cant figure this out

[psi4power]

my car almost feels like the timing is being pulled. I can hit throttle and it will build boost but isnt going then take my foot out of it and mash it again then boom it accels like it should. Talked to alot of ppl and cant figure it out. any suggestions on a fix would be greatly appriecated

 

[psi4power]

also i checked for vacuum leaks on the fuel pressure reg and on the turbo related lines and couldnt find any leaks

 

[eXploitedGST]

time for a new engine!

 

[psi4power]

plz no post whores, this is serious

 

[Newlogics]

You really need a logger.

Here's what I bet is happening:

You develop severe knock at higher loads during lower RPMs (High throttle + low RPM), which is not that common on 1Gs (I've been through it, so have many I know, and my have it currently as well)
but happens to 2Gs as well.

When knock is severe (arounf 40ish), your timing is being pulled to sh!t, and thus no go. When you let it go and then gun it again, usually you are in higher RPMs by then, and don't develop that knock. Get a logger and see what's happening. I'm willing to bet money it's what I said.

In most instances, it is refered to as 'phantom knock', meaning it is not your fuel mixture that is causing it, but rather a mechanical/electrical condition. Several possible culprits are: Balance Shafts (they show distinct knock pattern on the logger), Faulty/Overtightened/Loose knock sensor, Carbon build up on your pistons. Sometimes you may have more then one (like me)

Balance Shafts: When your balance shafts are out of , well, balance, they will sometimes trip your knock sensor. The knock pattern will look like a saw-tooth. You will see rather sharp increase, and then gradual decrease (or drop off if throttle is let go) Usually, this doesn't cause extreme inconvinience or performance issues, as knock would rarely get up past 15-17 counts.

Unfortunately, the only way to really fix it is to remove your balance shafts all together. Doing anything else is simply not worth the effort.

Knock Sensor: Knock sensor failure hasn't proved itself to be a very common problem, and would normally show up as erratic knock or absence of any knock whatsoever (can be checked by tapping something metal on the engine block or even intake manifold.) Much more common is to have knock sensor too loose (wabbling will trip it) or too tight (makes Knock sensor too sensitive to vibrations ) If memory serves, it should be tightened to approx 6ft/lb of torque.

Carbon crown: Carbon crown will form from bruning oil, blowby, running overly rich for a while etc.... Once that crown builds up high enough, it will actually start slapping the bottom of the head surface. That also has a distinct knock pattern. It seems to happen worst at high load - Low rpms and logger will usually show sharp increase to max (43) knock, and will keep knock count at max untill you let off the throttle. If rpms are high enough by then, it will not re-occur if thorttle is gunned again.

Possible fixes (I've tried them and it helped a lot):
Quick:
Get some Combustion Chaimber Cleaner (I used SeaFoam, but most suggest Mopar, as it comes in aerosol bottles and is easier to work with). Disconnect your PCV hose from your valve cover, insert a small funnel into the end of the hose. Start the engine and keep rpms at around 1500 (no higher then 2K). SLOWLY (!) start pouring cleaner into the funnel. (Or spray if using Mopar). Engine will try to stall from huge vacuum leak and all that shit in your cylinders, but you should compensate with throttle to keep it running.

IMPORTANT! Do it slowly. If using pouring type cleaner, go through a bottle in about 20 min ! That means adding VERY little at a time. Otherwise you're risking hydrolocking your engine. Aerosol-type cleaner is much safer in that aspect.

Advanced: (I didn't have to do that, simple way helped)
After you have used up a bottle of the cleaner, let the car idle for about 10 min (It will smoke like craze, don't worry). Then, turn the engine off and take spark plugs out. split about 1/2 bottle of the cleaner evenly between four cylinders (pouring it in through the spark plug hole). Leave it overnight, then SYPHONE IT OUT (Extremely important) and change oil (most of the cleaner will sip through the rings into your oil). Then start the engine and wait for all the grime and crap to fly out of your exhaust pipe. It will smoke like a b!tch for 10min.

You should see MUCH less (if any) of those problems after all this.

Hope this helps.

edit I just realized you have 2G, so you won't be able to see knock patternts. You'll have to look at your timing behaviour to determine the knock.

 

[Defiant]

Originally posted by Newlogics

Carbon crown: Carbon crown will form from bruning oil, blowby, running overly rich for a while etc.... Once that crown builds up high enough, it will actually start hitting the bottom of the head surface.

Quick:
Get some Combustion Chaimber Cleaner (I used SeaFoam, but most suggest Mopar, as it comes in aerosol bottles and is easier to work with).

Egad, will these things get that much buildup?

We used to use a 50/50 mix of brake fluid and water. The smoke was extravagant. Diesel oil will do the job, too.
But it's really a risky job for the casual mechanic....

 

[blackawdturbo]

Originally posted by psi4power
my car almost feels like the timing is being pulled. I can hit throttle and it will build boost but isnt going then take my foot out of it and mash it again then boom it accels like it should. Talked to alot of ppl and cant figure it out. any suggestions on a fix would be greatly appriecated

Sounds like massive timing retard caused by knock, possibly phantom.

 

[doug]

Originally posted by Newlogics
Much more ocmmong

ocmmong?

But seriously, good post dude. I can tell you really went through a learning experience with that knock problem. I've been reading a lot of your posts on the subject since I think I have knock issues now. I'm gonna have to save this thread as a good reference.

 

[Newlogics]

Originally posted by doug

ocmmong?

But seriously, good post dude. I can tell you really went through a learning experience with that knock problem. I've been reading a lot of your posts on the subject since I think I have knock issues now. I'm gonna have to save this thread as a good reference.

It was the end of my long workday, when I was typing it
Now when I re-read it, it looks to be written by a 10yr old delinquent

 

[psi4power]

so where do i go to find this cleaner, ive heard of it but never actually seen it. and thanx for the help dude, i thought i would never find an answer

 

[Newlogics]

Originally posted by psi4power
so where do i go to find this cleaner, ive heard of it but never actually seen it. and thanx for the help dude, i thought i would never find an answer

Here's where you get MCCC:
http://www.buymopar.com/store/chem.html

As for the regular pour-type cleaner, they're sold in most parts stors. Thing is called Sea-Foam. Than one will work best for soaking your chaimbers overnight.