Blind troubleshooting

[Thatch]

I just purchased an 86 GW in a generally good, but non-running state. The story (assuming it is true) is that the truck ran fine with no significant issues before the owner, trying to splash his wife in the passenger seat with an open window, by driving through a puddle. The truck apparently continued to run and they parked shortly thereafter at a park and upon returning to the truck It would not start (did not engage the starter itself) and has been in that state for the last year.

He tried for some time to get it fixed but ultimately was unable. Unfortunately that means there are a few things undone on the truck that I have to figure how to put back together.... He was able to get the starter to crank by jumping at the solenoid, but apparently was unable to otherwise address the issue. He stated that he wasn't able to get the voltage from the ignition switch to the starter. That is the extent of what I know / was told.

So, my question is a general one. Assuming the story is true. What could running through a puddle have done to cause a fault within the starter/ignition? And is there a way I might could bypass a potential issue to see if I can at least get it running for some initial triage?

I've not done anything yet with it other than to clean it up, get rid of the interior mildew and throw a charger on the (disconnected) battery. I thought I'd get some opinions before I leave from the office as some 'first steps to try'.

Thanks,

[rang-a-stang]

What could running through a puddle have done to cause a fault within the starter/ignition?

When did he drive through the puddle? days ago? years ago? If it was years ago, I would assume water got in places like the firewall bulkhead connectors (next to your master cylinder) and rusted them. Not hard to take apart and clean but time consuming. Water also creates shorts so check your fuse block with a multimeter and make sure all the fuses are good.
Days ago... I would park it in a warm dry place for a few weeks and hope it dries out.

And is there a way I might could bypass a potential issue to see if I can at least get it running for some initial triage?

I am not sure. I know you can turn the starter by jumping the solenoid signal but you still have to get power to your ignition. BUT, you can check compression by turning with the starter and that may be all you need for now.

Honestly, I say, download the service manual (here) and start by studying the starter circuit. Fix that and make sure it works, first. Then move on to finding where your spark went. The start and ignition circuits are pretty basic and pretty easy to troubleshoot with the service manual.

[Thatch]

Thanks for the suggestions. The water incident happened about a year and a half ago. I plan on spending tomorrow trying to fire it up. I did find out one additional and probably inconsequential issue, apparently the writing harness as it passes through the passenger back door, ribbed through and was shorting. I can't personally see how this would be connected, but thought it best to share regardless.

Hopefully I'll have some more solid info or guesses after I've had some time with it.

[wiley-moeracing]

Check your neutral safety switch down by the trans? Been a long time since I worked on a 727, but going through the puddle may have damaged the wiring down there. Then look at the ignition switch under the dash on the column.

[chubbinius]

Truth in advertising...I have no expertise but some things to check-Is there a good charge on the battery? Clean lugs and terminals up there?

All wires plugged into distributor cap/ignition? Does it have an ignition module on the engine fender/well? If so is it good or is it melted?

Any breaks in the wires to starter or from the ignition switch?

How are all the connections and terminals? Clean and corrosion free? Wire brush or sandpaper all of them to clean it up.

How are all the grounds? Clean metal to metal connections on all of them?

Good luck.

[bkilby]

Check your neutral safety switch down by the trans? Been a long time since I worked on a 727, but going through the puddle may have damaged the wiring down there. Then look at the ignition switch under the dash on the column.

...or popped the plastic connector off the NSS.

[tgreese]

You can blindly try some stuff, but the right thing to do is to be systematic and trace out the problem. The TSM has schematics of the vehicle wiring that you can test to make sure you have voltage at the right locations to get spark. Make sure you have fuel at the carburetor. No-fuel or no-spark are the two things that happen to give a sudden no-start condition. Most everything else that cause no-start will be accompanied by some catastrophic and obvious problem.

This no-start may have had nothing to do with the puddle. Do you have a multimeter? Test where you should have power, and trace out the problem. If that's too vague, the TSM has flow charts that will help you with a no-start condition.

Condensation under the distributor cap (and resulting no-start) is the usual result problem associated with splash. The rest of the car should not be much affected by splashing water.

[Thatch]

Thanks for all the suggestions. I played with it a bit this weekend, but as I'm in coastal Georgia I had to give it up to start hurricane prepping. I hope to get back to it this weekend.

I did recall he said something about changing out the solenoid relay more than once and said he "didn't know what was making them crap out"... I don't know if this was really a thing, or if he was misdiagnosing the issue and throwing parts at it. However, the problem is that it doesn't attempt to start, (will not crank) not that it won't start when cranking.

I do need to order a new battery for it? ... and perhaps a tender since this is going to be in project status for a while.

[tgreese]

Do you have a battery charger? I'd suggest you remove the battery from the Jeep and charge it fully a few times. The charger will shut off when it reaches its target voltage, then let the battery sit for a day or two and charge it again. I'd repeat this at least 2 or 3 times, giving you the best chance of reviving a battery that sat idle for a long time. Then take the battery to your local parts store and ask them to test if for you. Many cranking problems are really battery problems. You should also make all the cables and connections clean, bright and tight.

Your '86 should have a Ford-type solenoid like this - https://www.rockauto.com/en/moreinfo...182349&jsn=383
Standard is a good brand. Be sure to get the proper part for an automatic transmission that has a ground connection on the bottom. This goes to the neutral safety switch that prevents starting in gear. You can use the part for a manual transmission (Standard SS581) but then the Jeep will start in any gear and that's dangerous. You also need to make sure the safety switch functions, or again the Jeep may not crank.

Start at the battery, go step by step through all the pieces and check that it all works before you go to the next part.

[selkplitt]

Maybe the starter switch on the lower steering column. Mine wouldn