Engine/Transmission (1998.5 - 2002) voltage, slow recovering amp gauge

[Don Blaisdell]

Hi Iam wondering if there is anyone out there that can tell me why my 99 quad cab takes so long to get amp gauge back to normal after cold start, I know that these beasts draw a lot of amps for the grid heaters, but if I start it and get it thourghly warmed up like a 25 or 30 mile run shut it down for 10 min. it still draws real heavy for about 1min is there a sensor in there getting ready for a vacation? I wouldn't be to concerned but it has never acted this way before. any ideas will be greatly appreciated Thanks in advance Don

 

[KOREDISH]

Same Thing

My 99 acts the same way. Be interested if you get an answer.

 

[EdK]

I can only speak for my experience with my '99 so... I found the negative battery terminal connection on the passenger-side battery to be a little dirty and loose. I removed the connection, cleaned it and tightened it again and the problem went away. I'd clean the connections on both batteries to be sure. If you have the original batteries and the cleaning doesn't work, have them load tested.



Ed

 

[Beast2B]

I get the same thing occasionally. I chalk it up to the cold ambient air getting into the IAT sensor so that on initial restart the engine goes into cold mode, activating the grid heaters momentarily. as soon as warmer air gets into the system it goes back o normal operating condition. (I've been way off base before, but it sounds like others get the same scenario).

BTW, I just replaced both batteries and made good connections. Still happens when below 55* or so outside

 

[MPalachuk]

My 99 also does it but the check guages light comes on untill the volts come up. If someone has a idea let us now.



Thanks Mike

 

[bnbrown]

my 99 still shows down towards the bottom end of normal after starting (when cold) I replaced the batts (were only 6 months old to begin with) after having a no start (starter wouldnt even crank) on a cold morning after letting it sit for a day, that didnt fix it, so had the batts individually load tested, then put an amp meter on with only one batt hooked up, would jump around between +65 amps, to -20 (fully warmed motor, grid heaters not being needed) also was starting to notice the volts meter fluctuating between 12 and 14 even going down the highway so figured my alt was on the way out... replaced the alt... now have 14volts, but still only get 11-12 or so after starting if the grid heaters are going. still get the dang dinging and check guages light after starting, but because the oil pressure guage comes up after a second or less, maybe 2 seconds if it has sat over night... impatient i guess

 

[Beast2B]

Does the ECM/alternator have a lower output mode when the heater is working? ... or is it just the draw of the heater eating up all of the alt output? I know my volt gauge stays low while they are cycling, usually doesn't come up >12 until I'm above the temp or speed required to stop cycling the heater.

 

[bnbrown]

I am sure someone on here would be able to give a better answer than mine, but I believe the grid heater just has a very large draw, can often see the headlights dim some if it is dark, also the wire running to the solonoids for the grid heaters is a really large chunk of cable, larger than the alternator charge wire... both of my trucks dont get above 12 volts atleast for the first 5-10 seconds sometimes takes a little longer. Once you get the rpms up, should be cranking the alternator enough to help counteract the draw of the grid heater, also the rpms help warm the exhasust, thus warm the turbo, and also warm the intake air, making the grid heaters no longer needed.

 

[RNixon]

I've been noticing this on my 1999 truck also. Thought the alternator might be failing. When I start the engine with outside temp below about 40 F, the volt meter stays way down at the bottom of scale. After I drive for maybe 1-2 minutes, it comes up and stays up.



I've also noticed while the voltmeter reading is down, the lights dim and brighten in a cycle. I was guessing a heater was cycling on and off and knocking down the voltage.



Is there something wrong with my alternator or voltage regulator, or is this normal for a truck with 90k miles and original alternator?

 

[2-ND TIME]

No nothing wrong with the alt. the heaters draw about 110A each so they make the alt and batteries make up the difference then the alt charges the batteries. If you need to measure the resistance of the heaters and divide that into noniminal 12 volts to find current. It's the IAT sensing the cold air and so running the heaters when we refire it up again. The starter takes about 480 Amps to start turning the motor and then 240 A once it is moving to get it going. Now take the noniminal 12 and X that by 22o to find the watts. Nice heater.

 

[AKAMAC]

The alternator cycles with the grid heaters. Heaters on, alt. off. The drop you see is normal. This protects your alt. from an over current condition. 140A alt. 200A heaters.

 

[EGaskamp]

My '02 also does the same. I'm going to clean the terminals and tighten them back up and see if that helps. I'll let yall know what happens.



Eric

 

[SCeslow]

When I got my truck a little over 1 year ago, I noticed that the alternator took longer to recover the battery charge than I had liked. The batteries tested ok (New batteries were already installed when I bought the truck. ) 6 months later, the alternator failed on my way to work, no output at all. I checked the wiring etc. and found the alternator output wire was chafing on the steering shaft. Maybe a wire tie broke or something. Further testing showed that the alternator had failed diodes. I changed the alternator with a rebuilt unit and fixed the wire. Since then, my battery voltage recovers very quickly and the voltage is about 1/2 volt higher then before. I think that the alternator had a bad diode before, then they all finally went later. I think you should have your charging system output and batteries tested at a good alternator shop, also check for chafing wire at the steering shaft. Good Luck

 

[RWhites]

I thought my alternator was on it's way out, Voltage was low and codes were set. The engine cranked over slower than normal (speed) and took longer to fire. I checked the voltage with my Fluke and found output voltage was low. . Bummer. . I figured the alternator was gone... Read the manual and discovered that the voltage regulator was in the computer, Bigger bummer. What the heck maybe Sears will check the charging system and TELL ME what the problem is for $10. Besides the wife is letting me know she does not want to be stranded! Sears sets up the test stuff (rather basic, no computer interface) and finds a broken negative battery post. (inside the battery) Changed the batteries and problem goes away, that was 4 months ago.



:-{} Last place to work on the truck was the FIVE STAR dealership... .

Rich