53Block

Thanks Mike, now if only they would charge the 60's or even 90's prices for all these parts I need for my truck, haha. Well, I finally threw some wrenches at my truck this weekend, replaced the battery temp sensor, replaced the alt fuse (ohms were .001 out of truck on original fuse but replaced it anyway), cleaned up and reconnected all my main grounds (bat to block to frame to body) and the pos post connections including in the fuse box, reset all fuses and relays while in there, cleaned off bat posts, sprayed contact cleaner on the C1-C3 PCM connectors, double checked the ohms on the original blue and green wires from alt back to the Cx connectors (both showed .002), hooked everything back up and.... still no charging from internal regulator/PCM... So I rerouted the external voltage regulator wires and relay for a more permanent setup, threw some wire loom in there and connected that back up, it's back to charging on the external regulator, so I'm just assuming the internal regulator in the PCM is toast. It does charge at about 14.6 (between 14.3-14.7 on edge) so I'm curious to see if the warmer weather will make that change at all or if it's always fixed at that number, but I'll have to keep an eye on it because I don't plan on a new PCM just for the alt to get a charge to the batteries, unless I start having other electrical issues down the line.

Is this an updated one for the 99? The one I have doesn't show the bat sensor (but I definitely have one). Once all my parts come in I'll test everything out and report back.

Thanks, I should have checked actual voltage on that lead when I did that test, maybe I'll do it again and play with the rpms and AC to see if it changes at all. But I don't think it's blown since I got matching battery voltage at the alternator + post, I guess it's possible it could be cracked or making just enough of a connection to match the voltage but not the amps. Either way I'll try the ohm test with it off the truck and see, I just ordered 2 fuses today so if that is the issue I can replace it and have a spare, hopefully that's all it is.

That wasn't mentioned in the write up but I thought that would be the thing to do. Cables were good between the alt and PCM so I assume the PCM is bad and threw on an external voltage regulator and now it's at least charging again! It's ~14.7 which is kind of high I think but the operating range so far (according to edge monitor) is 14.3-14.9 from what I am seeing on the edge gauge and regular gauge, voltmeter to batteries match at idle ~14.7. The problem now is it's throwing these codes: P1693, P1594, P0622. I thought these were here from before the regulator change out so I cleared them and turned off the truck, then started up and took it for another test derive, they came back on when I got home. I'm seeing this is common for these external regulators on my year truck to do that, but that's another days battle, at least it will get me to work until I decide to make that permanent or not.

I had the check gauges lamp come on and noticed low volts the other morning, it climbed back up after a few seconds and the check gauges lamp went off but the voltage was only at about 11-12v range on the gauge (usually 13-14). I took the alternator to autozone, bench tested showed bad, got a replacement and bench tested before leaving, that one tested good. Also tested batteries, both good. I installed everything and still nothing for charge voltage though. After reading some other sites about the PCM voltage regulator going bad, I got an external voltage regulator and was about to connect it up today, but I read a post here a couple of days ago and it got me thinking about the connector/cable and testing that first. I pulled the little 2 wire connector from the alternator, started the truck and tested from the alt plug using a test lamp between the blue wire and neg- post and get light, but when I tested between the green wire and pos+ post I only get a dim light. The next thing it says to check if everything is good is the cables from the alt to the PCM but I don't know if the dim light for the green wire is good or bad... I'm about to check that out now, just wondering, do you have to remove the neg battery posts before removing the PCM connectors for that resistance check on those cables, or just keep the key turned off and pull the connectors off with the batteries connected?

Well, I found the problem with the code being thrown this time, but I still don't know what caused the sensor to do what it did (this time). I finally got under the truck today to put on the new crank sensor (from RockAuto, PC292, super cheap there too) and I found something a little strange. Once I removed the starter and went to pull the connector off of the sensor, I saw that the little bracket (or brace) that holds or pinches the sensor was not actually holding the sensor like it was when I put it on. The bolt was super tight as it took a bit of force to take it off so it wasn't a loose screw at the sensor. I could turn the sensor in the bracket while it was still screwed down in the block... Normally there is a little wiggle that is there when it's not in the block, the bracket just pinches the sides of it, but when it's in the block and the bracket has that screw in it, it doesn't (or shouldn't) move. I took it off and the sensor looked OK but I replaced it to be safe. The bottom part of the bracket I took off was bent way down, the top looked OK, if it was bent it was minimal and I couldn't really tell but the bottom was for sure. Also on the sensor there was a grove in the part where the bracket pinches it, looks like it turned hard to get that to bend the little metal (or aluminum) bracket if that's what happened. It looks like the sensor turning (not tilting or being popped back) caused the bracket to do this. Maybe the screw that holds the bracket to the block might have magically turned counter clockwise and then back enough to space out the little grab arms of the bracket (just kidding).. Any thoughts on this?? It looks like the sensor either turned hard enough to cause the bracket to open up and let the sensor spin around some, or the bracket just bent down and allowed the sensor to turn. I'll be checking the sensor bracket for a while now anyway.

I've had that P0336 with the same issues (sometimes no start, tach drops to 0 while driving, etc.) I went for about a month or two of that before I finally took the starter off and changed the sensor out with one from Autozone, did that about 4~5 months ago and it ran fine. Just last week I had the same code trip again while driving and the RPMs went to 0 for about 2 seconds then back to normal (just like before)... I'm not saying the Autozone sensor is the problem, I'm actually hoping it's a connector/connection problem at this point. Either way I have to start checking cables and connectors and see what else (if anything) it could be.