I'm about tired of this damn car... Here's the details.

Brand new GM crate motor, LT4 HotCam, custom tune from TWong. In the last month and ½ the car has received brand new PCM, O2's, plugs, wires, and opti. Car still has a missfire. It's always there, sometimes very slight, sometimes to the point where the car spits and bucks and barely accellerates. Car is running noticeably rich, from smell, and smoke from time to time. When I pulled the old plugs before changine, all driver sides were black they were so rich, #2, 4, & 6 were lean, and #8 was wet with gas. Car pops a lot through the exhaust too, probably due to unburnt fuel in the exhaust. Just went out and recorded a Datamaster file. Started the car, idled for a min, drove out the neighborhood, then a couple WOT blasts, then a little constant speed cruise. Anyone care to look at the file, and/or speculate on what to try next?

Got a low mile set of stock injectors I'm planning to swap into the car this weekend, as well as change the fuel filter and check all the engine grounds. Past that, I'm done, don't know anything else it could be.

Here's the link to the Datamaster file:

http://www.hi-psi.com/Corvette/Corvette.uni

Thanks in advance.

 

If you post the files as a ".csv" file, people without DataMaster can look at them using Excel.... not everyone nas DataMaster.

 

Ahh,...did not know that. Will do.

 

For any of you who do not have Datamaster, here is the file exported in CSV format.


http://www.hi-psi.com/Corvette/Corvette.csv

 

Well, first I would check to see if you are getting spark at #8. If it's wet then there is no spark, it's flaming out, or the #8 injector is leaking. Pull the fuel rail up and have someone turn the key to the "on" position and see if any of the injectors are leaking. All the cylinders on that side should be running the same (lean like 2,4,&6). I would get that out of the way first.

Your driverside O2 sensor voltage is crazy low. Something wrong here. It's got to be fresh air being sucked in from a exhaust leak on this side or something. The low voltage is causing the injectors on this side to hit 130% duty cycle. This tells me that the air that the sensor is reading is not being combusted. I can see why the plugs are black. I would first swap the left and right O2 senors and see if the problems switches sides.

 

Thanks for the help guys. At least I have some direction now and a gameplan of things to check tomorrow.

 

Just realized something... With the long tube headers on the new motor, we had to extend the O2 wires to reach. I'm thinking it could be possible that while doing this a wire got crossed on the left side? Anyone have a diagram or can tell me the order/color of the wires on the left side, and their correspondence on the O2 sensor? THanks in advance..

 

http://shbox.com/1/heatedsensor2.jpg

Here is some pic that says it shows how to convert a 1 wire to a 4 wire heated O2. I don't know, may help.

If I remember correctly both O2's will read 450mv steady with the key "on" and the engine not running. May want to see if datamaster shows that.

 

Here's an update guys...

Swapped the injectors out, and then unplugged the driverside O2 sensor and took her down the road. There is still a VERY slight miss there, maybe a fouled plug or something, but the car is running noticeably better. Looks like I'll be rewiting the O2 sensor, then changing the plugs. Hopefully that will be it. I'll update again once I have that done.