Mrdarkmonkey96 Posted January 16, 2014 Share Posted January 16, 2014 My aunts truck has been acting up lately according to her. I test drove it and the tach would not read accurately, and the transmission would not shift properly. I hooked in to the OBD2 and It was throwing a skip code. According to the device cylinder 7 wss not firing. I checked the plug amd it was shot, as were the other 7. I replaced all plugs and changed the transmission fluid. The tach still does not read properly and the tranny does not shift properly. Has any one experienced this problem? I've tested all the logical failure points, and fixed them... a bit lost for ideas here... Quote Link to comment Share on other sites More sharing options...
Rob Hall Posted January 16, 2014 Share Posted January 16, 2014 Hmmm...this sounds very similar to what happened w/ my Jeep (4.0 6) a few years ago. The check engine light came on and it kind of hiccuped--was shifting strangely. it threw a code that indicated cylinder 5 wasn't firing, turned out it was a bad coil pack and a bad crankshaft position sensor. I would check on allpar or a Ram-specific forum also. Quote Link to comment Share on other sites More sharing options...
Mrdarkmonkey96 Posted January 16, 2014 Author Share Posted January 16, 2014 Hmmm...this sounds very similar to what happened w/ my Jeep (4.0 6) a few years ago. The check engine light came on and it kind of hiccuped--was shifting strangely. it threw a code that indicated cylinder 5 wasn't firing, turned out it was a bad coil pack and a bad crankshaft position sensor. I would check on allpar or a Ram-specific forum also. We just rechecked everything and the coils are good. So plugs and coils are good. It doesn't sound like its skipping. Havent been able to test drive it to see if its shifting bad still, but the tach is still wacky. Quote Link to comment Share on other sites More sharing options...
Greg Cullinan Posted January 16, 2014 Share Posted January 16, 2014 I know fords have the coil packs now a days opposed to distributor and they fail Quote Link to comment Share on other sites More sharing options...
JM485 Posted January 17, 2014 Share Posted January 17, 2014 Just throwing out ideas here, but I would assume that the transmission not shifting correctly and the tach not reading correctly are connected. My godfather has been shifting his (I think it's an 02) manually on the lever for years because of a similar problem. I believe his tach was working alright though so it might be a little bit different. I would assume that there is a sensor that shifts the transmission based on engine rpm, so if your tach is not reading correctly, then the transmission would not shift correctly either. Maybe focus on fixing the tach, and I am willing to bet that the transmission problem goes away. I'm no expert, but it might just be something to try. Quote Link to comment Share on other sites More sharing options...
slusher Posted January 17, 2014 Share Posted January 17, 2014 Very good point Josh. I was thinking the same thing... Quote Link to comment Share on other sites More sharing options...
Rob Hall Posted January 17, 2014 Share Posted January 17, 2014 Could be the transmission range sensor--usually a P0700 or P0705 code. There is also the differential position sensor. Replaced both of those on my Jeep. Quote Link to comment Share on other sites More sharing options...
Mrdarkmonkey96 Posted January 17, 2014 Author Share Posted January 17, 2014 Could be the transmission range sensor--usually a P0700 or P0705 code. There is also the differential position sensor. Replaced both of those on my Jeep. I checked after the coils and plugs were checked, and it wasn't throwing any codes at all.. I'm going ti have to check those sensors everyone mentioned. Thanks for thr help guys Quote Link to comment Share on other sites More sharing options...
Mrdarkmonkey96 Posted January 17, 2014 Author Share Posted January 17, 2014 Just throwing out ideas here, but I would assume that the transmission not shifting correctly and the tach not reading correctly are connected. My godfather has been shifting his (I think it's an 02) manually on the lever for years because of a similar problem. I believe his tach was working alright though so it might be a little bit different. I would assume that there is a sensor that shifts the transmission based on engine rpm, so if your tach is not reading correctly, then the transmission would not shift correctly either. Maybe focus on fixing the tach, and I am willing to bet that the transmission problem goes away. I'm no expert, but it might just be something to try. That's what we were thinking, we just lack the electrical expertise to fix that kind if thing. We will check the sensors and if that doesnt do it, to the dealer it goes.. Quote Link to comment Share on other sites More sharing options...
Patrick2005 Posted January 17, 2014 Share Posted January 17, 2014 99% is the crank position sensor. Without it the computer doesn't know how fast the engine is spinning and therefore doesn't know how to determine it's shifts. Quote Link to comment Share on other sites More sharing options...
Mrdarkmonkey96 Posted January 17, 2014 Author Share Posted January 17, 2014 99% is the crank position sensor. Without it the computer doesn't know how fast the engine is spinning and therefore doesn't know how to determine it's shifts. I thought it coukd be that, as the same thing would happen with my 7.3 f350, but that normally throws a code right? Quote Link to comment Share on other sites More sharing options...
Rob Hall Posted January 17, 2014 Share Posted January 17, 2014 (edited) I thought it coukd be that, as the same thing would happen with my 7.3 f350, but that normally throws a code right? Not necessarily. When one of the sensors on my Jeep failed (it may have been the crank one--had to replace many sensors in the last 5 years), it didn't throw a code..it just had anomalous behavior like the engine shutting off at 70 mph and then being hard to to start. Edited January 17, 2014 by Rob Hall Quote Link to comment Share on other sites More sharing options...
Mrdarkmonkey96 Posted January 17, 2014 Author Share Posted January 17, 2014 Not necessarily. When one of the sensors on my Jeep failed (it may have been the crank one--had to replace many sensors in the last 5 years), it didn't throw a code..it just had anomalous behavior like the engine shutting off at 70 mph and then being hard to to start. thanks for the heads up. We are goimg to have to figure out why the tach is screwed up. I have a feeling were going to be chasing tHis problem for a while. Quote Link to comment Share on other sites More sharing options...
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