TJ stoped when driving (like the ignition was turned off).

1997 TJ Houston · 07-06-2007, 07:33 PM

I have a 1997 TJ with ~200K on it. It has been runing a bit rough latley, mainly during idle and when turning the engine off (it shakes and clanks). Today when driving from work ( 3 minutes into the drive) it started to heasitate (it has been doing this a well latley). I normaly just give it a little gas and it clears. This time it just stoped like I turned the ignition off. I tried clutch starting with a small response then no more. I pulled into a parking lot and tried starting with no success (about 4 times). The 5th time the engine seemed to be stuck. I poped the hood and to see if I saw any external obstructions. I went back in and it truned over without any ignition again. Since then I have checke and verified that there is gasoline to the injectors, I hav puled one of the plugs and verifed fire when cranking and can see the mist like gasoline smoke in the plug hole. Is it possible the timming has gotten off? How can I check this? What other things can this be? I know the O2 snesors have been needing to be replaced for a while. I have just not done it yet.

Thanks for any help.

silvereagle · 07-06-2007, 08:18 PM

check your TPS and CPS.

**Jerry Bransford** · 07-06-2007, 08:22 PM

Sounds exactly like your crankshaft position sensor has gone bad. This sensor mounts next to the flywheel on the driver's side and provides the engine's master timing signal. When it goes bad, and they do go bad, it causes the exact symptom you saw.

Several other possibilities exist of course but the crankshaft position sensor would be my #1 suspect.

JEEP97TJ · 07-06-2007, 08:38 PM

Quote:

Originally Posted by Jerry Bransford

Sounds exactly like your crankshaft position sensor has gone bad. This sensor mounts next to the flywheel on the driver's side and provides the engine's master timing signal. When it goes bad, and they do go bad, it causes the exact symptom you saw.

Several other possibilities exist of course but the crankshaft position sensor would be my #1 suspect.

I agree. Check the wires from the CPS to the plug, might be getting burnt up by the exhaust manifold.

Nonya · 07-06-2007, 11:13 PM

sounds like it may have jumped time,check the timing chain.

1997 TJ Houston · 07-07-2007, 08:51 AM

What is the easiest way to check the CPS? This is a hall sensor right? Do you know how they fail? Can I check the output signal or look at the impedance to determin if it is failed? What is the TPS?

How do I check the timing chain? Is there an easy way to see what the timing position should be without the engine runing?

Thanks for your help.

1997 TJ Houston · 07-07-2007, 10:52 AM

I looked at the CPS wiring and it was burned as you thought. I seperated the wires and after about 6 attempt it started (very rough). The entire area filled with grey exaust. It runs a little rougher that before. Do you recommend replacing the CPS or just taping up the wires? What could be casuing it to run rough during idle then desleing when I turn it off?

JEEP97TJ · 07-08-2007, 04:06 PM

Quote:

Originally Posted by 1997 TJ Houston

I looked at the CPS wiring and it was burned as you thought. I seperated the wires and after about 6 attempt it started (very rough). The entire area filled with grey exaust. It runs a little rougher that before. Do you recommend replacing the CPS or just taping up the wires? What could be casuing it to run rough during idle then desleing when I turn it off?

What I did was order a new CPS from Advanceauto parts, different part numbers depending on the manual or auto transmission. All you have to do is unplug it, take one bolt out, and put the new one in. There is a write-up on 4x4xplorer. com, Let me find it, its what I went by. Now, my engine has been perfectly fine, its been about 3 or 4 months since it was replaced. Also, I zip tied the wires up around, and out of the way of, the exhaust manifold. Since your engine isnt running very well, you might just want to replace it, I wouldnt think itd be good to have the wires exposed and such, where the weather may affect the sensor. I think the sensor was about $65, you can get them for about $45, so its not that expensive at all.

Yours is a 97, heres the link to advance auto: http://www.partsamerica.com/ProductList.aspx?PartType=762&PTSet=A&SearchFor=Cr ank+Position+Sensor
I purchased the one at the top, but they should all be the same.
And here you go for the install : http://www.4x4xplor.com/cps.htm

I am sure Jerry can chime in with some more advice

07-06-2007, 08:18 PM	#2
silvereagle Registered User Join Date: Mar 2005 Location: Arkansas Posts: 48 Profile Gallery Classifieds My Jeeps	check your TPS and CPS.

07-07-2007, 08:51 AM	#6
1997 TJ Houston Registered User Join Date: Jul 2007 Location: houston Posts: 4 Profile Gallery Classifieds My Jeeps	What is the easiest way to check the CPS? This is a hall sensor right? Do you know how they fail? Can I check the output signal or look at the impedance to determin if it is failed? What is the TPS? How do I check the timing chain? Is there an easy way to see what the timing position should be without the engine runing? Thanks for your help.

07-07-2007, 10:52 AM	#7
1997 TJ Houston Registered User Join Date: Jul 2007 Location: houston Posts: 4 Profile Gallery Classifieds My Jeeps	I looked at the CPS wiring and it was burned as you thought. I seperated the wires and after about 6 attempt it started (very rough). The entire area filled with grey exaust. It runs a little rougher that before. Do you recommend replacing the CPS or just taping up the wires? What could be casuing it to run rough during idle then desleing when I turn it off?