Still hesitating..need an answer

[b_dues]

So, my car has been hesitating for quite some time. I recently got a Unichip installed and "tuned", but who knows how well. My MSP hesitates under WOT and the boost fluctuates from 5-10psi and it is supposed to be set at stock on Map A and 8psi on Map B. These settings don't matter as it does what it wants, when it wants. I believe the solution to this problem would be a new wastegate - would this cure the hesitation problem also?

To define the hesitation I am experiencing, it is like the car won't hold boost. For example, my boost gauge will read 8psi but my car will feel as if it is lagging and it will do this under WOT through the rpm range. I checked for leaks with soapy water and didn't find any. I have a minor misfire. I say minor because you can only hear it missing when you listen to the exhaust and you cannot notice it when driving (no stuttering from the misfire). Any ideas?

 

[shane02pro5]

Did you check if the wga holds pressure? If you have a misfire at idle it would be much worse under load. Possibly bad coilpacks but could also be bad plugs or wires. Is the misfire throwing a code?

 

[b_dues]

Did you check if the wga holds pressure? If you have a misfire at idle it would be much worse under load. Possibly bad coilpacks but could also be bad plugs or wires. Is the misfire throwing a code?

Nope, no CEL. It just has a bit of an inconsistent idle that you can hear from the exhaust. It also nearly stalls when it's put in neutral after driving freeway speeds, or when it is idling it will randomly drop to 200rpm and then rise back to regular idle, around 700rpm. Can this all be blamed on ignition issues (coil pack, wires, plugs) or can part of it be blamed on a dirty EGR?

And negative on checking if the WGA holds pressure, not even sure how to. I'm not sure if I should blame the sporadic boost level on the WGA or the Unichip.

 

[b_dues]

To update, I just checked for leaks again and found nothing. I could not find a leak in a vacuum line or in a coupler on the cold pipe or hot pipe. I checked for a leak in between my exhaust manifold and head and there is a perfect seal. My boost gauge is reading a vacuum of 10-15 at idle and it should be around 22. What now?

 

[codex]

I had a problem like this with a vacuum gauge. It turned out to be the gauge needle was sticking, if you tap the gauge see if the vacuum goes lower.

 

[b_dues]

Tried that, didn't fix it. But, I do have another boost gauge and I switched them out...same problem so I have found that it is the lines. When I checked all my vacuum lines I did not check the line for the boost gauge. When I was investigating the source that it is T'd into I noticed that there is a tube in which the air passes through and another tube wrapped around it for heat protection. The tube that is used as a heat protector was clamped the the T, not the actual/functional tube (which was cut 1/2" too short to even contact the T). As you can imagine a substantial amount of air was leaking from this source. Once I fixed this my boost gauge was idling at a vacuum range of 21-22; however, it does still sit at 10 from time to time so I will have to follow each line and clamp them tight. This also solved my hesitation issue for the most part. There is still some hesitation but I think that can be blamed on the lines T'd off of the boost gauge line not being clamped. I will try it out tomorrow and repost with the end result..this does look promising.

 

[joghia]

Had the same problem; rough idle, rpms dropping when put in neutral, etc. Fixed a vacuum leak and gave the boost gauge it's own vacuum from the brake booster line. That helped a lot and vacuum was at -20 now but rpms would still drop when put in neutral. What fixed everything for me was the WGA. Put in an ATP WGA and ALL the problems are gone. Car runs like a champ and has not once dropped rpms or idled funny. Check your wastegate by blowing in the line to see if it's blown.

 

[b_dues]

Awesome, i'll try that.

 

[bradboyd80]

I recently got a Unichip installed and "tuned", but who knows how well.

Perhaps this is part of the problem? Personally I'd remove the unichip and see how the car responds. +1 on the WGA though; its a good idea to replace it anyway since the stocker is garbage.

 

[b_dues]

Bump. The car only hesitates when it has warmed up. When cold it will run strong and not over boost. Does this look like a MAF problem? I think that I am also running rich as there is a decent amount of carbon build up on my exhaust tip. Could that be the culprit?