Old Jeep, hasn't been started in ten years.

So this old Comanche I bought. Even though the whole drivetrain will be replaced by a newer set up out of a 99 XJ I thought it would be interesting to see if I could get it to run. According to the dude I bought it from, it ran when they parked it in 03 but the trans was bad.

I have manually cranked the engine over to make sure the pistons weren't glued to the cylinders. I have dealt with old carberated motors but have never dealt with a fuel injected engine. I'm sure the gas is bad but the gauge says its empty so hopefully it won't have a full tank to get rid of.

What should I be looking for? We finally got it to turn over but it won't fire. Haven't checked for spark yet. Is it common for fuel injectors to get gummed up like the jets in an older carberated set up? Fuel pump?

I would like to start it. If it runs I could possibly sell the engine.

I hear a lot of concerns in posts..... about so called bad gas from rigs sitting up too long, but in spite of being a procrastinator, and lazy, I have yet to see bad gas myself. I have had carburetor rigs set up for 4-6 years (72 ford LTD, 78 Dodge wagon, Renix jeeps, 1996 Ford Taurus.....) and never had a bad gas restart problem.

Diesel fuel is another story!

I have had renix rigs set up for two years and start fine with no gas problems.

Recently restarted an 84 XJ carb'd 4 banger we bought, after replacing the bad fuel pump (old style leaking into the crank case). It started right up using carburetor cleaner to prime it, but would not stay running. New fuel pump did the trick, but it was not bad gas....

What year is this rig?

87 MJ 4.0L

And I have seen carbs gel up with green nasty goop from sitting too long.

I bought a MJ that had not run or started in 4 years for $400. It was living in a barn, the battery was dead when it was delivered to my house on a flat bed. Coolant was still green.

I put a new battery in it. All the gauges were operating, it had a 1/2 tank of gas in it. I removed all the plugs and put a teaspoon of oil in each cylinder, let it sit for a day, put new plugs in it. Turned the key, fuel pump came to life, gauges came up, all the lights came on and it cranked fine but wouldn't start.

Did a compression check on it, every cylinder was 130 or more. No spark. Fuel was in rail. I replaced the CPS because the wire was melted on the manifold (my suspicion was that's why they parked it in the first place). Then I checked for spark...success. Sprayed some staring fluid in the
intake and crossed my fingers.

Took three trys turning the motor for about 3-5 secs each time. On the third try the thing came to life. It was a little rough...but it was running. Blew out some black smoke for about 2 seconds and then smoothed out considerably.

My advice would be to take it one step at a time. Shoot some oil or PB into the cylinders. Check the electrics, NSS, CPS etc. Give it a shot. If it all goes "flump" you got nothin' to lose.

I've put about 3K on it so far, and although I've replaced alot of stuff and built it up, the engine is still intact, original and has plenty of power.

Good luck.

P.S. The heater cowls, fan housing and ductwork for the HVAC was packed with a mouse nest, including mouse crap, two dead mice and little bits of the carpet, straw, grass and some dead bug bodies. Other than that no other mouse problems, like chewed wires etc. I cleaned it all out but I still get a random piece of floor insulation fly out a vent every once in awhile.

ParadiseXJ said:

P.S. The heater cowls, fan housing and ductwork for the HVAC was packed with a mouse nest, including mouse crap, two dead mice and little bits of the carpet, straw, grass and some dead bug bodies. Other than that no other mouse problems, like chewed wires etc. I cleaned it all out but I still get a random piece of floor insulation fly out a vent every once in awhile.

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When I bought this jeep we couldn't find the PO's registration. I found it in a mouse nest.

It actually has me a little worried. We have a lot of hanta virus in this area. It's going to get a good Clorox bath before I tear into the interior much.

I've got the interior including all the dash pieces and the whole front clip from a 99 XJ going on. Don't have to be too worried about what the mice have chewed up.

You might try a good ozone gas generator to disinfect it. It will kill stuff Clorox does not kill.

The 4.0 renix is a pretty bulletproof engine, the only stuff that tends to let it down are the electronic controls. I have brought quite a few XJ's back to life after 1yr+ of sitting, which isn't terribly hard, usually if you throw some fresh gas in them and hotwire the fuel pump and open up the bypass valve with a vacuum pump and let it run for a few minutes (this flushes new gas into the fuel line) it will usually start back up with a bit of cranking.

One thing I do is I will pull the coil wire, and then turn it over for about 5-10 seconds to cycle oil back up into the filter and lubrication system. Otherwise it makes a really scary noise once it starts up.

It may run like a model T for the first tank of gas or so, I usually run some seafoam through it to clean the injectors out and get the fuel system back up to snuff.

Ecomike is right, gas doesn't really go "bad" it just gets not very good once some of the volatiles like butane evaporate off. The only caveat to this, is ethanol gas in wet climates. Ethanol is hygroscopic, and will make water mix with the gas, just from sitting this usually isn't too much of an issue except for corrosion. If you dump in some fresh gas, this will usually dilute it, but it may require dropping the tank for a good cleaning, followed by a new fuel filter.

I've never really had an issue with the fuel system or engine... but you should definitely flush the brake system and I'd probably put oil in the cylinders, crank it over a bit with the plugs out, then give it an oil change and crank it till the pressure comes up before putting the plugs back in and trying to start it. Maybe even do the oil change before turning it over at all (any more than you have) because that way you'll get all the old crap oil out of it instead of pushing it up into the oiling system where it can lurk before draining everything else out.

All gasoline and diesel will deteriorate over time.

How the fuels are stored, ambient temperatures, presence of contaminants are all variables that can extend or shorten the useful life of fuels.

The clock starts running on the day the fuels are refined--made--and it is downhill from there.

Vehicles/equipment with CARBS will experience problems sooner than "closed" fuel injection system.

Fuels evaporate faster than they deteriorate. The leftovers from evaporation form the gummy "varnishes" in CARB vehicles.

Re-engineered fuels are worse than leaded/unleaded fuels--E10/E15 or E85.

Moisture will speed the deterioration of fuels.

So, in the right area of the country where ambient temperatures are moderate year round, in a fuel injected vehicle or sealed fuel storage cans, low to zero contaminants in the fuel, it should still be USEABLE for a long time. Note USEABLE--as in you can put it in an engine and run it, drive around, etc. You won't get the same power/MPG as you would from fresh fuel.

That reminds me, the 72 Ford LTD I had that set up for 6-7 + years only had one problem, the rear drums locked up, rusted or something. Had to smack the drums a few times IIRC to free them up. Oh, and the trunk cancer (rust) had spread.

kastein said:

I've never really had an issue with the fuel system or engine... but you should definitely flush the brake system and I'd probably put oil in the cylinders, crank it over a bit with the plugs out, then give it an oil change and crank it till the pressure comes up before putting the plugs back in and trying to start it. Maybe even do the oil change before turning it over at all (any more than you have) because that way you'll get all the old crap oil out of it instead of pushing it up into the oiling system where it can lurk before draining everything else out.

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When I got my 88 it had been sitting in the back lot of a Jeep dealer for a long time. The owner said the bill was to high and told them to keep the XJ. In hind sight he likely did a smart thing, there were numerous problems and bugs still in that XJ.

I couldn't get any fuel to the rail, made sure the pump was pumping at the rear near the fuel filter, I actually had to bang on the side of the tank with a rubber hammer to get the pump going. Still no fuel to the rail. On a hunch I disconnect both ends of the fuel line and pumped high pressure air through there, it was amazing the amount of junk that came out of that fuel line.

What came out of that fuel line was rust flakes, grey metal flakes and chunks of what looked like Jello.

Half a tank of fresh fuel, a bottle of injector cleaner and she has been fine since. Ten years later, still the same pump and injectors.

The '88 Waggy I just got was sitting for 13 years. Smelled varnish but I put some fresh gas in it and gave it a shot. No fuel press, no noise from pump. Pulled the sending unit and the pump was a mass of brown varnishy goo and the lines inside the tank were rotted.

I threw in a used tank and a new filter, pumped some gas back to the return. It fired right up. I ended up have to put injectors in it too, though.