- Location
- MilkyWay Galaxy
Well its out of my league, Haynes does not show the Tach in a wiring schem.
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Need Help Diagnosing a Problem
- Thread starter 2jeepdrivers
- Start date
2jeepdrivers
NAXJA Forum User
- Location
- Rogersville,mo
I am glad you posted that, I was starting to feel like an idiot because I couldn't find any tach wires in my haynes or on autozone's wiring diagrams. Now that I have took a few days away from my Jeep I actually feel like working on it again so maybe I will have some luck this weekend. Oh yeah it is a 92'.
2jeepdrivers
NAXJA Forum User
- Location
- Rogersville,mo
I have went over everything again, wiggled every wire with a meter on it and no change everything checks perfect but it still dies when I plug in the TPS or the MAP. I am going to the salvage yard sometime this week and going to yank a complete harness out of the only 92' within a hundred miles of here.
2jeepdrivers
NAXJA Forum User
- Location
- Rogersville,mo
Alright I haven't had time to go yank a harness so I decided to rewire the Tps and the Map. After I got done I was able to plug the electrical side of the map sensor in and it wouldn't die, but if I plug in the vacuum side it does. I have a couple of different map sensors that I tried to make sure it wasn't a bad map sensor. But if I plug in the TPS it still dies. If this helps out in the diagnostics I am not real sure how but if any of you all have any more input I am open to it. I am hoping to be able to go yank the other harness Wednesday but we will see, for some reason between school, overtime and two kids I seem to be lacking in time. :dunno:
- Location
- MilkyWay Galaxy
2jeepdrivers said:
Hook the vacuum up to the MAP, only, restart it, then hook up the MAP electrical and see what happens, or hook them both up and restart it.
Also, try disconnecting the battery for a while to clear the computer memory, then reconnect the MAP sensor vac and Elec lines, then try starting it.
You may have some od, bad sensor data from something you already fixed, still stored in the computer memory.
Hooking up the Vac line to the MAP sensor with the engine running may be sending a MAP signal to the ECU changing timing while also closing a vacuum leak that has the IAC closed causing it too die, if the ECU and IAC can not respond fast enough.
2jeepdrivers
NAXJA Forum User
- Location
- Rogersville,mo
Alright I have cleared the computer, and now I can hook up the map electrical and vacuum. But I have to leave a vacuum line loose or it idles at like 450 rpm w/ one loose it idles around 700 rpm. Also if I take the ground off of the Tps I can plug it in and it will still run, as long as I have a vacuum line loose but it won't rev just idle. So maybe I am getting a little closer.
PuddinHead
NAXJA Forum User
- Location
- Virginia
Ok looking back at this thread you mentioned the tach starting to work:
The tack signal comes from the ignition control module to the instrument cluster. The ignition control module get its signal from the distributor-- I assume from the camshaft position sensor inside the distributor. On you year XJ this 'sensor' can be changed without pulling the distributor. This sensor sometimes called the distributor's stator or the CKS sensor.
The tack signal comes from the ignition control module to the instrument cluster. The ignition control module get its signal from the distributor-- I assume from the camshaft position sensor inside the distributor. On you year XJ this 'sensor' can be changed without pulling the distributor. This sensor sometimes called the distributor's stator or the CKS sensor.
Last edited:
- Location
- MilkyWay Galaxy
2jeepdrivers said:
OK, good. Now the low idle sounds like a sticking IAC, Idle Air Controller, little elctric motor operated valve that controls air flow to the engine idle. Several good threads in this forum on cleaning and oiling the IAC beasty.
I am wondering if you have miss identified one of the TPS wires? or crossed a pair of them? I made that mistake once and got very odd idle behavior??? I noted that the ABC is on top on one side (connector) and on the bottom on the other side (connector) when it is connected properly which I found odd. The alignment pin that keeps it from being criss cross connected was broken on mine. So I am wondering if you are grounding the +5 volts from the ECU or something odd like that.
Might try reconnecting the TPS and trying to start it with the TPS connected.
2jeepdrivers
NAXJA Forum User
- Location
- Rogersville,mo
The gremlin is finally solved, kind of. My 4.0 now has a 2bbl on it with hei. I know this is a step down but this jeep was bought as a cheap toy and I just keep throwing money at it so it was worth a step back to be able to wheel the little jeep again while I am working on my Scout. Once it is done I will probably build the cherokee for some stock class tough truck racing but that will be all.