kbouchard1092

SO i have been having some issues with the car breaking up in high rpm...say about after 6500 rpm i hit a wall. So i wanted to check my timing so i went to hook up the light and on cyl one i cant get a steady enough reading to even set the timing. Every other wire gets a good steady flash from the timing light. cylinder one breaks up big time it will flash then stop completly for a few seconds then start flashing again but never steady enough to get a accurate reading.

i did have a msd that **** the bed before i went back to the stock ignition. So i wouldnt be suprised if that msd crap messed something up with my distributor.

if i unplug clyinder one it does change the idle so its getting spark it just has to be super weak so after i start getting into higher boost it breaks up big time.

i pulled both spark plugs out and its even showing cylinder 1 much blacker then the other 3. So it is def misfiring only in that cylinder.see picture

im stumped that only cylinder one has issues. its def not the wires so im not sure what else could cause this? has anyone ever had a similar issue?

i did the basic stuff cleaned cap and rotor and switched spark plug wires and the problem did not change with wires. No matter which wires i used cylinder one still had issues with the timing light even picking up a signal while all other three had perfect steady readings

Hulkdon1

You have a lot more to try. You should get a set of plug wires with a distributor from a proper running motor, swap yours out and see.

You should change the distributor cap and rotor (not clean up, change). Short cuts get you no where in these instances. GL.

Muckman

iTrader: (2)

Agreed. If your plug wires are old you should get new ones anways. Same with cap and rotor, right from the start. Your ignition system needs to be in top shape.

You can also try swapping the #1 injector around to see if its squirting alot more fuel than it should be.

kbouchard1092

i completly agree i will be changing the cap and rotor. I just didnt have a extra set on hand. The distributor cap is really the only thing i could think be causing this. Did some research and found sometimes the prongs are too far away from the rotor. I cant see the rotor having much effect since all cylinders would be effected, but i will change it anyways its not expensive. I dont think the wires are bad they are NGK wires and have maybe 3500 miles on them. And i switched wires and the problem stayed with cylinder one. The fuel injectors are also new less than 3500 miles. I dont see how that would effect the spark though. i can see it causing a rich condition in cylinder one ( as shown on spark plug) but i feel this is due to the weak spark on cylinder one, not too much fuel. It runs fine at idle no misses at all...only when in boost above 5500-6000rpm. Plugs are all gapped to .024" so its not blowing out the spark due to too large of a gap its just too weak

I will change the cap and rotor and check and clean all engine grounds and go from there

kbouchard1092

Recieved OEM cap and rotor today...will be installing it in a few hours.

If this does not fix it i am clueless... i dont see what else could be causing weak spark to only one cylinder.

If coil/ignitor realted then all cylinders would be effected. Same goes for rotor but i replaced it anyways.

It has to be distributor cap. We will see...

If it does not fix it i will post up a video showing how every other cylinder has steady flash and when you clip onto cylinder 1 wire you get hardly any response. Still gets spark, but must just be weak since when its unplugged you can clearly hear the misfire. however the timing light has a hard time picking up the signal on clyinder one

So my hypothesis is its getting a weak enough of a spark to fire at idle and under light load but under boost it is not strong enough to spark and the boost is blowing the spark out causing the misfire. seems like dist cap must be the culprit i have no idea what else could cause this

vwbased

have a nice day

Turbo-LS

iTrader: (4)

its not the distributor, if it was the distributor it would effect all four cylinders. its either a wire or cap/rotor, could be ecu or possibly the ICM but usually if thats going it would effect all four cylinders not just one.

what msd setup was on there prior ? How was it wired?

Hulkdon1

It is definitely an ignition problem. If he can't get a steady spark to set the timing, then it has to do with ignition system. The motor compression will not affect setting the timing. I hope replacing the cap works. GL.

kbouchard1092

Ok So last night changed Spark plugs, CAp and Rotor. Still having the same issue. At first it was a steady spark but once it warmed up it started to miss here and there...ITs better but clearly did not fix the problem

BAsically the car runs fine until it starts to pull in boost then hits a wall around 6k rpms

When i took the plugs out to change i noticed the plugs looked fouled still a little wet....but to me seemed normal since it is missfiring.

Now im thinking it could be a injector? could this cause a rich condition at idle?

IF not it has to be the following.
- low compression ...Burnt valve maybe? Although it does run fine besides high rpm.
-too tIght valve lash?
- Injector
-ECU? i have s300 installed w/boost control hardware

It seem like thats what it would be narrowed down too...im going to do a compression test before i go and buy anything else. If im getting good compression then im leaning towards the injectors. would would think low compression is possible since if the plug starts getting really dowsed with fuel then it wouldnt spark and that would be why the timing light is picking up on the misfire. I guess the bad injector could do the same thing.

here is a picture of the plugs on 2 and bad cylinder 1

this is after 10 min idling and a 4 mile drive tops...you can clearly see it is still running rich (these are brand new plugs 4 miles driven)

kbouchard1092

This is the picture after 4 miles of driving...clearly it is fouling out and running richer. i dont htink its the distributor anymore...either low compression or injeector

kbouchard1092

ohh and to turbo LS i had previosuly a MSD SCI...it was wired corretly. It worked great for about a year then it would cut out completly, it was melting my spark plugs ground straps. After i went back to factory igniton it worked great... i read factory is the way to go anyways...my power will never exceed 450whp with my turbo. beyond that i would upgrade to the m&w pro 10 kit

kbouchard1092

injector or compression....its one or the other.

with valve lash being highly unlikely...but i will check it out if the compression is there

Then ill have to switch injectors and see if the problem switches cylinders

kbouchard1092

what compression should i see at i beleive there 9:1 JE could be 8.5:1 tho...its def one or the other tho no more than 9:1

kbouchard1092

Ok finished compression testing here are results
#4,3,2,-175
#1-180

I'm also switched injectors and cylinder one spark plug still looks much more fouled then all the others

I'm stumped...

Only thing I can think of is ecu... The distribution would make all 4 mess up.

Any ideas...might have to schedule an appt for tuning I wanted to get water meth injection anyways . Maybe now is the time. Not sure what's wrong but it seems the issues are def related to cylinder one running rich

vwbased

have a nice day

kbouchard1092

Swapping the connectors? i dont think that would be the best idea

Would it even run if you switched connectors?

i have 750cc so no reistor box....the wires were solidered and shrink wrapped

if there was a issue i would think within the ECU. it seems like there may just be a bad connection somewhere since it does spark but misfires often

vwbased

have a nice day

stock95coupe

If the distributor is somehow warped (entire housing), your rotor could be farther away from one prong than the others. Clay each prong like you would pistons/valves.

Think of it like a ceiling fan. If the shaft or a blade (rotor tip) are off, the gap is changed between every wall (prong). If the fan is mounted at an angle, it would be closer to one of the walls and farther from the opposite wall.

turbohatch96y7

iTrader: (15)

If this were true wouldnt pne prong on the cap be smashed or broken since ots spinning in a circle if its too far from one prong it will hit the opposite.

And if you swap injector connectors wouldnt it spray gas at the wrong time throwing the timing of the whole motor off?

What I was thinking maybe you have something on the head or threads of the head where the plug goes not allowing the spark plug to ground properly? Causing a weak spark. Have you put a screw driver on the plug wire and arked the plug to see what color spark your getting?

stock95coupe

There is something like a 1/16" gap normally. Just like a spark plug, a 25% increase is gap may be enough to **** it up. The actual timing would not be off, since the ecu controlls the timing, not the angle or exact possition of the rotor.

Given the coil charges up to a couple thousand volts, gunk in the threads won't be an issue. It's enough to jump through your body (half a million ohms at times), and definately would jump through the hex portion to the metal tube around the plug hole.



I'd try another distributor.

Spawne32

iTrader: (3)

ok i gotta get this off my chest, are those things caked in antisieze? you realize that all plugs are coated on the threads to prevent seizing and galling right? lol

turbohatch96y7

iTrader: (15)

I bet all that antiseize is the problem. I never put that stuff on once. Ever. I just never tighten the hell out of my plugs

Turbo-LS

iTrader: (4)

if your going to put antisieze on a plug you literally just put a tin dab on one small part of the thred no caked on

Spawne32

iTrader: (3)

has there been any mention of what type of plugs the OP is using? I see BKR on the first part of the plug, what is the heat range etc, and what kind of mods are we looking at here on this engine.

Spawne32

iTrader: (3)

if that one particular injector is leaky, causing the cylinder to run much richer, you can swap the injectors between cylinders, and see if the one you swapped it too does the same thing.