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Need help with this engine problem...lol

Zack

4 Doors 4 Life
Mar 21, 2004
6,297
20
NW Indiana
Need help with this engine problem...I THINK I FOUND THE PROBLEM!!!

My beater breaks up under load...especially when its hot out.
Just swapped new coils in, engine has 20in of vacuum, tps ramps up voltage just fine and the fuel pump maintains 40psi under all conditions.
No visible wiring harness problems, new plugs and squeaky clean maf.
I even took the egr out of the equation and that didn't help.
Im stumped!

I've had a bad FRPS before but not symptoms like this.
The car idles smooth as glass but sometimes sounds like it has a dead cylinder when cranking.
 
Last edited:

Silverback

Member
Oct 19, 2011
83
0
Please define "breaking up"? Misfire, back fire, "snap crackle pop".

Define under load? WOT, going up a hill, passing another car, what RPM range?

Perhaps a fouled injector(s) or poorly responding one.

BTW, my car seems to have a noticeable improvement in city MPG since you repaired the engine.

Regards,
 

Zack

4 Doors 4 Life
Mar 21, 2004
6,297
20
NW Indiana
Did a compression test:
All cylinders are around 180psi with the exception of #6 at 150psi.
Checked it again and it was 145.

I know its not the shortblock because this was in a different car running fine.
I had the heads done when I swapped it in this car.


Im HOPING its a valve spring thats the problem. I also put a stethescope on the drivers cams cover and there is definitely a noise thats not normal.
Ill pop the cam cover tomorrow and report back.
Maybe Ill get really lucky and find a follower that popped off and got lodged in the spring.
 

Zack

4 Doors 4 Life
Mar 21, 2004
6,297
20
NW Indiana
Nothing wrong with the head.
The more I study the piston in #6 and #7...it appears as though there was never a good seal between the two. The areas at the top are clean like a bit of coolant washed them off...maybe hole to hole leak as well....which would explain why I heard it out the exhaust because #7 exhaust valves were open when I pressurized #6.

Only on my car...lol
 

Zack

4 Doors 4 Life
Mar 21, 2004
6,297
20
NW Indiana
Does this mean a faulty head gasket, a warped head or head bolt torque no longer uniform or tight enough.

I think you saw that on Mark's car a few months back.

Yes I did.
Dont have a clue what happened....gasket didnt show any signs of leaking.

The only thing I did different (i think) is coat the bolts liberally with 30w oil.
Normally I just throw them in and tighten.
 
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