bizkit
bonofied SyTy junkie
Well I've been struggling with a misfire on my Ty for a couple weeks now and can't figure it out. It's not a dead miss and is erratic and is worse when the Ty is warm, and does not go away at higher rpm's though you don't notice any driveablility problems on the highway. There is NO hesitation off idle or stumble when accelerating/cruising. The only time I notice it from in the cab is at idle. When leaning down listening at the tail pipe I can hear a missfire from idle and up as high as you want to rev it in park. It's bad enough that it will die every now and then when idleing and you put it into gear, or when you are on the brake in drive at a redlight. Under load for example a boost launch, you don't notice anything is wrong.
New plugs, wires, cap, rotor, tried two different HEI modules, 3 different coils, and purged the injectors with Wynns VIC injector/top end cleaner. All the plugs I pulled out looked exactly the same, a nice brown color. What is really weird is that the misfire gets worse when I put on a MSD blaster coil. So does that mean the MSD puts out less energy than the stock coil and makes the miss worse, or does it put out more energy and arc out somewhere that much more to make the miss worse? On tunerpro the vaccuum is at 17 - 18 Hg at idle, and you can watch the O2 mv go rich whenever you hear it missfire. The plug wires are absolutely not arcing out onto anything, and are not rubbing/burning on anything. Although it sure acts like only one plug is causing the problem, it's not bad enough to make me think all plugs are erratically misfiring.
Im grabbing at straws now. Tomorrow night I will try swapping in the MAP sensor from my S-10, and try to track down which plug is misfiring using a timing light by looking for an erratic light signal.
Any other ideas on what to check next? I don't want to let this stop me from going to Canadian Nats, but I'm just not sure if I should go that far with a truck that's not 100%. The best thing would be to put it on an oscilloscope at a dealership to check all the plug wires/injectors at once and graph it all out, but there aren't any in town anymore.
What do you guys think?
I've also played with the fuel pressure, changing it from 30 to 60 psi and it made no difference. I've had it and it is right now set at 50 psi. I am running on the stock chip again to try and figure this out. Looks to me like it's an ignition problem, but everything this side of the distributer has been checked over and over.
New plugs, wires, cap, rotor, tried two different HEI modules, 3 different coils, and purged the injectors with Wynns VIC injector/top end cleaner. All the plugs I pulled out looked exactly the same, a nice brown color. What is really weird is that the misfire gets worse when I put on a MSD blaster coil. So does that mean the MSD puts out less energy than the stock coil and makes the miss worse, or does it put out more energy and arc out somewhere that much more to make the miss worse? On tunerpro the vaccuum is at 17 - 18 Hg at idle, and you can watch the O2 mv go rich whenever you hear it missfire. The plug wires are absolutely not arcing out onto anything, and are not rubbing/burning on anything. Although it sure acts like only one plug is causing the problem, it's not bad enough to make me think all plugs are erratically misfiring.
Im grabbing at straws now. Tomorrow night I will try swapping in the MAP sensor from my S-10, and try to track down which plug is misfiring using a timing light by looking for an erratic light signal.
Any other ideas on what to check next? I don't want to let this stop me from going to Canadian Nats, but I'm just not sure if I should go that far with a truck that's not 100%. The best thing would be to put it on an oscilloscope at a dealership to check all the plug wires/injectors at once and graph it all out, but there aren't any in town anymore.
What do you guys think?
I've also played with the fuel pressure, changing it from 30 to 60 psi and it made no difference. I've had it and it is right now set at 50 psi. I am running on the stock chip again to try and figure this out. Looks to me like it's an ignition problem, but everything this side of the distributer has been checked over and over.
