Need Help with No Start

I have a 90 XJ all stock that I use as a daily driver and I washed down the the battery side of the engine compartment and now it will crank fine but no start. I started it up afterwards and it ran for about 30 sec and completely died.

So I checked for fuel and pressure is fine and pulled spark plug and there was fuel on it, so the injectors are firing. But no spark. Checked the resistance on the coil and the secondary resistance was somewhat low and the primary resistance jumped around when I moved the coil around. So that seems a little suspect.

Now I also checked out the CPS because I know that can be a major cause of no starts and the sensor checked out with all the tests but I checked the ground and there is very high resistance from the white wire ground at the sensor to the negative cable. Checked and cleaned the grounds and they seem okay. So I checked for continuity from the ground wire at the sensor to the ECU and its good so now I am suspecting the ECU's ground possibly.

Any ideas and thoughts would be greatly appreciated because I am fast running out of idea's myself.

If your injectors are in fact firing, the CPS is an unlikely suspect.

The CPS is little more than a tiny generator, the circuit you are testing for ground likely travels through electronics (an amplifier) to be used by the ECU.

Check the *larger* yellow wire at the ignition module for voltage. Then do a voltage test at the coil test point (a spade type connector an inch above the center module connector). The coil and the ignition module separate, the clips/contacts between the ignition module and the coil are wide open and unsealed, they tend to corrode. To test the coil/module group, many auto parts stores have a tester for this.

My first guess would be you have a high voltage short someplace, in the coil to cap boots or inside the distributor cap itself. Water can collect in the bottom of the distributor housing. Most of the distributor caps have an air vent that leaks.

Yeah I was wondering if that ground was not a true ground. I checked the yellow wire and there was voltage I think it was like 11 or 12 volts. I have not checked voltage at test point on the coil. It has been drying out for 4 days now so I would think all the water would be gone.

My main suspect right now is the coil so I need to get that out and test it. I will post the results when I do.

If you have water in your cable boots, it will never dry out, you have to dry it out with a rag, Q-tips or air. They sell ignition spray, never tried it myself.
Did you try to see if you have spark at the coil to cap wire? Could be shorted inside the distributor cap through the moisture, pretty common really, happens a lot when mudding.

I checked for voltage at the coil and I got a voltage ranging from 8-11V at the spade connection and 12V at the round exposed connection below and to the left. I checked for spark from the coil to the cap and there is none. checked for water in the distributor and the plug wires and all seems dry. So I think I'll try another coil and see what happens.

Take your Ignition module off and have it tested at your auto parts store. On my 88 the module went bad but the coil was good. I had voltage to the ign mod but nothing coming out. And the test was free!!!

B.RAIDER said:

Take your Ignition module off and have it tested at your auto parts store. On my 88 the module went bad but the coil was good. I had voltage to the ign mod but nothing coming out. And the test was free!!!

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Good idea. Located below the ignition coil, and is about the only thing on a RENIX that can't be tested with a meter!

I think I found the root problem. A friend of mine suggested baking the coil in an oven to get any water out that might have collected in there. So I did that and put the coil back on and it started right up and ran perfectly for about 5 minutes and then suddenly quit again. So that should be my problem. Thanks for the suggestions.

Greets; Consider cleaning your engine compartment in the future with a rental steam cleaner, rather than copious amounts of water. Me, I live dangerously, I use gasoline in a half gallon jug with a hose in it going to a trigger nozzel that receives air pressure from a compressor. The nozzel is adjustable.., so it can deliver a mist, or stream, or somewheres inbetween. Does a great job of removing oil soaked mud, etc. Another thing.., when it is raining, before I go anywhere, I pop open the hood, and spray the entire engine compartment with WD-40 especially targeting all wires, connections, and electronic components. Any water that splashes up into the engine compartment, or additionally sprayed about by the mechanical fan will simply and practically just bounce off of the WD-40 thin coat barrier, rather than having droplets cling and puddle into connectors, etc. Water and Electricity.., hmmmm. Hope your issue with the Renix is fixed.., let us know!

Well I got a new coil today and it starts and runs good. So I think that takes care of that finally. It took me awhile to getting to that point. Looking at the old coil I see some cracks in the resin or whatever it is that seals it so I am thinking that water got in that way. Yeah I think I learned my lesson with water. I think its probably better just to leave it an oily mess than to have a clean engine bay and a Jeep that doesn't run.