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Sensor Issue...Which one?


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01 Ram 2500 4x with V8 360 105K

I haven't used the truck since June and now am getting it ready to sell. I started it up and let it idol (about 10 minutes) and then it kills. It fired up on the 2nd turn over (as usual) and runs fine, then when it starts to get warm, it dogs out and kills. I can restart it, but unless i keep the pedal down to get the rpms over 1800 it will simply immediately choke out. So fuel supply isn't the issue, nor would spark (as i also checked the wires and plugs and all are good.

If i let the truck sit for a couple hours, i can do it all over again, where it will start and run and then kill as it gets a little warm.

Fluid in radiator is in good supply and also the oil is good too.

Does anything stand out that i should look at? I dont want to try to drive it to a shop because i probably would be stalled at the first light i hit.

Just wondering if there is a simple sensor that i can change?

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I would look at the air induction system first. Since it has been sitting, check the air filter housing for any signs of a mouse nest. Dirty throttle body could be suspect also.

The fuel system could still be suspect also. I would check pressures if you can when issues is occurring. The choking out could be lack of fuel and not too much fuel. Weak fuel pump, sediment in the tank, maybe vapo locking.

Is the check eng. Light on at all?

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No lights coming on in the dash.

The only thing out of the norm is that i had an older K & N air filter in it in June that was dirty when i was pulling heavy trailer and it was just sucking the gas, so i pulled it out. Haven't cleaned it out or put new one back in yet, so it was running with out air filter.

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Quote:
The only thing out of the norm is that i had an older K & N air filter in it in June that was dirty when i was pulling heavy trailer and it was just sucking the gas, so i pulled it out. Haven't cleaned it out or put new one back in yet, so it was running with out air filter.

I would say you need to put an air filter in and then try it. I would clean the throttle body and MAF sensor also. I would say the large amount of air and dirty air going into the eng. could be suspect. Those eng. need air filters now-a-days to run proper. If not the calibrations get way out of wack and things start running poor.

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No MAF sensor on these motors. They would have a MAP sensor instead. A MAP is Manifold Absolute Pressure which measures the difference in pressure between the atmosphere and the intake manifold. A MAF sensor is a little more accurate, it measures the amount of air that goes into the intake. The typical symptom for a MAP sensor is a start and immediate stall and could act up any time.

Does this motor use a lot of oil?

I would like to monitor the data on a scan tool while it warms up. I would be most interested in the coolant temp sensor.

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I've got one of those hand scanning tools from Napa, i never thought to plug that in to see if it gives me any codes.

does it use oil? Not an abnormal amount, typically have to add a quart every other month when it was driven every day as a work truck.

I know that on a 97' that I had, we had to replace the head gasket at about this mileage and have read that is a common problem with these motors.

I'll put an air filter in later in the week and then see what it does.

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Alright, got some more information on this.

First, i put a new air filter in.

Then i hooked up my actron hand scanner to the truck and used the clear codes function and then proceeded to start the truck.

The truck started (cold) right away and RPM's were dancing around 1000, then at 900 then settled at about 750.

I kept trying the Read codes option every so often and it kept saying "no codes" passed. Then there was another option for I/M monitoring and these were the results of that

* Misfire Monitor OK

* Fuel System Monitor OK

* Comp Component OK

* Cat Mon INC

* HTD Catalyst NA

* Evap System Mon INC

* Sec Air System NA

* AC Refrig Mon NA

* Oxy Sen Mon INC

* Oxy Sen Htr INC

* EGR System Mon NA

Now the truck was running good for exactly 5 minutes (at Idle) and then it killed just like that, no sputtering, slow death, just shuts off and then you can hear a solenoid click out after that. All this happens when the temp needle just starts to rise above the 130 mark (which is baseline). I rescan as it was killing and still says no codes and the above stuff didn't change either.

Now i started it again, (and it fired right off) and held RPM at 2500 and it ran fine for another 2 minutes and then suddenly just killed, no sputter, or crappie flop. At that point the temp was about 2/3 of the way up to the normal running mark of 200. Now it wont restart at all.

Does this help in some diagnosis?

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I held the pedal down to keep the 2500 rpm, because at that point it would not idle by itself anymore.

Once it got to the third time trying to start it (with the temp up), pressing the gas pedal didn't make any difference. I went thru that last weekend, pedal down, pedal up, tapping the pedal...nothing. It has to cool and then it will start again.

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You need to check for spark. I'm thinking you have a coil that is flakin out after it gets hot. One thing you can try is wait until it won't start. Fill a sandwich bag with ice and hold it on the coil. Let it cool for about 5 minutes then try to start. if it starts I'm thinking the coil, if it doesn't than its time to bring it in!

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I went down to the local auto parts store on Monday and looked into getting a coil and a ignition control thingy that goes under the distributor and try that. The guy tells me to go talk to the owner of an auto shop just down the road. SO i go there and explain the problem to him and he tells me that its just a computer problem, so go drive it and it will reprogram it self. So i take the bait and take the truck for a spin around the neighborhood, and just like clock work when the temp hits the 170 she clunked a couple times and then died about a mile and a half from home and wouldn't restart.

So after an hour waiting, I got a tow to the dealership. I explained the problem and they said they would be able to look at Tuesday. They called me Tuesday afternoon with diagnosis. He said that they think they have it narrowed down to the crank sensor. I said "you think?" he said we're pretty sure and if it isn't we wont charge you for any more. they wont have it back running until Wednesday to see if that was "The" problem or if there is something else. Even the guys at the big dealership never seen this issue before.

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Actually now that it is brought up, I have seen a couple crank sensors on Dodges. Not as common at the Jeeps though, but still occur. I have also seen those pesky coolant temp sensors cause concerns also like Jer said.

I think the Chryslers, when it won’t start and it is cam senor (and possibly the crank), you can just unplug them and the computer will go into limp mode and at least let the eng. start. It will not run the best, but enough to get to a shop.

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