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MilesFox

Horrible misfiring, Phase1 frankenmotor, 98 forester

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I have just swapped a frankenmotor into a 98 forester. The franken motor is a ej25d block and ej22e heads. The forester originally had an ej25d.

 

This engine came from a 95 legacy, from which the intake and heads are original to. The engine had this horrible misfire before swapping. I assumed maybe the misfire could have been an anomale in the ecu or harness of the 95, but it is still present in the 98 forester.

 

The #2 injector has been replaced, no cure. The #2 injector drops out at idle, and under load, the #1 injector drops out as well.

 

I thought i had read something about a bad signal from the IAC will cause this. Upon startup, the engine sems to run smooth until it idles down to the point the IAC closes, then misfires. 

 

So i swapped the intake harnesses. The car now has the forester's original harness on teh intake. So my problem is not the intake. It must be an individual component on the intake itself. i had to swap over the purge control solenoid and the knock sensor to match the harness I have not attempted to swap the coil. I loathe to change the IAC with the little hoses of death under the intake (i don't want tp pull the intake-again!)

 

HAs anyone had this trouble before, swap or not, and what should be my troubleshooting route: to reiterate, i have swapped over the forester's original engine harness, knock sensor, and purge control solenoid. All of the forester's original components are known working order before the swap. I can rule out any ecu or harness as the problem.

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Unpugging the injectors individually. Fresh head gaskets, motor put together this last feb. #2 injector had been replaced before.

 

So far i have changed the IAC and it helped a little in the idle, but still have the misfire under load. I have changed the coil with no difference. 

 

Could I be having EGR problems? 

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I am going to change the ECTS today and see if that helps. I suggested this when the engine belonged to my dude in his car, although for some reason he refused to change it even though he had the part. If this fixes it, i will feel like a total toolbag....................Short of swapping all 4 injectors from the ej25 intake, i am contemplating stealing the whole intake off a 96 brighton and be done with it.

Edited by MilesFox

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Valve not sealing correctly.

 

Rule this out with a compresion test.

 

But if the injectors Ohm out O.K. then I'll bet it's a burnt valve.

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The valves seemed to be in good order when assembling the engine. But the misfire was a pre-existing condition before swapping on the 2.5d block. But the misfire is intermittent, mainly under load. If i manually shift, and am light on the throttle, i can get it to rev out smoothly, and at about 5,000 rpm i can gie her all she got and she goes! It seems like the misfire wants to clear just before the next gear hits, then misses under load. The check engine lite will flash each time it does this.

 

So today I did the following, to rule out any one of these as causes: 

Changed ECTS with the one original to the forester.. .No change, but the old one crumbled as it came out, and i observed the fans are working of and on ash she idles-working normally.

I replaced the TPS sensor

I swapped out first the little diaphragm thingee that sits above the EGR. this seemed to help with the idle. I forced open the EGR with a screwdriver. Although this caused a rough idle, it seemed to help mid-rpm. I noticed the EGR actually working after i did this, but only after the engine reached operating temp. If i work the throttle from under the hood, the valve opens right off throttle, but closes as i hold the throttle open. Then i removed the EGR valve itself and inspected. pintle moves and the intake port is not clogged with gunk. Then i replaced the EGR solenoid itself. This greatly improved the idle. There is virtually no misfire at idle.

 

So far, every electrical component on the intake has been swapped out with original components to the body of the forester, which are all known-working condition.

 

Now, assuming there is no burnt valve (ej22e), the only other variables to consider are either the fuel filter, or the fuel pressure regulator. I am considering swapping out the fuel rails and the fuel filter as last resort. 

 

I do not have a compression tester to confirm or deny compression numbers. The compression feels strong as i turn it over by hand, and is noticeably stronger than a stock ej22 turning by hand. 

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One thing i can tell you for certain is that now she is only misfiring on one injector and not 2, and that my troubleshooting has cleared up the condition quite a bit, also eliminating misfires at idle, with the EGR solenoid and the IAC having the best effect with the idle.

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Does the fuel pressure remain constant at all four injectors while under load or accelerating? Sounds like the fuel supply is dropping off at injectors #1 and #2 ? Fuel pressure regulator? I think you're on the right track for sure. Determine the cause of failure and reap the rewards of victory. :)

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Just because you unplugged an injector and it didnt make a difference doesn't mean the injector is bad. It's a dead cylinder misfire, unplugging the injector doesn't rule out spark or compression as the cause.

 

Confirm the timing is correct (maybe it jumped), and do a compression or leak down test.

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Just because you unplugged an injector and it didnt make a difference doesn't mean the injector is bad. It's a dead cylinder misfire, unplugging the injector doesn't rule out spark or compression as the cause.

 

Confirm the timing is correct (maybe it jumped), and do a compression or leak down test.

New plugs, wires, i put this motor together, timing is correct.

 

INTERMITTENT misfire, cannot be caused by a static occurrence such as the timing belt being off a notch, which it is not. I won't rule out a cpmpression reading since i don't have a gauge.

 

I am not assuming the injector is bad considering replacing # 2 didn't cure anything (the other guy did this), but rather something that has to do with the operation of the fuel injector is bugging out.

 

This is an HLA engine with no valve adjustment. HG's fine, no bubbles, no over heats.

 

This far in the troubleshooting i now suspect fuel pressure regulator. It was sort of a trial and error shotgun approach, but nothing wrong with shot gunning the car's original components back onto itself. At least there is a control (the forester's original components).  This makes sense that the injectors farthest form the fuel supply would bug out. So far i am going by instinct and my own troubleshooting abilities since i haven't bothered with multi meters and specifications, since shotgunning (original) parts onto it is a free option.

 

Tomorrow i swap the FPR/fuel rail and will post my result.

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You can shotgun all the parts you want but until you know for sure that compression is correct you're wasting time.

Timing is easy to check and will produce random misfires if its one tooth out, (Easy to do on the drivers side where number 2 cylinder is) that will go away at high Rpm.

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All that is left to shot gun is the FPR. so far anything i have screwed with regarding vacuum lines has had an effect.

 

I can assure you that the timing is correct. This engine used to run correctly, and the misfire has gotten progressively worse over time. What i am trying to solve is a pre-existing condition outside of the engine build itself. 

 

And either way, all of the foresters known working original components have found their way onto the donor engine.

 

I figure i can at least waste my time with the FPR before i consider my time wasted.

 

This engine is running coverless. I suppose i can check the belt timing just because i am staring at it.

 

Now that i am remembering, i think i may have suspected the FPR a while ago when the engine was first put togehter, but somehow didn't think of it this time around. I guess my mind was stuck on the idea it was the harness or something electrical. Thus thinking of the FPR after scratcing my head and thinking "well what can be left on this manifold that could fail?" 

 

I suppose i should rephrase 'shotgun approach' as 'process of elimination'

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I have now swapped the FPR and 3 of the injectors. The injectors i put in match the first one that has been installed.

 

I am going to take fairtax's advice and check the timing belt. It looks like it may be a notch off, actually. I am going to remove it and re-hang it with the marks and see if that helps. I shouldn;t have been so stubborn! 

 

If that don;t fix it, the only other possibility would be the heads. 

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Timing belt didnt fix it. timing was correct.

 

the #3 spark plug wire was bad. She is 100% now. Going backwards in troubleshooting really pays off!

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I changed the spark plugs and that cured it. The joke is the part i changed las should have been the part i changed first, saving me all that trouble. But the forester now has all of its original components to the intake. I am one the wiser now.

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Read the one about the broken ring land. that is how it's doing today. I blame the failure on unknown history and rusty cylinder walls combined with low octane fuel and woman driver. The misfire was jus the plugs wires, which somehow i assumed were done, but weren't

 

http://www.ultimatesubaru.org/forum/topic/144928-frankenmotor-failure/?hl=frankenmotor

 

By the way, the misfire and the failure later on have no correlation with eachother. Aside frm the integrity of the used block, the misfire issue was cured with another set of wires

Edited by MilesFox

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