Buddy changed out his timing equipment cause he had bad TC rattling. Well, now the car hesitates and bucks after 2k or so. Timing was not changed everything was marked and all that stuff. It's not the MAF as it was changed out. Plugs are fine, injectors sound fine. The car will get to 2k, and just buck for a sec, then be ok, and buck again. Also, seems to just die between 3-4k rpm in 4th...

 

Well this doesnt have anything to do with "advanced performance", but I'll assume you posted it here to get a quick answer w/o the n00b comments you could get on the generla discussion forums...

Even if its all lined it all up properly, its possible that at that initial cranking it could have skipped a tooth if there wasnt enough tention on the tentioner (was it primed???). Its happened to me before, and it sucks, because you have to take off that outer timing cover and check it all over again.

Is the cam pos sensor head clean? check for metal shavings on it.

and of course, check for codes.

tell ur boy good luck

 

well, I figured the timing stuff was advanced enough to merit me posting here. Yeah, I said it is prolly the timing but he was sure it's not...

 

if the chain did skip a tooth, would the hesitation not happen across the entire RPM band?

 

Idle would be funny if timing skipped IIRC. How is the TPS?

 

his idle is funny, stays at around 1k but jumps up once in a while. TPS wasn't touched so we didn't check it. The car ran fine with no problems before the 5spd swap and before the timing job...

I saw the insides of your trans earlier today kev, where did you get all the parts from again???

 

The idle isn't always funny, mine was like a dream using iacv. To confirm, vacuum reading, if low like 16-17" then hook up an obdII w/live data and check ignition timing @ idle, or easier yet, do step 1 using step 2.

 

subscribed because i'm also curious of symptoms with timing barely off a tooth.

 

lack of power all across the board, when mine was off 1 tooth it was barely faster than before, I also noticed that my optimal vias activation point was about 3,900-4k, if I set it anywhere in between their or 3,600 there was a huge dip in power immediatly after it opened until about 4k. Also, my IACV was able to compensate, but without it my car would idle like MDEEZY'S when his timing was off

 

Ah alright, yeah I just have a bit of a lumpy idle and it had me wondering but I'd probably know by now if it was off.
Sorry for the threadjack. As you were..

 

Ok, new engine is in, same problem. So it wasn't the timing and thankfully the new motor does pull harder meaning the old one was fukked. It has to be fuel or air related. Hooked it up to my scanner and as soon as it started bucking, the short term fuel trim numbers jumped up +25% for both banks while cruising they usaually stay between -10% and +11%. When the bucking kicks in they jump o +25% right away. I'm not 100% sure what it means but I'm guessing it's dumping too much fuel in?

 

Check the grounds for the crank/cam sensors.

 

weird my car has been doing this for awhile, and i cant figure out what it is!

 

grounds for those are both fine. Plus wouldn't the car have a hard time starting/running with those two being at fault? We're going over all the grounds and stuff that could've been forgotten during the 5spd swap...

 

Change or clean the sensors?

 

as I said all sensors were brought in with the newer engine. The engine was perfectly fine running in my car. All I can think of is a ground somewhere...

 

I'm having the same problems with my 3.5 swap in a 4th gen. but its only under WOT. went to the dyno yesterday and was only able to pull of 178whp on a dynojet. i'll post a graph up later.

 

MY 3.5 does it under reguler driving conditions, and i cant figure out what is it!

 

How old are the o2 sensors?

 

wiring possibly? almost has to be something that was used with BOTH engines