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Anyone know what this part is called?

W

wgregt

NAXJA Forum User
Location
SoCal
'88 XJ. 300k+ on the clock. This weekend, I was backing into a parking spot, wheel cranked as far as it would go. Suddenly, it cuts off and I'm pushing it into the spot. Would crank all day long, but not start. So...it's electrical in nature, right? After looking around, I notice a wire hanging near the firewall with a small black quick-connector plug about halfway down. The quick-connector plug is a mass of melted plastic though. Even when unplugged, it would not separate in half. This wire starts by sticking thru a small hole and grommet in the firewall. I THINK the other end goes to the small aluminum-colored box under the dash by my feet...the TPS box? Idle control box?

The other half of this wire (past the quick-connector junction) disappears and runs to...the block? Anyhow, I found the other half of the wire past the quick-connector block, stripped the wires back, twisted them together, and it cranks right over. I made a repair with duct tape that would make McGyver proud, taped it to the firewall securely (the plastic corrugated hose covering had melted thru as well, probably from contact with the block) to keep it from touching the block and melting thru again, and made it home.

So...I ask the Almighty Wisdom Of The List:
-what is this wire (along with the in-line black quick-connector block) called?
-any idea of it's available separate from the AL/TPS/Idle control box?
-what does the other end connect to? The block?
-Install: Easy? Hard? Dealer only?

Ideas? I'm at [email protected]. Love to get this taken care of this weekend if possible.

-greg
 
Sounds like the Crank Position Sensor (CPS) to me.
 
wgregt said:
'88 XJ. 300k+ on the clock. This weekend, I was backing into a parking spot, wheel cranked as far as it would go. Suddenly, it cuts off and I'm pushing it into the spot. Would crank all day long, but not start. So...it's electrical in nature, right? After looking around, I notice a wire hanging near the firewall with a small black quick-connector plug about halfway down. The quick-connector plug is a mass of melted plastic though. Even when unplugged, it would not separate in half. This wire starts by sticking thru a small hole and grommet in the firewall. I THINK the other end goes to the small aluminum-colored box under the dash by my feet...the TPS box? Idle control box?

The other half of this wire (past the quick-connector junction) disappears and runs to...the block? Anyhow, I found the other half of the wire past the quick-connector block, stripped the wires back, twisted them together, and it cranks right over. I made a repair with duct tape that would make McGyver proud, taped it to the firewall securely (the plastic corrugated hose covering had melted thru as well, probably from contact with the block) to keep it from touching the block and melting thru again, and made it home.

So...I ask the Almighty Wisdom Of The List:
-what is this wire (along with the in-line black quick-connector block) called?
-any idea of it's available separate from the AL/TPS/Idle control box?
-what does the other end connect to? The block?
-Install: Easy? Hard? Dealer only?

Ideas? I'm at [email protected]. Love to get this taken care of this weekend if possible.

-greg
Click to expand...
How big is this seperate TPS control box? I am thinking that you are reffering to the ECM and the harness that was melted was for the CPS (ask me how I know). At one point there was a patch kit for the CPS that gave it a direct route to the ECM. If that is the case, then I would replace the rednecked setup with new parts.
 
Yup, CPS I had the same thing happen after I replaced mine and didn't tie up the loose wire. The Crank Position Sensor tells the motor where it is in it's rotation. It is bolted to the bellhousing of the transmission, replacement is fairly easy as long as you have a couple good length extensions.
 
OK. Sounds like the CPS. Does the other end (not the one that plugs into the tranny) simply plug into the ECM fairly easily? Thread it thru the firewall grommett and plug & play into the ECM under the dash? Or is there some sort of dealer-only diagnostic that needs to be done?

-gregt
 
wgregt said:
Local dealer is telling me it's called a Map Sensor, p/n 33004761. That name sound right to you guys?
Click to expand...

On your 88, the MAP sensor is on the firewall - has a three-wire connector and a vacuum hose going to it. If you want to locate the thing, there is a small vacuum line that comes off the passenger side of the throttle body - follow that, and you'll go right to it. But, it will run without a MAP.

If it's a "crank, no start" and you've got a melted connection, it's probably the CPS (the wiring came loose and hit the exhaust. Oops.)

However, if you can take a picture and host it somewhere, we can more positively identify the failed part.
 
Well....I'm halfway there. Stopped by the dealer yesterday, and yep...it IS the CPS sensor for HALF of my problem. They only had the part of the wire that goes from the bell housing on the tranny to the lower half of the quick-connect clip. The OTHER half of the wire that goes from the quick-connect clip and disappears into the firewall is only available as the main harness for the vehicle...which is not available anymore apparently.

Hmmm....I guess I'll try a local junkyard. You guys got any favorites you visit?

-greg
 
It sounds like you have a lazy parts guy, or at least uninformed. I'll try to find the part number for the patch kit, but I think I lost it. The patch kit will have everything from the transmission to the ECM.
 
CPS patch kit for auto trans ..87 to 91 Renix injection,#83100066.........
CPS patch kit formanual trans.....87 to 91 Renix injection....#83100063
There is also a TSB (Technical service bulletin) that has instructions on how to install it, the service department should be able to print you a copy (If they are any better than the parts department)
 
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