91 4.0..transplanted from my YJ into my CJ5. 4.0 runs great everything seems fine but it stalls when coming from a high rpm to idle. Anytime I go from cruise to a stop it dies. Does not do it if I go from a slow RPM to a stop. Idles and runs fine otherwise. CPS was first thought after searching and asking around. Replaced that with no change. Thoughts?

Thx

Is the speedomiter hooked up? If it is not that is your problem. The computer needs the input from the speedomiter to adjust the RPMs when coming to a stop.

Is the speedomiter hooked up? If it is not that is your problem. The computer needs the input from the speedomiter to adjust the RPMs when coming to a stop.

It is hooked up but it is the old CJ speedo. I will persue this angle. I do not recall the speedo being electronic though when it was in the YJ.

Would I be correct to assume that since it runs fine otherwise that the TPS is not an issue here. In searching it appears the TPS would not exibit my problem.

Thx..

I had the same problem with my 93 but the speedomiter was electric. ( It was not working) I would come to a stop sign and it would stall unless I would give it some gas before the stop sign. Not sure if the 91 had a electric speedo but I would be willing to guess if it is a 4.0L it would.
Really though except on the road and having to give it a little gas before stopping it was not a big deal. Offroad in 4 wheel drive there was not any problem.

Mine does it too. my sensor is bad or installed wrong. I just live with it

I just had this happen to me. It is your senor that is either not hooked up or is bad. I bet your check engine light is on as well. I replaced my and it fixed it. Hope this helps. It is hooked up but it is the old CJ speedo. I will persue this angle. I do not recall the speedo being electronic though when it was in the YJ.

Would I be correct to assume that since it runs fine otherwise that the TPS is not an issue here. In searching it appears the TPS would not exibit my problem.

Thx..

Thanks, guys. When you say sensor do you mean speedo sensor? If it is a speedo sensor then is there anyway to work it out since the motor is transplanted into a CJ5? You are right TSE, it runs flawless with this exception.

I will persue this angle. I too use the three pedal -two foot molly but it gets old. Its a little harder in the CJ5 when you are crammed up.

Is the speedomiter hooked up? If it is not that is your problem. The computer needs the input from the speedomiter to adjust the RPMs when coming to a stop.

I thought they didn't start using the electronic speed sensor until 1992?

91 4.0..transplanted From My Yj Into My Cj5. 4.0 Runs Great Everything Seems Fine But It Stalls When Coming From A High Rpm To Idle. Anytime I Go From Cruise To A Stop It Dies. Does Not Do It If I Go From A Slow Rpm To A Stop. Idles And Runs Fine Otherwise. Cps Was First Thought After Searching And Asking Around. Replaced That With No Change. Thoughts?

Thx

Egr?

The manual does not show a speed sensor for a 91 YJ. So I can eliminate that. The Speedo is cable and the tach receives the signal from the ECU pin 43. Since it indicates "the tach receives engine speed from the ECU' and the speedo is cable is it safe to assume that not having the factor ones installed is not my problem?

I will look the the egr and further...

Just to save a lot of time can anyone eliminate for me the AIS motor or the vehicle distance sensor, based on my symptoms? I know the VDS is not hooked up because I replaced the auto with a T18...mmmm, thoughts?

Fixed!

I removed the AIS and inspected/cleaned the pintle and reinstalled. It ran perfect with no stalls for the most part. I did have two instances where it did stall but it cleared up again. I can probably just replace the part to get 100%.

Just an update for those who may search this issue in the future.