help: 93 vr4 running rough suddenly (datalogs incl.)

[Chris@Rvengeperformance]

is it just me or does your TDC indicator on the crank pulley seem WAY off? Is that just a nick in the pulley?

yeah that's like a 99% chance the valves are bent up. It is amazing it runs at all.

Pull the crank pulley off and see the timing cog mark vs the oil pump.

[NOMIEZVR4]

Finally someone is giving this guy some useful advice...

[Jimvr4]

Best case, PO broke off the roll pin and misaligned the crank pulley

[stealthtuner]

so on earth do all the cam gear timing marks line up perfectly?

im not convinced its a timing issue. but ill look into it.

[anyonebutme]

Cam gear timing just tells you how the cams are phased in relation to each other, not the crank, that's why there's a timing mark on the crank and you HAVE to align all 5 when setting timing. The crank gear can jump teeth without the cam gears jumping, it's most common when something drops down there like a stray old timing cover seal. Also, the aftermarket crank dampers don't have the timing mark in the correct position so the only surefire way to check is to pull it off the look at the actual timing mark on the crank cog. If you don't want to remove 2 belts and a bolt (I think you can see the marks with the cover still on), a rod down #1 cylinder will get you close enough to even see if your damper mark is correct or not.

The bottom line is, if that's an OEM pulley that has not begun to separate from old age, and the roll pin is still in tact, your cam timing is off and you're pulling the heads to get new valves.

[CoopKill]

[stealthtuner]

timing was done by the person I bought the car from. he built the car from the ground up and knew what he was doing. I had no issues for months. so if timing is off its not because it was set wrong, its because tooth were skipped by the crank pulley.

I certainly dont think I need to pull heads and replace the valves. The car is running too rich. That is the only thing that is certain. like 10.5 afr when attempting to drive. i dont think timing being off would result in that.

cant you check the timing in the datalogs anyways? Ill attempt the timing check method through the spark plug but i would probably need some help with that to make sure I do it right.


also what are the instructions for a rod down cylinder 1 method? how exactly do I do this?

[stealthtuner]

Best case, PO broke off the roll pin and misaligned the crank pulley

could this possibly explain the misalignment?

Remember the cars timing WAS set correct and it DID drive fine for several months. It started up like this one morning random. And no I wasn't beating on it.

[Chris@Rvengeperformance]

yeah the tensioner relaxed overnight and skipped time.

With the amount of time spent speculating you could easy get the crank pulley off and check or the spark plug screwdriver check at least.

[CoopKill]

Pull front drivers side spark plug, stick long screwdriver in, turn crank with 1/2 inch ratchet till screwdriver is at highest point, check all 5 timing marks.