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!!!
that seems low on compression.
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
should i have the ignition module checked? going down the road (barely), the oil pressure is around 40 or so.
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?
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
Quote from: Jjay78 on June 24, 2011, 10:48:08 PM
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.
Quote from: big red on June 24, 2011, 11:46:02 PM
Quote from: Jjay78 on June 24, 2011, 10:48:08 PM
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
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
under 100 lbs is re-ring time
Oil pressure ok, compression bad
Quote from: Bowtie972 on June 25, 2011, 01:26:55 AM
Oil pressure ok, compression bad
x2
its tired , time to over haul it.
Quote from: Orangecrush on June 25, 2011, 03:54:22 AM
Quote from: Bowtie972 on June 25, 2011, 01:26:55 AM
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.
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.
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!!!!
it will if you hook it up right. im gonna be switching to carb with my new motor
So I can pull the computer right out, and not have too many problems?
When ever someone post something on a tech board asking (is this a bad thing?) the answer is almost always yes ==roll
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.
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!
Quote from: Yankee Hick on June 26, 2011, 03:06:38 PM
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.
what are you going to do with the old motor?
Quote from: Disturban on June 26, 2011, 03:13:52 PM
Quote from: Yankee Hick on June 26, 2011, 03:06:38 PM
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.
Toggle switch or have a buddy twist the wires together when you tell him loll
Quote from: old school truck dude on June 26, 2011, 03:15:17 PM
Quote from: Disturban on June 26, 2011, 03:13:52 PM
Quote from: Yankee Hick on June 26, 2011, 03:06:38 PM
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.
Toggle switch or have a buddy twist the wires together when you tell him loll
Summit actually sells a kit that is automatic...that's the way I would go. But yes a lot of people just run a toggle switch, problem with that is a lot of those people forget to switch it and if you are going on a long trip or something you could burn up your tranny.
not a problem for the converter. i've got the 5 spd manual. lol.
what all does the computer control? if i yank the computer, what's affected? the O2 sensor was disabled a long time ago, so no issue there. i just need to know if i nee dto go buy new gauges or not. i'm hoping not.
Quote from: old school truck dude on June 26, 2011, 03:14:17 PM
what are you going to do with the old motor?
you help me put the new one in, the old motor is yours, TBI, and intake as well. i only need to keep the accessories and whatnot that i'll need to put on the new motor. hell, you can even have the distributor / cap / rotor! it's all just a boat anchor to me anyway.
price for all that w/o the help (lol).... i dunno. $100 too much to ask for it? you pick up.
EDIT: i'd rather have the help, though. lol.
Quote from: Disturban on June 26, 2011, 03:13:52 PM
Quote from: Yankee Hick on June 26, 2011, 03:06:38 PM
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.
What he said. If you decide to go that route I will find out from my brother where he got his, its adjustable...
Quote from: Yankee Hick on June 26, 2011, 05:34:32 PM
Quote from: old school truck dude on June 26, 2011, 03:14:17 PM
what are you going to do with the old motor?
you help me put the new one in, the old motor is yours, TBI, and intake as well. i only need to keep the accessories and whatnot that i'll need to put on the new motor. hell, you can even have the distributor / cap / rotor! it's all just a boat anchor to me anyway.
price for all that w/o the help (lol).... i dunno. $100 too much to ask for it? you pick up.
EDIT: i'd rather have the help, though. lol.
pm sent
when doing a compression test you highest number and lowest number should be no more the 10% difference.
Quote from: chevyjake on June 28, 2011, 12:42:48 AM
when doing a compression test you highest number and lowest number should be no more the 10% difference.
And if you do get a wide variation, then you do a leakdown test
There was a HUGE variance. Highest was around 102, lowest was about 47 or so. Had 3 cylinders below 60. Kinda sucks, too, because I just replaced the intake gasket about 3 months ago. Oh well.
Quote from Disturban,"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." A simple toggle switch will do the trick
I work for parts loll
There will be beer involved as well, along with food afterward.
Quote from: Yankee Hick on July 02, 2011, 05:21:32 AM
There will be beer involved as well, along with food afterward.
You can drink it, I wont, but thanks! Im all jacked up on Pepsi! ;D ++peace
Me too, mainly cuz I work for them!!!!
Quote from: Yankee Hick on July 02, 2011, 08:31:24 PM
Me too, mainly cuz I work for them!!!!
You work for Pepsi?
Sure do. I work as summer help in the warehouse, loading trucks.
Yup they put you on to make sure the supply to me is uninterrupted in the summer cuz I drink a bunch when its hot loll
We're looking at possibly getting the motor Saturday the 9th. I'll let you know as time progresses. Trying to figure out where to do the swap.
Quote from: Yankee Hick on July 04, 2011, 06:57:51 AM
We're looking at possibly getting the motor Saturday the 9th. I'll let you know as time progresses. Trying to figure out where to do the swap.
We can do it here if you want, dont have no air tools though.. Corn fest comp bog and Middle rd play bog on Saturday, and Big dog has a meet n greet on Sunday goin on too.. kinda planned on those but we can work around it, I think
I'd like to do the corn fest bog. Afraid to blow the old engine though.
Im just goin to spectate, nothin runnin around here due to severe lack of funding :(