88G35

iTrader: (3)

Ok so over the past few weeks of driving my car I have been pushing some pretty high boost for a stock auto tranny. However it doesn't seem to be making the power it should be. So I went to take a look at the engine. I pulled all the plugs and all were fine except for cylinder #4. When I pulled the plug it was like brand new with basically no carbon buildup on the plug or the piston. Now I thought I might be running down a cylinder but they car seems to run smooth and fine just doesn't have the power. Another thing I noticed when the engine is cold and you see the exhaust coming out the back on cylinders 1,3,5 there is more exhaust coming out then on the side with cylinders 2,4,6, I do not have an exhaust leak. I remember back when I had my Emanage Ultimate and it blew out a coil pack and I was running on 5 cylinders and this doesn't feel anything like that. I have tried adjusting the Haltech Cylinder trim but nothing seems to do it.

I have also taken off the fuel rail and primed it and only connected cylinder # 4 injector to the harness and it was spraying fuel, and yes I am getting spark. If anyone has any idea as to what might be going on please let me know.

Dynosty

iTrader: (27)

What brand injectors? Maybe send them all out for flow testing - sounds like the #4 is barely flowing at all? If you set cylinder trim #4 to +100% is there any noticeable difference?

KRRZ350

A blown headgasket will steam clean everything. The rev-up I'm rebuilding right now coincidentaly had a blown HG on cylinder #4 from juicing for to long in 4th gear, everything was much cleaner, along with some other damage.

Anyways, you need to do a compression test on #4 before driving it any further, a blown HG get's my vote.

88G35

iTrader: (3)

I have only tried minor adjustments on the cylinder trim for cylinder #4 but I will try putting it up to +100% to see if there is any difference. I am running RC injectors. If I dont find anymore results then I will send them out to get flow tested. Thank you for your input Hal!

Will do the compression test later when I get home today. Thanks for the help!


I will report back later today when I get home from work.

track1z

iTrader: (4)

Comprssion,then leak down.

88G35

iTrader: (3)

Did the compression test it came to 120psi at a 9:1 CR.

undrgnd

iTrader: (2)

What were the other cylinders? You only checked #4?

88G35

iTrader: (3)

Cylinder #1-117 PSI
Cylinder #2-121PSI
Cylinder #3-123PSI
Cylinder #4-120PSI
Cylinder #5-119PSI
Cylinder #6-122PSI

go-fast

pics of the plug compared to the others would help but given the symptoms it can only really be one of two things,bad hg or bad injector.move the injector to another hole and you will have your answer.(put a dirty plug in #4 so you can see if it gets steam cleaned)

Eazzy

iTrader: (8)

Sounds like you have---as kinda mentioned, a bad injector or signal to it. Pull the connector and inspect it---for a laugh put a new plug in. I think you can position that coil pack, ground the plug and visually check the spark.

But ---a spark not under compression does not always mean you have a spark under compression

Eazzy

iTrader: (8)

Whats odd here is---the comp should be in the 180 range. Maybe 170 Min


I just checked ---142 is Minimum....185 is ideal----Chime in , but even with 9:1 those comps seem low

If your Cammed --That may lower them @ starting RPMs

KRRZ350

I agree with you that those numbers might be a tad on the low side as well even for a low-comp motor, But the consistency between cylinders is very good.

No codes correct?

Condition & level of coolant and oil?

With engine idling have you tried to unplug #4 to see if it is indeed running on all 6?

That is worth a shot, if it is not pull the coil-pack and plug it back in & insert a spare spark plug and check for spark, allthough I have a feeling that something else is going on simply because you stated it is nothing like when you were previously running on 6, this scares me.

SO, next steps IMHO:

Check fluids, allthough I'm sure you have done so already.

Check vacuum reading @ idle, I know your car is boosted but if your gauge isn't accurate (Meaning well defined) plug in a good vacuum gauge temporarily in the 'bay

Above advice, check for firing than spark if applicable

Perform another compression test, only make this one a WET compression test

Perform a Leak-down test

go-fast

it's probably not a spark problem.if it was dropping spark the plug would be fouled with carbon soot,not clean.

88G35

iTrader: (3)

I have checked all my levels and they are fine. I did also ground the spark plug and cranked the engine and I was getting a spark. I also have already pulled the coil pack while the engine was running and nothing changed when I pulled it.

Correct me if I am wrong here guys but if I had blown a head gasket wouldn't I run into other problems like the engine smoking from coolant running into the cylinder and stuff?

I will do the next steps that you guys stated about and I will report back to you with the results. Thank you for all the help guys!!!!

Eazzy

iTrader: (8)

Leak down is important --run that. and as far as Gasket--do a radiator pressure test in the morn when the engine is cold. Inspect your radiator coolant IN the radiator and see if there is dis colorization.

But the main thing is check that injector to see if it getting a signal. I have had many diesel injectors tested but never a pulse activated injector---If nothing else switch it out.