99 TJ no start (has fuel pressure and no spark at plug)

[99greenTJ]

Jeep stopped on highway with grandson last night. This morning I have found, it has fuel pressure and no spark with plug removed and near ground.
My friend with a trailer has towed it to another friends house, for further investigation. Getting 10 to 11 VDC to coil pack. Ohm out coil, 2.1 at secondary wires. Coil tower 6 ohms to either of the two secondary wire. Ground was on fender well okay.
I am lost to find out next step. BTW I switched the relays in the fuse box for the ADS? relay. Has volts coming to relay terminals also.
I guess its down to the cam sensor and or the distributor? Would like to keep the parts changing to a minimum if not needed but will do it to get it back going.
No check engine light, has ran great for months.

 

[Ashim]

My experience with the 4.0 is when it stops running it's either the fuel pump or Crankshaft Position Sensor. You've already ruled out the fuel pump.

 

[99greenTJ]

OK thanks for the input. Always a question, it seems the CRANKshaft postion sensor is the most common. Why was I thinking Cam shaft sensor?

 

[99greenTJ]

Update
99 TJ still not running. Fortunately I had another vehicle being prepared for a grandchild need. I can still troubleshoot the Jeep without pressure.
Has spark, my have all along, its weak.
Currently no injector pulse. No voltage to injectors.
I have replacement the crank sensor with no change. Trying to replace the cam sensor (inside the distributor housing), having trouble finding one local that will actually fit. Unbelievable what is sold for replacement parts.
Still trying to get this jeep started.

 

[Chris]

Update
99 TJ still not running. Fortunately I had another vehicle being prepared for a grandchild need. I can still troubleshoot the Jeep without pressure.
Has spark, my have all along, its weak.
Currently no injector pulse. No voltage to injectors.
I have replacement the crank sensor with no change. Trying to replace the cam sensor (inside the distributor housing), having trouble finding one local that will actually fit. Unbelievable what is sold for replacement parts.
Still trying to get this jeep started.

Look for any damaged wires or loose connectors leading to the injectors. Sometimes a simple connection issue can cause these types of problems.

In addition, the PCM might be the culprit if it’s not sending signals to the injectors. I'd talk to @Wranglerfix about this.

As for the cam sensor, I wouldn't trust any brand of replacement sensor from any local shop for the most part. I'd order a quality brand from RockAuto or similar. Walker usually seems to be a good choice.

 

[99greenTJ]

Okay thanks. I know the pitfalls of general availability of parts other than the factory or known usable brands.

 

[macleanflood]

How healthy is your battery? I'd start with the basics and check your battery voltage, clean your terminals...check the ground on the engine block and firewall.

Next I'd check your neutral safety switch or clutch switch. Most TJs have a spare fuse in 19 that can be moved to 20.

The issue you're having is with what's called the ASD relay. Google wranglertjforum asd relay if you want a deep dive.

Ignition switch and swapping the ASD relay for something known good...honk the horn to verify and swap for example...are other possible causes.

-Mac

 

[99greenTJ]

The battery is being assisted by chargers and maintainer during this work. Battery has always started the jeep but not a great one.
ASD has been investigated. Swapped with adjacent relay. The swap with the horn relay and honk horn will be done.
The transmission is auto. Will put the neutral safety on the watch list.
I am struggling with what fuses behind the glove box would be suspect?
I have downloaded the 99TJ wiring from the resources section.
Is there a "service manual" on that list?

 

[macleanflood]

Might want to pull the crank position sensor off the edge of the bellhousing. Check and see if it's gunked up. It's a hall affect sensor and measures the gaps in the metal on the flywheel.

-Mac

 

[99greenTJ]

It was replaced this week.

 

[99greenTJ]

With a delay in being able to return to the jeep repair, I wanted to share .
These pics are of a checking tool for this sensor. After wasting several hours locally, in buying the replacement part, only to find out the new part would not have even come close to going over the two bolts. To the necked eye it looked great, now I tested the Autozone CR142 replacement. FYI

 

[macleanflood]

You should make and post a video on how that works!

-Mac

 

[JKP]

It will be easier, and even possibly cheaper, to just get another distributor instead of trying to replace the snyc/cam sensor.

 

[99greenTJ]

That part in the picture was $50.
I dont think I could get a whole distributor at pull a part?
My distributor only has that cam sensor flat plate, a rotor bug, a distributor cap.

 

[hear]

It will be easier, and even possibly cheaper, to just get another distributor instead of trying to replace the snyc/cam sensor.

Easier?? You just take the cap off, gently pull off the rotor, then slide the cam sensor off the shaft. The sensor will only fit one way, and the rotor only goes back on one way, and since you didn't touch the dizzy you don't need to worry about finding TDC or anything.


to OP whenever somebody says "check your crank sensor" all I can think about is the fact that the cam & crank sensors work the same way, off the same ground & 5V supply, and peform nearly identical functions for the computer. Always check both, and the wiring to them as well.

 

[JKP]

It's been quite some time since the one on my YJ went, but I wound up with a complete distributor with a lifetime warranty for about the same price as the sensor. I think it was $60.

Rock Auto has a complete new distributor for yours for $80.

 

[JKP]

Easier?? You just take the cap off, gently pull off the rotor, then slide the cam sensor off the shaft. The sensor will only fit one way, and the rotor only goes back on one way, and since you didn't touch the dizzy you don't need to worry about finding TDC or anything.

They may have changed the way it's put together for the TJ. I seem to recall I was going to have to pull the distributor, remove the gear and shaft, then pull the sensor on the YJ version. But it has been 15 yrs or so.

 

[hear]

They may have changed the way it's put together for the TJ. I seem to recall I was going to have to pull the distributor, remove the gear and shaft, then pull the sensor on the YJ version. But it has been 15 yrs or so.

Nah, it's supes easy on the TJ.

 

[99greenTJ]

Continued work on 99 TJ 4.0. Changed the coil and was able to get it to start. A change of crank sensor was the only other part replaced. The cam sensor saga was just to put the existing sensor back in. The two new sensors as noted had issues.
The jeep is running ruff, code P0201 is now being thrown. Injector 1 circuit fires improperly. A check engine light is new to the diag. but need to deal with it. ?

Nah, it's supes easy on the TJ.

 

[99greenTJ]

99TJ no start update.
As mentioned an ignition coil got the jeep to run. Why all of the injectors were not firing and the ASD RELAY would not energize may be a mystery for another day.
Now the only known issue is the P0201 code, #1 injector is not firing. We have proven all is good back to the ECM. Currently looking at sources for an ECM. Local salvage yards are already robbed for the ECM.