91ToySR5

hey all...i had posted a few weeks back that i thought i was in for a top end rebuild. 91 toyota pickup sr5 v6 with 180k miles. did a compression test and had found cyl 6 to be at only 25psi, all others above 150. did a leak down test (oil added in spark plug hole), compression didn't increase so figured rings were good, must be leaking through the valve which is typical for the 3.0 to burn #6...

so anyway, this last week i tore down the motor and found somethings i wasn't expecting to see. got some pictures and would like some opinions... i can't figure out how to attach them, but ya can see them at http://photos.yahoo.com/rlcarnev they are in the "toyota folder"

first up... the plugs. in the pic of the plugs, i have them arranged 5-3-1 and 6-4-2 from left to right. all but cylinder six were fairly white... means i'm running fairly lean right? curiuos as to why cyl 6 is dark, was a little oily possibly from blow by?

carbon - found LOTS of it in the cylinders. not just caked on, but bits of it just floating around. couple pics of those...

couple pics of some scratches in the cylinder walls. can't get my finger nail in them, but just about all of the cylinders have vertical scratches. cannot see any cross hatching in any of the cylinders. pic of cyl 6.. no vertical scratches, but has weired circular marks all around the cylinder walls... am guessing the piston was wobbling around in the cylinder?


some pics of the cam and bearings - some light scratching as well. can't get finger nail in them and tech at work said they didn't look too bad either...


i checked the head with it off - put some gas in the combustion chamber with it upside down, didn't leak down so valves must be seating...

so i guess my questions are... why so much carbon (and flakes) in all the cylinders, any ideas of the circular marks in cylinder 6 and why 5 of the plugs white and cyl 6 black and oily (blow by?)...

thanks in advance everyone... i've ordered a short block and will be sending the heads out - stainless valves to be installed...

91ToySR5

another thing i noticed when i was doing disassembly... when i disconnected the rubber hose (vacuum line) to the fuel pressure regulator, fuel came out of it... that shouldn't happen correct? do i need a new pressure regulator?

Bumpin' Yota

Well if that's carbon deposits (and a lot of them too) that would explain the white on the spark plugs...detonation. Have you had to run 93 to keep from pinging like me?


Right now my HG on #6 let go, and honestly Im expecting to see something like what you have there. All ofmy sparkers are white with deposits save #6 which was clean...lol

About the FPR. There are acutally 2 rubber hoses on it. The one on the very top hooks to a vacuum line that connects with the lines on top of the throttle body. This one should only have vacuum. The lower line which is a little bigger is the fuel return line that goes back to the gas tank...

91ToySR5

bumpin yota - thanks for the info... i was running only 87 octane (yuck). only time i had pinging was when i'd start out in like a parking lot or my driveway where i didn't pick up the idle - no pinging while acceleration or under load surprisingly...

always had kinda poopy idle, it'd be level but ya could tell it wasn't smooth, definately had loss of power, any kind of incline on the highway and it just couldn't keep up even 65mph. i had gone thru most everything else in the truck, ignition, fuel filter, TPS sensor, timing, tested AFM and coil... when i did the compression test is where i found #6 to be at 25psi. i added some oil to the cylinder thru the spark plug hole and it didnt' go up, so figured it had to have been just from a burned valve on #6 as is most common. but once i got the head off and saw what the cylinder liner looked like in #6, am guessing it just had very bad blow by... still not sure what all the ringed marks are on the cylinder walls... headgaskets showed no signs of leakage! they were replaced under the recall back in '97... 9 years later they're still good...

the FPR - definately is the larger line, so must be the fuel return as u said...

so i found a SMOKIN deal on a new (reman) short block ($500), have a lead on some heads already done, or i have someone that can redo mine...

omg - i forgot about my radiator - i have to put a pic up of it. the whole engine side of the radiator is green like the statue of liberty and if u gently touch any of the fins on the lower end they literally disintigrate... i'm just really shocked cuz i didn't have any kind of overheating problems...

again thanks for the info bumpin yota... good luck with ur project.