I just rebuilt my EJ22t. Before the rebuild, the car ran great.

 

After the rebuild, the first time I started the car for break in, it ran great. It came up to temp normally, and idled fairly smooth. I drained the oil, and drove the car for about two days normally.

 

After about the 2nd day, the engine started missing/stuttering at cruise and under accel. It went downhill progressively from there as I can remember. It kept missing or stuttering at cruise, then it would start hard, rough idle, then started dying at idle, then eventually stopped starting/running.

 

When cranking, it at least tries to fire. After cranking for a few seconds (10 seconds or less), the car is completely flooded (plugs are fuel fouled, gas in cylinders, smells of gas).

 

Does anyone have any ideas at all? I've performed all of the diagnostic steps from the FSM for:

 

Control Unit Power supply and ground line

Ignition Control System

Fuel Pump Circuit

Fuel Injector Circuit

 

All tests come back within spec. I am now totally stumped. Does anyone have any ideas what could be wrong?

 

If it matters, it's an EJ22t in an '86 GL.

 

Thank,

-Jason

others will be in with some ideas. First, will it start with the pedal on the floor? That's the typical 'clear flood' routine.

 

do a compression test, maybe the oil control rings or some other issue with compression has cropped up. When you pull the plugs, see if they are uniformly wet or just some of them.

 

recheck cam timing

 

Check fuel pressure - maybe high?

 

just some ideas

sounds like a bad FPR, pull the vacuum line off while you try cranking. if fuel comes out, bingo.

 

my$0.02

Sounds to me like a bad connection in the harness. Seeing how you had to disconnect everything to pull the engine, I would check all the electrical plug connections and grounds.

others will be in with some ideas. First, will it start with the pedal on the floor? That's the typical 'clear flood' routine.

 

It bucks a lot more, it may fire for a second, but won't run longer than a second or two.

 

do a compression test, maybe the oil control rings or some other issue with compression has cropped up. When you pull the plugs, see if they are uniformly wet or just some of them.

 

Compression is 150-160 on all four cyls cold. Plugs are uniformly wet with fuel on all four cyls.

 

recheck cam timing

 

Timing has been checked, is good.

 

Check fuel pressure - maybe high?

 

What's the best way to check FP?

 

sounds like a bad FPR, pull the vacuum line off while you try cranking. if fuel comes out, bingo.

 

my$0.02

 

I will try this tomorrow and post back what happens.

 

Sounds to me like a bad connection in the harness. Seeing how you had to disconnect everything to pull the engine, I would check all the electrical plug connections and grounds.

 

I've checked all the connectors in the engine bay, along with at the ECU. I've also done quite a few voltage and resistance tests for the harness and ECU/sensors/injectors/coil, and all were within spec.

 

Thank you all for the help, much appreciated!

Fuel fouling could just be due to lack of spark. Possibly a bad coil pack or igniter. Or low voltage to the coil. Check for 12V on the center pin of the coil harness with the key On.

What kind of spark plugs are installed, and what is the gap?

 

ECT sensor could be bad. Or there could just be a big air leak somewhere. Does that setup have a MAF sensor?

Fuel fouling could just be due to lack of spark. Possibly a bad coil pack or igniter. Or low voltage to the coil. Check for 12V on the center pin of the coil harness with the key On.

What kind of spark plugs are installed, and what is the gap?

 

ECT sensor could be bad. Or there could just be a big air leak somewhere. Does that setup have a MAF sensor?

 

I've swapped between 2 coil packs, and had the same results. I've tested the coil pack as well per the FSM, and I've also tested for 12v on pin 2 (the center pin) and got 11.5v or so.

 

I think the plugs installed are cheap Autolites. I don't recall the gap.

 

What is the ECT sensor? I've checked for boost leaks every time I've troubleshot (which is a dozen times or so now), but have come up empty handed. Yes, it has a MAF sensor (the metal body type).

Try new NGK iridium plugs and clean the MAF with the appropriate cleaner.

You don't need to look for boost leaks, you need to look for unmetered air leaks. Air entering the intake stream behind the MAF. This throws the ECUs fuel mixture calculation off, and forces the mixture lean which is no good for starting or for idle.

The idle control valve hose is a big culprit on the non-turbo motors. Any hose that hooks into the intake tubing post MAF can be a source of unmetered air. Check the breather hoses, PCV valve hoses, all of them at both ends for loose connection.

 

ECT is engine coolant temperature. Generally when these fail the ECU gets a signal that the engine temp is something like -40 degrees. Makes hot starting a pain because it tells the ECU it needs an insanely rich mixture. Usually not an issue on cold starts, especially if its actually cold outside. But occasionally they fail the opposite way, or there is some kind of problem such as corrosion or bad wiring that tells the ECU the engine is hot, so you don't get enough fuel.

Try new NGK iridium plugs and clean the MAF with the appropriate cleaner.

 

I've cleaned the MAF, but I will try getting NGK Iridium plugs today. I don't know the difference between plug types really, could you explain why Iridium plugs are worth the $6 per plug more than copper plugs?

 

You don't need to look for boost leaks, you need to look for unmetered air leaks. Air entering the intake stream behind the MAF. This throws the ECUs fuel mixture calculation off, and forces the mixture lean which is no good for starting or for idle.

The idle control valve hose is a big culprit on the non-turbo motors. Any hose that hooks into the intake tubing post MAF can be a source of unmetered air. Check the breather hoses, PCV valve hoses, all of them at both ends for loose connection.

 

ECT is engine coolant temperature. Generally when these fail the ECU gets a signal that the engine temp is something like -40 degrees. Makes hot starting a pain because it tells the ECU it needs an insanely rich mixture. Usually not an issue on cold starts, especially if its actually cold outside. But occasionally they fail the opposite way, or there is some kind of problem such as corrosion or bad wiring that tells the ECU the engine is hot, so you don't get enough fuel.

 

Ah, ECT. Yes, I've tried swapping between the one I had and a new one, but I get the same results. I've tested resistance on both of them too, and they are the same when they are the same temp.

 

As for unmetered air leaks, I did check for them (sorry, I called them boost leaks above). I've checked every hose and vac line I can after the MAF, but I haven't found anything.

 

Thanks again,

-Jason

All turboed Subaru's come with NGK iridium plugs from the factory, its what they recommend for replacement also. They handle the high temps better and last longer.

^ Awesome, thank you!

Crank sensor? Cam sensor?

Check fuel pressure and volume/sec.

ECT is engine coolant temperature. Generally when these fail the ECU gets a signal that the engine temp is something like -40 degrees. Makes hot starting a pain because it tells the ECU it needs an insanely rich mixture. Usually not an issue on cold starts, especially if its actually cold outside. But occasionally they fail the opposite way, or there is some kind of problem such as corrosion or bad wiring that tells the ECU the engine is hot, so you don't get enough fuel.

 

I had this happening on my 94 2.2t. It was always a gamble if the thing would start when it was hot without me matting the gas pedal. In fact when I read Original Poster's post there this immediately sprang to mind but I don't know enough to volunteer it before others do

A bit of an update:

 

Yesterday I went out to try to start it, and it fired and ran? I let it idle up to operating temp, then shut it off because I had to go. While it was idling, it was pretty erratic, and if I gave it throttle, it would die sometimes, and other times it would respond. If I brought the RPMs up to 3-3.5k or so, I could hear it miss or stutter.

 

This morning, when I came out to try to start it again, it wouldn't start. I pulled the plugs, and behold, fuel fouled. I went over all of the intake hoses again and made sure they were ok, but found nothing.

 

BTW, I've had NGK plugs in the whole time, I must have been thinking about my other car with the Autolites.

 

Tomorrow I'm going to go get a fuel pressure tester. I'll post results when I have them.

 

Thanks again all.

Any chance the fuel and return lines got swapped?

Any chance the fuel and return lines got swapped?

 

He said originally it was running fine after the rebuild then quickly got worse.

I still think you should try new plugs.

Turbone is thinking the same thing I am.

Fouled plugs are a common problem on turbo engines because of the low heat range of the plugs. Entirely possible the plugs are just fouled beyond use. A new set of spark plugs could be the cure.

^Sounds good guys. I'll get some new plugs tomorrow if I get off work in time and let you know how it goes.

Ok, I finally have an update and some results. Last Wednesday, I was finally able to pick up some new plugs (NGK iridium's). I swapped them in, and it fired right up. Sweet! I let it idle up to operating temp, then shut it off because I had to leave.

 

The next day (Thursday), I had to start it in flood clear mode (start WOT). I let it warm up, and I drove it about 25 miles. It drove fairly smooth, but at cruise it misses/stumbles/stutters.

 

Saturday, I drove it another 10-15 miles. It still drove pretty well. I was able to start it normally, let it warm up for 5 minutes or so. It still stumbles at cruise.

 

I haven't driven it since, but last night, I pulled one of the plugs to see what we had, and it was covered in black soot:

 

 

If I get off work early enough tomorrow, I'm going to test fuel pressure.

 

Any idea why the plugs are getting fouled like this?

 

Thanks again!

Sounds like an injector is leaking

Are you using genuine Subaru plug wires?

change the maf senser defaults to full ritch when bad had two go bad thiss year water had got into the workings of the maf senser car was pooring black smoke and stunk like gas whouldent rev up and was overheating cats

So, I finally got around to doing a fuel pressure test, and this is definitely the issue: 66 psi!

 

So, I think I'm going to end up replacing all of my fuel lines (feed and return). Does anyone have any suggestion on what to use? Can I just use regular rubber fuel hose (MPI rated), or should I use SS braided hose, or something else? I'd prefer not to use hardlines, just because I don't like dealing with unions and bending that length of line.