XT6 won't run!! @!#&*

[awlllwa]

So i leave my friends house and i accelerate away, i push in the clutch at 3000rpm's and break for the stop sign and the rpm's just keep going up to about 5000. Then i loose all power and the car dies. I start it up again and its barely able to idle, i give it gas and it dies. Well i have my friend push me so i can hold it above idle and limp it home about 1 mile. I get there and do some testing around, pull out my service manual and put the MPFI unit into D-Check mode and it gives me a O2 sensor light code of 22. Witch is my knock sensor, so i go to check it out and the damn thing is unplugged. So i start the engine back up again, and it runs rough as hell, dies sometimes and has no power. My mechanic friend who helped me though the procedure said that after clearing the MPFI memory it takes a while for the engine to relearn. But its been like 4 20 minute driving cycles since then and it still runs like ************. Any one know what i should do next. or should i just keep driving it, will it eventually get better?!?

 

Things ive done

 

checked for a exhaust blockage

checked fuel pressure

checked MAF sensor

checked Distirbutor

all fluids and filters good.

 

Things i havent done

 

The O2 light gives me a code for the airflow bypass valve malfunctioning when the engines death is imminent.

 

 

 

The engine has 177777.7 miles on it (yes ironic but im not kidding, i took a picture of the odo if you want proof)

 

Any one got any ideas, im :confused: dumbfounded. :confused:

[LegAC]

Check for a leak in your intake after the MAF. That would throw the O2 sensor off because it wouldn't correspond with what the MAF thinks is coming in.

[daeron]

can you get to the injectors to touch them with a large screwdriver? (I don't know the engine bay, heh) If you can, try sticking a big screwdriver at the base of each injector with the engine running, and put your ear on the butt of the handle to listen for the clicking sound of the injector firing. Have you checked the quality of the spark at all yet?

 

Another step you could take in troubleshooting is try removing one spark plug wire at a time, while the engine is running, to see if you make the engine stall. If the engine stalls or slows down, you know that with the wire connected that cylinder is firing as much as the others.. if any pulled wire results in NO change, you know that there is some sort of problem limited to one (or more?) cylinder.

 

The way it failed says strange things.. it *might* just be a fuel pump that somehow got zappered, inscreased output for a moment, and is now barely functioning.. but that takes a fuel pressure gauge to test (or a known working fuel pump and pressure regulator)

 

You said you have a FSM? if so I might run through the diagnostic procedures for the "airflow bypass valve" (is that the idle air controller? again, not a 6 person, heh) just to see if it is functioning as it should be. After that, check the MAF for sheets and giggles... after that I would throw spark plugs, cap, and rotor at it, maybe a fuel filter to rule all that junk out and then start getting rather puzzled.

[john in KY]

Timing belt? Rotor button loose? IAS stuck in fully open position? The O2 and knock sensors will not produce this problem.

[Huck369]

I'm betting a broke pass side timing belt...or maybe just jumped a tooth or 2

[idosubaru]

let's start from the top, some very important info:

does the check engine light every come on?

if so, what code is it showing? (real time, not in D Check mode)

when is the last time a tune up was done? spark plugs, wires, distributor cap, rotor?

 

i'm betting it's just the IAC (Idle Air Control Valve) is sticking. very common and costs 98 cents for a can of cleaner to fix it. you'll see the large valve sticking up above the engine on the passengers side of the engine cover, it's one of he "highest" items sticking out the top of the engine. it has a wiring harness plug right on the top of it. it has a hose going in one side from the intake hose and the other side hose is just a real short one going into the intake manifold. based on that description you really can't miss it. remove that and clean it out really well. keep runnning cleaner through it until it's perfectly clean. or just swap in another one.

 

at the same time you're doing this, remove the intake hose (the big black hose from the air box to the throttle body). these often crack around the bends. remove it so you can look underneath, flex it a bit and make sure it doesn't have any cracks - which are essentially vaccuum leaks.

[Turbone]

Might need to clear the codes also. The easy way to do it is disconnect the battery overnight.

[Gloyale]

So i leave my friends house and i accelerate away, i push in the clutch at 3000rpm's and break for the stop sign and the rpm's just keep going up to about 5000.

This indicates too much air getting into the engine. Either a Vacuum leak or a fault in the IAC. Something is letting unmetered air in. Start the car and srpay starter fluid around the base of the intake manifold, see if it changes idle.

[awlllwa]

I did my last tune up in febuary.

 

it dose give me an IAC fault code right before it dies.

 

should I unplug the knock sensor again and see how it runs?

 

I m going to check all the spark plugs when I get home, and I will get some cleaner for the IAC and see where that gets me.

 

this car is also my daily driver, it was pretty intresting driving this thing to school this morning. it now sounds like an american muscle car. it has a glass pack muff so that helps a bit. but it has no power and it stalls out at lights if I don't keep the rpms up.

 

thanks guys for all the help and info.

[idosubaru]

it dose give me an IAC fault code right before it dies.

bingo, start there. clean it, then source a used one if that doesn't fix it. this is good news, it should be simple.

 

should I unplug the knock sensor again and see how it runs?

no, start with the IAC, see above.

 

I m going to check all the spark plugs when I get home

probably unnecessary, see above.

[awlllwa]

i got some starter fluid and cleaned out the IAC, nasty black carbon build up inside. Also i cleaned out the intake hose and the throttle body. I didnt check the plugs, and i kept the knock sensor plugged in. I also put about a half bottle of octane boost in the tank.

 

The verdict.

 

It runs better, in fact the idle almost sounds normal, it no longer has that sound like its only firing 4 cylinders. but when i give it gas it sputters and the rpms climb speraticly, also i think its outputting like 10 hp, cause i cant get the thing to move now.

 

No more IAC code before it dies though. I do have a complete other engine, should i start swapping parts, such as the IAC. Should i go as far as swapping the injectors too?

 

Thanks for the help so far.

 

Its getting closer to running good.

Witch is nice because this weekend im going to put rotors pads, and a clutch in, and next month i was going to install a new suspension (it has coilovers, but it sits high in the back and the fronts are soft)

And ive already ordered all the parts

 

Also through out all of this. My check engine light used to be on for the first 5 min of driving then turn off. Now it doesn't come on unless it throws a code.

[awlllwa]

well its back to running the same as it did before. And i just got a IAC fault before it died. Im going to go look for another IAC. Also could low fuel pressure cause this problem?

[hooziewhatsit]

There could be a problem with the solenoid controlling the IAC valve. I'd swap that out and see if it helps.

 

I'd try that before changing anything else out.

 

-Dave

[idosubaru]

if you have another IAC, then swap it, it's so easy to do. but i'd start suspecting the wiring too. gently bend the wiring between your fingers as it idles. start at the harness and work your way back as far as you can. if it starts sputtering and stalls or starts running great...any change as you're massaging the wiring, means the wiring is corroded. also check the plug that plugs into the IAC and see if it's corroded or green.

 

he's got a point about the solenoid i suppose. never seen or heard of that failure, but it certainly can. not sure if or where the solenoid is that controls the IAC, never replaced or removed one on the 20 or so XT6's i've had. there is a black solenoid underneath the IAC though that i do remember, that's probalby it unless that's for the charcoal canister/emissions system.

 

fuel injectors are probably not your problem, i can almost promise that. if the check engine light ever comes on, you have to start there, it's telling you something. even if it doesn't make sense right away, it's telling you something, don't ignore it.

 

one of the most common XT6 issues comes to mind...how is your CTS (coolant temperature sensor)? of the 20 or so XT6's that have come through my hands, that is the most common problem hands down. it screws into the thermostat housing. actually the sensor isn't hte problem, remove the wiring plug/harness that connects to it. how dirty is that connection? if it's green and nasty (most are by now), then your issue likely resides there. i have a permanent fix for that issue that i've posted on here. cleaning will not fix it, buying a new sensor will not fix it...those are both temporary fixes, it will return. inspect yours and when you see how nasty it is, go read my thread about it or at least put it in your "to-do" list.

[awlllwa]

damn, i cant find my extra IAC. I will keep looking. I do have another engine harness, i could just switch that out because the one on the engine now looks honorable compared to my spare.

 

About the CTS, the previous owner leadfootracin told me something about that, cant remember what though. He apparently did some special fix.

 

The one thing that is broken is my primary cooling fan or thermo switch, or relay. the aux fan just stays on most of the time but It dosent over heat unless the AC is on. the temp here in texas is getting closer to 100 and my temp right now runs just under half way and its ~80. i planned to fix that when i do my breaks this weekend, could that be the problem.

 

If i hook up my MPFI unit to a scanner will it tell me any useful info, Or will i just give me the codes that it already is giving me?

[idosubaru]

If i hook up my MPFI unit to a scanner will it tell me any useful info, Or will i just give me the codes that it already is giving me?

you can't, unless you have access to very rare, almost non-existent equipment. these are not OBDII systems like your 02 subaru which can easily be plugged in and checked. it wouldn't do you much good anyway, like you said, that it's showing a code is telling you something already.

 

i wouldn't swap the harness, that's a rather annoying job and most likely the "nicer" one isn't as nice as you'd think. address each connector independently. have you actually looked at it yet, sounds like you haven't? check it out and let us know what the TPS connector looks like.

 

the fan issue isn't causing your non-runnign issues...unless the running hot is deteriorating the wires quicker...but the bottom line is the problem is elsewhere.

[awlllwa]

my friend who is helping me out a little works on bmw and porsche, at a dealer ship. So i have axcess to a $14k or something scanner that dose have a profile for my car and he can borrow the cables from the scanner company to check my car.

 

The boot on the IAC is cracked pretty bad and the TPS plug looks good, i havent checked the coolant sensor yet, and its now dark out. The previous owner swapped the TPS because it was idling funny. I also found my extra IAC, It also looks pretty carbon coated. I checked my spark plugs again too and they look fouled, prolly form the engine running so bad. Also there is excessive scorching and corrosion on the dist. cap and rotor im going to warrenty the plugs, cap wires, and rotor tomorrow. i looked back on my records and the timing belt is actualy due for a change so i guess i will do that too, if it has lumped in timing it will get sorted out then. Also i forgot to mention that one time i did get a crank position sensor code when it died once, and my mechanic friend told me to swap out my distributor.

 

Im going to drive my loyale until the xt6 is sorted out.

[idosubaru]

did it run okay awhile ago? the TPS is a pain to adjust and there's no spec's to adjust it by. i'd make sure all the tune up stuff is good - particularly the ignition stuff, plugs, wires, distributor cap and rotor.

 

the crank angle sensor is located in the distributor housing, so swapping the distributor replaces the CAS.

[Gloyale]

did it run okay awhile ago? the TPS is a pain to adjust and there's no spec's to adjust it by.

 

There is an adjustment spec for the TPS. At least for the idle switch portion of it. It should be adjusted so that at fully closed, there is continuity between The blue/wgite wire and the Black wire. Insert a .55mm feeler gauge inbetween the idle stop screw and the throttle lever. There should now be no continuity.

 

Adjust by way of the 2 hold down screws for the TPS, loosen and rotate TPS body until it comes into spec. Do not adjust the throttle stop screw

 

Closed throttle=switch closed

throttle open just a hair=switch open

[idosubaru]

There is an adjustment spec for the TPS. At least for the idle switch portion of it.

didn't think that this portion might meet specifications, that should be fairly simple. the FSM is dead wrong almost entirely for the IAC, no XT6 IAC will meet the spec's in the FSM. i adjust it by ear...basically turn it until it wants to stall then back it off a hair.

[awlllwa]

yeay, everyone i am an idiot.

 

I was pulling the spark plugs and the ones on the driver side were carbon fouled, so then i pulled the ones on the passenger sider and they were wet fouled, so i undid the timing belt cover and the belt was shredded. I ordered all the parts i need from my store, and im going to install tonight (parts don't get here for anther 2 hours):-p

 

so im going to clean all the carbon gunk outta the system and hopefully it will run good after everything is back together.

 

next time i will be sure to pull plugs from both sides of the engine.

 

Thanks guys for helping me out, i feel so stupid. I will let you know how the fix goes.

[Gloyale]

Busted passenger side belt= XT3(cyl)

 

I'm sure it will run great once it's back toghether.

[awlllwa]

well i think im outta luck now. The timing belt idler pully stripped the bolt hole that it screws into on the head. Can i just put a helicoil in to fix, and can i pull that off without pulling the engine? Now it started raining outside when i discovered this, something doesn't want this car to run.

 

I guess this thing won't be moving this week.

[idosubaru]

this is a really annoying job but i've dealt with it a number of times on XT6's. which pulley exactly? yes, use a helicoil. get a right angle drill or a right angle drill attachment - basically whatever you can find that is shallower, the shorter the better so it fits down in front of the engine. remove the radiator for extra room and anything else that's in the way....a/c, alternator, etc. then get the right size drill bit and you'll probably have to cut it in half. or just put it in a vice, wear some goggles and whack it with a hammer to break the bit in half, that's what i do. then use that in combination with the right angle drill. you can rent a right angle drill from tool rental places. hang in there, it's definitely doable...annoying, but you can swing it.

[awlllwa]

Its the driver-side idler pulley. It screws into the head. I think i can get all the right tools together for the job, i just wasn't sure if it was worth it, cause i was thinking that if the metal was stressed enough to strip then it would just strip out the helicoil threads. You are the 3rd person that told me that this just happens and a helicoil dose the job well, so thats reassuring. But it will still take me a while to do. Ill let you know how it goes.