[RESOLVED] Hesitaion under accel.

[mattdev]

It seems pretty basic, here it is:

Basically whenever I go full throttle the engine hesitates back and forth. Pretty sure it's missing, it goes in and out of accelerating. It only does it when I go full throttle. I just got a new o2 sensor and 2.5" housing (w/ stock exhaust). I have practically no mods; Intake, and BCS restrictor removal. It has done this since I got the car, so shouldn't have to do w/ any mods.

I've been thinking plugs and wires, but they are fairly new. I have no boost leaks that I know of. Is this a possible boost leak? I have a rig to test, but no air compressor, and I can't build enough pressure w/ a bike pump. I can use a friends if necessary. After boost test, plugs and wires, where would I go next??

Thank You!!

 

[romeen]

A few places to start:

1) Boost leaks--you need to do an actual test. Always a good idea whenever driveability issues pop up. Air tanks (not compressors) are pretty cheap and will work great.
2) Misfire from excessive plug gap. Make sure yours are gapped to .028"
3) Fuel starvation causing knock in turn causing ECU to pull timing. If you pull your plugs to check gap also examine for signs of running lean. Or better yet see if you can borrow a friends logger.

Other things may be going on but these are good places to start.

 

[VETTE_50_TH]

I had the same problem with my car a year back. It was fine until you got on it and just hesitated terribly. What i found was my wires were bad. The one was blown out and wasnt giving a good signal to the plug. Remove the wires and see if your spark plug wire has white film on the bottom of them. If so, youve got bad ones. Hopefully that is the case. Also, is your car knocking at all? Even under a light load. Recommend what the guy above me said if so.

Hopefully everything gets fixed.

James

 

[oldman]

Boost Leak Test!!!

 

[mattdev]

Igght, did a real boost leak test. My stock BOV leaks ALOTTT from the dump end. (expected it to leak at 15psi) I couldn't hold enough pressure to read on a tire gauge. Is there something I'm missing? When driving I make about 10 psi (only at full throttle). Should I be making more than that?

Everything else holds pressure (at least before the BOV), so thats a relief. (based on the fact that my stock intercooler pipes were inflated like a tire and had no leaks before or after intercooler).

I checked spark plug gap and it's damn close to perfect, so that ain't the problem. Plugs seem to have pretty normal wear (Slight amount of white on tip). Does that mean I'm in for wires?

My BOV seems to be the culprit. Whats your opinion?...

 

[mattdev]

FYI. I figured it out. The boost leak was not the problem, although it is A problem. I replaced my plugs and am getting wires in the mail. It no longer hesitates. The plugs fixed it.