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Mechanics...help figure out whats holding back the RX wagon from running!


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Symtoms:

 

car will only start when it's cold...it will idle fine(sometimes), you can "move" it but you have to keep the revs high and it feels like it has 30hp, real boggy.. other times the idle will fluxuate between 2k and like 400! up and down almost ready to die(which it usually does)...once you turn it off it will not start back up unless you wait like 6 hours..the computer is throwing codes for nearly everything..

 

Motor:

 

EA82 turbo, spider intake, new HG, and the heads are in awesome shape. new timming belts and timming set correctly, all new seals. RX wirring harness and ECU

 

Actions taken:

 

replaced hot cams with stock cams the fix the variable compression issue.

replaced thermo unit

tried a stock intake manifold, so rule out bad sensors on the top end

 

 

Whats left to try:

 

try a different ECU

 

 

 

so please throw out some suggestions as this car has made quite a few people pull their hair out...

 

 

and yes i have lubed the muffler bearings!

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Hey Styles

 

First suggestion, start at the beginning, assume nothing, check everything… compression, valve timing, ignition timing, fuel pressure, spark…

 

Second idea, follow the lead you have… it will start cold. Cold engines require a richer mixture, maybe you’re running VERY rich and the cold engine can take it, but once warmed a bit it just floods out? Pull a spark plug and look for lots of raw fuel.

 

OR, what’s different about the control system on cold start? You said you replaced the “thermo unit”, is that the auxiliary air valve (AAV) for cold start? Coolant temp sensor?

 

I’ve seen ignition coils that fail after they warm up a bit…

 

Just some thoughts

Gary

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Check all wiring.

 

Also, did you swap the RX intake manifold wiring harness over onto the Spyder? If not...that could be the issue.

 

When i did the spyder swap, I took the 86 intake wiring harness and swapped it right over onto the spyder. I also redid the fuel rail, moved the FPR, and did away with the stock and the spyder's idle control.

 

That could be the issue on idle, is the RX ECU does not know how to control the Spyder's idle vavle. Try swapping that.

 

Oh and answer my Q's.

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If you didn`t have "codes for nearly everything", I would suspect low fuel pressure.

Recently worked on one w/identical symptoms except codes.

When cold there was just enough extra fuel to make it run (poorly).

 

Mega codes suggest a bad ground to the ECU.

Perhaps this is related to an incompatible idle control as suggested.I would try it w/the idle control disconnected.

 

A more far out possibility would be AC voltage from bad alternator diodes blowing the ECUs mind.Try it w/the belt off.

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also, flapper or hotwire? i can drive down the road without my maf hooked up on my flapper system.

 

try this. with it running, kink the return line. if it starts runing good, then its super duper lean, and its most likely a sensor telling the computer someting it shouldnt.

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Every single time I run into this problem on putting in an ea82 or ea81 motor its because I am playing stupid and thought the distributor was rotating the other direction.. so only 2 cylinders were doing anything. Try switching cylinders 3 & 4 on the cap (opposite of eachother) and see if your motor suddenly comes to life.-Mike

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the disrtubuter and timing are all normal(it is not 180* off)

 

oddcomp...if you ever in the area i was thinking about trying the MS

 

alltalk- alltiming s are fine...compresssion has been checked, as far as the cold start thing..last month we driving my car all around...turned it off, then it would fire back up no problem..then it went ghey again...

 

WJM-i used a turbo spider manifld and its harnress...it's intake harness has been pined out to prove it's the same as the stock unit.we have also tried the tps from a stock turbo manifold

 

naru- we have tryed unpluggng the maf or tps while it's running. fuel pressure is great..it does run rich. alternator has been replaced with a good unit...

 

i will check the ground on the computer

 

 

archemitis-allready tried unplugging the O2, not the water temp though...no flapper..i have hot wire maf

 

RenaissanceMan - nope plug wires are fine

 

 

 

 

i hope i got everyhting...that was alot of replies to do!

:lol:

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have you tried taking sweet to it and giving it a hug?

subarus are strange cars..

 

but really, im thinking you have a bad ground somewhere, which is preventing the car from running right.. check that ground straps on the motor AND the one that goes from the battery to the body.. hell, even the one on the tranny.. theese cars are strange like that

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