Running on 5 cylinders!

[camino70]

My car is running not so good!

Not really sure where to look, so...

If feels like a miss, running on four or five cylinders, maybe super rich. I swapped out the coil pack and module, both coil packs ohmed out good 11K-13K, and no difference in idle. Good and steady fuel pressure, steady as in not erratic, moves up proportionally with boost. One thing I did notice was that the O2's weren't jumping as far or as fast as seen in the past. They still jump around, but mostly hover in the 4-500 range.

I pulled wires one at a time at idle, some would kill the car, some would have slight difference in idle and number 3 didn't change a thing! I pulled the boot off of the cap and it is getting as good of spark as the rest. So I pulled the plug, looks good, and started it up. Thats getting good spark too! The boot felt like it was on there good, but.... Its hot and I am annoyed, so here I am, I will put it back in tomorrow and make sure the boot is on very good! But in the meantime are there any other ideas for me to look at.

TIA

Ron

 

[Wicked]

Do a compression check on the weak cylinders. If they are low you
have an internal problem.


Wickey Wickey Wickey

 

[camino70]

Thats not what I wanted to hear

Someone also said to do a leak down test. I am not sure what that is?

What should I look for with the compression test? Ratios between all the cylinders or a certain number for each.

I did compression test last year some time and I believe they are all within 10% of each other. I am not sure what the numbers were, but I think they were in the 130-140 range.

I will try to do one tonight and let you know.

Ron

 

[Wicked]

You don't have to do a leakdown test a compression test will twll you right away. As long as all cylinders are close your OK. If any
are lower and you will know, bad cylinders usually read 0 to 90
psi.. Bad news. If test is good try another plug and wire from
another cylinder and see if it fires.

Wicked

 

[b231v6]

Pull all the plugs out and look at them. 10 minute job. That way you know if all your plugs are firing. Good luck.

 

[camino70]

Thanks!

I pulled all the plugs and all look very good, the passenger side bank looks leaner then the drivers side and #6 is definitely the leanest! I put a new set in and a new set of wires too. Started her up and still seems to be running pig rich! I got my extender chip in yesterday and decided to try that out. Cleaned the idle up, but it was pouring out so I didn't test drive it...

Before I put new plugs in I did a compression test. 135-148 psi on all cylinders, so I think/hope they are ok!

Ron

 

[Chuck Leeper]

Some places to look

If #3 cyl is dead, then it could be the injector harness at the EGR valve is toasted. #3 wire is wrapped on the rail, and can rub on the base of the EGR.

If the cyl is dead, the compression is good, and the plug is firing, fuel is about all that's left. How old are the injectors??

Also, any cracks in the headers?? If not, and the O2 x counts are low, I'd change the sensor out w/ a new DELCO piece...What's the O2 readings when you drive it?

Don't be mis-lead by the ohm check on the coil.
The ign should be tested under load w/ a CASPER'S tester.. You can be surprized at what is found when it's tested that way...

My $.02 worth.. Back under my rock

 

[Ormand]

Number 3?

Isn't it usually the number 3 cylinder that loses a cam lobe? A bad lobe would make the cylinder weak, but I don't think it would show up on a leak-down or on a compression test. If you pull the valve cover, and check the valve movement of that cylinder, you would know for sure.

 

[camino70]

The injectors are only a few months old. I will take a look at the injector harness.

My headers are not solid, I ran some TEC through a little while ago and got some smoke out of them. After I let the car warm up, the O2s started to bounce around more from down in the 0XX's to 7-800.

Does Ormand's idea hold water? I guess it wouldn't be too hard to check it anyway. Is it usually intake or exhaust?

Hopefully it will stay dry for more then an hour here so I can take it out for a spin.

Thanks again!

 

[Wicked]

Your engine compression is good. As for the cam lobes the intake
lobe would show on a compression test. If it was wore you would have low or no compression. The exhaust side won't , gauge valve holds compession in the gauge. If the exhaust lobe was wore it would pop back out of the throttle body rythmicly. Your
engine is more than likely OK. I would also check the injector harness at the main connector. You could swap injectors around to see if the dead miss moves with that injector.


Wicked

 

[dadmomcat]

2 cent worth

I had the same problem for a while, could not figure it out, every thing was right on. I was running on 5 cylinder, checked my ECM and found that one wire had worked loose in the plug that fired the injector. You could not see it by looking at it, just started the car and pull on each injector wire, till i found the loose wire.

I purchase Casper ECM wire harness, and rewire both plugs going to the ECM. Just maybe you may have the same problem.
Good luck

 

[camino70]

Wiped Cam

Well,
I got on it today, it seemed to be running ok. The boost went well past, what I thought it was limited to and there was 14 degrees of retard. On the way home I limped because it didn't like a load. I let it cool down and decided I was gonna pull the valve covers, but before I did that, I pulled the breater. And right there #3 exhaust wasn't moving!

So now what? And why does #3 seem to be such an unpopular lobe that gets wiped out!

Thanks for the help!

Ron

 

[86gn]

I have never had a lobe wipe on on me,sorry to here it happend to ya.Looks like its time to pick out another cam to swap in there,as far as what other problems it causes I will let someone who it has happend too answer that one.