turbosparky

This is my 1999 XJ 4.0L. Most everything is stock.
-31x10.50x15 Procomp A/T2
-Late 90s TJ Front Axle w/ Posi-Lok
-thank you RTorrez1

I hopped into my jeep this morning and tried starting her like any other day. It started, but after a couple seconds it was almost as if fuel was cut off. I didn't think much of it so I tried again. Same result. This is where I started troubleshooting.

What was happening was similar to what would happen if I was using the wrong key (one without a transponder) except the security light wasn't on. So it wasn't that.

I also noticed that the airbag light was on. This was getting a little strange.

What I didn't notice until now was that most of my dials were not working. The battery gauge read about 10v, oil was almost fully on the left and when I tried starting it (only to get the same result as before) the Tach wouldn't budge.

What really makes things weird is that after I tried keeping it running multiple times (sometimes by keeping the accelerator pressed only to have it fail again) I'd sit in the truck wondering what would cause this and I hit the driver's unlock button and BAM! Up popped a CHECK ENGINE and SECURITY light. They wouldn't go away until I turned the key to off and back on again.

I've tried searching for a resolution to this all morning. Some have suggested the Airbag module under the seat needs to be relocated. Other have said the Fuses and/or Idle Air Motor need replacement. Another post suggested the ASD relay. These all sounded close, but none sounded close enough to my issue for me to go about spending time and money fixing this.

I've invested a little time into this already, despite my last sentence. I've ripped off the dash and removed the cluster. The pins looked fine, but I cleaned 'em up anyway.

Any suggestions or additional troubleshooting steps would be greatly appreciated. Thank you.

RTorrez1

First things first. What kind of vehicle are you talking about? Give us a year, Model engine and trans. All Jeeps are not the same. Anyone giving any advice without knowing this things would only be guessing. Once we know the basics we can be of more help.
BTW, Welcome to the forum.

turbosparky

Thanks for that. I added it to the original post as well, but it's a 1999 xj 4.0L

RTorrez1

If you can get your hands on a code reader you should see if you have any stored codes. With a little luck it will give you a direction to look at and we can go from there. BTW, even if you don't have a cel on it can still have some stored codes. Once you get the codes read post them and some one can give you there meanings and what to look for.

turbosparky

Thanks! I'll source out a code reader and get on that.

Similar to Xcessive's thread, this is my daily driver and I need to get it going today if possible.

tjwalker

Yes, codes are the first step. As you had a CEL, there should be stored code or codes.

This can be tricky territory so you don't want to throw parts at this on a hunch.

Post the EXACT code here for comment (not just a description). With OBD, the devil is in the details.

77olds

Slow down there pal, you're going way overboard.

First thing you need to test is the battery.

Yes, I know what you're thinking, but trust me - these computerized engines need full voltage or a lot of weird things can happen.

When my battery started dying, it would run rough and I'd get all sorts of DLC lights on the dash. New battery, cleared the codes, never saw them again.

Start with the battery, have it tested, make sure it's putting out its full voltage, and go from there. Don't cause yourself a massive headache because of assumptions.

turbosparky

I'm going to pick up a reader tonight.

I've been spending all day on this (seeing as how I can't go anywhere) and I've come across some new details:

- The ECL I receive is only after pressing the unlock switch with the key in the ON position. Will this give me a code? Maybe. I'll check in a couple hours.

- There may be a factory alarm system that's disabling fuel flow. Where the factory system is, I don't know. I don't have the fob to disarm it.

- I can also try jumpering the fuel pump to see if that keeps it running. If so, I'll install a killswitch and call it a day.

- After consulting numerous wiring diagrams, I found that in the Power Distribution Centre, there's an Automatic Shutdown Relay right next to the Fuel Pump Relay. The load side of the ASR goes through a 15A fuse straight into the ASD Relay Sensor aboard the PCM. Interesting.

turbosparky

I've recently replaced a frozen battery and this one checks out fine, but thank you for the suggestion. I too have had crazy things happen on other vehicles due to a low battery.

tjwalker

Yes, gotta rule factory alarm in or out along with retrieving those codes.

Freshening all engine grounds is also never a bad idea for electrical "gremlins". Here's more.
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Grounds can be the root cause of many electrical gremlins. Refreshing grounds is NEVER a bad idea, and the investment of your time in this procedure is always well worth it!

You can't tell much of anything by looking at ground connections!! You must remove, scrape, clean until shiny the cable/wire ends and whatever they bolt to. Be sure to remove all paint from any ground connections.

Start with the one on the back corner of the head, and where it attaches to the firewall, as it deteriorates over time and is an area that makes it susceptible to damage. Best to replace that woven cable with a #4 or #2 gauge cable. You can attach the one end to the intake manifold if you would like.

Next go over to the engine dipstick tube stud. Remove the nut and clean the wire ends and scrape the block until shiny at the stud. Reattach tightly.

If you are so inclined, add at least a #6 cable from the negative terminal of your battery to one of the bolts on your radiator support.

turbosparky

Alright, new update!

I got it running!!!

Here's what I did:

I got a replacement relay. This was kind of on a hunch based on everything I read today. That and a pretty in-depth look at the wiring schematics. I went and got a 30A ASD (Automatic Shutdown) relay. Exact same as your starter, fuel pump and cooling fan relays. As soon as I replaced that, she started and ran like before!

Standing at the Passenger side looking at your power center (with all the fuses and relays), it's the square one at the top right.

Unfortunately, this hasn't resolved all of my issues.

I also got a fancy pants bluetooth OBD2 scanner and it threw code P1686.

P-1686 - No SKIM Bus Message Received (Sentry Key Immobilization Module)

When it's running, it's all fine. Eventually the AIRBAG light comes on and my TACH and SPEEDO die. The other gauges are fine. I've found that to disable that light and get my dials working, I have to UNLOCK the doors. Doing so turns out the AIRBAG light and the dials work again. UNLOCKING the doors also turns on a new light. The SECURITY light. After this point, the gauges will die and the AIRBAG light comes on again after a period of time (5min?). This is cleared by hitting UNLOCK again.

I know that the SKIM error shows that I may have a key without a transponder in it. This is the same key I've been using for a year now with no issues. Why is it acting up now? Is there some way to bypass the SKIM?