Engine dies when vehicle is clutched.

cardana24 · 10-23-2008, 11:13 AM

I have a 3.4 in my jeep cherokee. When I clutch the vehicle coming up to a stop sign the rpm's dip down low and the engine dies. This only happens when the vehicle is up to operating temp, it works fine when the engine is cold. How can I fix this?

Currently I do not have the Vehicle Speed Sensor hook up, and I do not have a brake switch hooked up (I thought this was only necessary for automatics, and I have a manual trans.) Would either one of those being un hooked cause this problem?

Any ideas?

**bszopi** · 10-23-2008, 12:14 PM

Do you have AC hooked up? If so, see if your idle changes when you turn on the AC. I'm just wondering if your IAC valve is operating properly. If not, then you could see the symptoms you are describing.

IsaacHayes · 10-23-2008, 12:15 PM

VSS not hooked up is your problem. I'm pretty sure of it.

Since the trans is turning the engine when slowing down, then when you push in the clutch it no longer is being turned and the ECM doesn't expect this and the engine speed drops too fast for it to react. I believe I've heard of others having this issue with VSS not connected. If it was connected the ECM would know you are slowing down and see that the RPMs are high and figure out what is going on and anticipate it better.

cardana24 · 10-23-2008, 12:36 PM

Quote:

Originally Posted by bszopi

Do you have AC hooked up? If so, see if your idle changes when you turn on the AC. I'm just wondering if your IAC valve is operating properly. If not, then you could see the symptoms you are describing.

AC is not hooked up.

I'll look into getting an adaptor so I can run the VSS.

cardana24 · 10-23-2008, 02:39 PM

http://www.jagsthatrun.com/Pages/Spe...eedometer.html

Would any of these sensors work for me? I want something that fits with little to modification, and I don't want to loose the function of my speedometer.

CNCguy · 10-23-2008, 09:10 PM

I vote for the VSS as well.

Be sure to get a VSS that has the correct pulse/rev output. Too many pulses/rev and the ECM would think your Jeep was going much faster and would hit the speed limiter at a lower speed.

cardana24 · 10-23-2008, 10:27 PM

Quote:

Originally Posted by CNCguy

I vote for the VSS as well.

Be sure to get a VSS that has the correct pulse/rev output. Too many pulses/rev and the ECM would think your Jeep was going much faster and would hit the speed limiter at a lower speed.

Do you think any of the ones on the site I posted will work? I need one that is 4000 pulses per minute and I see one on that site. But how do I make it work with my current speedo? I do not have a digital speedo. I need something that will work while maintaing my cable driven speedo.

CNCguy · 10-23-2008, 11:56 PM

I am no expert and not the one to advise you on this. Perhaps someone else who is knowledgeable will jump in with some info for you. My post was just my observation and to give you a heads up on a potential problem.

**bszopi** · 10-24-2008, 08:30 AM

I'd say call/email them and ask. But looking at the site, it looks like #6 might be your answer: http://www.jagsthatrun.com/Pages/Spe...integralsleeve

cardana24 · 10-24-2008, 09:58 AM

Quote:

Originally Posted by bszopi

I'd say call/email them and ask. But looking at the site, it looks like #6 might be your answer: http://www.jagsthatrun.com/Pages/Spe...integralsleeve

I sent an email yesterday, and I left a voice mail today.