GPR Voltage Question

[bdlight4]

It seems the truck is starting harder this fall. I thought I would check my GPR. On the battery side I have 12.4volts. Engage the relay and it starts at 10.0volts and slowly goes to 11.4volts. Guessed the the relay was going out and replaced it with a NAPA 109. Same result. Next, I checked the batteries with my meter. Both at 12.4v in the AM. Batteries are 1 year old. Stopped by and had them tested.; According to them, both are good and will not replace. The truck seems to crank over on the slow side, and has to crank longer before it will start. Odd thing is even when warm, it seems to crank over more before it will start. Any ideas would be great. I hate to take it to you know who...

[ridiculously_necessary]

get the batterys load tested, unless they did that. actually pull them out and go through the multi hour test.

but more than likely though your starter is weak. i had this happen, repalced with a High Torque starter from DB Electrical. price was great and that sucker has some power!

OHM your glows too, just so you dont have to come back and do that.

[bdlight4]

They did a load test and said the batteries were fine. I also have a high torque Nipondenso starter. Glow plugs were new Motocrafts the start of last winter.

[TruckeePSD]

Im having the same issue, but after cycling the gp's three or so times the voltage gets up to 12.1 to 12.2 but both batteries are sitting at 12.6. any help would be great.

[NoRalPh]

The relay is just a switch, with switch like contacts inside, if you see a noticeable Voltage Drop across those contacts they're bad.

BUT, you can't compare the Non-Loaded voltage on the supply side with the Loaded voltage on the load side. So, compare Both sides with the relay energized.

[Turbostang500]

I agree with above.
It sounds like a bsd ground connection to me.
Each bat has its own ground cable to the block.

[TruckeePSD]

I amgoing to check ground in the AM. I also cleaned all the battery terminals. thanks for the assistance. I'll let you know what happens

[ag-lad]

I was having the same problem a while back. Turned out that there was a poor connection at the positive terminal on the passenger side battery. It wasn't the connection to the battery post, but the connection where the extra cable is connected to the cable clamp. The way I found the problem was the battery post clamp was getting hot after start-up.