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1998 Forester wont stay running


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I'm too cool to ask for help most of the time, but this time....????:banana:

 

 

so, replaced the long block, tranny and rear diff. now, starts but won't run longer than 5-10 seconds, then stumbles and dies. have check all the obvious, ( replaced fuel pump, fuel filter, alternator, injectors etc...) have checked the MAS, EMC, IAC, vacuum tests good, replaced ECU, no change at all with all new parts....any ideas anyone??? 100 bucks to the one that figures it out...

 

:horse:

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Are you getting fuel to the filter? I still think you have air problem, you can pull that vacum line off at the air filter housing tube and spray inj. cleaner into it to clean that I.A.C. valve.

If you had the intake off during the motor switch you may have left something off under there, we just put a rebuidt 2.2 in my Legacy wagon and if I remember correct I think their were around seven things to hook back up there counting all of the little vacum lines and sensors.

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I'd check to make sure you have the proper fuel pressure, and then check the cam and crank sensor mounting bolts to make sure they are tight and the plugs are good. Double check all the engine wire harness connections and pins in the plugs.

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Sounds like you may have left the big vacum line off, that runs from the I.A.C. valve to the air intake tube. It is the one that is around 3/4 in. in dia.

 

I still think this (or a similar issue) is the problem. It's happened to me.

 

Lets face it - you have spark, air, timing, etc. This is one of the few things (other than a bad ECU) that can cause a car to crap out in a few seconds.

 

Are the injectors still getting signal when it stops running? I just saw this issue on a Toyota that I wouldn't have believed had I not seen it myself. After a few seconds the ECU no longer sent a pulse to the injectors. Now whether the ECU was the problem or reacting to other inputs I don't know.

 

I've also had the 'runs a few seconds' issue with VW's. In that case the injectors are different(mechanical if you will - stamped brass kinda things) and would leak down, put some fuel in the cylinders but when you started the car the injectors were bad and in essence only the 'old' fuel that trickled into the cylinder was all the car could run on. Don't know if a similar thing could happen with Suby injectors.

 

Dave

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all good sugestions and i have tryed them all .

cam and crank

new fuel pump , has pressure

fuel lines are corect

replaced MAFS with a known working one

replaced ECU with working one

new ALT.

new fuel filter

replaced injectors and injector rails with good ones

fuel regulator .

 

 

ill give a little back story .

 

i got the Forester form a lady that was driving it around with a leaky water pump and was just adding water to it all summer and then it died on her , took it to a shop and they told here it had no fuel pressure and she had no money to fix the water pump and the fuel pump , shop said 1000$ for the fuel and water pump replaced along with the timing belt and related parts for both .

So i got the forester for 2000$ in november and it was frozen solid she had run it long with out coolent that it was all water so it cracked the heads , i just replaced the motor , used the orignal intake , replaced the fuel pump and alt. , and since i had it that far apart i changed the tranny and rear diff for a realy good 93 turbo automatic i had .

 

but now it will start and run for a short time and then die it has spark because i can keep it running with a spray bottle if fuel down the throddle body with no miss or stumble .

 

the injectors seem to keep pulsing right to the point of it stoping turning over , tested with injector lights

 

its like something it limmiting the injectors from spraying fuel like a pluged line after the filter ? but i have replaced the injectors with good ones and there filters are good too .

 

thanks for the ideas i have that 100$ :)

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Are you getting fuel on the outlet side of the filter? Also check and see if the pigtails of the inj. are getting the noid light to flash, if I remember correct you said you changed the E.C.U. did the numbers on the two units match? When I replaced my E.C.U. I was told the numbers had to match.

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Are you getting fuel on the outlet side of the filter? Also check and see if the pigtails of the inj. are getting the noid light to flash, if I remember correct you said you changed the E.C.U. did the numbers on the two units match? When I replaced my E.C.U. I was told the numbers had to match.

 

ill do a recheck on the noid light flash on the injectors .

 

no the ecu didnt match but i ran my 98 forester ecu in a 98 outback wagon and it ran fine so that settled that

 

oh ya i only get a ecu code that is P1722 and it is a tranny code some sorta signal is high ? but i tryed just unpluging the tranny and it still had the same problem ?

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When my E.C.U. went out I was not getting a flash to the # three inj. pigtail, however the # three pigtail did have current from the battery when tested with a meter. I dont understand your comment on the E.C.U. the numbers are different but it worked on another car were these two Subaru's just like the two you switched with now?

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When my E.C.U. went out I was not getting a flash to the # three inj. pigtail, however the # three pigtail did have current from the battery when tested with a meter. I dont understand your comment on the E.C.U. the numbers are different but it worked on another car were these two Subaru's just like the two you switched with now?

 

With the E.C.U i swaped my 98 forester comp. in to my dads 98 outback and it ran fine no codes and no miss fire or stalling but it was a compleetly diffrent p# and my dads car is a U.S. built car and my forester is a Japan built car i think ? so in doing that i expect that my ecm is good ! i didnt try his in my car because i didnt want to damage it if my car has a short that could wreck it .

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Since the engine is being fuel starved somehow it must be the injector circuit is causing this or the fuel pressure is being cut off somehow.

 

Check the power going to the injectors and make sure it isn't being cut out somehow. Using an analog meter may help to check that. You may need a scope also to see if the pulse width of the signal is decreasing. You may need to check the fuel pressure using a gauge.

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Since the engine is being fuel starved somehow it must be the injector circuit is causing this or the fuel pressure is being cut off somehow.

 

Check the power going to the injectors and make sure it isn't being cut out somehow. Using an analog meter may help to check that. You may need a scope also to see if the pulse width of the signal is decreasing. You may need to check the fuel pressure using a gauge.

 

i agree this is the likely cause ! but i dont know how to fix it, if its a pulse problem or cut some how ?

 

it gets constant 40+ psi fuel pressure no real drop when it dies .

 

im looking for the injector relay and hoping its the culpret i think its the one next to the fuel pump and main relay :confused:

 

also im going to try to lift the injector rails and see how they are spraying and if they are ?

 

going to cleen the ground wires too .

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Here is a couple more thoughts. Since the engine is always dying at a certain time it would seem unlikely to me that this problem is due to a faulty relay but I won't rule it out totally. It seems to me that the ECU is shutting things down for some reason.

 

Another relay to check out is the main relay. Make sure power is getting to ECU pins 1 and 2 when the trouble occurs. The same power connection goes to the injectors also so maybe this relay is causing the trouble.

 

Since there is a code being set, the problem may be related to it. Even though you disconnected the lead, it may need to see a voltage signal to make things work correctly. The code description is:

 

P1722 Subaru - Automatic Transmission Diagnosis Circuit High Input

 

While I am not sure what this signal does, it may cause the ECU to shut the engine down. Looking at the engine schematic I noticed that there is a connection from the TPS to the transmission area. The wiper of the TPS goes to the system somewhere so maybe this is related to the trouble.

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OK get this i've narrowed it down to what i think is a injector ground problem ?

 

the injectors pulse but the noid light is really dim , the + side gets a constant 12V but i dont know how to test the ground side , the ECM pulses the ground side .

 

i used the light on my 2.2 car and it pulses and gets brighter as the engine is revved but i cant keep the 2.5 running unless i spray fuel down the throttle body and the light keeps pulsing when revved but stays dim so i think thats my problem but all i can think to fix it is trace the injector ground out of the ECM and see if its good ? ill be getting a pin out diagram from the Dealer this weekend .

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I think the E.C.U. might need to be replaced with one that has the same # as the one that was originally in that car, I know they cost a lot of money but you can get these from Rock auto for a lot less then through Subaru.

Or post for one with your # on junk yard dog.

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I think the E.C.U. might need to be replaced with one that has the same # as the one that was originally in that car, I know they cost a lot of money but you can get these from Rock auto for a lot less then through Subaru.

Or post for one with your # on junk yard dog.

 

 

The pecific #s often designate changes to the programming to compenste for different wieghts, transmissions, tire sizes, etc... for different applications.

 

But in the end, if all the senors and solenoids hook up to the same pins, these ECU can run any EJ engine. It just won't be *exactly* tuned for that application.

 

For testing purposes, I think it's worked to rule out the ECU.

 

I think perhaps the injector Dropping Resitor i the problem?? or part of it?

 

On a side note. You may need to use the Forrester Trans. IDK, but I think some of the solenoids in the 4EAT where changed from the earlier. Plus I would think the taller 3.9 gear would hurt the Forresters torque and crawling abilities.

 

I suppose if you really wanted the Legacy trans, you could just swap in the valve body w/solenoid and wiring from the Forrester to the Legacy tran.

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  • 1 month later...

well no one wins the bet !!!!

 

guess what!! when the shop had the air box off they neglected to tell me that they pulled out all the wires going to the mas air flow plug and then went and re pined it all backwards :mad::mad: so after discovering that they were wrong i wired it and it runs great now !! but what gets me is that the comp. didnt give me a fault code for the mass air flow meter ? i didnt really know something was up till i tryed unplugging my dads cars and it ran and stumbled then died the same way .

 

 

DONT BUY A CAR THAT A SHOP HAS MESSED WITH !!!

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