GSC 6.5L diesel battery cables and grounds

6.5L diesels are known for grounding issues. This is a short walk through explaining where to look or check for your grounds in the event you are experiencing electrical issues. Hopefully this helps some of you out!

[@gordonbryan8381]

I have to give you a compliment about a simple electrical system hint: I couldn’t see the forest for all the trees that were in the way! 1994 Chevrolet C-3500 6.5l TD. After replacing the PMD, fuel filter that was still clean, adding the Leroy Diesel power cable for the lift pump: MF still wouldn’t start. One of your videos advises to get two new batteries, even if your current batteries seem okay. Guess what: those 2 new batteries spin the 6.5 over so fast it starts just like new. Without the simple but obvious battery suggestion, I would have been on the way to spending tens of thousands of dollars on a replacement truck. Costco green Interstate batteries were more than 50% below the auto parts houses battery prices, so I saved money, and in effect saved my 29 year old truck for $225, less than the price for 1 auto parts place battery. Thanks again GSC ! 🛻

[@diannamorris9225]

Thanks a bunch for this video. Ivan, my 93 Chevy diesel needed some tlc. Your video showed all pts I needed to check!

[@gingersnapcustoms]

Glad the video helped!!

[@sonyatipton7264]

Great video. Simple straight to the point. Thanx.

[@joestone2068]

Thank you that was a good video at all Casper looks like it’s in pretty good shape

[@horsemindedwtp]

Casper lol great now I have to name mine

[@Desertjoe789]

Great information! Thanks!

[@blackincawston]

Great info. I was wondering if maybe any of your 6.5 truck might have done this is past, like I have like new PMD relocated, new oil pressure sensor, new vacuum pump, ground wire looks good but once in awhile after starting truck and in drive,after maybe 2-3secs will shut down, will take 4-5 turns and truck will start again, does that once in awhile

[@gingersnapcustoms]

Most times that’s due to the lift pump not running and you suck the fuel bowl dry. My 99 did some odd stuff like that when the injection pump started to fail as well. You’ll have to do a fuel pressure test then get a scanner and check the injection pump closer time to see what’s going on.

[@blackincawston]

@@gingersnapcustoms thanks you so much. Been thinking of changing the fuel lift pump, I'll change it and try next the injector if still remains same.

[@WintersMachining]

Great video. My truck has new LP, bypass LP harness, pmd relocate kit to bumper. It randomly shuts off. Sometimes starts right back up some times it doesn't. When it happens the LP won't turn on and has zero pressure and engine just cranks. Maybe bad PMD extension? Maybe bad grounds?

[@gingersnapcustoms]

It could be a bad PMD extension harness or a burned resistor in the PMD itself. Possibly a tired crank position sensor as well.

[@greenthumb2856]

Your fuel pump relay in fuse panel is bad under the hood from drivers side top far left relay, I just replaced because one pin burned out. Runs great now. Pump runs perfect. I first replaced PMD with relocation, sensor on pump sensor on turbo reworked everything I could find and turned out to be relay.

[@WintersMachining]

@@greenthumb2856 awesome I'll take a look in the AM

[@theodorefaulkner693]

Great videos! I have a 1992 Chevy K2500 with the 6.5 that I just bought. Charging warning light was on and batteries were dead when I bought it. Replaced both batteries and the alternator. Light on the dash is now off but is only charging on the gauge at just under 14 volts. On each battery with a voltmeter the driver side battery reads charging at 12.6 and the other is 13.3. All grounds look good as are other cables (passover, etc.) Any ideas on why they aren't charging over 14 is greatly appreciated.

[@gingersnapcustoms]

A lot of times these new alternators aren’t good out of the box. I would take all of the grounds off and clean them along with replacing the grounds from the intake to the battery. That should improve things.

[@theodorefaulkner693]

@@gingersnapcustoms Thank you.

[@connorbrandt3207]

Idk if you have a 94 to show grounds on I’d assume they are the same but I got electrical issue when I hit brakes roll windows up or down or have headlights on the gauges go crazy I’ve checked barriers and junction box on the cowl and nothing seems to work

[@gingersnapcustoms]

I don’t have any others now. Just casper remains. I can say I’ve never had one do that. Sounds like you have something in the tail light wiring that’s grounding out which is messing with the power in the rest of the truck. Or it’s the dash harness itself.

[@mydogsnameistablecloth1736]

So I've always waited until the glow plug light stops flashing to start my truck. You said this is the after glow cycle. So it wont harm the glow plugs to start the engine after the initial wait period? Thanks for the video.

[@gingersnapcustoms]

It won’t hurt it at all. I’ve started mine after the end of the initial cycle for 60+k miles. I’ve pulled the glow plugs even and they had no damage or issues. The afterglow allows them to cool off leaving the chamber cold by the time you fire it.

[@mydogsnameistablecloth1736]

@@gingersnapcustoms Good to know. 🤙

[@khills1181]

Question for ya. My 98 c2500 started to shutter ever so slightly and got worse over 2 weeks to the point that now it wont start. Ive covered all the basic issues with it. It has a new ip that im suspicious of. I got it from a place that auctions off unclaimed freight for $350. Its been running great since i put it on until now. (8 months) There is no fuel going to the injectors and im wondering in the fuel solenoid on the rear of the pump is pooched. The question is how can I check it and is it a plug and deal or is recalibration necessary? Also i had at one time an overhaul manual for the DS4 that i found online. Cant find it now of course. Do you have an resources for that manual? Thanks in advance!

[@gingersnapcustoms]

It sounds like your pump is smoked. Time to order a new one. I have an injection pump replacement video if you look on here. It will give you an idea of what the job will take to complete.

[@gingersnapcustoms]

kzbin.info/www/bejne/bZiteJWNmrSGapI

[@chzx88able]

Wow, you have good oil pressure I can see. Is there a specific reason for this good oil pressure? Mine don't have that good oil pressure ☺️ the guage is staying in the middle after warm-up. I'm going to change oil and oil filter today. Thinking about maybe do an engine oil clean at the same time to get sludge out of the system.

[@gingersnapcustoms]

That normally means your oil pressure switch is bad.

[@chzx88able]

@@gingersnapcustoms thanks for the reply, I will change it ☺️ thanks 🙏

[@SamuraiJeff]

Having some issues with my 01 C3500HD - Went to start it one day and the brake lights were stuck on. I assumed it was the switch, so I pulled the relay and sure enough, it sparks on plug in. Pulled the relay, charged the truck, ordered the switch. Plugged the relay back in later in the day... No spark. Brake lights work fine now? Today I went to start it, completely dead. Hooked up the jump pack and as soon as I didn the horn started sounding. pulled the fuse now. I'll try all your grounds in this video but wanted to see if you'd run into those (seemingly related) issues. Brand new batteries.

[@gingersnapcustoms]

Make sure you don’t have a tail light ground touching a frame rail. Also if one of the battery cables are worn and touching something they shouldn’t, that too will cause issues.

[@SamuraiJeff]

@@gingersnapcustoms is the tail light ground not supposed to go to the frame? I’ll trace it and be sure. Definitely some gremlins in this truck with the battery running down and all. Might just put a battery cutoff switch in it and call it a day honestly.

[@gingersnapcustoms]

@@SamuraiJeff it should ground to the rear frame and up by the fuse block if I remember right

[@SamuraiJeff]

I got lazy and just put in the battery cutoff switch. In the process I tied the battery negatives together like you suggested and it starts strong every time now (in the relatively warm weather). Thanks for that. Now I'm trying to decide if I want to try replacing my glow plug relay - As soon as I key on it skips the warm up and goes straight to afterglow. Cleaned all the grounds as you suggested. No luck. @@gingersnapcustoms

[@gingersnapcustoms]

@@SamuraiJeff if it is going right to afterglow that relay is most likely bad or isn’t grounding well to the coolant block off plate.

[@barberson5904]

Do you start it with 24 v or 12 v ? 🤔 how do you take awy the beep sound when door open ?

[@gingersnapcustoms]

This is a 12 volt system due to the battery’s being in series. Voltage stays the same. Amperage increases. The door buzzer has never worked in Casper. I’ve had the truck for ten years and none of the alarms work.

[@eedom69]

Do all 6.5's have grounds on the intake? Because I got a 2003 P42 with a 6.5 and I can't see any ground wire's going to the intake studs.

[@gingersnapcustoms]

Pickups and vans all have the same ground structure from what I’ve seen and been around. They may have been relocated to the side of the heads or chassis?

[@eedom69]

@@gingersnapcustoms The ones on the intake are from the battery or smthg else? I found one on top of the injection pump for the pmd. And I found 3 drivers side back going to one post near the glow plug module.

[@eedom69]

@@gingersnapcustoms Should you disconnect the battery when working on grounds? Can you get a shock or no worries. I disconnected but not sure I needed to.

[@gingersnapcustoms]

@@eedom69 I normally disconnect the batteries when cleaning cables to prevent any unwanted surprises.

[@patrickconrad396]

Hi at 2:00 there is a little hose running across just above your hand. What is that. Replaced a pmd and noticed a little tube in a black sheath and it wasnt running to anything. I touched it to inspect it and it was so brittle it snapped. But the color of the actual hose part looks just like that. I have a 1999 Savana so the van chassis are different and I'm waiting on the service manual. Didn't have issues while running after the pmd swap but I can't get it started very easily. Really worried we broke that brittle tube and it was important

[@gingersnapcustoms]

That’s the drain for the water separator on the fuel filter housing.

[@patrickconrad396]

@@gingersnapcustoms okay thank you. Hoping i can track it back to the source and it's easily fixable but these van chassis arent fun usually

[@waydebarnes6209]

Just curious 🤔 br0.. what CCA izz your Battery " z gott... my dad needs new batteries on hiz & they both had different cca .. on them.. yepp kinda wierd. But know i curious because yours definitely started smoother than hiz duzz..

[@gingersnapcustoms]

870cca from Napa.

[@theotheronetoknow5828]

Hi, 6.5 starts and revs high and dies now. Fuel pump? Going to have to send you a christmas present, haha.

[@gingersnapcustoms]

Check engine light? I’m betting the injection pump has left the chat if it does the rev and die now on start up.

[@theotheronetoknow5828]

yeah yeah, check engine light. Thanks.@@gingersnapcustoms

[@gingersnapcustoms]

@@theotheronetoknow5828 if it’s a cam position pump error or a pulse width error that would be the pump dying.

[@charlier3647]

I got a 96 1500 6.5. My ac compressor is not kicking on and when I press the ac button my antiloc brake warning and brake lights come on. Lol I guess I better check grounds.

[@gingersnapcustoms]

Start with the grounds. Don’t be shocked if the ABS pump is needing replaced and that the dash switch is bad for the AC. Two very common issues in the 96-00 trucks.

[@camdencalloway2647]

I went out to start my 6.5 today and I had a few clicks and now I have nothing. I have had no real issues. It did before this problem tend to turn over decently slower than Casper does. What should I look at? Would it be the grounds 1:09

[@gingersnapcustoms]

Start with the battery to intake grounds. It may be that the starter is getting lazy.

[@camdencalloway2647]

@@gingersnapcustoms it has been kinda slow to turn over. I mean not terribly slow but not as fast as Casper. Shoild I also check the power wire?

[@gingersnapcustoms]

@@camdencalloway2647 typically when they start getting slow it’s a ground issue. Or the starter itself is just tired

[@gingersnapcustoms]

@@camdencalloway2647 you can check the power wire. But that typically isn’t the issue. An amp draw test would be the best bet to see if the starter is pulling a lot more current

[@camdencalloway2647]

@@gingersnapcustoms so if the ground was bad then would that mean my starter wouldn’t even click because when I first tried to start it, it did click and then I got a jump from a friend thinking my batteries were low from something but now it doesn’t even click. Would the grounds being bad cause it to do nothing?

[@joestone2068]

What do you run for a lift pump on your truck

[@gingersnapcustoms]

Fass from Leroy and PTwiring upgraded lift pump harness

[@zyrockdaddy7060]

I need to see where the battery ground wire connects to the body of the truck off of the driver's side, Was having starting problems and noticed that the battery groundwire to the driver's side was disconnected

[@gingersnapcustoms]

There isn’t one from the battery to body on the driver side. Only passenger side to the fender. Then the main grounds to the intake.