Diésel engines

[ArmyRunner]

Hola, i have this 2001 Chevy 4 window school bus with Diesel engine and this is new to me. When it’s cold, it won’t start. Is there a block heater for this engine? Also, every time I drive long distance (@ 65mph for 2-2.5 hrs) and I stop to pump diesel, the engine won’t start. It will crank but not start. It will start after waiting for 30-60 mins. What am I missing here? A tow truck driver once told me that the fuel pump shuts off when it’s hot. Help! This is driving me nuts. 🤣 Thank you.

[CHEESE_WAGON]

Originally Posted by ArmyRunner

Hola, i have this 2001 Chevy 4 window school bus with Diesel engine and this is new to me. When it’s cold, it won’t start. Is there a block heater for this engine? Also, every time I drive long distance (@ 65mph for 2-2.5 hrs) and I stop to pump diesel, the engine won’t start. It will crank but not start. It will start after waiting for 30-60 mins. What am I missing here? A tow truck driver once told me that the fuel pump shuts off when it’s hot. Help! This is driving me nuts. �� Thank you.

2001 could be a Duramax 6.6L, but GM was still rolling out 6.5 turbos that year. FYI, GM doesn't make a 6.0 diesel, they do make a 6.0 gas, although the older tall-deck versions were out of production by then, and the LS-block variant was post-01 as far as I know. There should be a catalyst sticker under the hood that stated the displacement, and the 8th digit of the VIN should also tell you which one you have. F is a 6.5 turbo, 1 is a 6.6 DuraMax. Here is a block heater for a 6.5, what I believe is likely.

6.5 Engine Block Heater Kit :: SSDiesel Supply :: GM 6.5 TD Specialists

The crank / no start when hot issue could be a solenoid / connection at the injection pump. On older full-mechanical 6.2s (the 6.5's predecessor), the injection pump had an electric connection for some sort of fuel enable valve in the injection pump that needed power or the engine would not fire. Likely this was retained on the 6.5, so that's one place to start.

As for the fuel feed pump, if I'm not mistaken, the 6.2 used a mechanical lift pump that generally worked or it didn't. But a later model with the 6.5 could possibly have in-line or in-tank electric pumps that can experience bleed-back into the tank, or pressure / volume problems when hot.

Here's a link to one for a 1994-1999 6.5, later models are likely similar.

If it is a 6.6L DuraMax, these are known for losing the fuel prime to the system, I believe there is an aftermarket pump upgrade that fixes this.

[FrugalFannie]

Originally Posted by ArmyRunner

Hola, i have this 2001 Chevy 4 window school bus with Diesel engine and this is new to me. When it’s cold, it won’t start. Is there a block heater for this engine? Also, every time I drive long distance (@ 65mph for 2-2.5 hrs) and I stop to pump diesel, the engine won’t start. It will crank but not start. It will start after waiting for 30-60 mins. What am I missing here? A tow truck driver once told me that the fuel pump shuts off when it’s hot. Help! This is driving me nuts. 🤣 Thank you.

If you aren't plugging it in then even if it has an engine block heater you are out of luck on COLD days. You would have to check your engine to see if it has a heater plug. You may have a plug but need a cord. Cords are fairly cheap. Dont get ripped off.

When we are driving and filling with fuel we leave the bus running rather than letting it "cool down" and then needing to "air up" on restart. We are 2 people so one can stay with the bus while the other uses the restrooms, etc.

[Johnny Mullet]

Those old 6.5 engines will not start without the glow plug system working despite the temp.

[ArmyRunner]

Thank you for the responses. Yes, I left the engine running and pumped diesel. �� It worked. As for the cold starts, I’ll search by the front bumper for the “plug” and find a way to plug it in or stay in warmer States (currently in Prescott AZ). For the fuel pump issues, Bianca starts without any issues if she’s not driven for a long time. Short trips and she’s ok, starts right up. Again, thanks for the feedback. Really appreciate it! ��

[Tentacles]

Hello. If you have the 6.5 Detroit Diesel engine it will serve you well to become familiar with the engines unique ailments and needs. The 6.5 does not do well with heat. Engine temps above 190 degrees f can reduce engine life in a variety of ways. They are also sensitive to the quality of electricity they receive. A non start when hot issue may be you PMD. The PMD is an electrical component that controls your fuel delivery to the cylinders. When they get hot they stop working properly. Once they cool they will work again. Eventually they will stop working all together. Many 6.5 owners suggest relocating your PMD even if your vehicle is running well, since they are known to fail and can leave you stranded. Luckily there is a lot of info online about the 6.5 issues and how to remedy them. Your first step in trouble shooting is to confirm which engine your vehicle has.

[ArmyRunner]

Originally Posted by Tentacles

Hello. If you have the 6.5 Detroit Diesel engine it will serve you well to become familiar with the engines unique ailments and needs. The 6.5 does not do well with heat. Engine temps above 190 degrees f can reduce engine life in a variety of ways. They are also sensitive to the quality of electricity they receive. A non start when hot issue may be you PMD. The PMD is an electrical component that controls your fuel delivery to the cylinders. When they get hot they stop working properly. Once they cool they will work again. Eventually they will stop working all together. Many 6.5 owners suggest relocating your PMD even if your vehicle is running well, since they are known to fail and can leave you stranded. Luckily there is a lot of info online about the 6.5 issues and how to remedy them. Your first step in trouble shooting is to confirm which engine your vehicle has.

Alas! I have the 6.5! So, time to get started with the PMD. Thanks.

[ArmyRunner]

Originally Posted by FrugalFannie

If you aren't plugging it in then even if it has an engine block heater you are out of luck on COLD days. You would have to check your engine to see if it has a heater plug. You may have a plug but need a cord. Cords are fairly cheap. Dont get ripped off.

When we are driving and filling with fuel we leave the bus running rather than letting it "cool down" and then needing to "air up" on restart. We are 2 people so one can stay with the bus while the other uses the restrooms, etc.

Thank you. Will find that plug somewhere by the front bumper (?) and get a cord then see how it goes. Thank you.

[Doktari]

Those are indirect injection Diesel engines. Ive read that direct injection Diesel engines have less cold start issues. I think the trick way to go would be hydronic floor heating system and a valve that dumps heat into the engine quickly. That’s what I’d love to do with the 4BD1-T (direct injection) engine in the Isuzu.
Yes, the PMD overheating is a well known issue with the 6.5L. Move it from the “valley” to a cooler location is one fix I read about. Or there are heavy duty models I believe can be left in the original location if memory serves.

[Beirdo]

Originally Posted by Doktari

Those are indirect injection Diesel engines. Ive read that direct injection Diesel engines have less cold start issues. I think the trick way to go would be hydronic floor heating system and a valve that dumps heat into the engine quickly. That’s what I’d love to do with the 4BD1-T (direct injection) engine in the Isuzu.
Yes, the PMD overheating is a well known issue with the 6.5L. Move it from the “valley” to a cooler location is one fix I read about. Or there are heavy duty models I believe can be left in the original location if memory serves.

For me, replacing the PMD (and relocating it) has made my 6.5L Turbo start every time now, even on the few days I tried below freezing. I highly suggest it. The PMD that's in there now could well be fried or on its way to utter failure, so you likely want to replace it while you relocate.

I'm still going to be connecting up a Webasto diesel-powered coolant heater, but haven't got to it yet still. I decided against a block heater as it only really heats in one specific spot, and that doesn't help nearly as much as circulating pre-heated coolant (although WAY cheaper!)... also, a block heater is pretty useless when you are boondocking and have nowhere to plug it in.