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1987 XJ PROBLEMS

M

Matt2001TJ

NAXJA Forum User
Location
Apple Valley California
1987 xj problems
Hey guys, I am looking at a 1987 (AMC) XJ it has the throttle body injection 4.0 motor, 5 speed with 150,000 miles. This jeep has been sitting for 5 plus years. I tried to fire it up today and it does not seem to be getting fuel. I put a few gallons of gas in it and it shows on the gauge. I primed gas through the air intake and it runs briefly 5 or 10 seconds and did this numerous times. Then the top end does not want to quiet down like it is not getting oil. I would think that the fuel pump is bad and there is no fuel at the injection pressure test bus bar but the oil thing I am not sure about.
I have not really messed around much with a vehicle that has sat for years like that. Any ideas would be nice and yes I can get this for a song and dance cheap. interior is super clean no rips or tears for a 1987 and everything is there it's not a butcher job...Matt
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For sure sitting 5 years the engine has lost its prime. You should attach a mechanical oil pressure gauge and spin up the oil pump with a drill until you get pressure and then pump it for another minute to be sure.

No telling about the fuel system, expect rotted hoses and plugged filter for sure. If there was any gas left in the system it has gone way bad and gummed things up.
 
It will need to run to get her to stop tapping..It has been awhile.. It does sound like the fuel pump..Can you hear it when you turn the key on? So buy it an fix it.
 
I've played with a few that have sit for awhile. The fuel can turn to varnish and Jello, the oil can get really thick. I try to get as much of the old stuff out as possible and replace it with new fuel and oil. A can of injector cleaner and a half cup of acetone in with the fuel. If your lucky the injectors aren't too gummed up, they may need a cleaning or replacement.
Sounds like the pump is gunked up, you might try a rubber mallet on the side of the gas tank in the front. Sometimes jarring things a little may get it going for awhile at least. Or remove the pump and clean it out as good as possible and give it a try on the workbench. Don't run it dry for more than 15 seconds or so, it can overheat.
I usually squirt a pretty good blast of penetrating oil into the spark plug hole and turn it over by hand. Then a couple of squirts of motor oil into the spark plug holes. But it is a little late for that.
Drive it easy for the first few hundred miles, the cylinder walls may need to re-glaze and hopefully the rings seat back in.
I've actually had good luck at firing up old motors that have been sitting for a long time, maybe I've been lucky.
 
First - the 242ci I6 never came with TBI, they're all PFI (individual injectors for each cylinder.) The 150ci I4 was TBI in between carburettors and PFI.

Second - get a Small Block Chevvy oil pump priming rod, and a mechanical oil pressure gage. Install gage in place of electronic sender, remove distributor, run the pump (using the rod and a drill motor) until you see oil pressure and for at least one full minute afterwards. Reinstall distributor, replace mechanical gage with sensor.

Third - Sounds like you've checked for fuel at the Schrader on the rail, and you're not getting any. As mentioned, the fuel pump (on pretty much any fuel-injected vehicle) is in the tank, there's a "sock" prefilter and the in-line filter on the driver's side framerail just forward of the tank. Replace the in-line filter, it's cheaper and easier. If you have to replace the pump, you won't need to drop the tank to do so - but you want to be at a half-tank or lower before you pull the fuel pump "stinger" assembly (the access is in the forward upper half of the tank. Use a brass rod and/or brass or lead hammer to drive the lockring - even if your fuel is shot, sparks down there suck.) Syphon out the old fuel while you've got the hole opened up, and replace with fresh.

Other things I'd check? Make sure the spark plugs aren't too fouled to run, make sure the distributor cap contacts aren't too burned to run, and the like. Make sure some rodent hasn't chewed through any of the HT leads to/from the distributor cap. Make sure the coil hasn't opened up. You get the idea.
 
i would drop the gas tank and clean out all the crap thats in it. take fuel pump and manuelly run the fuel pump out side the car in fresh bucket of gas so you can beat on the acctual pump and not just the tank. if this works put the pump back in and repace fuel filter. also check sprark at the plugs by grounding them and check distributor cap for any moisture i think as long as you have changed the oil before you tried to fire it the sending unit should be fine. but do not try to run it with 5 yaer old oil in it. btw the pump is loud and can clearly be heard inside the car if it is working.

the fuel pump is in the tank i also thought to check the wires leading to the pump before droping the tank. if you dont drop the tank as it was mentioned before, your going to have a hell of a time puttin the pump back in the tank. plus your still have all the old gas and rust particals in the tank.
 
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The gas is probably too *far gone* to even run. As suggested, get it out of there. When testing the fuel pump, realize that it only runs when the key is in start/crank position. In normal run position, it only runs for 3 seconds unless it gets the signal that the engine is running. In other words, just because the key is in "run", the fuel pump is not supposed to run.

Play nice. This is your warning...
 
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bigkeegs said:
i would drop the gas tank and clean out all the crap thats in it. take fuel pump and manuelly run the fuel pump out side the car in fresh bucket of gas so you can beat on the acctual pump and not just the tank. if this works put the pump back in and repace fuel filter. also check sprark at the plugs by grounding them and check distributor cap for any moisture i think as long as you have changed the oil before you tried to fire it the sending unit should be fine. but do not try to run it with 5 yaer old oil in it. btw the pump is loud and can clearly be heard inside the car if it is working.

the fuel pump is in the tank i also thought to check the wires leading to the pump before droping the tank. if you dont drop the tank as it was mentioned before, your going to have a hell of a time puttin the pump back in the tank. plus your still have all the old gas and rust particals in the tank.
Click to expand...

Not necessarily - I've changed a couple of pumps on RENIX without dropping the tank to take them out or put them in.

If the sock is doing its job, it should catch any rust or crud in the tank - but change it if you change the pump (it's probably crapped up anyhow.) The fuel pump is usually a rotary vane type, similar to a "trash pump," which is why it needs a filter inline (either on the suction side or the pressure side - usually on the pressure side.)

Do you get any starting action at all when you try to start it without dumping fuel down the TB?
 
Ya sounds like your pump is bad. My XJ sat for 5 years too, and before I started it, I changed the oil. It even ran good on the bad gas.
 
Matt2001TJ said:
No I dont, at all.
Click to expand...

Check for obstructions in the intake system (clogged filter?) and pull a couple of random plugs and ground them on the block while someone else cranks for you. You should see a nice, fat spark.

If the intake system is clear and at least 2-3 plugs pass spark for you, go after the fuel system next, starting with the fuel filter. Fuel turns into varnish when stored for the long term, and that varnish can coat your filter media and clog things up...

An engine is just like any other fire - fuel, heat, air. Figure out what isn't getting there, then figure out why it's not.
 
man if your worried about cost the wrecker yard is your friend the amc 4.0 runs forever it gotta be the three components mentioned before fuel spark and air and to me sound like gas
 
bigkeegs said:
man if your worried about cost the wrecker yard is your friend the amc 4.0 runs forever it gotta be the three components mentioned before fuel spark and air and to me sound like gas
Click to expand...
I agree, if it was more like I posted, after todays further inspection which displayed much more problems and just straight radical lies from the seller of this vehicle things would have been different. This seller straight tried to screw me over with lies and any other story to take my money. Good thing I caught that situation. There will be a second cherokee in my possesion in time,... just gotta watch out for snakes in the world like how this guy tried to burn me,... better things like this did not happen to ANY jeeper.....MATT....
PS. Once again,...thanks guys for the great advice.
 
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