97 TJ won’t start, but turns over

[Beowulf]

97 TJ won’t start, but turns over

My friend’s 97 TJ will not start. It is a 4.0 with an automatic.

The engine turns over just fine, but it acts like it is getting no fuel. He says it has a full tank of gas. We cannot verify this as the gauges don’t seem to work.

Normally, when you turn the key to ON the gauges will slowly creep up. Neither the Volt or Gas Gauge moves when the key is moved to ON.

We have checked all the fuses in the Glove Box and in the PDC.

Any thoughts on what might be causing this?

 

[Hawkz]

My first guess would be the fuel pump, but there are cheaper things to look at first like fuel filters, ect.

When you turn the key to the On position without starting it do you hear the fuel pump prime? If the sending unit is out it's possible the pump is out too.

 

[Beowulf]

I thought Fuel Pump as well. I really don't hear anything when he turns it on sadly. Unfortunately that whole thing is up inside the Gas Tank and of course is a pain to get to.

One person over on Jeepforum suggested it could be something with the Cam Position Sensor.

 

[BushHead]

This may sound stupid, but if you have a "chipped" key, try your other key, I've been amazed how many people's cars I've "fixed" that way...


Matt

but usually when its the key, it will kinda crank then die, but its worth a shot...

 

[Beowulf]

Sadly it is just a normal key.

 

[SWbySWesty]

x2 on fuel pump. My 97 XJ had a good whine on the fuel pump when priming. It went dead and it was quite obvious. Just siphon the fuel out of the tank before attempting to drop it! Odd about the voltage guage - did you put a amp meter to the battery to verify a FULL charge? I've had nearly dead batteries give starting a good go, but corroded terminals and low voltage wouldn't cut it.

 

[expedition4x4]

Check the Crankshaft position sensor

 

[Dan Grec]

Any engine codes?

 

[bob91yj]

There should be a schraeder valve on the fuel rail that you can use to check fuel pressure. If you do it the old fashioned way, and push on the plunger, there's a good chance you're going to get a shot of fuel coming at you at around 45PSI, use caution.

CRANKSHAFT position sensor is the likely culprit. When you crank the engine does the tach needle bounce? If it doesn't bounce it's most likely the CRANKSHAFT position sensor, not the cam position sensor. The CRANK sensor is what fires the tach. The good news is it's a relatively cheap fix, the bad news is it totally sucks to get to it.

Looking at the engine from the back, over the top of the transfer case/transmission, at about 11 o'clock on the bell housing you will see a sensor held on by 2 small bolts (want to say it's a 10mm head, but not 100% on that). With a 3 ft extension you can "just" get to it to get the bolts out. If the Jeep has a body lift, it's MUCH easier. I recommend replacing with a factory sensor, aftermarket sensors seem to be hit/miss on quality, not a job you want to do twice.

 

[Doctor W]

I don't know if your TJ has an Anti-Theft system with a separate push button fob, but sometimes they go crazy......the cure is to disconnect the battery for a minute or pull Fuse #12 (from memory) for a few seconds, in the PDC under the hood.

 

[bob91yj]

^^^^Unless it has an aftermarket alarm system, the only "factory" security is the coded key option on a pre-07 Wrangler. Power windows/locks were never even a factory option, hand cranks and push buttons!

 

[1stDeuce]

If you're getting no voltage at the gage, there's a good chance it may be your ignition switch too. The '97 and '98's had a decent failure rate, particularly on Jeeps left in the rain with the top down... Check the rail pressure and see if there's any... Just use a key to press in the little schrader valve, just like on a tire. If gas squirts out all over, then move on to crank/cam sensors. If no gas (It should re-pressurize EVERY time you key off and back on.) then check the fuel pump relay to see if it's got power, turning on/off, etc... Post up what you find with fuel, voltage at the fuel pump relay, etc.
Chris

 

[monk]

I have a 97 TJ. I have solved many issues by checking the codes.
http://www.offroaders.com/tech/jeep/TJ_diagnostic_codes.htm

It sounds like the crankshaft sensor. That should have put the "check engine" light on. I think.

Good luck.

 

[irish1371]

did the gauges work before? but do not now that this issue has popped up?

If so then it is most likely the large buss connector directly under the steering wheel. that is usually where after market alarms get tied in, and they do not always get this plug back together all the way. over time it loosens and when it shorts then the whole gauge assembly goes out. was a lot of fun to have my jeep die going down the road at 70 due to this.

luckily I got pissed slammed on the dash and poof it came back to life so I could get home.

if the above doesn't fit then I would listen to the others saying to check the crank/cam sensors and possibly the key switch

 

[Judoka]

Throttle positioning sensor.