Misfire in one cylinder

[acidflux]

I have a misfire in cylinder number 3 and when I pull all the plugs and check for spark, all the other plugs light up just fine, and number 3 has a really weak erratic spark. I have changed coilpacks, have a brand new oem transistor, replaced ECU, and CAS and plugs/wires... I'm running out of parts to replace.

What else could it be?? The plug is gapped just fine, it is brand new also.

I'm really scratching my head on this one, any ideas?

Before this all started, the car was running fine in 4 cylinders and then for no obvious reason cut down to 2 cylinders and would intermittently try to pick the missing two back up. Finally it fell on its face and was only trying to fire one cylinder. I figured out that a massive backfire (while starting it that day) cracked the cermaic insulator in the plugs and was causing them to arc internally instead of at the tip of the electrode. I replaced the plugs and got it to run on 3 cylinders, then started swapping parts trying to get that last cylinder to fire.

I'm not going to bother with a compression test or anything else like that until i figure out why I'm getting almost no spark on #3. I could almost guarantee once I get spark to that cylinder the car will run just fine.

 

[acidflux]

I'll get help from another forum. Thanks.

 

[Boot92]

do a compression test next. that will help solve your missing.
also spark plugs need to be ground for the spark to occur (which is what happens when you tighten it down) i would make sure theres not dirt or corrosion or anything in the spark plug hole or on the threads.

could also be sticky valves.

 

[DSM1G90]

Have you tried a different sparkplug wire? You could have a faulty wire there.... 2-3 runs on the same coil, so you could have a bad ground from one, or weak connection to the plug on the other.

How do you test - lay the two sparkplugs over the head then crank it over to see how each plug looks like?

 

[rush2252]

So you said you replaced coils wires transistor pack etc. Did you try switching plugs and seeing if you have a possible fouled plug. Im assuming so but you didnt state.

If your not getting fire to #3 and you can switch coil packs and it still stays the same then the only possible explanation is a CAS. Its on the valve cover. Check the connections on this they corrode and lately everyone is having issues with the 1gs.

-Kolby

 

[acidflux]

I suspect I could have 2 different coilpacks malfunctioning, but it is strange to have one cylinder misfire when it is a wasted spark ignition.

As for the mechanical aspects of the car, everything is perfect. There is no reason to waste time with a compression test when I have an electrical problem. I'm a mechanic by trade, and usually work on heavy equipment (no spark plugs). The plugs were all grounded properly against my turbo manifold, all of them brand new, etc. I think im going to take everything apart and thoroughly inspect it all piece by piece... There has to be something obvious wrong with this car. The spark on cylinder 3 is pretty faint... I have to wonder if maybe the coilpack is cracked internally on the 2-3 pack and is arcing internally before it gets to the wire maybe, which could cause this problem... I'm not sure. I have 2 coilpacks though so I might just piece-part them into one good one and say a few prayers. I really need this thing running because my flow of parts coming in for this project is beginning to stack up and I really need to break the car in before I start the long list of mods. I'd hate to sell this thing because I cant get a cylinder to fire, so embarassing.

 

[odd-tay-lone]

hey man check the plug wire for cylinder 3.if you are getting spark but not very much that could be it. if there is an interferance then you wont get much spark. also, it is not uncommon for someone to get a part from a parts store and it not function properly, try a different plug. and deff check for corrosion in the threads.are all your injectors in properly?

 

[Boot92]

why dont you just say screw it and buy a new coil pack?

why would you sell the car if you KNEW it was just the CP?

 

[odd-tay-lone]

he said he already changed the coilpack

 

[acidflux]

Plug wires are brand new, plugs are brand new. I dont like being rude, but I dont like repeating myself either.

I'm fairly convinced it is a coilpack problem.

The only reason I considered selling the car is it is a 1gb 7bolt automatic car. It was too cheap to pass up at 300 bucks.

I think Ill disssemble the coilpacks and break out the multimeter and do some serious continuity checks. It has to be the coilpacks... CAS only triggers for TDC#1 I believe, transistor is brand new OEM, plugs/wires are brand new, coilpacks are both used.

I'm thinking if i take both coilpacks apart and pull the 1-4 from the other and slap it in place of the 2-3 I can make a good one... we'll see I guess.

I just want this damned car to run so I can blow it up this summer! Maybe it knows my plans for it

 

[rush2252]

I think Ill disssemble the coilpacks and break out the multimeter and do some serious continuity checks. It has to be the coilpacks... CAS only triggers for TDC#1 I believe, transistor is brand new OEM, plugs/wires are brand new, coilpacks are both used.

Dont overlook the CAS it actually reads TDS and CAM position. its a 2-in-1 sensor. Another guy with the exact same problem resolved this by cleaning the connection on the CAS. If the power transistor is good and swapping the coils doesnt solve the problem it probably the CAS.

One more thing im sure youve tried. Di Electric grease on the coil terminals. I had a random misfire w new coil packs wires plugs. It would come and go. I finally remove the leads to the coil and noticed carbon traces on one of the brass terminals. I put in some goop and it fixed the problem. Forgot about that until re reading this thread.

I hope you decide to keep the DSM

Kolby

 

[Boot92]

wow 300 really?

and sorry i must that he said he replaced the coil pack

my bad.

 

[odd-tay-lone]

dude, dont underestimate automatics. gears and a shift kit and youll be golden. No losing boost and faster shifts... if you get ## prob fixed i suggest you keep the car.

 

[acidflux]

Yeah, you guys know how it is though, when you hit a wall it is beyond frustrating. Ive already tried dieelectric grease. I'll check out my CAS, maybe that could be the culprit. I swapped it out thinking maybe it would fix it, maybe it is the connection. I can only work on the car one day a week since I work 6 days a week 10 hours a day. My day off I usually spend taking care of more important things but, I should set some time aside to get this thing going.

The only reason I would get rid of the car would be to get a better one. I'm in love with the 1ga talons, the 1gb's are plain ugly IMHO. I really just want a 1ga talon 6bolt 6/4 m/t setup but, I'll take what I can get.

There isnt a deal in the world that can beat a 300 dollar car... Half of the parts ive bought for it cost more than the car did. I'm money ahead keeping the damned thing