Motor no compression
Thread Starter
|
Junior Member
Joined: Jan 2005
Posts: 1
Likes: 0
From: indiana
Motor no compression
Hey guys, Just recently found this site. 2 weeks ago my f150 took a dump on me. I was pulling a small trailer and suddenly heard a weird noise. On several occasions I was gettting a spark knock while towing. I was told by a ford mechanic the fuel octane level was too low. I did use higher grade fuel but problem still existed. After tuning up the engine by replacing plugs, wires, coil packs and fuel filter I am basically done. Motor condition is still bad. Took the truck to a shop and they informed me only firing correctly on four cylinders. After a leak down test was completed I have 25lbs of compression on four cylinders and 125 on the rest. I have purchased a different motor but I am really disgusted with the truck. The truck has 104,000 miles on it today. Who would think a motor would go down yet. Any help or feedback would be appreciated.
Senior Member
Joined: Jan 2005
Posts: 5,389
Likes: 0
From: Fort Worth,Tx
might check head gasket seals... could have a bent valve... or rings on those cylnders are bad. check ur EGR valve could be clogged up would cause nock. but its most likely gonna be ur rings
Senior Member
Joined: Aug 2004
Posts: 384
Likes: 0
From: TX
Squirt oil into the cylinder and run another comp. test. The oil should seal the rings; if the comp. remains low, bad valves and vice versa with bad rings.
Detonation is destructive; your engine may be toast. Now is the time to check out what engines are options for your truck. My preference? 351M with C6/FMX auto or shop the transmission websites. Nice pulling power on the highway and you can get decent mileage.
Best of luck,
Detonation is destructive; your engine may be toast. Now is the time to check out what engines are options for your truck. My preference? 351M with C6/FMX auto or shop the transmission websites. Nice pulling power on the highway and you can get decent mileage.
Best of luck,
Senior Member
Joined: Dec 2004
Posts: 1,085
Likes: 0
From: poquoson virginia
Are the four good cylinders on one side and the four bad on the other side? If so, you could have jumped timing on one side. If the 4.6 or 5.4 jump timing, they most likely will bend valves. These motors are not very happy unless the cams are timed properly. If the cylinders are random, I'll have to think about it. The cylinders run from 1-4(front to back) on the pass side and 5-8(front to back) on the drivers side. Hope this helps.
Robbie
Robbie
