Misfire only at idle?
12-31-2009, 01:44 PM
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Misfire only at idle?
Background:
My Uncles 96 Eagle Vision TSI. 3.5l came to me with P0403 egr circuit code. the egr transducer tested bad in more ways than one, the solenoid was open and the transducer was not holding pressure or vacuum.
The Bone:
He was given the car from the inlaws as they knew it had a problem and it was diagnosed as "a common problem" and it needed a head (along with who knows what else to get the bill up to a couple grand... enough to make them say its not worth it). Personally I am a Chrysler CAP student in my 2nd year and got on dealerconnect, and alldata and didnt find ANY mention of common head/valve problems, nor in the last year at work seen any come in.
The Initial Repair:
I told my Uncle that the EGR valve / transducer was infact bad. My only concern is the previous diagnosis, WHICH in all fairness an open EGR valve would seem like a misfire. I didnt like how there was no misfire code though. So I put the valve in, started it up, it seemed to run much smoother now. Only now sitting in gear (reverse or drive) the car is shaking (misfire) and sure enough my test drive last night sitting in my driveway (after the drive) with it running and in gear *bing* the CEL comes on for a P0305 #5 cylinder misfire.
Checks:
So I dropped it for the night as it was about 2:30am, came out this morning and first thing I did was pulled the spark plug wire off #5. it was soaked in oil, the valve cover seal is bad... BINGO, right?! Its shorting out the spark through the oil, no.... I cleaned up the plug, sprayed out the wire with my trusty brake clean, cleaned out the tube with a rag around a screw driver, and it still runs the same.
I pulled the wire while it was running and it is contributing for sure as it got really bad while I had the plug wire off. It has a decently smooth idle, I would almost use "purr" to describe it, but the second you put it in gear it devlopes and obvious misfire, give it some gas and its perfectly smooth, it doesnt stumble off idle or anything... still has great power, I was quite blown away when the tires broke loose on wet roads at like 40ish (give or take). Its just in drive or reverse at idle its missing really bad.
I did a compression test and #5 of all cylinders was one of the most compression, 175ish, there was one other that high and the rest were about 160..
Where I am Headed:
My thoughts are see how its dynamic compression is to verify everything is still sealing up as it should while it is running (as compaired to known good cylinder). Possibly swap a fuel injector I want to swap sparkplugs and wires from a known good cylinder and see if it follows. My last step will be to purchase a leakdown tester (been wanting to get one anyway)... this would not be because anything I did warranted it but because the previous diagnosis done years ago. I wish I had a good enough lab scope to see the secondary coil in action, because it may just be a bad coilpack... Im sure with new years the junkyards will be having sales, maybe Ill just run out and try to pick up a coilpack out of the junkyard and give it a shot, trying it is the only way Im going to be able to verify it unfourtunatly.
Realistically Ill probably wait till saturday and take a DRBIII home so I can watch the cylinder misfire per cylinder along with any other actuators I would want to use.
If it means they need a head, so be it, BUT... first of all I just dont see how a head (valve issue, crack, etc.) would cause a misfire at idle ONLY, usually with anything its when the demand is there and your into the skinny pedal. Secondly, they are just not money bags and I dont want to keep pushing them to buy crap for this instead of say trading it in, or selling it off and replacing it with a car that will get through deq, just so when Im done it still wont get through deq and they will have tied up another grand into it.
The Question (finally right?):
Have you ever experienced something similar? Is there a common head problem that is unknown to all my co-workers and I? What could cause a misfire at idle in gear and not really any other time?
Thank you!
My Uncles 96 Eagle Vision TSI. 3.5l came to me with P0403 egr circuit code. the egr transducer tested bad in more ways than one, the solenoid was open and the transducer was not holding pressure or vacuum.
The Bone:
He was given the car from the inlaws as they knew it had a problem and it was diagnosed as "a common problem" and it needed a head (along with who knows what else to get the bill up to a couple grand... enough to make them say its not worth it). Personally I am a Chrysler CAP student in my 2nd year and got on dealerconnect, and alldata and didnt find ANY mention of common head/valve problems, nor in the last year at work seen any come in.
The Initial Repair:
I told my Uncle that the EGR valve / transducer was infact bad. My only concern is the previous diagnosis, WHICH in all fairness an open EGR valve would seem like a misfire. I didnt like how there was no misfire code though. So I put the valve in, started it up, it seemed to run much smoother now. Only now sitting in gear (reverse or drive) the car is shaking (misfire) and sure enough my test drive last night sitting in my driveway (after the drive) with it running and in gear *bing* the CEL comes on for a P0305 #5 cylinder misfire.
Checks:
So I dropped it for the night as it was about 2:30am, came out this morning and first thing I did was pulled the spark plug wire off #5. it was soaked in oil, the valve cover seal is bad... BINGO, right?! Its shorting out the spark through the oil, no.... I cleaned up the plug, sprayed out the wire with my trusty brake clean, cleaned out the tube with a rag around a screw driver, and it still runs the same.
I pulled the wire while it was running and it is contributing for sure as it got really bad while I had the plug wire off. It has a decently smooth idle, I would almost use "purr" to describe it, but the second you put it in gear it devlopes and obvious misfire, give it some gas and its perfectly smooth, it doesnt stumble off idle or anything... still has great power, I was quite blown away when the tires broke loose on wet roads at like 40ish (give or take). Its just in drive or reverse at idle its missing really bad.
I did a compression test and #5 of all cylinders was one of the most compression, 175ish, there was one other that high and the rest were about 160..
Where I am Headed:
My thoughts are see how its dynamic compression is to verify everything is still sealing up as it should while it is running (as compaired to known good cylinder). Possibly swap a fuel injector I want to swap sparkplugs and wires from a known good cylinder and see if it follows. My last step will be to purchase a leakdown tester (been wanting to get one anyway)... this would not be because anything I did warranted it but because the previous diagnosis done years ago. I wish I had a good enough lab scope to see the secondary coil in action, because it may just be a bad coilpack... Im sure with new years the junkyards will be having sales, maybe Ill just run out and try to pick up a coilpack out of the junkyard and give it a shot, trying it is the only way Im going to be able to verify it unfourtunatly.
Realistically Ill probably wait till saturday and take a DRBIII home so I can watch the cylinder misfire per cylinder along with any other actuators I would want to use.
If it means they need a head, so be it, BUT... first of all I just dont see how a head (valve issue, crack, etc.) would cause a misfire at idle ONLY, usually with anything its when the demand is there and your into the skinny pedal. Secondly, they are just not money bags and I dont want to keep pushing them to buy crap for this instead of say trading it in, or selling it off and replacing it with a car that will get through deq, just so when Im done it still wont get through deq and they will have tied up another grand into it.
The Question (finally right?):
Have you ever experienced something similar? Is there a common head problem that is unknown to all my co-workers and I? What could cause a misfire at idle in gear and not really any other time?
Thank you!
Last edited by stupidnoob; 12-31-2009 at 01:46 PM.
12-31-2009, 06:05 PM
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Sounds good so far. What actually picks-up, or generates the missfire signal? Is it a slight hic in the o2 sensor reading? I'd say you are on track with your troubleshooting, and your next steps should determine it for sure. I am cheap so I always try to isolate, or duplicate a problem before I start buying any parts. Good work! BTW, I have a link for a good leakdown tester. Its cheaper than a brand-name, and better than any Harbor Freight one you can buy.
Last edited by scotts74birds; 12-31-2009 at 06:07 PM.
01-01-2010, 12:35 AM
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What actually picks-up, or generates the misfire signal? Is it a slight hic in the o2 sensor reading?
Its unfourtunate, but I am fairly cirtain the catalytic converter is toast on the left bank due to the years of driving on a misfire it sounds blown out (rattling) so that is another 270 bucks to get through DEQ.
I'd say you are on track with your troubleshooting, and your next steps should determine it for sure. I am cheap so I always try to isolate, or duplicate a problem before I start buying any parts.
I have seen at work the coil packs on the 4.0l straight 6's do weird things when a pack goes bad and I would file this misfire under "weird things" I can get a used coil pack for 35 bucks from the junkyard and seeing as I don't have 1500 dollars worth of labscope to actually verify the condition of the current coil pack its worth throwing that part at it to me.
Good work! BTW, I have a link for a good leakdown tester. Its cheaper than a brand-name, and better than any Harbor Freight one you can buy.
BTW I am open to ANY tool suggestions you have!
Thank you!
Last edited by stupidnoob; 01-01-2010 at 12:39 AM.
01-05-2010, 10:39 PM
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Wow you are a bighearted fella. Seems to me that the car was given to your Uncle and that he probably hasn't put much into maintenance since he's had it.
Frankly, I think you're reading too much into the value of that car... maybe he just wanted to see if you could do a relatively simple or inexpensive fix to the vehicle to get it to pass the emissions test since it was coding EGR. As it is, you may be replacing seals, coils, a cat and investing lots of time on a car that you may never solve the misfire and not pass the emissions tests -- and that he's just gonna dump anyway (without ever knowing the nice gesture by you and his brother).
To survive the side job business, you'll need to shoot straight with folks. If you're good -- which it sounds like you are -- they'll know you're not jacking them... plus they're probably more than happy to give you a reasonable hourly wage than get raped by dealership diagnosis and cookbook job time charges -- or incompetent techs at an independent repair shop. Heck, you may end up fixing this at a cost to you -- and your uncle may end up selling the car because it now passes the emissions tests because HE knows its a junker -- never knowing your sacrifice.
You wont survive the side-job business by subsidizing what sounds like a large family and the other "friends" who will show up at your doorstep knowing you fix cars... you should really be square with your "customers" (uncle, brother, friends, or whoever) so no hard feelings are created one way or the other. In my experience, unless you come from a selfish circle of folk, most people would happily pay a good, competent, honest private tech -- and they would like you to stay in "business" rather than burn out because of a big heart and empty wallet.
As far as the misfire, good luck. Sounds like a lemon to me and a timewasting black hole. Close the hood and break the news...
My 2 cents.
Frankly, I think you're reading too much into the value of that car... maybe he just wanted to see if you could do a relatively simple or inexpensive fix to the vehicle to get it to pass the emissions test since it was coding EGR. As it is, you may be replacing seals, coils, a cat and investing lots of time on a car that you may never solve the misfire and not pass the emissions tests -- and that he's just gonna dump anyway (without ever knowing the nice gesture by you and his brother).
To survive the side job business, you'll need to shoot straight with folks. If you're good -- which it sounds like you are -- they'll know you're not jacking them... plus they're probably more than happy to give you a reasonable hourly wage than get raped by dealership diagnosis and cookbook job time charges -- or incompetent techs at an independent repair shop. Heck, you may end up fixing this at a cost to you -- and your uncle may end up selling the car because it now passes the emissions tests because HE knows its a junker -- never knowing your sacrifice.
You wont survive the side-job business by subsidizing what sounds like a large family and the other "friends" who will show up at your doorstep knowing you fix cars... you should really be square with your "customers" (uncle, brother, friends, or whoever) so no hard feelings are created one way or the other. In my experience, unless you come from a selfish circle of folk, most people would happily pay a good, competent, honest private tech -- and they would like you to stay in "business" rather than burn out because of a big heart and empty wallet.
As far as the misfire, good luck. Sounds like a lemon to me and a timewasting black hole. Close the hood and break the news...
My 2 cents.
01-07-2010, 12:07 PM
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ha ha... thank you
I know all of the above. This is a special thing, I am not throwing any parts at it. I have considered everything you said, the fact that even if I get it fixed there will be a cat issue. I am trying to invest as little as possible into the car.
Right now I am going to throw lower intake manifold gaskets ont the car as they came with the plenum gasket i purchased, if that doesnt solve the misfire its going back to them, as-is with at least 1 known bad cat, a cracked head and some oil leaks.
They are very respectful people, I know this buisness will be full of people with their hand out looking for free work. that is not the case with my uncle, he keeps telling me to keep track of my hours as he is going to pay me an hourly wage, and if I ever get to the point where I feel I cannot go further then just let him know and he will pick the car up.
as for the value of the car, I know the car on a good day, with no known problems is worth 2k dollars. its more than the resale value I am taking into consideration, if I can cure this misfire he has another 50k+/- miles left in it and it doesnt see alot of work, that could be upwards of 7 years the car could last them. If it comes down to the head, im throwing in the towel, but this simple stuff, plugs, and gaskets is cheap, easy and if it means 7 years of use of transportation this car is worth WAY more than 2k when its running properly. This is compaired to selling it for pennies and then assuming more debt to buy a replacement (which it may come to).
I appreciate all the comments. I am working on my side job stratigies to make these things profitable... my 50 dollars an hour at book time to do my neighbors waterpump on his pt cruiser (7hrs) turned him away which was probably the best outcome for the situation.
I know all of the above. This is a special thing, I am not throwing any parts at it. I have considered everything you said, the fact that even if I get it fixed there will be a cat issue. I am trying to invest as little as possible into the car.
Right now I am going to throw lower intake manifold gaskets ont the car as they came with the plenum gasket i purchased, if that doesnt solve the misfire its going back to them, as-is with at least 1 known bad cat, a cracked head and some oil leaks.
They are very respectful people, I know this buisness will be full of people with their hand out looking for free work. that is not the case with my uncle, he keeps telling me to keep track of my hours as he is going to pay me an hourly wage, and if I ever get to the point where I feel I cannot go further then just let him know and he will pick the car up.
as for the value of the car, I know the car on a good day, with no known problems is worth 2k dollars. its more than the resale value I am taking into consideration, if I can cure this misfire he has another 50k+/- miles left in it and it doesnt see alot of work, that could be upwards of 7 years the car could last them. If it comes down to the head, im throwing in the towel, but this simple stuff, plugs, and gaskets is cheap, easy and if it means 7 years of use of transportation this car is worth WAY more than 2k when its running properly. This is compaired to selling it for pennies and then assuming more debt to buy a replacement (which it may come to).
I appreciate all the comments. I am working on my side job stratigies to make these things profitable... my 50 dollars an hour at book time to do my neighbors waterpump on his pt cruiser (7hrs) turned him away which was probably the best outcome for the situation.
01-19-2010, 12:27 AM
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to bring closure to the situation... the lower intake manifold gasket was missing about 2" of the gasket around #5 cylinder (hidden down on the lower portion of the gasket, flamable aresol never would have found this hole)... replaced the gasket and she purrs like a kitten... even got through deq with catalytic converter guts rattling round in the exhaust ha ha... the downstream cat must be in good shape still fortunatly!
best part is that my aunt (in law)'s parents whom gave the car to them came to church with them this sunday and he was at a loss... they paid 3200 for the car and shortly after getting it a shop did a tuneup to cure the misfire (unsuccessfully) then told them it was going to be like 4500 dollars for heads. after I explained it was just a gasket that was bad he asked me if I worked on diesels as he drives a ford 7.3l ha ha. worst thing about it is a "head" would have cured the problem as a gasket set would have fixed the real problem, so the shop would have taken them to the bank for no reason but still come out like they were legit.
best part is that my aunt (in law)'s parents whom gave the car to them came to church with them this sunday and he was at a loss... they paid 3200 for the car and shortly after getting it a shop did a tuneup to cure the misfire (unsuccessfully) then told them it was going to be like 4500 dollars for heads. after I explained it was just a gasket that was bad he asked me if I worked on diesels as he drives a ford 7.3l ha ha. worst thing about it is a "head" would have cured the problem as a gasket set would have fixed the real problem, so the shop would have taken them to the bank for no reason but still come out like they were legit.
Last edited by stupidnoob; 01-19-2010 at 12:34 AM.
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