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endless misfires w 3800 V6
- Thread starter lght1
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I would still replace with the AC Delco Plugs (Rapidfires come with a money back satisfaction guarantee). Also, use a small dab of Silicon Grease on the Ceremic Part of each plug.quote:
Originally posted by lght1:
hi
replaced the icm today. no change.
could some bolts on the UIM worked loose and i have a small vac leak?
Did you check the electrical connector to the injector on cylinder 4 to make sure it's OK?
Preignition can be due to carbon buildup in the cylinders. This is more likely if the engine has had a lot of use. An example of bad ignition due to carbon buildup is dieseling after the car is turned. Get rid of it by using the water decarbonization technique. The carbon will come out and the engine will run smoother and with more power.
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Q: This has two plugs per jug, correct?
Q: Can I assume that they are sequenced (wires placed) so that they both fire at the same time? The other while its cylinder is on exhaust?
Q: How would the PCM determine that any ONE plug was misfiring? (maybe if the missfire occured when it was allegedly near TDC for that power stroke??)
Q: If you experience a missfire and the coil pack is reponsible, it it reasonable to assume that the mirror plug would also missfire??
The only reason that I threw this out here is that some of the 00 and later jeep 4.0 would only show that #1 plug was missfiring ..even if the plug wasn't the cause. It never showed the mated plug as a missfire. The coil pack was the cause (and all three were sold as a unit).
Q: Can I assume that they are sequenced (wires placed) so that they both fire at the same time? The other while its cylinder is on exhaust?
Q: How would the PCM determine that any ONE plug was misfiring? (maybe if the missfire occured when it was allegedly near TDC for that power stroke??)
Q: If you experience a missfire and the coil pack is reponsible, it it reasonable to assume that the mirror plug would also missfire??
The only reason that I threw this out here is that some of the 00 and later jeep 4.0 would only show that #1 plug was missfiring ..even if the plug wasn't the cause. It never showed the mated plug as a missfire. The coil pack was the cause (and all three were sold as a unit).
hi
based on a compression test, it looks the head needs to be pulled. however, when the cost of the machine shop is thrown in, it seems more cost effective to repower the car.
its a possibility that i made trade her for a low mi '01 Regal Ls with 20k if the price is right.
they've had the car all winter, and still am asking $13k for it.
based on a compression test, it looks the head needs to be pulled. however, when the cost of the machine shop is thrown in, it seems more cost effective to repower the car.
its a possibility that i made trade her for a low mi '01 Regal Ls with 20k if the price is right.
they've had the car all winter, and still am asking $13k for it.
lght1, The symptoms you describe are almost exactly what I had with my 1997 Buick also with Vin code K engine! The manifold was the casue on mine. A year later the symptoms returned and I found that some of the bolts had loosened.I could see some oil sepage from between the UIM and the LIM. I took them out and cleaned them and then I used blue loc-tite instead of the white GM thread sealant and reinstalled them. It fixed the problem right away.
A vacum check willt tell you if you have a vacum related issue real quick!
A vacum check willt tell you if you have a vacum related issue real quick!
hi
i did have some very loose UIM bolts, which I have since torqued down again, but to no avail.
compression in #4 is about 120lbs where as the other 5 are around 150 +/- 2-3lbs.
it seems a valve isnt seating, but the machine shop has doomed this engine because of its high price.
i'll likely decide to repower unless that Regal becomes very affordable today.
i did have some very loose UIM bolts, which I have since torqued down again, but to no avail.
compression in #4 is about 120lbs where as the other 5 are around 150 +/- 2-3lbs.
it seems a valve isnt seating, but the machine shop has doomed this engine because of its high price.
i'll likely decide to repower unless that Regal becomes very affordable today.
I would use a can of Amsoil Power Foam. I would also buy a gallon of either FP or 131 and start useing it every tank full! If the valve is not burnt you will be fine. The combination of carbon on piston tops and and the valve could easily account for the variance in compression readings. I would drive the engine until it is DOA! I am almost sure that most of this not all of it could be solved with the above recomendation. By the time you have run a gallon of the fuel additive through it youshould have seen a huge improvement.
Their are places that reman the "K" 3.8! Jasper is one company. A nice low milage one is usaly a safe bet as well! While a lot of places will not taouch the block due to thin wall casting etc.... THe heads are straight forward and easy to repair!
Their are places that reman the "K" 3.8! Jasper is one company. A nice low milage one is usaly a safe bet as well! While a lot of places will not taouch the block due to thin wall casting etc.... THe heads are straight forward and easy to repair!
HI
The car is a work/pleasure car. This car has done over 100k in two yrs and must be able to run each day.
It seems that the problem came over it almost overnight. One day if was running smoothe as silk, the next day..mis fires #4.
I have suspected carbon, but the comp was down so badly in that cyl so i just sort of condemned it in favor of a "yard" engine.
I am currently looking for a nice engine in my area, and then i am going to install the L26 alum UIM and finally be done with the plstic garbage on top.
The car is a work/pleasure car. This car has done over 100k in two yrs and must be able to run each day.
It seems that the problem came over it almost overnight. One day if was running smoothe as silk, the next day..mis fires #4.
I have suspected carbon, but the comp was down so badly in that cyl so i just sort of condemned it in favor of a "yard" engine.
I am currently looking for a nice engine in my area, and then i am going to install the L26 alum UIM and finally be done with the plstic garbage on top.
Hi
Just some observations on this...
Since re-torquing the UIM , only one code has been set..which was first time started. Since then, 768 miles without any light.
Engine is still missing when cold but nothing like it was.
Engine misses much less once at operating temp, esp after a lengthy interstate drive.
I may Sea Foam it tomottow. It cant hurt...
Just some observations on this...
Since re-torquing the UIM , only one code has been set..which was first time started. Since then, 768 miles without any light.
Engine is still missing when cold but nothing like it was.
Engine misses much less once at operating temp, esp after a lengthy interstate drive.
I may Sea Foam it tomottow. It cant hurt...
If your really planning on getting a new engine why not try everything you can on this one before u let it go? I like the seafoam Idea but i might try B-12 Chemtool too as i think its a tad stronger. but with an engine i was gonna swap out if it does not get better i d run both, and anything else that looks like a decent additive at the parts store. Whats the worst that can happen?
Just My .02$
Just My .02$
hi
the worst is that i'll have to rent a car....lol
i dont think an additive will cure this. i ran seafoam this morning thru the vac line. there wasnt a bit of smoke like others reported even though directions were followed to the "t".
Later today, I rev'd the thing up a bit by the use of the tb cables and i could hear a bit of valve train noise from in back.
I am slightly entertaining trading for a more fuel efficient car. The last of the Olds ALeros with the 2.2L would be nice if I could just find one with leather.
The Corolla also is a possibility, buit I hate that "built in" step on the driver's floorboard.
What kind of "feature" is that?
the worst is that i'll have to rent a car....lol
i dont think an additive will cure this. i ran seafoam this morning thru the vac line. there wasnt a bit of smoke like others reported even though directions were followed to the "t".
Later today, I rev'd the thing up a bit by the use of the tb cables and i could hear a bit of valve train noise from in back.
I am slightly entertaining trading for a more fuel efficient car. The last of the Olds ALeros with the 2.2L would be nice if I could just find one with leather.
The Corolla also is a possibility, buit I hate that "built in" step on the driver's floorboard.
What kind of "feature" is that?
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