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Discussion Starter #21
Did find a leak..... the clutch master cylinder, damp underneath and the reservoir was near empty.
That happens when it's located out of sight.
 

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Thanks, thats the test I was waiting for, but the results says I've something else to think about.
Are you using the FSS (fuel shutoff solenoid) or a cable pull on the emergency stop?
Good call. I'm using the FSS. I can repeat the test with the estop lever if you'd like.

My piston lift pump just showed up the other day, so my diaphragm lift pump is not long for this world, lol.
 

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Discussion Starter #23
GLTHFJ60, no need to redo the test, it was a bad gauge and cold engine. Still interesting readings on the cold engine.
I'll be wanting to read up on your piston pump install and results. I've been hesitant to change over to one as I've read so many people were sold high pressure pumps as low pressure pumps and were out a lot of money.
 

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If you change to the piston, just be sure it is the correct pump. It also requires an new fuel feed line to filter along with the block spacer, 2 gaskets, and correct bolts. Same line as the P7100 used on the 4bt. Some people make the mistake of getting the setup for the 1st Gen Dodge 6bt. Right pump but wrong fuel line. Here's the diagram of what all it takes.
 

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If you change to the piston, just be sure it is the correct pump. It also requires an new fuel feed line to filter along with the block spacer, 2 gaskets, and correct bolts. Same line as the P7100 used on the 4bt. Some people make the mistake of getting the setup for the 1st Gen Dodge 6bt. Right pump but wrong fuel line. Here's the diagram of what all it takes.
The original bolts for the diaphragm pump works fine on piston pump, but yes the 4bt hard line is the opposite angle from the 6bt kit.
 

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Mark, it's interesting that on your site you show the fuel pipe as 3927637 and that's the same number as the P7100 on the 4bt I have on Quick Serve. In my industrial catalog it also has the piston lift pump on a 4bt with the A100 pump but shows a different part # 3917280. In the diagram it appears to be the exact same part. Wonder if the 3927637 is just an updated number. You can find both parts in the marketplace and the 391 number is a bit cheaper. Didn't know if you had run across this or not.
 

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Charles, correct, it doesn't matter if you are running the VE or the P7100 the 3927637 hard line works on both....that's the only one I supply in the 4bt kit...I have verified it works on both. I don't think the 3917280 is even avail anymore. As you know, Cummins changes the part #'s like we change our underwear. lol
And for some reason the 3927637 4bt line is way more $ than the 6bt one....supply & demand I guess.
 

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Turns out I bought a low pressure piston pump intended to retrofit to a VE pump 6BT, so the line was wrong. I was able to bend the stock diaphragm pump line to fit the new piston pump. Took some figuring, but wasn't too hard, and seems to work just fine.

I can confirm, that regardless of pump and regardless of engine temperature, when the engine is cut off by the fuel cut solenoid, the fuel pressure at the feed banjo bolt decreases from operating PSI to zero, as expected.
 

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Turns out I bought a low pressure piston pump intended to retrofit to a VE pump 6BT, so the line was wrong. I was able to bend the stock diaphragm pump line to fit the new piston pump. Took some figuring, but wasn't too hard, and seems to work just fine.

I can confirm, that regardless of pump and regardless of engine temperature, when the engine is cut off by the fuel cut solenoid, the fuel pressure at the feed banjo bolt decreases from operating PSI to zero, as expected.
Well I'm glad you was able to bend your old line to work. May I ask who you bought your kit from ? I know it wasn't me, as you would have received the right line, so just curious.
 

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I have bought several of these HVLP kits from Crewcab(Scott). They have all the correct genuine Cummins parts. The newer Cummins lines are banjo to hose barbs. I like the banjo/barb as I plan to run the Cat 1 or 2 micron fuel filters in the future. I have also rebent the old lines to work fine in the past.
 

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I got my kit from Hungry Diesel. They seemed to be the preferred place in the older threads.

Steve, you make any progress on your issue losing prime?
 

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I got my kit from Hungry Diesel. They seemed to be the preferred place in the older threads.

Steve, you make any progress on your issue losing prime?
Ok, thanks. So you know, you paid too much & I know why you received the wrong kit. Their kit for the 6bt is $265 & if you want the 4bt kit, it is an extra $20 & you have to click another button to add the 4bt line.......I have a dedicated 4bt kit under 4bt parts & it is $260 with free shipping & no way for anyone to get confused. Been selling them this way for yers. I just don't spend big $ to advertise like some others.
 

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Ok, thanks. So you know, you paid too much & I know why you received the wrong kit. Their kit for the 6bt is $265 & if you want the 4bt kit, it is an extra $20 & you have to click another button to add the 4bt line.......I have a dedicated 4bt kit under 4bt parts & it is $260 with free shipping & no way for anyone to get confused. Been selling them this way for yers. I just don't spend big $ to advertise like some others.
This thread isn't about my piston pump purchase. If you want to discuss further, send me a PM.
 

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Discussion Starter #34
edit.......
Steve, you make any progress on your issue losing prime?
Had to spend the week in Tucson so no progress. But I have a plan. First going to bleed and bleed every connection from the lift pump on until the engine is soaking wet with fuel. My theory is it was a accumulation of air over time. Other than that I'll go back and reread some of my "cures" for losing prime with the Scout. I've had two major times that it lost prime from sitting one was caused by using regular fuel line for the tank pick up, must use submersible fuel line and the 2nd was crud in the lift pump. Will see.
 

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Had to spend the week in Tucson so no progress. But I have a plan. First going to bleed and bleed every connection from the lift pump on until the engine is soaking wet with fuel. My theory is it was a accumulation of air over time. Other than that I'll go back and reread some of my "cures" for losing prime with the Scout. I've had two major times that it lost prime from sitting one was caused by using regular fuel line for the tank pick up, must use submersible fuel line and the 2nd was crud in the lift pump. Will see.
Check/change the fuel filter. I've had issues with it not being tight enough in the winter, and losing prime there.

HTH if and when you need it.
 

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Discussion Starter #36
Check/change the fuel filter. I've had issues with it not being tight enough in the winter, and losing prime there.

HTH if and when you need it.
Yea was just thinking about that. Theres a date on the filter of NOV 2011, only 8 years.:emb: NAPA in the morning.
 

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Discussion Starter #37 (Edited)
Replaced the filter and bleed the engine till it was soaked. Of course it starts right up. 5 days later crank it over and it hesitates a little but starts. It was 40F so gave it a pass. Another 3 days go by, went out to try it again. Looked at the temp fuel pressure gauge and it's reading 2.5 lbs!. Going to wait a few more days checking the gauge before starting it. This is good.
 

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Discussion Starter #38
24 hrs later gauge reads 1.9 lbs, a .6 lb loss. As I have no reference to this being an issue I consider the leak fixed until it doesn't start.
 

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Discussion Starter #39
That Glow Shift gauges is are going to bite ya. Sorry to say but they are regarded by many as pure junk. Just one of many I have seen over the years by word of mouth or on the forums - Dodge Diesel - Diesel Truck Resource Forums
edit....
I'd purchased the Glow Shift max tow several years ago. After putting it in the Scout Oct 2019 it lasted 6 months. Sensor was mounted remote so not vibrations problems. Had power, no blow fuse. Piece of crap.
At least my Harbor Freight 20 ton press still works.
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