cylinder not firing

[jastrckl]

Leaky injector, too much gas is dousing spark? Try leakdown of fuel rail, see how long it takes. PITA, but maybe move injector and see if problem follows. After that, I give up.

 

[bandwidthpolice]

Don't forget crank sensor controls spark, cam sensor controls injector pulse. Sounds like the cam sensor could be 180° out of sync and pulsing fuel on the exhaust stroke rather than the power stroke. Only one way to tell and that is to find TDC on #1 cylinder and set it to spec.

FAQ from gnttype

FYI, this is a free test and here's how to do it:
How to set cam sensor

Don't throw parts at it yet.

 

[TurboJim]

Originally posted by 1970gsx
You could try and switch the plug wires at the coil on cyl 6 and it's corresponding terminal (the one that shares the same coil pack, I think it's #3) and see if the problem moves to that cylinder. Then you'll know it's not something in the combustion chamber itself. If it moves than it has to do with the coil pack and or module.

GSX is on the right track, however, its pair (#3) will be misfiring/weak as well. Each cylinders pair completes the circuit for each other..... er.... in other words, #3 and #5 need each other to fire. If either is bad electrically, NEITHER will work. So my bet, is if you have a weak coil (which it wounds like you do) you're actually running on 4 cyls.

 

[GotGas8668]

I have swapped injectors around, the problem does not follow but stays in the same place. I have swapped coil wires around, the problem does not follow but stays in the same place. I think I knw someone with a cam sensing tool that might be able to help check the timing.

 

[GotGas8668]

I piddled a little bit with the car this weekend, nothing new. I have no clue what the problem is. Wish I would at least get a code to go off of.

 

[Old Car Guy]

Does your friend have an ECM you could swap in, at least temporarily, or have you already tried that?

 

[GotGas8668]

Yeah, tried that one, too. The only thing I feel I still have left to check is the harness gong to the ignition module. I don't know what every wire should read, maybe Buick can tell me at the dealership here. Unless someone has a link to somethign I haven't found yet?

 

[jastrckl]

gnttype.org has information w/ the pinout for that harness.

 

[GotGas8668]

I have a problem finding information I want on that site, you don't have a link do you?

 

[GotGas8668]

Well, I changed the crank sensor today, played with the wiring harnesses and found nothing new as to what is causing my dead cylinder. I'm not sure what to do. There isn't a shop around here I trust with doing good work on Turbo Regals. Maybe it is time to start pulling the motor apart from the topside. I really don't want to do this, because I feel comfortable that it isn't in the head or cylinder. I'm not sure of my options right now. Does anyone have any ideas for me?

 

[bandwidthpolice]

Two final things: Do you still have a trouble code set? Unplug the ECM power wire and clear it. Did you try a fresh sparkplug on #6? It might be cracked and barely noticable. I'm out of ideas other than checking for vacuum leaks, hole in MAF tube, etc. The #6 spark issue might be taking your attention away from the real problem. I just can't think of much more. Hate it that you are so far away from Dallas and Houston; there's lots of folks in those areas.

 

[GotGas8668]

Well, engine is almost out. Waiting on a hoist from a friend and it should be there. Got some ARP head bolts and 2 new head gaskets on the way. Also ordered some new injectors. Guess ill find out what the problem is if it is there when I get it out (hopefully tomorrow). Any ideas on a nice cam? Have a friend who has a 206/206 and one with a 212/212.

 

[TClassic]

Dude, BEFORE you pull the motor why don't you simply remove the intake and take a look at your cam, and then if it Visually looks good go ahead and measure the lift to verify your cam is good.

ALSO, If its NOT a Bad cam you COULD have a Bad Mass-Air!
My Mass-Air was bad, and it did NOT set a code for quite some time, yet I also seemed to have a miss.

 

[GotGas8668]

Well, I have changed MAFs with two other people's cars. No difference. It does run similar to a MAF problem (I had one a few months ago), but doing a tap test on the sensor and changing the sensor doesnt do anything for it. The intake is off the car now. Most of the accessories and the turbo are gone as well. I am looking down at the cam, and I don't see anything wrong, yet. John Pearcy is guessing I have a cracked or burnt valve that didn't show up in the compression or leak down test.

 

[GotGas8668]

Well, engine is out. Nothing on the block but crank, main caps and the fly wheel. Can't find a thing wrong, everything looks sound. Off to the machine shop!

 

[GotGas8668]

Well, for those still listening, I have everything back form the machine shop now, along with lots of goodies from John's Performance. The only thing we did find wrong with anything was that all 6 exhaust valves were burned.

I had the block bored 30 over with TRW pistons. Pocket ported the heads and put in LT1 valve springs. Turned the crank 10 over and put in steel center main caps, along with the ARP main stud set. Comp cams 206/206 cam shaft going in. There is a set of MSD 50 pound injectors going in, along with a new chip. Decided to upgrade to a Houston 3" downpipe. I bought a 3000-3200 9 and a half inch stall with a 12 inch clutch from PTC and a T-66 ball bearing turbo on the way. I also had plenty of time to do a lot of cleaning and painting on all parts and the engine bay, so it will look mighty spiffyAnd I'm sure there is something I am forgetting.

Hopefully all problems are fixed and there is a new sleeper running the streets of West Texas.

 

[Roger]

Take a resistance reading across the two plug wire leads on the coilpack. Anything over 12k ohms is suspect. My last one that failed was ok when cold & read 76k ohms when hot - I replaced the coilpack & fixed the miss.

 

[GotGas8668]

Well, motor is back in, haven't got the new turbo in yet, but everything else is together. No more problems as it seems. I guess it was what I was told, the exhaust valves. All 6 exhaust valves were burned, thinking that No. 6 was burned badly enough to keep it from holding compression under combustion. Only thing I am having a problem with now is a minor exhaust leak, which I think is causing the car to throw the 44 code. I can live with this, it should be an easy fix. Thanks for all the support.