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'87 XT jumping tach, won't stay running


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I have an '87 XT, MPFI non-turbo.

 

I took it out for a drive last night (did quite well for about 15 miles) and then upon trying to get back on the highway from the gas station, the tach started violently jumping, the check engine light was intermittently coming on/turning off (flickering, i suppose), and finally died. In a parking lot, thank goodness.

 

So I have it sitting, let it sit a while... sometimes it would start, sometimes not. If it did, it would kill itself within a few seconds. If I managed to rev it up when it started, it sounded like terrible misfiring/popping and the check engine light would flicker.. then it would just die.

 

I tried checking the codes from the ECU, all it's giving me is 6 (or 66?) but nothing else.

 

I checked the distributor shaft, its tight with no play. Checked the rotor, the screw is in and it's turning, so ruled out the timing belt. Took off the plate on the distributor to check for moisture; there is none. Checked the wiring in the general coil/distributor area, all is tight without corrosion from what I can tell.

 

I'm going to get the battery charged up again and take another swing at fixing the car. Any ideas? Alternator? Wiring? Ignore my thread? :rolleyes:

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Sounds like a dirty MAF sensor if it dies within seconds. I am not 100% sure about your model but speaking from experience, the MAF sensor will definitely do that if it's not working/weak connection or if it is dirty. If you find out that the MAF works again after a shot of carb or throttle body cleaner (DO NOT USE WD40), check your PCV hoses and valve because when they gum up, they can spew out the air cleaner and contaminate the sensor in doing so. Shes a fragile little element so don't touch it with your hands. Oil/mayo in the air box would be a good indicator that the MAF is dirty.

 

If the MAF sensor is good I would check that you didn't slip a tooth on one of the timing belts (are they tight still?). Failing those two options...TPS, and less likely the CTS and IAC.

 

Good luck!

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Not sure about those other compounds, I have only used the TB cleaner and the carb cleaner and had success with both. I know brake cleaner cleans fairly well for other things and doesn't leave much residue - you just dont want to leave any reside on that sensor. Maybe someone else can chime in if it will work or not.

 

If you start it and then 'stomp and feather' the throttle can you keep it running? When I was desperate once (in the middle of nowhere with no tools) I popped the air cleaner off and blew on the element with a straw, which was just enough to get me going again but I had to really work the throttle in order to get her to limp home. My particular issue was caused by toasted rings on one piston causing excessive blow-by that coated the MAF.

 

Coverless is the way to go for sure, all of my EA82's run that way. Have you tried reconnecting the TPS connection...maybe even the injector wire? Just some thoughts.

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Sometimes when I get it started up, I can feather it and keep it going, but not for long. It misfires horribly while doing this, however. When it started acting up, I managed to feather it in 1st in order to get it into a parking lot and off the highway.

 

Yeah, I don't want to screw up my MAF, looks rather unique.

 

I'll try the TPS connection (and the other sensors) and as for the injector.... well, I have four so I guess check the connections on all of them too? Wouldn't hurt to check, I suppose.

 

Thanks for the input! Gotta love these nerve-wracking problems :lol:

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Yeah, that's my main issue at hand... I know the ins and outs of the SPFI system yet have no clue about MPFI stuff. Took me a while to figure out the ECU is in the trunk :lol: I've owned a 6 but never got into any of the electrical...

 

MAF looked OK, but it still MAY be it.... because now that I think about it, the freakin' car started acting up like this RIGHT after I took a right turn... hmmm!

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Well the right hand turn thing sounds like a PCV issue where there was a kit you could buy to fix the issue but you would have seen a cloud of smoke in the rear view though. The kit consisted of a T fitting and IIRC some more/better PCV hoses. Hopefully it's not your ECU. Check everything...voltages, air, fuel pressure, spark, a midget under the spare tire playing with the throttle cable....

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I've been here a little while, this is not my first Subaru (9th, as a matter of fact) and I am well aware of the PCV fix.

 

I bought some electronic cleaner and some wire brushes so I'm going to start cleaning things up under the hood.... Took the alternator in to be tested, came out A-OK. Battery has a full charge now as well.

 

My alternator connection (the plastic t-connector) looks TERRIBLE inside, so I'm going to take care of that, as well as the fusible link box, the grounds, the connections to the disty and coil... and whatever else I run into, I guess. Would be nice if the dang thing threw a code so I could have something to work with.....

 

Hah! The midget has nowhere to hide under there, as my spare is in the trunk as well :lol: Maybe he's under the intake.... hahaha!

Edited by misledxcracker
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Hey Miles, would that also cause her to run really frickin rich?

 

I cleaned up all the grounds (broke one, grrr) and I cleaned out ALL sensor connectors, the alternator and CTS on the radiator were both terrible...

 

Had my alternator checked for a second time just to get a second opinion, passed.

 

She's back together now, I'm getting codes 11, 13, and 23. Going to look them up right now...

 

It starts, but runs terribly rich and also dies within short order, hitting the gas will keep it running SOMETIMES, but even in that event, it ends up falling on it's face. This MPFI crap is confusing me!

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Make sure your Disty is bolted down ad check under your cap for moisture, wear and corrosion.

 

Since your alternator checks out it could be your disty.

 

Try pumping some gas into a glass jar, it could be that you have water in your fuel.

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That's probably the only sensor I did not clean, hmmm....

 

I took the cap, rotor, and top cover off... no sign of any sort of moisture or corrosion, and the shaft has absolutely no play. Sprayed it down with electronic cleaner as it was a little dusty, put it all back together, seems A-OK. I'll check the bolt and make sure it's tightened down later today.

 

Hmmm.... water in the fuel... what exactly can cause that? I'll pump some out into a jar with the help of the diagnostic connector.

 

I managed to get it to run and stay running longer... still eventually dies, and backfires... maybe it's a misfire, but sure is loud! It only does that when you rev it up to around 3K... the check engine light comes on also, yet disappears when you let off the gas.

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Check the air intake hose for cracks or dangling extra hoses. Chance you may be drawing a lot of unmetered air. Also the IAS may be stuck open. I would just replace the air meter if no cracks are found in the hoses. The XT turbo and all the sedan and wagon models with the MPFI, along with the XT6, used the same air flow meter.

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Nice, yesterday I go to randomly start the car, and whaddaya know, the thing runs AWESOME. Drive it around a little bit.... cool, we're in business!

 

I had taken off the fan shroud to take off the drivers side timing belt cover, and forgot to put it back on, so the car was running a tad hot. Figure OK, I'll crank the heater to help dissipate the heat....

 

....And the minute I turned the heater on, the car died. Will not start whatsoever now.

 

Please someone help me out here, else I'm going to gladly hand this thing over to the junkyard...

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