finally got around to the compression check since i finally had a few minutes of free time. personally i dont see anything alarming in the results, but hopefully i can get one of the gurus here to interpret the results.

cylinder, first test, second test
1, 137, 142
2, 150, 150
3, 142, 143
4, 134, 135
5, 146, 145
6, 145, 144

i dunno but they look pretty good to me... was holding my breath doing the test. all of the plugs looked similar, however there was one exception... the number 1. there appeared to be a little bit of rust on it... you need water for rust right? might be my imagination... but i doubt it.
any help on interpreting those results would be greatly appreaciated. tia.

not bad but not great either.i have 223000 miles and i have 180 across all 4.but yours is ok.anything below 120 is time to start thinking about a rebiuld,and below 100 your in seruis need of a rebiuld.

Those look OK, but approaching marginal. I see about a 13psi difference between low and high, almost 10%, which is the diff limit, 8% if you're conservative - didn't do the math but think you're over that one. The next test options are a cylinder leakage test and a text for exhaust products in the coolant. I'd do an oil test, too.

From an engineering economy standpoint, I'd say you don't need the $ for a rebuild right now, but I'd start saving.

I agree with the others - 119 psi is the low service limit with a difference of 14 psi high-to-low.... you're a little beyond the differential limit, but not enough to worry about - yet. It won't be long, though. You're not making peak power now, and probably using a little oil.

Frank

If you take your numbers taken at SLC altitude (4,500 ft.) and multiply them by 1.16 you will see what your compression would be at sea level. Example 142 X 1.16 = 165.

There is a huge difference when you take into account elevation. 14.6 PSI at sea level is only 12.6 PSI in Salt Lake City.

Hang in there, those numbers aren't bad at all. How many miles on your motor? <img src="/forums/images/graemlins/kewl.gif" alt="" /> <img src="/forums/images/graemlins/kewl.gif" alt="" /> <img src="/forums/images/graemlins/kewl.gif" alt="" />

mialge wise im in the mid 180's... unless you take the meats into account which would tack on probably a few thousand more. as to your point frank, i am using a little bit of oil... very little. the consumption is less than a quart every 3k miles or more. not liking what your saying about the rebuild... even if racers theory is correct. the heads are new, but everything in the block is original. ive got the spare block in the shed... mabey i should start saving my pennies for the guts. just hope its not now.
p.s. i thought the bottom end was supposed to be bulletproof.

The bottom end is fairly bullet-proof, but that only includes the crankshaft, bearings, rods and pistons. The wear is faster in the cylinder bores and rings - mostly cylinder bores.

I'm real curious about the other thread and the change when the fuel return line is pinched..... pay real close attention to what Eddy said.... he's absolutely correct. If I had experienced your problem and found that it disappeared when the return line was pinched, I'd first replace the fuel filter and see if it fixed the problem.... if not, I'd check the voltage at the fuel pump. If that was ok, I'd replace the fuel pump AND the FPR - just because I'd be damned tired of fooling with it and I would have confidence that there was a pony in the pile of parts.

Frank

fuel filter has been replaced most recently at about 3 months ago. havnt checked the voltage at the pump or replaced the fuel regulator. what should it be at the pump and besides replacing the regulator is there anything to do that is maintenance?

fuel filter has been replaced most recently at about 3 months ago. havnt checked the voltage at the pump or replaced the fuel regulator. what should it be at the pump and besides replacing the regulator is there anything to do maintenance wise?

The fuel pump should see battery voltage or ~12.0vdc. You can check the voltage drop in the wiring by putting one voltmeter lead on the battery (+) and the other lead on the fuel pump (+) terminal.... the reading is the amount of voltage drop.... you will have some, but it shouldn't be more than .5 volt or so.

There's no maintenance to perform on the fuel pressure regulator... it either works correctly or it doesn't. Unfortunately, without a mechanic's fuel pressure test kit, you can't check fuel pressure on our trucks.... and by the time you do the work to hook up a gauge port, you have the regulator exposed and might as well replace it.

Before you go to a lot of trouble, check the vacuum hose on the regulator and make sure it's not cracked or unplugged. The regulator is the round can on the rear of the fuel rail.... passenger side.

Frank