1995 F150 Speed problems
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1995 F150 Speed problems
I recently bought a 1995 F150 5.7l with a blown motor. We performed an engine swap with on from a junk yard. Engine runs great but now I have other problems. Speedometer does not work, ABS light comes on, and transmission shifts hard and late. When it does shift good it surges in high gear like it can't figure out if it wants to be there. I have replaced the VSS sensor and all wiring under the truck looks good. Is there any wiring in the engine compartment we could have missed. What should I change next?
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From: Kentucky
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Tried
I replaced the VSS, The instrument cluster, and the ABS module. I checked voltage on pins 1&3 of the instrument module and get 12vdc to pin 2.
I put the truck on jack stands and only get 2vac at the ABS test plug. It starts at zero and climbs. I am pretty sure I am way over the suggested 30mph but the voltage will not go above 3vac. I ohmed the wire from the instrument cluster to the VSS and all ohms good. I even disconnected the cruise control to make sure it wasn't causing a problem. The speedometer is dead and bounces between 0 and 5mph.
I put the truck on jack stands and only get 2vac at the ABS test plug. It starts at zero and climbs. I am pretty sure I am way over the suggested 30mph but the voltage will not go above 3vac. I ohmed the wire from the instrument cluster to the VSS and all ohms good. I even disconnected the cruise control to make sure it wasn't causing a problem. The speedometer is dead and bounces between 0 and 5mph.
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From: Kentucky
In step 2 of the procedure I linked to it has you check for stored codes. Have you done that too? We need to see what the PCM thinks is wrong. That may help narrow down the cause. You should definitely have more than 3 VAC going to the PCM from the RABS module. The VSS signal is routed to the RABS in a parallel fashion. From there is goes to the PSOM and PCM. The PSOM output is fed to the instrument cluster.
The VSS signal is measured as VSS+ and VSS-. Make sure both lines have continuity back to the VSS connector. As well as no short to ground.
The VSS signal is measured as VSS+ and VSS-. Make sure both lines have continuity back to the VSS connector. As well as no short to ground.
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VSS
I have not run the codes yet. i thought they may be eronious since the computer is receiving bad data from the VSS. I ohmed both wires of the VSS as well as checked them to ground for a short. All checked good. How often is the problem the ring in the rear?
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Not as often as the VSS or cabling problem causing the issue. You could open up the rear differential and look for a build up of debris. Also look for runout on the ring gear assembly or missing teeth on the tone ring. If the ring gear is "wobbling" back and forth the VSS is the least of your worries.
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