is this a bad thing? lol.

[Yankee Hick]

i've got a stock 350 TBI in my 91 K1500.

*** oil pressure (even with 20W-50 oil), after warm up, is still roughly 30psi at idle, never gets about 60psi.
*** did a compression check on all 8.  best was 100psi, worst was 57psi.  i had 3 total cylinders that were between 57 and 70.
*** new fuel filter installed last week.

engine is lurching and surging, tach is all over the place, no power (obviously), and the idle is up and down.  i (correctly) replaced the intake gasket last month, and have changed the oil twice since then, to insure there wasn't any leftover antifreeze in the oil.  there are no leaks.

am i correct in thinking that this motor has seen it's last days?  she's got 215,000 on it, and i haven't been nice to it.  i'm thinking it's time for either a rebuild or a different motor.

opinions are welcomed.  thanks!!!

[blasterguy911]

that seems low on compression.

[Kyle]

i would almost think more of an ignition issue....

and the oil pressure never gets that high on tbi motors. it can idle down at like 5 psi but as long as it makes 25 psi with throttle ur fine

[Yankee Hick]

should i have the ignition module checked?  going down the road (barely), the oil pressure is around 40 or so.

[Kyle]

wouldnt hurt to have it checked since its free. clean up the ground wire for the computer. o2 sensor still good? clean out the egr valve. hows the fuel filter?

[Jjay78]

sounds like you got a bad head gasket and bad rings, the psi on that should be between 135-165 depending on the heads and gakets, your barely making enough compression to run man, you need to check and make sure the valves are not to tight and are closing properly, and that your head gaskets aren't leaking  and if your rings are even there any more, do a leak down test on each cylinder, if ya don't know how i'll walk ya through it, that will tell you a lot about the condition of all those parts

[big red]

sounds like you got a bad head gasket and bad rings, the psi on that should be between 135-165 depending on the heads and gakets, your barely making enough compression to run man, you need to check and make sure the valves are not to tight and are closing properly, and that your head gaskets aren't leaking  and if your rings are even there any more, do a leak down test on each cylinder, if ya don't know how i'll walk ya through it, that will tell you a lot about the condition of all those parts

135-165 seems way high for any tbi motor i have ever seen.

[OHEARN.2012]

sounds like you got a bad head gasket and bad rings, the psi on that should be between 135-165 depending on the heads and gakets, your barely making enough compression to run man, you need to check and make sure the valves are not to tight and are closing properly, and that your head gaskets aren't leaking  and if your rings are even there any more, do a leak down test on each cylinder, if ya don't know how i'll walk ya through it, that will tell you a lot about the condition of all those parts

135-165 seems way high for any tbi motor i have ever seen.

hes talking about compression in the cylinders not oil

[OHEARN.2012]

maximum mileage man mine does the same thing low oil pressure when at idle take off it goes back up i do believe i have a bad head gasket havnt checked compression on mine tho and mine idles rough as hell but it still has power

[ricthewrench]

under 100 lbs is re-ring time

[Bowtie972]

Oil pressure ok, compression bad

[Orangecrush]

Oil pressure ok, compression bad

x2
its tired , time to over haul it.

[Yankee Hick]

Oil pressure ok, compression bad

x2
its tired , time to over haul it.

. I was hoping you'd say that.  Now I can show the wifey that the "pros" say i should huy this 355 I've been eying.  Lol.

[old school truck dude]

Pull it out, its had it. Compression should be even across the board, whatever the numbers are. When you have a wide variation you got trouble. Oil pressure is ok, long as you got some. No need to put ignition or other parts on it, problem is internal.

[Yankee Hick]

Thanks again to everyone for their advice!  Here's the next question (buy one question, get one free)......

The current motor is computer controlled.  The new motor will be carb'd.  Is my rachael still going to work if I remove the computer?  I've got someone who wants the computer.  Thanks again!!!!

[Kyle]

it will if you hook it up right. im gonna be switching to carb with my new motor

[Yankee Hick]

So I can pull the computer right out, and not have too many problems?

[Disturban]

When ever someone post something on a tech board asking (is this a bad thing?) the answer is almost always yes

You need a rebuild if your compression test is accurate, I would just look at some motors from junk yards and try to find one with some what low mileage. 

[Yankee Hick]

i've got a buddy that is coming back from Afghanistan in a couple weeks.  he's got a 355 with very low mileage that he's gonna sell me.  it's carb'd, which is what i wanna do anyway.  i want to get away from the computer crap.  another friend wants my computer, so i just wanna make sure everything is still going to work, or if i need different gauges.  trying to make sure the funds are ready.

can't wait for this dang thing to be done!  i forgot what power is! 

[Disturban]

i've got a buddy that is coming back from Afghanistan in a couple weeks.  he's got a 355 with very low mileage that he's gonna sell me.  it's carb'd, which is what i wanna do anyway.  i want to get away from the computer crap.  another friend wants my computer, so i just wanna make sure everything is still going to work, or if i need different gauges.  trying to make sure the funds are ready.

can't wait for this dang thing to be done!  i forgot what power is! 

If you have an automatic you will need a way to lock up the torque converter if you plan on driving it on the road.