97 auto 4.0l FYI... So went wheeling today and the speedo started going crazy on the way to the trail... It jumps all around and starts running like crap and shifts in and out of 2-3 and 1-2 at slower speeds... It loses power bad to where a few times I was in 4lo uphill offroad and I was foot to floor and no power... I managed to get a video on the road... http://youtu.be/B5CinCMaezc
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Speedo goes crazy and starts to run bad!
- Thread starter Alboy97XJ
- Start date
O-Gauge Steamer
NAXJA Forum User
- Location
- Colorado Springs, Colorado
Possible Cluster or Vehicle Speed Sensor failure.
Located on the Driver's side of the Transfer Case. The VSS is driven by a gear in the TC. As it rotates, it generates a "pulse train" signal to the Powertrain Control Module. The PCM measures the frequency of the signal and sends that data in a multiplexed signal to the Instrument Cluster where it is all decoded and the gauges are driven.
As there does not appear to be any CEL (Check Engine Light) events happening (or are there?) then the cluster is a bit, IMO, more suspect. Re-seating the cluster in it's connectors may be in order. there are threads here that document the process. Not difficult, just consumes a bit of time...
The "normal" Speedometer failure is that it stops working all together. This one is different which may be why no advice.
Usually, when the VSS fails, you get a CEL for the VSS. It is a monitored component.
Located on the Driver's side of the Transfer Case. The VSS is driven by a gear in the TC. As it rotates, it generates a "pulse train" signal to the Powertrain Control Module. The PCM measures the frequency of the signal and sends that data in a multiplexed signal to the Instrument Cluster where it is all decoded and the gauges are driven.
As there does not appear to be any CEL (Check Engine Light) events happening (or are there?) then the cluster is a bit, IMO, more suspect. Re-seating the cluster in it's connectors may be in order. there are threads here that document the process. Not difficult, just consumes a bit of time...
The "normal" Speedometer failure is that it stops working all together. This one is different which may be why no advice.
Usually, when the VSS fails, you get a CEL for the VSS. It is a monitored component.
Dragonslayer
NAXJA Forum User
- Location
- Los Angeles
Check your grounds. I'd start with the ones attached to the engine block by the
oil dipstick tube.
oil dipstick tube.
Dragonslayer
NAXJA Forum User
- Location
- Los Angeles
Check the TPS (Throttle Position Sensor) with an analog-type ohmmeter (the kind with
a needle pointer dial). Hook it up and, with engine off, s-s-slowly work the throttle
by hand from the idle position to wide open throttle while keeping an eye on the ohmmeter.
Any blips or hiccups in the needle as it sweeps across the dial means the TPS is bad.
a needle pointer dial). Hook it up and, with engine off, s-s-slowly work the throttle
by hand from the idle position to wide open throttle while keeping an eye on the ohmmeter.
Any blips or hiccups in the needle as it sweeps across the dial means the TPS is bad.
Sidewinder CC
NAXJA Forum User
- Location
- Canton, Michigan
The '97+ XJ ground connection at the oil dipstick tube attach stud is for the Data Link Connector.
The ground at the firewall to engine is a radio noise suppresion bond.
Here's the grounds you should be looking at (Detaching, inspecting, and cleaning) - see pic. It's called ground G101. The pic shows the circuits that are grounded there.
The ground at the firewall to engine is a radio noise suppresion bond.
Here's the grounds you should be looking at (Detaching, inspecting, and cleaning) - see pic. It's called ground G101. The pic shows the circuits that are grounded there.
Cleaned those up and replaced vss for the hell of it... when I replaced it I found that the three wires where exposed from being melted and looked to be againts the exhaust. Fixed all that up and so far its good... will find out more in tonights wheeling adventure. .. thanks for the ideas people!!!
