OP
I changed out my Speedo gear too. This is the part I was referring to.
https://www.quadratec.com/products/55200_0101.htm
I have no idea what it does but wondering if it can cause misfiring?
Dealer suspects a cracked head. What do the experts think?
- Thread starter primetime4
- Start date
https://www.quadratec.com/products/55200_0101.htm
I have no idea what it does but wondering if it can cause misfiring?
Try calling Roberson Chrysler Jeep here in Salem Oregon. I called them a few months ago searching for a crank sensor for my 2002 with the 32rh. They were able to find one still in stock at a dealer somewhere in Washington. I paid over the phone and they had it shipped right to my door.
IOwnCalculus
TJ Enthusiast
For what it's worth, even with "the same" live data and even "the same" waveforms on a scope, it's been documented time and time again that whatever spec the aftermarket builds its Mopar-compatible sensors to, is looser than what Mopar JTEC and NGC PCMs expect.
Case in point - not a TJ but still a Mopar, and Eric specifically calls out 4.0s as vehicles where he's had the same problem. Car comes in with a misfire and a new no-name crank sensor. No discernible error on the scope, but swapping for a Mopar sensor solves the problem.
Nope, that is in the transfer case and just tells the PCM how fast you are going.
OP
That's what I am wondering out loud here. My engine does not appear to be misfiring at any speed, RPM or temperature. So I am wondering if the PCM is just getting some bad data from somewhere else and concluding it to be a misfire. Would the PCM care if I am going faster/slower than an expected speed at a specific RPM?
IOwnCalculus
TJ Enthusiast
No, because there's not even a fixed correlation between speed and RPM. The computer doesn't even know what gear you're in.
Misfire codes are set by the PCM's interpretation of the cam and crank signals, nothing else. The question is whether the signals are accurate and there is an actual misfire happening, or the signals / PCM's interpretation of them is faulty and it is seeing a misfire that doesn't actually exist.
Misfire codes are set by the PCM's interpretation of the cam and crank signals, nothing else. The question is whether the signals are accurate and there is an actual misfire happening, or the signals / PCM's interpretation of them is faulty and it is seeing a misfire that doesn't actually exist.
Tj Jay
New Member
I dropped in the new CPS sensor recommended by the dealer. Hit the highway for about 30 miles at 75 mph around 3100 rpm on cruise control with no issues. On the way back same thing no issues. A couple of miles before my exit I wanted to push it and cranked it up to about 85 mph and the misfire came back. When I got home I reset the CEL light again and jumped back on the highway. Got back up to 75 with no CEL lights. I'm going to keep it below 80 and call it good.
Hope this helps!
OP
Thanks for the update. I did a similar drive yesterday but keeping it below 70 with no issues. I am overdue for an emissions test and didn’t want to check the limits again so I can take it in. I am just going to live with it driving below 70 which isn’t hard. If I was being honest, I feel like the engine felt a little smoother with the NTK sensor so I might swap it back in at some point but I’m so tired of fiddling with this thing I’m just going to leave it. Will update if 70 becomes 65.
OP
Yeah man. They’re not strict with it from my experience but if the computer has been recently reset it’s an automatic fail. I need to drive it about 100 miles and bring it in. I don’t think they actually check anything else.