[dajeep]

I recently replaced the 2.5 l. in my 95 Dakota and am still working out the bugs on it. I have replaced the IAC valve,temp.sender, new plugs,wires and vacuum lines. It showed 17 inches of vacuum when I checked it. The idle is too fast and it tries to die when I come to a stop. It showed a code 44 when did the key check for the computer codes. Does anyone have any ideas where the problem is. I did not want to replace the computer if it is another problem. Also the gas mileage is only 17 mpg.

 

[ImperialCrown]

See fault code descriptions here:
http://www.allpar.com/fix/80s-codes.html

You don't have the old external logic module, so I think that code 44 is the battery (ambient) temperature sensor. I also don't think that it is your running problem.
The PCM adjusts charging voltage according to temperature.
It sounds like you have a large manifold vacuum leak or a large disconnected or mis-routed hose or a loose throtle body or failed gasket somewhere.
Take a spray bottle of water and squirt around the intake manifold and throttle body. Listen for a change in 'hiss' or engine speed.

 

[dajeep]

Thanks, Imperial Crown. I will try that. I wasn't sure about the vacuum hose routing when I installed the new hoses. There were several hoses that were missing or not connected when I bought the truck. I tried to follow the hose routing schematic on the inside of the engine compartment and am not sure if they are correct. I will also check the other areas you mentioned for leaks.

 

[dajeep]

I spent several hours yesterday trying to find the vacuum leak with no luck. I tried the water spray bottle but it didn't show anything. I am wondering where I can find a schematic showing all of the vacuum hose routing. I would welcome any other suggestions to cure this problem. Thanks, Don.

 

[ImperialCrown]

The Jeep Wrangler 2.5L would have a similar vacuum diagram and there may be more about that on the web than Dakota.
Google: 1991 Wrangler 2.5L vacuum diagrams or Label part # 5277113.

 

[valiant67]

Wouldn't the 1995 Dakota 2.5 still be the Chrysler 2.5, not the Jeep 2.5?

 

[ImperialCrown]

Valiant, you are 100% correct. The '95 Dakota is the OHC engine like the K-car 2.2L, not the AMC OHV. I was thinking newer. I think that it was the only truck application for the 2.5L OHC.
The vacuum routing would be different than the Wrangler 4-cyl and probably closer to the 2.5L OHC passenger cars.

 

[dajeep]

I did find a loose ground connection at the rear of the head. The truck seems to run a little better but it still idles too fast and tries to die when pulling up to a stop sign. The problem seems more prevalent after the truck warms up to temperature.

 

[ImperialCrown]

As it is racing, try to hold your finger over the hole inside the throttle body that is the air intake for the IAC. If you feel a strong vacuum and the engine speed slows to an idle, then the IAC is staying or being commanded to stay open too far. The IAC steps can be read with a scan tool like the DRB III (or equivalent) and the older OBD I engine cable.
The TPS can also make an engine race at idle if the PCM thinks that the throttle is open further than it actually is. The 3 wires on the TPS: one should measure 5 volts supply and one should measure close to ground (or about 0.3 v). The signal wire is the one that tells the PCM where your right foot is and should read around 0.65 v at idle and increase as the throttle is opened to about 4.5 v wide-open.
OEM parts are important as aftermarket sensors may not match calibrations correctly. If you still have the old parts, you may want to compare them to the new parts. Chrysler part #'s were a 7-digit number that may be printed on the part.
Does the engine slow if you pinch off the power brake booster or PCV hose?

 

[Bob Lincoln]

Check the throttle body for loose hold-down bolts or leaky gaskets.

It's also possible that someone messed with the air mass flow screw on the throttle body, thinking that it's an idle screw. It's not, it's set at the factory and must not be touched after that.

 

[dajeep]

Well, I finally decided to take the Dakota to a mechanic and he found that the MAP sensor hose was connected in the wrong location on the throttle body and the canister hose was also wrong. It seems to run like it should now. That was my mistake and am happy it runs well now, Thanks for the help that you guys gave me. Don.

 

[ImperialCrown]

I can see where that would cause an issue. I'm glad that it was something simple.

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