kenworth speedometer

[djz4248]

has anyone had a kw that cruise and speedo are surging up and down. looked at wiring and replaced speed sensor and still malfunctions. when running throttle by foot if you are just maintaining speed and just push accelerater a liitle bit speedo drops about 5 mph. if you let off accelerater a little bit speedo rises about 5 mph. have a t2000 with n14 cummins and a t800 with a s60 detroit both doing this. im guessing it is vehice problem but cant find the problem. any help would be appreciated. thanks

[kwtech]

has anyone had a kw that cruise and speedo are surging up and down. looked at wiring and replaced speed sensor and still malfunctions. when running throttle by foot if you are just maintaining speed and just push accelerater a liitle bit speedo drops about 5 mph. if you let off accelerater a little bit speedo rises about 5 mph. have a t2000 with n14 cummins and a t800 with a s60 detroit both doing this. im guessing it is vehice problem but cant find the problem. any help would be appreciated. thanks

I would start by running a new set of twisted wires from the speedo head to the sensor

[djz4248]

units have only 1 speed sensor. how does it split signal between speedo and ecm? to my understanding this signal cant be split. most truck apps that iv seen have 2 sensors. local kw has no idea-not much help.are you sure wires go directly to speedo? is it possible you can get wire diagams for vin 797937? just pages to do with speedo and ecm wiring . thanks if you can help

[kwtech]

units have only 1 speed sensor. how does it split signal between speedo and ecm? to my understanding this signal cant be split. most truck apps that iv seen have 2 sensors. local kw has no idea-not much help.are you sure wires go directly to speedo? is it possible you can get wire diagams for vin 797937? just pages to do with speedo and ecm wiring . thanks if you can help

Some KW's maybe your T8 have one sensor and a break out harness that splits into a Y right after, if I remember corectly the sensor is 4 pin though. But a T2000 is a totally different animal, it has sensor wired to ECM, and looks like the cluster is another module wired through a datalink, here are the diags.

[kwtech]

I would still start with new twisted wires to ECM, its cheap and has worked for me often

[djz4248]

thanks a lot for the diagrams. its a lot easyer to fix when you can see how its wired. will look at it when it gets back in. thanks again

[shisik]

T2000 Caterpillar Engine Wiring pliz


found
T2000 Cummins Engine Wiring.pdf (https://rapidshare.com/files/3948787192/T2000_CATERPILLAR_ENGINE_WIRING.pdf)

[torqueman]

Had faced the same problem with speedo up/down T-800 with n-14 and also showing speedo working to 10 kmph while engine is idle and vehicle stationary.
Just replace twisted paired wiring from ecm to speedo and after replacing,it was working fine.

[superc0]

hi kw tech , you can help me with the complete wiring diagram
for one t300 2007 with cummins engine, i have one truck with
cad damage, i need replace with other but the other cab is of the year 2000, the spedo and tacho works on 1587, 1939 or 1708 ,thanks

[shisik]

hi kw tech , you can help me with the complete wiring diagram
for one t300 2007 with cummins engine, i have one truck with
cad damage, i need replace with other but the other cab is of the year 2000, the spedo and tacho works on 1587, 1939 or 1708 ,thanks

T300 (https://rapidshare.com/files/800778023/T300.RAR)

[superc0]

thanks shisik, i see the wiring but i cant find the harnes for
idle validation switch and tps this is the number of chasis 312065 with cummins isb engine, you can help me whith this, and thanks again my friend.

[shisik]

engine number (ESN)

[truckcomm]

I may be very late with this reply, but anyone who senses the speedo dropping, or surging when under cruise is most likey caused by the rear bearing in the gearbox loose and allowing the pulse ring to move away from the speed sensor. the other cause is the pulse ring is spinning on the gearbox output shaft. either way, driveshaft out to fix.

seen it many times. it is not electronic when both ecm and speedo are doing it. kw is one of the few trucks that use two speed sensors.

this makes it easy to bypass the speed limiter and allow the km's to add up at the end of the trip.

I didn't say that though.

before anybody argues with me on that, I'm an auto sparky with 25 years experience, and have clients wiht a combined total of around 600 kenworths. I've seen those exact symptoms once or twice before..........

[djz4248]

thats what it was on both of these units. yokenut loose. 40 years in truck repair and first time ive ran into it.