Let's play Name this Symptom!!!

[Spaceace]

I have a few ideas. Let's hear it from the contestants.



Symptoms

1. The voltmeter drops to 12. 5vdc when cold and running.

2. While in motion the lights brighten and voltage goes to 14. 5vdc.

3. Outside temp is higher than actual. Block heater was used.

4. repeat step 1.

5. Outdoor temp springs from 60 to 39 actual.

6. Voltage stablized.



My theorys:



A. Grid heater cycling on and off.

B. Voltage regulator unloaded electrically til temp and rpms are sufficient.

C. Outdoor temp reading who knows what. (underhood air?) Maybe a delay there too. Definitely related to the block heater though.

 

[George D]

I believe you are right, it is the intake heater cycling on and off. I have noticed the same thing in cold weather. Can't say if it was only when heater had been plugged in or anytime it was cold. There is a delay on the outside temp to avoid insane readings from engine heat. My '98 didn't have it and sometimes when you started with a hot engine it would read 120 when the real temp was in the 50's.

 

[DCTECH]

intake heaters are designed to be engaged till vehicle speed is approx 22 mph or until intake manifold air temp reaches a desired level. outside temp display needs air moving across sensor to read correctly also last temp it sees when shut off is locked into its memory.

 

[SteveAZ]

Around here in the summer it can be hard to tell if 130 is really that far off from actual. It's at least that in the cab for a few moments.



Glad it's down to the 90's. (Almost chilly)

 

[Bob Cochran]

Where is my PARKA anyway!!!!

 

[Spaceace]

We have a tie!

George D and DCTECH have 500 pts each... now for the tiebreaker round. 1000 pts



Under extreme acceleration(Lots-o-Fuel), what is the noise that sounds like a rattling loose cat converter shield. It sounds like the clutch area and is not exhaust related. Let off and it goes away. Pretty loud and make you consider letting up the go pedal.



I was thinking lift pump or injection pump straining.

 

[GDouglas]

The programed temperature for the grid heater to come on is 66 degrees and below and they seem to run until the coolant temp is about 140. The grid heater can pull 120 amps when on and they cycle on and off after a cold startup for a while. Also, the DC computer has your voltage regulator built into it and it doesn't seem to alow full charging ability right after a cold startup for the first couple of minutes.



The main sensor that is relied on for the grid heaters is the IAT. Other members in past topics have found some IAT sensors very dirty or out of range affecting MPG, cold start issues, etc. HTH

 

[pwr2tow]

spaceace its your injector pump, the colder the louder. when it gets -20 degrees or colder it sounds like ten thousand squirrels loose on an exercise wheel.



Ron

 

[Spaceace]

AND

I'm not ruling out driveshaft twisting or ringing. Sorta a hollow sound.

 

[WOWZY]

Whatever is rattling will eventually fall off and then it won't rattle anymore.

 

[CRuD]

I had a friend tell his wife to turn the radio up and she wouldn't hear the noise when she pushed on the brakes.

He ended up replacing the pads and the rotors.

If you haven't already get on your creeper and touch and feel things under your truck.

Good luck. Noises are hard to find sometimes.

See Ya

Chris

 

[Mopar-muscle]

grid heaters will cycle till you reach 18mph , unless it was changed , at that point the doors automaticly lock and the voltage jumps up .



as far as that noise ? trans ???