black spark plug, 7-9 psi on vacuum, etc...

[TurkF26]

im having a major issue with my car here. i just bought this car a coupel days ago. The previous owner told me that he just did the timing belt and water pump and that ever since he did that, it idles like crap, and runs like crap when NOT under boost. Now i figured that the timing was off a little bit.

When you drive the car, and boost, it feels fine and pulls REAL good but once you are under vacuum or idle, it runs like crap. I pulled the spark plugs and wires cause i figured id need new ones anyways. when i pulled the #1 plug, the plug was all black. The rest of the plugs were fine though. I replaced them all with NGK BPR6ES plus and Autolite wires. it still runs like crap.

my question is this, i dont think the timing is off because of the #1 cylinder plug being black. Also my vacuum is never less that 10 and usually sits between 0 and 8 which i know is not good. What does this sound like to you?? ive checked every vacuum hose and they all seem fine. The only other thing i can think of is when it is idling, back by the intake manifold, it always sounds like theres an exhaust leak kind of sound and i dont think its the exhaust cause it doesnt sound like that when driving. Any help with this would be greatly appreciated.

 

[DSM90AWD]

Sounds like the exhaust cam may be off a tooth or two (happened to me).

With the #1 piston at TDC (screwdriver in the sparkplug well trick) check that the cam timing marks are faceing each other at 3 and 9 o'clock and that the crankshaft pulley timing mark is at DC on the timing scale.

Remember to only turn the crankpully clockwise when finding TDC.

 

[TurkF26]

that sounds right or close too because the marks on the cam gears dont line up perfectly. but with the exhaust cam off, wouldnt all the spark plugs or at least more than 1 of them be black???

 

[armandovivoni]

did you do a compression test?

maybe the #1 injector is leaking.

 

[DSM90AWD]

that sounds right or close too because the marks on the cam gears dont line up perfectly. but with the exhaust cam off, wouldnt all the spark plugs or at least more than 1 of them be black???

Yes, this would not explain the sparkplug fouling so may want to check compression as you may also have more serious problem (bent valve, worn rings, headgasket).

Can check the injector by changing in a known good one or swapping btw #1 and #4 to see if any change.

BTW.. with the exhaust tooth off you would run lower vac at idle hence more fuel pressure (richer) than normal off-boost as the FPR is vaccume/boost dependant.

 

[TurkF26]

ahhh makes sense now. i just got new injectors from a friend and i am going to see if that helps at all but it seems like the exhaust cam is off a tooth and ill have to pull the whole belt off and realign everything