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Hi! I'm new here and am seeking some advice. I am having an issue that I can't solve with my 97 dakota ... she is trying to die while idling and 'chugging' when trying to down shift. I'm getting frustrated, she is the first vehicle to stump me in the 20 years I've been working on vehicles!

At first, I though my tranny was going as she has 190K on her. I tore apart my tranny, thinking the syncs were out .... I was wrong and mad!! :mad:

I have replaced the plugs, wires, and distributor without having her running smoothly. The fuel system is also new - pump, filter, and injectors. I am out of ideas, other than the O2 sensors, and need to get her up and running smooth for a road trip.

Thanks in advance for any suggestions.

~~Rayne~~
 

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hey Rayne and Welcome!!

wow you've been working on cars since you were 9? and you want us to help? :)

im only kidding :)

im not much of a mechanic, but my '00 5.9 kind of does the same thing, its not really trying to die when at idle but i do get a bit of blow back when i let off the accelerator so i get that chugging sound (if its the same as what you are getting) as well

ive been trying to find some time to check the TV cable to see if that will help, ive been told that if it is out of adjustment it might cause issues similar to what we are experiencing

cant hurt to check!
 

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I don't know the specifics of your engine but it sounds like the idle solenoid (not sure what the name actually is) in the side of your throttle body (I assume your engine has one). We had a Caravan that would idle rough and cut off when slowing down. Remove the throttle body and the solenoid and clean everything good.
 

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Discussion Starter · #4 ·
hey Rayne and Welcome!!

wow you've been working on cars since you were 9? and you want us to help? :)

im only kidding :)

im not much of a mechanic, but my '00 5.9 kind of does the same thing, its not really trying to die when at idle but i do get a bit of blow back when i let off the accelerator so i get that chugging sound (if its the same as what you are getting) as well

ive been trying to find some time to check the TV cable to see if that will help, ive been told that if it is out of adjustment it might cause issues similar to what we are experiencing

cant hurt to check!
My dad didn't want his only daughter stranded :) My truck idles fine, but when in motion it is doing the chuggy thing - and sometimes throws in a few misfires. It seems more like the tranny slipping when down shifting ... but the tranny is fine. I have run out of money for the rest of the week and options to change out. I'll check that cable and see if it needs adjusted. Hopefully it's something like that - free to fix lol. I am getting so frustrated, it's driving me nuts that I can't figure this out!! Thanks for the idea
 

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Discussion Starter · #5 ·
I don't know the specifics of your engine but it sounds like the idle solenoid (not sure what the name actually is) in the side of your throttle body (I assume your engine has one). We had a Caravan that would idle rough and cut off when slowing down. Remove the throttle body and the solenoid and clean everything good.
Thanks Joe .... I already went that route, my friend. It was replaced with the one from my parts dakota. She ran good for about a week, then started up again. I am ready to drop the motor and tranny and put in the set from my spare truck that was rebuilt recently ...
 

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my 97 dakota was back firing and missing after about 15 to 20 minutes of running so i changed the cam and crank sensor and still the same then i changed the low coolant sensor and its been running great for two days now if you got a parts truck wont hurt to try it
 

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On 96+ (OBD2 or on-board-diagnostics 2nd generation) vehicles, it's fairly simple to plug in a diagnostic tool or a code reader to see what the on-board computer thinks is going wrong. Often a failing or malfunctioning sensor is the cause of poor running, and it's a lot easier (and cheaper) to get an idea what on-board diagnostics might have failed. I've found the OBD2 equipped vehicles can be reasonably good at pointing at the problem area - you do need to read between the lines sometimes, especially for misfire codes, but with the application of a bit of logic and general engine understanding, these can be worked out as well.
 

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my 97 dakota was back firing and missing after about 15 to 20 minutes of running so i changed the cam and crank sensor and still the same then i changed the low coolant sensor and its been running great for two days now if you got a parts truck wont hurt to try it
The crank and cam sensors are of a type that very seldom malfunction - for the most part, they either work or they don't & when they don't the engine won't start. These sensors create a pulse-train to give the ECU/PCM the data it needs to "know" where the crank and cam are in their rotation. This way it understands when to squirt in the fuel and when to fire a spark.

A diagnostic code reading might have pointed towards a malfunctioning or failed sensor.
 

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The crank and cam sensors are of a type that very seldom malfunction - for the most part, they either work or they don't & when they don't the engine won't start. These sensors create a pulse-train to give the ECU/PCM the data it needs to "know" where the crank and cam are in their rotation. This way it understands when to squirt in the fuel and when to fire a spark.

A diagnostic code reading might have pointed towards a malfunctioning or failed sensor.
i hooked up my code reader and it gave me the codes came back as a faulty cam sensor thats why i changed it then it gave me a bunch of other codes like miss firing cylinders and it turned out to be the low coolant sensor which there was no code for it
 

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i hooked up my code reader and it gave me the codes came back as a faulty cam sensor thats why i changed it then it gave me a bunch of other codes like miss firing cylinders and it turned out to be the low coolant sensor which there was no code for it
The cam sensor is a solid state hall effect which has been known to
have intermittent and temperature sensitive failures. These sensors
are hard to diagnose and depending on HOW they fail...partially or
completely the check engine light may not come on and codes may
not be stored by the PCM.

Codes for the cam sensor: P1391 "intermittent loss of CMP or CKP"
CMP= CaMPosition sensor CKP (CranKPosition sensor).

Both of these are solid state "hall effect" (5 volt TTL logic sensors), where the semiconductor generates a pulse in the presence of a "magnetic field"timing mark..be it the ones on the flywheel that correspond to TDC
(Top Dead Center) of each cylinder piston on the compression stroke ..
or the magnetic ring that forms the cam "lobe" for detection of the timing mark (via the cam sensor), which is then used by the PCM to trigger the primary of the ignition coil (or coils), to provide correct timing of the spark.... (at so many degrees before TDC) and certainly after the injector for each cylinder has been activated by the PCM and the piston is coming up to TDC on it's compression stroke.

These two sensors although reliable, can go "squirrely" and you can get
some "interesting symptoms" when they go into semi-failure mode.

I had a symptom I was troubleshooting on a friend's '99 Ram 5.2 V8.
The truck would start and run fine for 15-20 minutes then just die and
not restart for about 1/2 to 1 hr. Tested the fuel pressure, it was fine
at 45psi. Swapped ignition coils with my Dakota, no change in the symptom,
so I put the original coils back on each truck. NO CODES! I figured it
was one of the sensors going dead due a heat related problem but didn't
know whether it was the CKP or the CMP, so we changed the CKP first..
same symptom. Then we changed the CMP and the symptom disappeared!

So, in a timing misfire, and you know it's not the cap, wires, rotor or plugs,
because you have already changed them, I would start with the CMP sensor first.

If it is a complete failure of the cam sensor, the PCM will produce a check engine indicator during cranking ..P0340 (no cam signal at PCM during cranking).

It will also operate the ASD relay, which is the Automatic shutdown of both the ignition coil primary driver in the PCM , and +12v to the injector solenoids via the ASD relay contacts.

(I came up with relay socket diagram to use some premade jumpers
and bypass the ASD relay contacts, (with the relay pulled out),
for troubleshooting my Dakota in case of NO START.)

If it is due to a complete failure of the crank sensor, the PCM will
produce a check engine light during cranking... P0320 (no crank reference
signal during cranking). The PCM will operate the ASD relay, shutting
down the ignition and injectors..as mentioned above.

The codes for the ECT (engine coolant temperature) sensor are:
P0117 (ect sensor voltage too low)
P0118 (ect sensor voltage too high)
 
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