Engine/Transmission (1994 - 1998) Alternator troubles

[CToney]

My alternator does not always charge immidiately after I start my truck. It sometimes takes several minutes for the voltmeter to read 14v. I have changed both grid heater relays. I have new bearings and brushes in the alternator, new Deka Intimidator batteries (dry cell, cheaper than Optima), two new cable ends. My tach works so the computer must be getting the signal that the engine is running. The only thing left is a faulty computer? I have a couple holes drilled in the cowl for the air cleaner to get cool air. Maybe some moisture has damaged the ECM. I don't want to be left on the side of the road without any juice.



Thanks



CR Toney

 

[JFaughn]

Have the system load tested , that may help to find the problem .
More often than not it seems to be connections , to & from computer , cranks sensor , batteries ect .

 

[Hammer]

It also could be as simple as the crank position sensor is not at the correct distance from the dampner. I forget the actual distance in thousandths but a doubled up match pack is about the pace required between the dampner and the sensor.



Also...



Have you checked the positive battery cable which runs down to the starter and attaches to the oil pan. Lots of time they wear and will short and cause symptons like your having... ... ... Andy

 

[WDaniels]

CToney,

It also could be your battery sensors. I see you live in a cooler climate. Do you have battery blankets or the battery pads? Are you using them yet? If so, ditch them. They would keep battery sensor from sending the proper signal and keep the batteries from charging until they cool down. Or they could be malfunctioning. Hope this helps.

WD

 

[CToney]

I went snooping around under the hood to see what I could find. I found that the rubber insulator that goes on top of the stud for the grid heater at the intake manifold was deformed. I have a oil pressure activated switch for the ground on the grid heater relays so they don't operate once the engine is running. But it seems that it might not be working all the time. I checked the grid heater trigger wire operation and they would not shut off. After the truck was warm and I would turn the key to the on position they would still send power to the relay. Maybe my intake temp sensor is not working properly or I have a bad connection like you guys said. Since I took the trigger wires off the relays my voltmeter charges right away. I don't have to wait for it to charge. I imagine that a IAT sensor is kind of pricey so I thought I should go with a simple push on style switch to operate the trigger wires for the relays. I know I might not be as convenient but it would be cheaper and simpler. Let me know what you guys think. I'm going to do some more diagnosing to see if both my grid heaters still work ok. This '97 doesn't start worth a hoot compared to all of our other 5. 9's.



Thanks



CR Toney