22 replies to this topic

[xrocketengineer]

yes i have spark and the problem is only on cylinder no 3...

Well, then is not electrical. Some weird thing is going on with the head. Maybe a (smart) sticky valve or something went down the intake manifold into the cylinder no 3 intake port. Regardless, it is a "smart" failure since it only happens with very specific conditions and then corrects itself. I had smart failures before but most of them were electrical.  Mechanical ones are usually related to parts not moving at the right speed when they are supposed to due to friction, inertia or interference by something else.

[jaydee]

Just do a compression test and post the results

[sledgehammer]

What cylinders are the servo pipe on ? (usually 2 cyl miss-fire low speed) -  may be worth blanking it off to eliminate it

 

my money is on a intake leak some where , or pipe cracked / loose / off

Edited by sledgehammer, 23 October 2013 - 09:11 PM.

[mikespicooper]

165psi no1

166psi no2

165psi no3

167psi no4

 

all possible leaking points checked and changed every pipe that was suspected to be a cause of the problem.

Edited by mikespicooper, 25 October 2013 - 04:23 PM.

[jaydee]

If you had a leaky valve or even a sticky one it should have affected the results, these are on the mid-low side but show no compression problems across the cylinders. I'm starting to think again its electrical..

Did you play with the TB and injectors? I had a similar problem with an spi when the owner decided to take out the injectors and the TB to clean them..

[mikespicooper]

I'm 85% that is electrical that's why I didn't take the head out if it was a valve it would still rev up on three cylinders not just at idle and even under load the engine still runs on all four cylinders.

[xrocketengineer]

I'm 85% that is electrical that's why I didn't take the head out if it was a valve it would still rev up on three cylinders not just at idle and even under load the engine still runs on all four cylinders.

In that case what about the coil? On the other hand, have you watched the valve train (valve cover off) while idling for anomalies?

Edited by xrocketengineer, 29 October 2013 - 02:52 PM.

[mikespicooper]

checked while running and turned by hand to observe with no oil splashing all over my face

Customer will bring the car back until the end of the week he has sent it to an automotive electrician sort of guy and he said that now it runs fine but i will check if it still runs like that.....what a headache but i still don't believe that is a valve problem because this happened after he tried to remove the inlet manifold by himself and when he got all back together s**t happened!