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1995 impreza coupe ej22t 2.5dohc swap, Robtuned, brembos. Sti seats and sti go fast goodies
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Discussion Starter · #1 ·
Hi, need some help if possible. My impreza is almost finished but I have a few kinks left and it's stumping me. We did a ej22t swap into the impreza using the engine harness and jdm wrx ecu from my 94 wagon due to bad rust on it. I made sure the wagon was running great before swap (I did no upgrades or changed anything during swap) so I could rule out issues and it was running fine. It runs great but about every 5-10 min the engine will just die, doesn't matter whether I'm applying gas or at a stop. I just turn key off and it starts right back up no problem and is fine for another 5-10 min (it did not do this in the wagon). I have changed main relay, fuel pump relay, swapped maf and got a new Robtune but it's not acting like fuel issue but electrical. It's like I turned the key to the off position. Any ideas of where to start looking???
 

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1995 impreza coupe ej22t 2.5dohc swap, Robtuned, brembos. Sti seats and sti go fast goodies
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Discussion Starter · #2 ·
I tried a few times to try and narrow down results on the dying issue. It does it after 5 min of driving but no more than 7 min, it did not turn off lights or radio each time it did it. None of the dummy lights come up on dash when it dies, I can pump throttle several times and it will sometimes fire back up for a second but it's like limp mode, the rpms just bounce up and down but won't go above 2k. I have to turn key off and restart for it to be normal again. It always starts right back when I recycle the key, has never not started back. I tried a few times of just starting the car and idle and it would never do it if I just let it idle, but as soon as I went and drove it then it did it after 5 min. It does have some trouble starting on first start and will throw code 12 if I just keep cranking on it but if I cycle key and retry about 6 times it will fire up.
 

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this may be a stupid question, but is the jdm ECU meant to be paired with the ej22T? The 91-94 legacy SS had the ej22t and it was a very indigenous setup without even an intercooler.
 

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1995 impreza coupe ej22t 2.5dohc swap, Robtuned, brembos. Sti seats and sti go fast goodies
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Discussion Starter · #4 ·
this may be a stupid question, but is the jdm ECU meant to be paired with the ej22T? The 91-94 legacy SS had the ej22t and it was a very indigenous setup without even an intercooler.
I had been running that jdm wrx ecu for over a year, common swap to do, I did the 2.5na dohc swap and the ecu and wired it up for coil on plug and that was in 2019. The ecu shouldn't be the issue since it was running fine before the swap and even tried another ecu just to make sure.
 

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1995 impreza coupe ej22t 2.5dohc swap, Robtuned, brembos. Sti seats and sti go fast goodies
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Discussion Starter · #5 ·
I had been running that jdm wrx ecu for over a year, common swap to do, I did the 2.5na dohc swap and the ecu and wired it up for coil on plug and that was in 2019. The ecu shouldn't be the issue since it was running fine before the swap and even tried another ecu just to make sure.
Also my wagon was a touring wagon so it was just like the ss, factory turbo car with the ej22t. I took complete drivetrain and wiring out of it and put in the impreza coupe.
 

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1995 1.8L Impreza Coupe
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Might be worthwhile to either get your battery/alternator tested and/or check your grounds. Otherwise it could also be a fuel issue, (when you're running the car above idle that is) and might be worthwhile to check/replace your fuel filter and/or your fuel pressure regulator. What fuel pressure regulator are you running btw?
 

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What are the saved codes in that ecu
 

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1995 impreza coupe ej22t 2.5dohc swap, Robtuned, brembos. Sti seats and sti go fast goodies
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Discussion Starter · #10 ·
That's the active code. What about the stored code(s)?
No stores codes, the active code 12 only happens if I keep cranking on it all at one time, if I just let it spin over for a few trys and stop it won't throw the code. The battery and alt test fine, im running an aeromotive afpr. Robtune seemed to think it's either cam or crank sensor related so I'm going to look into that, it's not throwing any codes for those but worth a recheck.
 

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Robtune? as in your CEL flashed a code for crank or cam sensor?
 

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When I did my head gaskets I also swapped the timing belt. Get it all together, take it out for a shakedown, everything seems fine for about 5min, then starts running like absolute garbage. Limp home, check everything, happens repeatably.
Long story short, I was off a tooth on one of the pulleys and when the ECU was open-loop everything was great, but as soon as it went to closed-loop and tried to do what it does in closed-loop mode (checking crank or cam sensor to know when to squirt or spark) it ran like shit because one of the sensors was off by a fraction.
tl;dr check the timing belt.
 

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1995 impreza coupe ej22t 2.5dohc swap, Robtuned, brembos. Sti seats and sti go fast goodies
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Discussion Starter · #13 ·
When I did my head gaskets I also swapped the timing belt. Get it all together, take it out for a shakedown, everything seems fine for about 5min, then starts running like absolute garbage. Limp home, check everything, happens repeatably.
Long story short, I was off a tooth on one of the pulleys and when the ECU was open-loop everything was great, but as soon as it went to closed-loop and tried to do what it does in closed-loop mode (checking crank or cam sensor to know when to squirt or spark) it ran like shit because one of the sensors was off by a fraction.
tl;dr check the timing belt.
I would say that's a possibility but I ran the engine setup like it is for a year in my wagon before we swapped it all over to the coupe
 

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1995 impreza coupe ej22t 2.5dohc swap, Robtuned, brembos. Sti seats and sti go fast goodies
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Discussion Starter · #14 ·
Robtune? as in your CEL flashed a code for crank or cam sensor?
Robtune is a guy that does tunes for the 93-96 jdm wrx ecu, no codes for cam or crank sensor faults.
 

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Out of curiosity, how long did you own the impreza before swapping the guts from the rusty wagon into it? Could this be a carried over issue from the shell that has nothing to do with the swap?
 

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1995 impreza coupe ej22t 2.5dohc swap, Robtuned, brembos. Sti seats and sti go fast goodies
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Discussion Starter · #16 ·
Out of curiosity, how long did you own the impreza before swapping the guts from the rusty wagon into it? Could this be a carried over issue from the shell that has nothing to do with the swap?
I drove the stock impreza around for about 2 weeks to make sure the engine and trans were worth selling and it ran just fine. I just changed the cam and crank sensor harness and sensors to see if that changed anything but still does it.....I'm losing my mind!!!
 

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Did you use the '95 impreza wiring harness? How did you adapt for the ECU?
Do you have a wideband? If so, how are the AFR's?

Well, it can only be so many things; so we'll get to it eventually. lol If it runs decently, it has compression. Unlikely for anything there to be the culprit. Between fuel and spark, ruling out any issues with fuel is probably the easiest of the two. If you rule out any fuel issues, start chasing wires and sensors. Ignition switch, starter, battery, grounds, cam/crank sensors, coil pack, random wire being grounded against the block... There's all sorts of stuff that could be the culprit lol
 

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1995 impreza coupe ej22t 2.5dohc swap, Robtuned, brembos. Sti seats and sti go fast goodies
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Discussion Starter · #18 ·
Did you use the '95 impreza wiring harness? How did you adapt for the ECU?
Do you have a wideband? If so, how are the AFR's?

Well, it can only be so many things; so we'll get to it eventually. lol If it runs decently, it has compression. Unlikely for anything there to be the culprit. Between fuel and spark, ruling out any issues with fuel is probably the easiest of the two. If you rule out any fuel issues, start chasing wires and sensors. Ignition switch, starter, battery, grounds, cam/crank sensors, coil pack, random wire being grounded against the block... There's all sorts of stuff that could be the culprit lol
We used the complete engine 94 legacy wiring harness, he disected it from the massive bundle of wires. I did the coil on plug conversion since I am running the jdm ecu (2 years ago when I went dohc). I have an aem afr gauge and it reads just fine until it dies, we used his computer and tapped into the power for the main relay, then fuel pump, ignition switch, injectors and other things and they never lose voltage when it happens. We narrowed it down to 4min30sec to 5min and it will die every time while driving. I lose all throttle response and I can come to a stop and it will stay idling but if I press the gas it won't Rev. I turn off and restart and runs just fine until 5 min later. It's like something is on a timer lol, I think it's the ghost of the wagon since it got crushed and it's mad.
 

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I think it's the ghost of the wagon since it got crushed and it's mad.
Lol fair enough. It sounds like you're getting a lot closer to it though; ruling things out. I'm unfamiliar with the tune though, does it run on separate loops? One for a warm-up cycle, then another loop for running at operating temperature? If that's the case, it might be set to a time, as opposed to setting it to a value for oil temp or coolant temp or something like that. I have very limited knowledge on that kind of stuff though.
The fact that it doesn't rev bothers me, since it's a manual throttle cable. Seems like it would open the throttle body, letting in air, but then it doesn't add adequate fuel and it would sputter/die.
 
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