Ignition woes

[Polaris]

Hey all. I've had my 2000 TJ since she was new. She's been in storage and needs some real work, so I got started this spring with getting new tires and getting her running again. Before I put her away I installed a new Bosch fuel pump. First on the list was a bad ignition actuator because it would crank but not stay on and jiggling the key would cut off ACC power.

After swapping the ignition actuator out it cranked and started right up... for about fifteen seconds then slowly died. Spraying some carb cleaner in the intake gets her running so I'm thinking it's a fuel issue. No CEL.

The schrader valve on the fuel rail has pressure, but I think I should get a gauge to make sure. Do y'all think I'm in the right direction in looking at the fuel pump? TIA.

 

[Steel City 06]

I would recommend testing the fuel pressure. Test it both with the engine off (key in the run position) and on. The fuel pressure should hold even after the key has been removed.

From there it is basically a game of follow the fuel.

How old is the gasoline? If it's been sitting too long it could be bad. If it's more than 6 months I would drain and refill the tank with fresh fuel. Modern ethanol diluted fuel unfortunately absorbs a lot of water

 

[Jerry Bransford]

For sure test the fuel pressure which should be very close to 49 psi idling and and while revving the engine to see if the fuel pump can keep up. Many auto parts stores, especially AutoZone, have fuel pressure test kits to rent out cheaply or loan for free.

 

[Polaris]

Thanks. I’ll give it a go tonorrow with the fuel pressure gauge.

With the only gauge that is working being the tach, I have a feeling it’s a bad PCM. Fingers crossed!

 

[Polaris]

Fuel pressure looks good at about 50. It will crank and start for a couple seconds then just sputter out. If I try and give it gas it just dies. CPS?

 

[Polaris]

I tried swapping in a new ignition coil, a computer from an 97 auto 4.0 TJ, (mines a 2000 auto 4.0 and I don’t think the pin outs were the same), and checked fuel pressure. No codes are being thrown. Dash gauges don’t work except for tach. New Bosch fuel filter installed. Relays are working as they should. Nothing has worked so far in keeping my TJ running.

It cranks starts for a few seconds until it just dies. If I put some gas on the air filter it stays on until that runs out.

Obviously this is a fuel issue, but could a bad PCM be the cause here?

 

[Polaris]

Turns out it was a bad two year old Bosch fuel pump and water in the fuel tank. Emptied and cleaned the fuel tank and installed a new Delphi pump. Seems like Bosch fuel pumps aren't in production anymore.

Cranks right up and runs strong.

 

[Chris]

Turns out it was a bad two year old Bosch fuel pump and water in the fuel tank. Emptied and cleaned the fuel tank and installed a new Delphi pump. Seems like Bosch fuel pumps aren't in production anymore.

Cranks right up and runs strong.

Bosch doesn't make the fuel pumps anymore for our TJs (unfortunately), you are correct.

Water in the tank will definitely do that, no doubt. How did the water get in there?

Thanks for the update too!

 

[Polaris]

It had been in outdoor storage for a couple years and I found it without a cap last fall. Didn't think I got that much water in there but so it goes.

Got some new LED headlights with integrated turn signals, RE monotube shocks, I welded on a new shock bracket to the rear 8.8, and gave her a tune up with Champion plugs and a K&N drop in filter.

The tires are new as well - 35x12.5R15 BFG KM3

She still has a ways to go - I need to get a new dash cluster as the gauges and display are dead, an aluminum radiator, new winch, seats, and need to decide what to do about the grenaded front HP30.

 

[Jerry Bransford]

Bosch still makes the fuel pumps for our TJs, they just no longer sell the entire fuel pump assembly including the pump, fuel pressure regulator, housing and fuel gauge sender.