rough running, here's the exact sequence:

 

in park and idling while cold - fine

in park and idling while warm - okay, but will randomly idle low and die

in drive and idling while cold - fine

in drive and idling while warm - bad, will idle low and die. when on the throttle (driving) a misfire develops, car runs rough all through the power band (gas is constantly manipulated to keep car running while warm, while in park or in drive)


Edited by lastchance, 06 November 2013 - 02:01 PM.


#78 Caboobaroo

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Posted 06 November 2013 - 03:39 PM

If you need another ECU, I found one in my parts when I was moving.

#79 lastchance

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Posted 06 November 2013 - 04:03 PM

is it from an 83 or 84 ea81t? 



#80 naru

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Posted 06 November 2013 - 05:33 PM

 

good deal. i have a propane torch that'll do the job. 
 
i've actually noticed some excess oil seepage around the intake plenum and had recently replaced the PCV valve, i seem to remember the hose being really fragile and/or cracked back in that area. 
 
inside diameter on the PCV valve hose should be 3/8" or is it 3/4"?

 

15mm so 1/2 should work.
I`m tempted to try silicone hoses.

#81 lastchance

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Posted 07 November 2013 - 10:58 AM

got it.

 

i'm going to work on the vacuum hoses and such this weekend, that's an easy/cheap fix to go through and really inspect those bits and pieces. 



#82 lastchance

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Posted 09 November 2013 - 07:41 PM

naru was right... he said vacuum/unmetered leak.

 

the intake boot from the air flow meter to the turbo was not only cracked on the base but the entire middle section was COMPLETELY ripped, almost completely in half. i was worried when i noticed oil at the base of the boot, thinking that something was dying, but nope... just the boot itself completely ripped apart. haha! 

 

will the intake boot from an ea82t fit? i assume it's the same part??? 



#83 turbosubarubrat

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Posted 09 November 2013 - 08:25 PM

naru was right... he said vacuum/unmetered leak.

 

the intake boot from the air flow meter to the turbo was not only cracked on the base but the entire middle section was COMPLETELY ripped, almost completely in half. i was worried when i noticed oil at the base of the boot, thinking that something was dying, but nope... just the boot itself completely ripped apart. haha! 

 

will the intake boot from an ea82t fit? i assume it's the same part??? 

There different atleast the ones on the xt-6's are. You could try fixing the one you got with jb weld.



#84 lastchance

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Posted 09 November 2013 - 10:04 PM

yeah, i have jb weld but would rather dig around the junkyard if one from an ea82t would fit. 

 

i could also rig something up with a silicone elbow, reducer, and tubing...



#85 ivans imports

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Posted 11 November 2013 - 10:41 AM

Auto have you check the vacume modulator on trans is not ruptured the diafram any white smoke ? also have you replaced the diss cap ? have seen many rotors arc to the shaft of diss thru the center of rotor striat down the center look for burns on bottom of rotor. This whould get worse hotter it gets and longer it runs and more load its under. Just a thought



#86 lastchance

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Posted 11 November 2013 - 10:49 AM

no smoke of any kind, actually.

 

i've replaced the rotor, disty cap, plugs, wires, coil, CTS, and a few other simple/cheap things all within the last 100 miles. 



#87 84brat_turbo

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Posted 11 November 2013 - 07:01 PM

I had a similar symptom..... multiple issues...

Stall,

misfire.

wont idle

wont rev

intermittent... all of those symptoms

 

38 bucks.... New Coil from advance auto.

FIXED ALL MY ERATIC BEHAVIOR

 

I replaced...

MAF

Distributor

Computer

plugs

wires

Rotor Cap and Button

o2 sensor

 

and a ball joint while I was at it. LOL

 

 

unhooked the antiknock system

 

 

in the end the Coil fixed it.

 

 

good luck

 



#88 lastchance

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Posted 11 November 2013 - 07:55 PM

I had a similar symptom..... multiple issues...

Stall,

misfire.

wont idle

wont rev

intermittent... all of those symptoms

 

38 bucks.... New Coil from advance auto.

FIXED ALL MY ERATIC BEHAVIOR

 

I replaced...

MAF

Distributor

Computer

plugs

wires

Rotor Cap and Button

o2 sensor

 

and a ball joint while I was at it. LOL

 

 

unhooked the antiknock system

 

 

in the end the Coil fixed it.

 

 

good luck

 

yeah dude, i've DEFINITELY gone through quite a bit diagnosing this thing, but the split intake/turbo boot was definitely the issue with the running problems.

 

as for the dead ECU, i'm still stumped why the replacement won't allow the car to run. weird. 



#89 coxy

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Posted 21 November 2013 - 12:49 PM

When checking vehicle electrics look for good mechanical connections as well as good electrical connections, you can for instance pull apart both sides of a multi plug connector and it all tests perfect electrically but when connected find that for instance the female side of the connector does not contact properly with the male pin from the mating connector in a mechanical fashion so the actual electrical connection will then be very poor or worse intermittent.






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