View Full Version : Misfire and TPS adjustment issues
I have a couple of issues here that may or may not be related. Car is a stock 1997 LSI.
Issue #1: For some time now I've had issues with the torque converter locking and unlocking when cruising around 70 mph (randomly), and also a hard 1-2 shift (all the time). I've been suspecting the TPS may be bad.
Issue #2: I've got a major misfire at idle while cold that started Monday evening. Car runs fine during acceleration, cruising, and just general driving. But at idle, when cold, it misfired very badly. By the time the car was warm, the misfire had gone away.
I've checked the coils/plugs and they look great. Plugs were done this year with OEM plugs. I've also checked around all of the vacuum lines, grounds, and cleaned the MAF sensor just for the heck of it. Everything looked good. When I started the car up after taking the coils off and checking them, it misfired worse… so bad that the whole car was shaking. I triple checked the coils and everything I took off. It’s all back together properly.
I figured I'd check the TPS adjustment while I was in there since I've been suspecting it to be bad anyway due to issue #1. The document in the how-to section states that with the key on and throttle closed it should give .5 volts through the white wire on the plug. I measured mine and the volt meter shows 5.14 volts. My first thought was that I have my volt meter set incorrectly, but when I measure the battery on the same setting, it shows 12.2 volts. When I loosen the screws and adjust the position, the voltage doesn't change at all, but I get a loud buzzing sound that sounds like it's coming from the trans while I rotate it. Do I have a bad TPS, something else, or am I doing something wrong here? Could the TPS be the cause of my massive misfire/rough idle? Or completely unrelated?
Recent work that was done: Last weekend I changed the accessory belt and the front right axle. I took the black plastic intake off while doing the axle thinking it would be the easiest way to access the axle pin, but apparently it was unnecessary. My first thought after the misfire came was that bumped something when taking the intake off, but everything is connected properly and I cannot see anything out of place.
Edit to add: There is no CEL on.
oab_au
11-07-2012, 08:49 PM
I have a couple of issues here that may or may not be related. Car is a stock 1997 LSI.
Issue #1: For some time now I've had issues with the torque converter locking and unlocking when cruising around 70 mph (randomly), and also a hard 1-2 shift (all the time). I've been suspecting the TPS may be bad.
I figured I'd check the TPS adjustment while I was in there since I've been suspecting it to be bad anyway due to issue #1. The document in the how-to section states that with the key on and throttle closed it should give .5 volts through the white wire on the plug. I measured mine and the volt meter shows 5.14 volts. My first thought was that I have my volt meter set incorrectly, but when I measure the battery on the same setting, it shows 12.2 volts. When I loosen the screws and adjust the position, the voltage doesn't change at all, but I get a loud buzzing sound that sounds like it's coming from the trans while I rotate it. Do I have a bad TPS, something else, or am I doing something wrong here? Could the TPS be the cause of my massive misfire/rough idle? Or completely unrelated?
Edit to add: There is no CEL on.
Excuse the chopping but this bit is odd.:) 5.14V on the white wire is not right, you would get that voltage across the supply and the ground. But when you rotate it, it may not change your voltage, but it is changing the TPV at the TCU as you can hear the solenoids responding to the change.
The lock-up clutch acting like that is a sign, so no idea what it is but the TPS would be suspect.
Harvey.
Excuse the chopping but this bit is odd.:) 5.14V on the white wire is not right, you would get that voltage across the supply and the ground. But when you rotate it, it may not change your voltage, but it is changing the TPV at the TCU as you can hear the solenoids responding to the change.
The lock-up clutch acting like that is a sign, so no idea what it is but the TPS would be suspect.
Harvey.
Talk about odd... after reading your response I went out and moved the pin from the white wire to the red wire (the middle one). I was able to measure the voltage and adjust it to .50 volts exactly. The solenoids were constantly buzzing at .50 volts until I turned the car off and back on again. I assume this is normal?
So is my TPS wired incorrectly? It looks 100% original...
Also, I drove it around the block again and the misfire is still there. Not as bad at idle, but it's now hesitating severely during acceleration. The good (or maybe bad) news is that the CEL light finally popped on. I guess I'll be picking up an OBDII scanner tomorrow...
michael
11-08-2012, 05:00 AM
If you have an Auto Zone near you, you can borrow one free of charge.
stiguy
11-08-2012, 07:19 AM
If you have an Auto Zone near you, you can borrow one free of charge.
Not any more at least in Ca some new law saying it was taking customers from repair shops by loaning the scanners out. So now they only sell them
Wow that sucks, but kinda funny. Around here you can go to any auto parts store and they will scan it for you, but I'm not sure if they let you take them home. I think it's time I just buy one, it would be nice to have...
Conn SVX
11-08-2012, 08:14 AM
The girl at Auto Zone said they can only scan 2000 or newer. Maybe she was lying cuz she did not know how or lazy , but did not get my 94 done.
stiguy
11-08-2012, 02:25 PM
Yes and no lol they can for 96 and newer as it would be obd2 system
Picked up a scanner today and checked the code.
"P0120 TPS/Pedal Position Sensor A Circuit Malfunction."
Of course, this didn't show up until after I adjusted the TPS... anybody got a used one laying around they want to get rid of?
redlightningsvx
11-08-2012, 06:33 PM
just ohm test the tps it shoud read 5 ohms i believe.
just ohm test the tps it shoud read 5 ohms i believe.
When removed from the car, mine reads about 5.80 ohms with a fairly consistent change throughout the range of motion.
Checked it again this morning, moving it very, very slowly. It starts around 5.80, and when rotating it, it will reach about 5.4 ohms and then jump back up to 5.9, to 6.0, to 6.5, to 7.0, to 7.8, to 14+, and then back down to 5.0 and consistently smooth the rest of the rotation down to .05 ohms...
"Well there's yer problem!" :rolleyes:
redlightningsvx
11-09-2012, 07:40 PM
Check the ground strap behind the dog bone on the bellhousing to see it its connected also.
That's the kind of thing I was hoping someone would come up with - something that I likely bumped when removing the intake. But nope. I just went and checked it and it looks good.
Replacement TPS on the way from Nate...
I installed the replacement TPS (used) today and still have issues, but they've changed slightly... :rolleyes: No CEL but now I have a high idle (1300 to 1500 rpm) in Park and Neutral, slight hesitation under very light throttle right off idle, and a random misfire at idle. But it's much better than it was before...
Car drives fine once you get past the slight stumble at take-off.
Also, the replacement TPS did not change the hard 1-2 shift. :rolleyes:
Update: I pulled the intake manifold off to begin replacing all of the vacuum lines. They are all very hard and brittle and I found a few cracks in some of them, but that may have been from removing the manifold. After seeing the condition of these hoses I am pretty confident this is my issue. I also replaced the PCV valve and will be replacing a few other things while I'm in there.
Unfortunately I broke one of the plastic nipples on the black plastic "mystery box" while removing a vacuum hose. At nearly $60 I think I'll just repair mine...but I will need to order a new IRIS check valve as that has a crack in it...
svxfiles
12-03-2012, 03:54 AM
Checked it again this morning, moving it very, very slowly. It starts around 5.80, and when rotating it, it will reach about 5.4 ohms and then jump back up to 5.9, to 6.0, to 6.5, to 7.0, to 7.8, to 14+, and then back down to 5.0 and consistently smooth the rest of the rotation down to .05 ohms...
"Well there's yer problem!" :rolleyes:
You are not checking the middle wire!
You are not checking the middle wire!
This was a resistance test with the tps removed from the car, and the replacement one was noticeably smoother in change. It was the original on car adjustment that I tested the wrong wire, because every instruction I found says to test the white wire. As I noted, the colors of my wires don't seem to match everyone else's... ;)
EdWindows
12-03-2012, 05:44 PM
Somewhat of a thread hijack: I have the same problems, but I'll be swapping in a manual transmission soon, and from what I've read the TPS is mainly used to determine when the auto shifts. Will I need a new TPS sensor for the car to run well or can I get by with my current one after cleaning and adjustment?
icingdeath88
12-03-2012, 05:57 PM
I would bet you can get by with the one you have, if it's just a little finicky and not completely trashed. TPSes I think tend to develop "dead spots" from being in one position (foot pedal in the same position) for a long time. Like cruising and such, so they might cause issues with an A/T, but not with an M/T, if that's the case.
Finally back at putting this thing back together. I've got all of the lines replaced and the manifold reinstalled. Everything is hooked up except one line that I cannot figure out where to connect it to. It's on the back passenger side of the manifold, and appears to be coming out of the top of the "BPT" according to the under hood vacuum diagram. The diagram looks like it goes to a solenoid that I already have hooked up to other vacuum lines. It's possible that I have some of this routed incorrectly.
This first picture is of the underside of the manifold before I reinstalled it, and the second picture is of the mystery hose that I cannot connect...
http://www.subaru-svx.net/forum/attachment.php?attachmentid=16911&stc=1&d=1355625340
http://www.subaru-svx.net/forum/attachment.php?attachmentid=16912&stc=1&d=1355625382
92 SVX
12-15-2012, 09:17 PM
in your second pic, that could be the vac for the fuel pressure regulator, however without seeing the other end I dont know, could possibly go to the egr as well but if so it should have a vac nipple under the manifold some.
The nipple right there should be going to the fpr.
I've got the FPR hooked up... In the second pic, you can see the hose on the right that is connected to the manifold, that one goes to the FPR.
This one looks like it goes under the manifold, but I just cannot see any tubes/nipples to connect it to. I've been looking and feeling around with my hand for a good 45 minutes with no success.
Is there a connection point under the manifold back there that is really difficult to see or feel?
92 SVX
12-15-2012, 09:58 PM
I've got the FPR hooked up... In the second pic, you can see the hose on the right that is connected to the manifold, that one goes to the FPR.
This one looks like it goes under the manifold, but I just cannot see any tubes/nipples to connect it to. I've been looking and feeling around with my hand for a good 45 minutes with no success.
Is there a connection point under the manifold back there that is really difficult to see or feel?
in that corner I can only think of a few things, the egr is there, it connects to one of 2 steel lines that slightly stick out from the manifold in that corner.
Then there is the egr solenoid that is the box with 2 nipples in that corner and finally the fpr.
icingdeath88
12-15-2012, 10:44 PM
in that corner I can only think of a few things, the egr is there, it connects to one of 2 steel lines that slightly stick out from the manifold in that corner.
Then there is the egr solenoid that is the box with 2 nipples in that corner and finally the fpr.
It's a 97, so it will be different from what you're familiar with.
Coan, have a look at this vac diagram, if you haven't seen it before. It's for a 97:
http://www.subaru-svx.net/forum/attachment.php?attachmentid=16913&stc=1&d=1355636655
It's a 97, so it will be different from what you're familiar with.
Coan, have a look at this vac diagram, if you haven't seen it before. It's for a 97:
http://www.subaru-svx.net/forum/attachment.php?attachmentid=16913&stc=1&d=1355636655
Thanks, I saw that posted in some old threads but the links were all broken. I believe it's the hose connected to the left side of #14 in that diagram...looks like it should go to the egr control solenoid valve, but I've already got that connected to a metal line that is right next to it. I think I've got it hooked up wrong. It's the solenoid on the top right of my first picture, you can see I have it hooked up to two metal lines right above it. I guess I need to go check over what I've already routed...:confused:
Upon closer inspection, I've noticed a broken nipple on the BPT. I believe the mystery hose routes to the egr solenoid control valve, and this broken nipple routes to the hard line that goes to the throttle body.
What really confuses me is that this hard line is pointing toward the front of the car, away from the BPT. The line will need to make a complete 180 under the manifold to connect, thus my hesitation and doubt to route it that way...
I got it all figured out and reinstalled. Everything is routed properly according to that diagram above. There is a metal line under the manifold that points to the front of the car which is supposed to be hooked up to a hose that routes to the BPT (located at the back of the engine bay). This requires a sharp 180 degree bend with the vacuum hose. I assume that the routing changed in later year cars and they didn't spend the extra time/money to redesign the metal line to point the correct direction...
I've now replaced every vacuum line and cleaned out both IAC valves. It still has a high idle (~1300 rpm when warm, ~1700 cold) and a slight stumble at low rpm when accelerating from a stop. I took it out for a 15 minute drive just now and it got a little better the more I drove. By the time I got back, the idle would bounce from ~800 to ~1300 when in neutral. It's pretty much exactly how it was when I started.
Tomorrow I will pick up a new coolant temp sensor. After that, I'm out of ideas... :rolleyes:
svxfiles
12-17-2012, 01:22 AM
I got it all figured out and reinstalled. Everything is routed properly according to that diagram above. There is a metal line under the manifold that points to the front of the car which is supposed to be hooked up to a hose that routes to the BPT (located at the back of the engine bay). This requires a sharp 180 degree bend with the vacuum hose. I assume that the routing changed in later year cars and they didn't spend the extra time/money to redesign the metal line to point the correct direction...
I've now replaced every vacuum line and cleaned out both IAC valves. It still has a high idle (~1300 rpm when warm, ~1700 cold) and a slight stumble at low rpm when accelerating from a stop. I took it out for a 15 minute drive just now and it got a little better the more I drove. By the time I got back, the idle would bounce from ~800 to ~1300 when in neutral. It's pretty much exactly how it was when I started.
Tomorrow I will pick up a new coolant temp sensor. After that, I'm out of ideas... :rolleyes:
Try pinching the (1/2" inside diameter) hose,
that goes from the drivers side throttle body,
to the IAC, closed.
Try pinching the (1/2" inside diameter) hose,
that goes from the drivers side throttle body,
to the IAC, closed.
Good idea, I'll try that tomorrow.
Try pinching the (1/2" inside diameter) hose,
that goes from the drivers side throttle body,
to the IAC, closed.
I wasn't able to pinch the hose shut, it was too stiff. So instead I disconnected it and plugged it with my finger. No change, still idling (smoothly this time) at 1500 rpm after a ten minute drive...
Changed the coolant temp sensor. No change. Out of ideas except to just try a different IAC. I'm getting tired of buying unnecessary parts though...
svxfiles
12-17-2012, 10:09 PM
This is most likely a stupid question, but how loose is/are your throttle cables?
There should be slack.
Yep there is a bit of slack to them. I had the same thought as I readjusted them after installing the manifold back on the car.
I once again removed the throttle body and IAC valve and cleaned them both out. I let the IAC soak in cleaner overnight this time. I still have a high idle that bounces around sometimes. The car is running fantastic other than that. :confused:
icingdeath88
12-28-2012, 07:29 PM
I once again removed the throttle body and IAC valve and cleaned them both out. I let the IAC soak in cleaner overnight this time. I still have a high idle that bounces around sometimes. The car is running fantastic other than that. :confused:
This thread has grown long, did you check the ground for the intake manifold at the back pass side near the nipple for the fpr?
Yeah it's getting way too long. Need moar resolution...
Oh and that ground looks good...
svxfiles
12-29-2012, 12:32 AM
Yeah it's getting way too long. Need moar resolution...
Oh and that ground looks good...
Evan if it looks good, take it apart, wire brush it, cover it with dielectrical grease and put it back together.
Other than the battery ground that is the most important ground.
steveherman
12-29-2012, 04:08 PM
This is my same scenario.
I have done alot of the same things.
I just went and checked on the ground with an ohmmeter to be sure. It measured .01 ohms between that ground wire and the manifold, and the same from the manifold to the negative battery cable.
I haven't done much on the car for a few days. I've been a little discouraged about it to say the least. :rolleyes:
I did notice the a/c compressor making some intermittent squealing noise from the pulley while idling. I wonder if the bearings are going bad and causing an extra load intermittently, resulting in an unstable idle? Or does that just sound totally crazy?
Edit to add: I hear the squeal from the a/c compressor/belt at startup too (very loudly). It's been doing that for a while, but just now was able to pin it down the the a/c compressor while hearing it at idle.
I did notice the a/c compressor making some intermittent squealing noise from the pulley while idling. I wonder if the bearings are going bad and causing an extra load intermittently, resulting in an unstable idle? Or does that just sound totally crazy?
After thinking some more about this, it could possibly explain my stumble, but not the high idle...:rolleyes:
Back at this again. I removed the MAF Monday night and took the cover off. I checked all of the connections with an ohm meter and they were perfect so I didn't resolder anything and put it back together.
Yesterday I finally got the CEL to come on. The codes are P0301 (cylinder 1 misfire detected) and P0306 (cylinder 6 misfire detected).
My Actron OBDII scanner also has "inspection & maintenance monitors" that test the operation of emission-related systems or components and detect out-of-range values. It came back showing that for the EGR system the "required driving conditions for that monitor have not been completed or it did not pass."
So I guess the next move is to remove the EGR to clean it out and check the connections.
My wife and I came home on Monday with a newborn baby... I started the SVX and backed it out of the garage so that I could pull the other car in the garage. It had a very metallic sounding tick coming from the engine bay that increased with RPM. :(
Sigh... The timing of this couldn't have been worse. Of course I have no time to work on it at this point. I haven't been able to drive it on a regular basis since October, and it's getting to the point that I really need something else to drive. As much as I love this car, it's not looking good right now... :(
dannmarr
03-21-2013, 08:55 PM
Congrats!:)
Still have not found the cause of this. I have not worked on it much since March, but am thinking about getting back to it now.
I made an EGR block off plate and installed it where the EGR pipe connects to the intake just to see what happens. Did not change a thing. The car still idles at 1500 warm with a misfire. Runs great above 2000 rpm.
The fact that the EGR block off plate made no difference, does that rule out an EGR issue?
Here's the latest from the OBDII scanner:
Codes
P301 misfire cylinder 1
P306 misfire cylinder 6
System monitors not meeting operating conditions:
EGR
Catalyst
Any fresh ideas?
Solved the misfire issue! Two bad coils (cylinders 1 and 6). Replaced them with a used set I got off Craigslist and now it runs great. :D
It still has a slightly high idle sometimes, very rarely though. Looking back through this thread, I didn't mention anything about a high idle until after I messed with the TPS. I'm going to swap the original TPS back in and see what happens.
I'm ecstatic to finally have the car back on the road again!
....It had a very metallic sounding tick coming from the engine bay that increased with RPM.....
Also, I solved this by running some Amsoil engine flush through the system. Must have been a sticky lifter as that cleared it right up. :cool:
scoobydrvr
10-13-2013, 12:55 PM
Also, I solved this by running some Amsoil engine flush through the system. Must have been a sticky lifter as that cleared it right up. :cool:
I have this same problem. My motor was quiet when we first put it together but its started making this ticking since I've got it back on the road. Is this stuff a gas additive or oil?
*edit*
Just realized how dumb a question that was. Time to see where I can find Amsoil.
Lol, yep it's on oil additive. Pour the bottle in and you're supposed to run the car at "fast idle" for 15-20 minutes. I went for a cruise around the block to help pass the time, very slowly - keeping the rpms below 2000. After a couple minutes the ticking disappeared. I then changed the oil and filter immediately afterwards. No more ticking! :cool:
Tonight I readjusted the TPS. It was at .52 volts when I started. I moved it around through it's range and then set it back at .50. Started the car and it gave me a P0120 code (TPS switch A circuit malfunction), probably from me adjusting it. I erased the code and went for a 20 minute drive. No more high idle and my 1-2 shift is noticeably softer (it's always been harsh).
I'm not yet convinced that the idle is fixed. I'll report back in a few days with an update, by then I'll have a pretty good idea if it has been resolved.
scoobydrvr
10-16-2013, 02:12 PM
Lol, yep it's on oil additive. Pour the bottle in and you're supposed to run the car at "fast idle" for 15-20 minutes. I went for a cruise around the block to help pass the time, very slowly - keeping the rpms below 2000. After a couple minutes the ticking disappeared. I then changed the oil and filter immediately afterwards. No more ticking! :cool:
Was your ticking noticable all the time? That is under load, at idle, off idle in neutral/park.
the ticking i'm experiencing sounds just like a lifter but can only be heard when the car is pulling itself. It would be nice if this will take care of it.
If it were a lifter tick it should be whenever the engine is running and would increase with rpms. That's how mine was.
Does your tick increase with speed? Does it increase with rpms? If it's only while driving, and doesn't do it in park or neutral, I would suspect that something else is the cause.
scoobydrvr
10-17-2013, 08:31 PM
The ticking is only when it's pulling itself and increases with engine RPMs. I'm really not sure what to make of it; hope it isn't too serious. I wish some of the Suby masters lived nearby, I'd have them give it a listen.
Tapani
10-17-2013, 09:10 PM
By "when it's pulling itself" you mean when you are accelerating?
Exhaust leak? A bad manifold gasket (or crack) may sound like a stuck lifter when on the move.
/T
scoobydrvr
10-18-2013, 07:34 AM
By "when it's pulling itself" you mean when you are accelerating?
Exhaust leak? A bad manifold gasket (or crack) may sound like a stuck lifter when on the move.
/T
I've wondered if this was the case. Is there a quick and dirty way to check for a leak like this? Seems to me that it would be hard to reproduce while sitting on jack stands.
Tonight I readjusted the TPS. It was at .52 volts when I started. I moved it around through it's range and then set it back at .50. Started the car and it gave me a P0120 code (TPS switch A circuit malfunction), probably from me adjusting it. I erased the code and went for a 20 minute drive. No more high idle and my 1-2 shift is noticeably softer (it's always been harsh).
I'm not yet convinced that the idle is fixed. I'll report back in a few days with an update, by then I'll have a pretty good idea if it has been resolved.
Update on this: idle rpms have been perfect ever since adjusting the TPS. That solved it!
I do still feel a VERY faint miss at idle. This was there before all of my troubles (and this thread) started though. It's so faint that it's hardly noticeable. I may try swapping some of the other coils out to see if it goes away.
Regardless, I'm very pleased with how well the car has been running! :D I forgot how much I love this car!
Tapani
10-18-2013, 08:33 PM
I've wondered if this was the case. Is there a quick and dirty way to check for a leak like this? Seems to me that it would be hard to reproduce while sitting on jack stands.
Carefully listen outside when in "D" and have an assistant press the loud pedal a little against brakes. Should be rather easy to pin point.
/T
trueblue
10-29-2013, 10:00 PM
"loud pedal" is that the same as the gas pedal?
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