DodgeTalk Forum banner

Code points to cyl#4 misfire.

1050 Views 2 Replies 2 Participants Last post by  BNTune
With a bad idle when hot,Eng. shakes with foot on brake.
Came down to doing a comp. test. #4 cly had 75lbs. :pissmonke with #2&6 reading 150+.
This being on a 97 GC [email protected]
A leak down test with #4 cly @TDC had air coming from Ex.
No air sound was heard from crankcase and intake.
Can a vavle lash adjustor cause the vavle to not seat.?
When eng. is cold the idle is smoother and eng. does not shake as bad when hot.
The Ex. has a putt,putt sound also when hot and also sounds like it's firing smoother when cold.
Is the 3.0 head pron to cracking,vavles burn,vavle seats cracking.?
Had thought maybe a head gasket leak between cyl#2 or #6.
Only had the Van for three weeks.Looks like I did not do a long enough test drive to get Eng. hot :VHOT:
Not open for further replies.
1 - 3 of 3 Posts
i have just looked at my factory service manual regarding the auto lash adjusters for the valves

these are not adjustable/repairable

the manual gives a procedure for checking the free play; if there is no free play, then the lash adjuster must be replaced

I quote "check auto adjusters for free play by inserting a small wire through the air bleed screw in the rocker arm and VERY GENTLY pushing the auto adjuster ball check down. While lightly holding the check ball down move the rocker up and down to check for free play. if there is no play replace the adjuster."

Thus ends the lesson.

conceivably, if there is no free play, the valve would not seat properly and presumably, the problem would get worse as the engine heats up.

however this is an educated guess

a poorly seating valve will cause a misfire and a burned valve

your leakdown test would seem to indicate a burned or poorly seating exhaust valve

I see a reconditioned head or two in your furure
See less See more
I thought so

Thats what I read about the Adj. also. This I'll do(CK for play) for this only needs vavle cover removed. Would be nice though if is was that simple. :cool:
1 - 3 of 3 Posts
Not open for further replies.