mercenary223

I have a 1992 toyota pickup with the 3vze and was wondering what would cause low compression 125psi in all 6 cylinders. I tried adding oil to the cylinders and the compression didnt raise at all. I had a used but low mileage engine put in last year, at which point the truck seemed the same as before i took it in I thought it was the stupid 3 inch exhaust causing big power loss, but putting 2 and 1/4 inch on made little difference. Also misses in 3 cylinders and I had to adjust the distributor to the max just to get it timed. Please help im sick to my stomach with all the money ive put in this stupid truck.

BMcEL

Was the throttle open all the way during the test? Is the cam timing off? Seems odd that all 6 cylinders are consistently low.

5runner

yes check and make sure your timing marks on your cams and crank all line up

mercenary223

The throttle body was open. I havent took the cover off yet to check timing, but there is something wrong with the timing im sure with the distributor going as far as it can just to set time, and that is leavin no room for advance. Also my spark plugs were super white so I changed them and still super white after almost 500 miles I would think there would be some kind of discoloration to them. Also the cam idler pulley is making some noise which im sure cant be good. Ill be honest ive about had it with this truck its a big money pit.

skypilot

iTrader: (1)

Maybe its just wore out? even pressure is good.

Not like these were good engines from the start.

They are not stupid trucks, they are very good trucks, they are however getting old & tempermental. It takes time at the fountain of youth to bring them back!

Marc

Are you sure your gauge is accurate?
Like BMcEL said it seems odd that they are all low AND the same pressure.

mercenary223

I tried another gauge and it read 150 across the board, but when I relieved the pressure it stopped at 25 psi so it was off from the start. Last year I put a newer engine in it and now I am having problems. I am just irritated with the problems and prices for these engines.

mercenary223

Also how come when I add oil to the cylinder holes my compression doesn't come up. In my experience even with newer rings this raises the compression.

ksti

How sure are you this is a low mileage motor? and what happened to make you do a compression test? Just curious

mercenary223

As of these recent findings I am very unsure of mileage. I started testing because this engine feels really weak and idles at about 500rpm when warm. While the truck is cold it runs ok but still weak even for the 3 slow. I checked my fuel pump and it has good pressure And when I crimp the fuel return line the truck runs better so im thinking I have clogged injectors as well which stinks because they were all cleaned 9 months ago supposedly. Im just frustrated because of how much this engine costs to work on and the feeling of somebody telling me lies about a engine I bought.

ksti

I know this is probably a foolish question, but was there any kind of warranty on motor?
or was it a leave the driveway warranty?

2ndgenrunner

try changing the the fuel pressure regulator. you said you crimped the return line and it ran better it sounds like a fuel issue not a compression issue. if was an injector you would have a miss. im leaning more towards the fuel pressure regulator

Toy3sgte

iTrader: (1)

Even compression on all cylinders is a good sign. Also altitude and different compression testers will give different readings. Are you at or near sea level? Your car shouldn't run better when cramping the fuel line. Check fpr

Toy3sgte

iTrader: (1)

temperature makes a difference as well. you did jump te1 and e1 when timing the dizzy right?

mercenary223

There is no warranty just a mans word and handshake. Where im from that means something but apparently in Seattle not so much. How do you check the regulator also the engine does misfire intermittent in at least 3 cylinders. Toyota specs say the lower compression threshold is 142 psi compression and im 120psi across the board wet/dry makes no difference at all. With the cam idler making a lot pelf noise and the fact my distributor is adjusted to the max to set my timing dead on makes me think maybe he mixed up the cam gears. Ill remove the upper timing cover and do a leakdown test tomorrow and hopefully find answers. Im hoping for a cheap fix my mustang project is taking a hit and its almost drag season.

mercenary223

I am at sea level in seattle washington. Temperature is around 40-50 and test was done with warm engine.I did the paperclip thing to set timing and I crimped the return line which forced the fuel rails to build more pressure then normal and the truck idles better and smoothes out. I took vice grips and did this a few times in short intervals and same result. Smoother idle and a little higher which makes me think 1 of the problems is clogged injectors which explains the running so lean.

2ndgenrunner

Try the regulator first sounds like its letting too much fuel go by it wich in turn causes it to run lean. And if it straitened out with claping it 10/1 its the regulator. If it were the injector u would have a dead miss not an intermittent miss. Injectors eather work or not work they don't work every now and then so try the regulator

mercenary223

Thanks for everyones help I really appreciate it. Ill just put a new regulator in and see if that fixes the fuel problem. Im still at a loss for every cylinder at 120 and no change wet or dry. Also the engine is from a 1989 truck idk if that makes a difference or not, but i do know he changed my power steering pump with the new engine because he said mine was leaking. I thought nothing of it at the time but now i think he did it because my truck is a later 92 model and the engine i have in there now is later. Is there any other differences with the early to later 3vze besides the way the tensioners are.

Toy3sgte

iTrader: (1)

Leakdown tells a better story than compression test

Marc

When you do the paperclip thing the check engine light has to flash.
If it doesn't, it probably means your TPS is shot or out of adjustment.
Either way you can't set the timing properly.