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89 xj no start help
- Thread starter Trixie03
- Start date
- Location
- Warsaw, IN
Well i just went and put the new cps in and still nothing. Went and pulled one of the plugs out to see if i could see if it was getting spark and it doesn't look like it is. Where should i look next? When you say that the ecu will not power up does this mean i need a new ecu?
it's possible that your shorted wires killed it yes.
did you check all of the ecu fusible links and relays?
swap the AC and the ASD relay.
I'd probably dig out the renix pinout and find out if you're getting power to the ECU, or check for 5V at the TPS. It's regulated and powered form the ECU, so if you've got 5V @ the tps then you know it's at least getting power. whether or not it's hosed from the short is another matter.
did you check all of the ecu fusible links and relays?
swap the AC and the ASD relay.
I'd probably dig out the renix pinout and find out if you're getting power to the ECU, or check for 5V at the TPS. It's regulated and powered form the ECU, so if you've got 5V @ the tps then you know it's at least getting power. whether or not it's hosed from the short is another matter.
- Location
- Warsaw, IN
If it is the computer, what exactly does that mean? Is it something I can swap with a junk yard part? Well check the tps tomarrow for power.
- Location
- Warsaw, IN
Is there a way to check the relays to see if they are good or not
yes, one renix is as good as any other, so 87-90 4.0 donors
appply 12v and ground to the coil(85-86), listen for click, test continuity across the load terminals (30-87)
- Location
- MilkyWay Galaxy
http://www.youtube.com/watch?v=3JB63ebFfgU
Google for others, "part name, Test, youtube"
The 89 or 90 Renix ECU are a little better than the 87-88. There were minor changes in the software, and the 89 seems to be more fuel efficient, and a little less buggy when some sensors are not working perfectly. Needs to be a 4.0 donor.
- Location
- Warsaw, IN
Well i went and checked to make sure today that i have got a signal coming from the cps and i have got .5 volts just like cruisers thread said i should have. Started tracing things down and i have got 12 volts going all the way to the cap. Do you guys think i should do new cap, rotor and plugs, and maybe wires? Is there a way to test the wires to see if they are any good? I looked at the coil wire and where it attached to the cap it was all nasty and corroded inside. So i grabbed one i had laying around just to see if anything would happen with 12 volts going to the distributor.
Also, i just seen that there is a relay that is up under the little shelf that the coolant reservor sits on. Can anyone tell me what this relay mite be for?
Any other tips to try to get this think started?
Also, i just seen that there is a relay that is up under the little shelf that the coolant reservor sits on. Can anyone tell me what this relay mite be for?
Any other tips to try to get this think started?
- Location
- MilkyWay Galaxy
There is no OEM relay under the bottle shelf. Must be custom.
The high voltage wires are typically 1000 ohms per foot IIRC, but some special wires are just a few ohms. Open, infinite are bad. Have you pulled the HV coil off the ICM to clean and tighten the two main contacts yet?
Have you pulled the spark plugs to see what they look like yet? Cap and rotor do last long, so it they look well used replace them. The corrosion on the HV wire sounds like it is ready for a tune up, cap, rotor, wires and plugs.
You mention 12 V to the dizzy, is that on the side? If so that is just to the CAM sensor for the ECU signal to fire the fuel injectors. It is not related to spark. There are three wires going the ICM, Ignition control module and the spark coil is mounted on top of it!!!!!
The high voltage wires are typically 1000 ohms per foot IIRC, but some special wires are just a few ohms. Open, infinite are bad. Have you pulled the HV coil off the ICM to clean and tighten the two main contacts yet?
Have you pulled the spark plugs to see what they look like yet? Cap and rotor do last long, so it they look well used replace them. The corrosion on the HV wire sounds like it is ready for a tune up, cap, rotor, wires and plugs.
You mention 12 V to the dizzy, is that on the side? If so that is just to the CAM sensor for the ECU signal to fire the fuel injectors. It is not related to spark. There are three wires going the ICM, Ignition control module and the spark coil is mounted on top of it!!!!!
- Location
- MilkyWay Galaxy
" Started tracing things down and i have got 12 volts going all the way to the cap"
What "cap"?????
What "cap"?????
- Location
- Warsaw, IN
To the distributor cap. Kinda wondering if I should just go and put new plugs, cap, rotor, and wires on it and see what that does.
- Location
- MilkyWay Galaxy
I don't think there should be any voltage on the primary spark wire except a very huge high voltage spark that would fry a volt meter!!!!
Hasta
12 volts sounds like a shorted HV coil?
Where exactly on the CAP (there are 7 posts) are you getting 12 volts? And why are you measuring voltage there?
Hasta
12 volts sounds like a shorted HV coil?
Where exactly on the CAP (there are 7 posts) are you getting 12 volts? And why are you measuring voltage there?
- Location
- Warsaw, IN
So far I here is what I have replaced, ignition switch, cps, cap, rotor, plugs, plug wires, and fusible links. should I look into replacing the coil next? Still not getting spark. Is there a good way to test the coil to see if its getting spark? Or something else I should look at?
- Location
- MilkyWay Galaxy
- Location
- Warsaw, IN
Well just put a new coil on and still nothing. Tried to see if it was getting spark and it still doesn't look like its getting any spark.
- Location
- Warsaw, IN
Would no signal from a throttle position sensor cause a no start? Found my sensor had no connectors where the plug would go.
- Location
- MilkyWay Galaxy
TPS is not needed to start or run the jeep. It is used to identify the idle position and to identify rate of change of throttle and direction of throttle, acceleration or deceleration.
- Location
- MilkyWay Galaxy
MAP and CPS sensors must be working and data reaching the ECU to start the jeep.
IAC can keep it from starting if it is stuck in the wrong place, but if that happens just press the accelerator to open the throttle body and let air in manually. Use WOT to unflood it is needed.
IAC can keep it from starting if it is stuck in the wrong place, but if that happens just press the accelerator to open the throttle body and let air in manually. Use WOT to unflood it is needed.
- Location
- Warsaw, IN
Thanks. Was just taking a shot in the dark on that one. Still needs replaced tho. Just still trying to figure out why i can't get it started.
When i try to see if the spark plugs are getting spark, where would be the best place to put the spark plug at to watch it to see if it actually is sparking?
When i try to see if the spark plugs are getting spark, where would be the best place to put the spark plug at to watch it to see if it actually is sparking?
- Location
- Warsaw, IN
Ok i guess i was thinking of the wrong part. The part i am talking about is the one right next to the throttle position sensor.
