Speedohealer potentially causing issues

Liv2Ryd

TJ Enthusiast
Original poster
Supporting Member
Joined
May 7, 2020
Messages
132
Location
Sutton MA
Thought I would create a new post related to my recent issues with CEL's. Hopefully, this helps someone in the future avoid the lengthy troubleshooting effort I put in. It all started when I replaced my OPDA with a Crown unit including the sensor (the OEM broke when removing it)...

For a month or two, it was all good. Then the dreaded P0340 showed up. For a while I could just clear it with my OBDII scanner and keep on keepin on. Then I started to notice a pattern. Every time I tried to point my TJR up something very steep, BANG, 0340 code! Of course, this would limit my revs so I had to get creative in order to finish the feature. Road riding was still fine and I could ride all day long with no issues. I tried doing a OPDA recalibration and relearn but eventually the same issues came back. Then about a month ago, things starting getting much worse, I started throwing P0129 (Barometric pressure), P0107 MAP Sensor, P0300 multiple cyl misfires along with the usual suspects. My TJR still ran when the codes were cleared but this past weekend everything went tits up. Now it runs like shit and is barely driveable. Frequently stalls and rough idle and acceleration. I'm not even sure I can drive it to a shop now.

Last year I did a tune up and replaced the plugs with Autolite APP985's. Other than the OPDA and a new fuel pump/splash valve fix, the rest of the motor/sensors are still stock. I've read thru tons of threads on PCM's, bad grounds, coil rails, fuel injectors, O2 sensors, crankshaft sensors. Seems like lots of 05/06 TJ's have been plagued with similar levels of torture.

So after replacing my PCM, cam and crank sensors, new battery/redone grounds, relearns, recals etc...I was still getting the same codes. I tested the wiring looms as best I could but could not find any issues. I was truly thinking my TJ issue may never be fixed. Looking back at when the trouble started, it all began shortly after putting in a new Crown OPDA so I was fixated on that especially after reading all the trouble others have had. The other night I decided to look back to the few months prior to the OPDA install and see what else I had done to my TJ. The only thing I found that might be a contributor was I added a Speedohealer. Well guess what! I disconnected that fucker and 100+ miles later not a single code. To date, I haven't done any hardcore wheeling so the jury is still out but I was getting so many 0344 and 0340 and 0129 codes that my TJR was basically unrideable.

I have inspected the cable and speedohealer and have not found any obvious issues like melted or frayed wires. I'm going to reach out the speedohealer and see what they have to say. The unit is less than 8 months old
 
Crap - I was planning on a speedohealer on mine - following...
I've installed three so far and haven't seen any bad behavior, whatsoever. That said, all were on 2003 and 2004 models, so I don't know if there are issues with the later PCMs? :unsure:
 
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I pulled my speedo healer when my VSS failed. Haven't reinstalled the healer but the new VSS seemed to fix the issue.
 
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I put a speedo healer In my 2006 maybe 6 months back to compensate for the larger tires and lower gears and to stop it from shutting down every time it hit around 80 mph reaching some limit in the PCM and so far have not had any issues yet.
 
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Same here, my Speedohealer is over a dozen years old and it's fine. They do install on the databus so if they're not installed properly, damaged, or go bad they could definitely cause problems.
 
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Well I just wanted to say thanks. I was having persistent code issues. I had swapped the OPDA about 20,000 miles ago at the same time I did a lot of other things... like a speedohealer. The codes I'd seen were the P0340 (Camshaft Position Sensor Circuit Malfunction), P0344 (intermittent camshaft position sensor), and P0129 (Barometric pressure). I'd also seen my speedometer reading bounce up and down as well as the tachometer on a couple of occasions. I'd tried replacing the camshaft position sensor with sensors from several manufacturers. I'd swapped in a new crankshaft sensor as well as bought a FOXWELL NT510 Code Reader and had adjusted the OPDA to be perfectly in sync. I still kept getting codes. Saw this and disconnected my speedohealer to try it. 1,000 miles later, no codes. I'd had the speedohealer for about 3.5 years and 20,000+ miles. No obvious signs of wear or damage. I'm saying the speedohealer was the issue at this point and I'm just glad to be able to drive my jeep around again. THANK YOU!