Ok compression test reads 180 on all except cylinder closest to distributor …#4? That one is 0…so car is running on 3 cylinders…maybe I should have said this before but car Burns oil horrkbly piston rings most likely…I was going to take engine in for rebuild soon. The spark plug in bad cylinder was also covered in black oil or gas idk but it was drenched…could a completely shot ring do this or is it more likely bent valve or something else? Friend swears bent valve but i don’t want just his opinion. Anyways I think I may just try to buy a different health engine instead of getting the rebuild and ill do it sooner than I was expecting lol…basically I just wanna know why this could be happening though…thanks a lot guys !
And one more thing…I found a ls motor Guy wants 350 motor is out of car already…what can I do, if anything, to tell if motor is legit or not if it is already pulled??
[QUOTE=LAMesa;2279388]I’m looking into injectors next lol…are you sure jumper is by overflow and not ecu???[/QUOTE]On my car, the test connector for the jumper is in the passenger foot well, just where the manual shows it to be. You can’t tell anything about the timing without the jumper plugged in (just for grins, I tried that) b/c the ecu is adjusting the advance trying to compensate. Only takes a small piece of copper wire.
If your timing is way off, the valves will not open and close when they are supposed to. Up to a point, the ecu seems to compensate for that. After that one or more cylinders will not fire, because the spark will not occur when it is supposed to. Same thing on other similar cars. So, a valve which is controlled by one of the cams may be open when it is supposed to be closed, and you may not have any compression at all.
Bottom line, if you do not look at the timing closely, first with the light at a steady idle, then with the valve cover off and crank pulley at TDC for cyl 1, and according to the directions, you may never know.
As for the injectors, you can swap them between cylinders.
The expense of a new engine on an older car is usually in paying someone to put it in, more than in the used engine.
you can run a compression test on the used motor. you’re not going to get as high numbers by cranking it by hand, of course. but you will get numbers. and as long as they aren’t far off from each other, it’s a good sign. your options are slim when testing a motor out of car. it’s not much. but it’s something. think if someone were trying to sell the motor you have in there now. at least the manual compression test would show you 0 in cyl4 and save your time and money.
another thing to do is have a close look at the plugs. they’ll explain a lot about the condition if you read them right. if the seller removed them prior to you coming over, be weary
Ok thanks so much for the help guys…like i said earlier the car does not have a steady idle right now…I’m still wondering if I can check/set timing with the map sensor unplugged. It seems to be the only way to get car to idle steady for any period of time.
But regardless I’m not going to buy that motor I’m going to take mine in for a rebuild in a couple days…I had my head done maybe 6 months ago so ill have him look over everything but I think most of the work needs to be done in the block…the guy will set the timing for me and when I get it back in the car ill do the ignition timing with a light…car is running (poorly) on 3 cylinders for now so it is getting me where I need to go but once rebuild is done I think it will be a lot easier to figure out any remaining problems, if any at all…
if you got no compression on 1 cylinder no amount of timing adjustmment is going to help… you definitely need to do a rebuild on it probably has a blown ring. all you are gonna do running the current engine is completely trash that cylinder beyond reasonable repair.
I’d personally follow welfare’s advice and go check out the LS for 350. that is the great thing about these cars is you can almost always find a spare engine to have ready to swap at a moment’s notice haha.
I am pretty set on the rebuild unless what you said has happened…ive put about 150 - 175 miles on the car since this happened, is it likely that the cylinder is done for?
hard to say without doing a visual inspection. you really won’t know till they dig into it on the rebuild. irregardless I wouldn’t drive the car right now till you get it sorted
since you had recent work done on the head, i’d be suspecting a burned exhaust valve. if the valves and seats weren’t ground right, it would cause this. run a leakdown test on it. or even just blow compressed air into the spark plug hole with the piston at tdc and see where the air leaks out. if it leaks out the tailpipe, it’s an exhaust valve. if it comes out the intake, intake valve. if it leaks out the dipstick tube, it’s a ring or land.
another trick you can try to determine if it’s an exhaust valve is, with the vehicle running, hold a piece of paper to the tailpipe. if the paper sucks toward the tailpipe at all, it’s an exhaust valve. because the piston will pull vacuum through the open exhaust valve, it’ll basically pulse the paper in and out.
or you can throw a vacuum gauge on it. if you know how to read the gauge, it’ll tell you exactly what’s going on
You need to confirm valve timing is correct before doing anything else, you can not set ign. timing if valve timing is off, [timing belt has skipped a tooth].
When was the last time the timing belt was replaced, when was the last time the timing belt tensioner was replaced/checked.
Another possible problem, [car runs rich/poor gas milage] is a bad ECT sensor.
Before anything else, check the valve triming, unless it is confirmed to be correct any other troubleshooting, [or tossing parts at the engine] is pointless, a wast of time and money. 94
^^he’s got a dead hole. that’s his problem
Well thanks for help guys the motor is out of the car now and I’m about to go drop it off for the rebuild …he will tell me what he finds after he opens it up and set the timing on it before giving it back…even before this problem it needed it…
Btw the belt and tensioned were replaced 5 or 6 months ago and ect sensor a few weeks ago
Yea I saw that after posting. I got busy and got kicked out so by the time I got back in to post OP had posted about the 0 compression, would have been good to know about the 0 comp. from the getgo. :sipread:94
lol. indeed