Will L.
Well-Known Member
The lift pumps that went on the 6.5 rigs were designed for an older injection pump that didn’t require as high pressure. GM was pinching pennies and kept making tiny improvements to the lift pump, just enough to make Stanadyne who make the injection pump honor their warranty while the rig was in its 3 year/ 36,000 mile warranty.
GM didn’t care when the liftpump dies because the engine still starts and runs. The majority of owners don’t notice the longer start times, the loss of performance going down the road. So they profit the difference.
It is only from fleets that own huge quantities of these rigs and owners that have a descent mechanical ability (many are mechanics as a day job) that it is learned how bad underperforming the factory lift pump is.
The injection pump is ballpark $1000 plus labor- so a really expensive lift pump becomes hard to justify. Newer diesels where parts and labor run around $15,000 the price makes sense.
6.5 pickup guys choke on the idea of $800 for a lift pump- especially considering resell value of the rig. But when the rig has value of $40,000-$100,000 like a Hummer… and you ever have a breakdown, tow bill, or even think about it again- many hummer owners easily justify it. An RV… very situational. It might be a $150,000 rv, but if it is only driven 2,000 miles a year and a HUGE FACTOR is how much labor to replace the injection pump - makes the difference.
I once bought an RV just for the engine. It had a bad waterpump- the weep hole was dripping. The nose of the rv had to be literally cut off to gain required access. Estimated repair cost back in 2002 was $24,500 average- he had 4 quotes and all were within $1100 of each other. It sat for 5 years before he gave up and sold it to me for a couple grand - I removed some of the interior stuff = tv, 2 recliners and delivered them to his house. I took a forklift and ripped the body to shreds and into a dumpster. Chopped the frame with a torch to roll out the engine and transmission. Everything else went into the roll off dumpster.
Some RVs are easy to work on.
Labor for replacing an injection pump is double to triple on a hummer vs a pickup.
Van labor is triple a pickup, if it has 150,000 miles it goes to a junkyard, regardless of condition.
Some people keep buying the poor working factory lift pump and just replace it every year. My hummer is the older injection pump that only needs 5psi- so I replaced my lift pump about every 1.5-2 years. But the lift pump used to be $40.
Now $110 is about right. But the diesel fuel now has ethanol in it. Look at your gas station for the word OXYGENATED that is ethanol. It shortens the life of these pumps, and higher percentage does it faster. 10% means about 1 year- and it doesn’t matter how many miles. Once the fuel soaks into the plunger of the pump it is eating it slowly. Taken apart and soaked in the fuel you cant tell the difference until you use a magnifying glass to see the edges getting messed up. It simply rots it away.
If you dont measure the pressure AT THE INJECTION PUMP - you wont know what is really happening. I have had the argument with literally hundreds of people over the decades. But I am the guy that the dealership and small shop mechanics called and paid a consultation fee to when they could not fix a 6.5 rig. I was once flown to Texas from Nv where they paid their mechanics and had 8 trucks still under warranty all set up in the mechanics bays. I wlaked through one at a time and did the diagnostics on trucks they took back in on trade and lost money on each one. I told them over the phone what I am repeating to you & many others here. Then when I got there, they finally did what I said. Half of them were fixed and on the lot for sale that day as good reliable trucks- they others took a week for parts to get there.
I’m not being picky. I don’t care when people don’t listen. But I tell the same lessons to people over and over again. Eventually some listen and are happy. Those who don’t can just keep throwing money at it and sell it later in disgust.
To be clear- I don’t think your hard start will be fixed by improving the incoming fuel pressure at this point. I think your injection pump has already suffered some internal wear it shouldn’t have. You can slow that progression by putting on a Fass or equivalent pump and getting the pressure adjusted to higher pressure meausred at the pump never exceeding 14 psi, never below 8. The wear on yours will determine where the best exact level is. But adjusting and testing as something most dont do. Adjust, test, record results. Repeat. Examine the numbers and make the final adjustment. Once in the 8-14 range, the gains to get it exactly at say 11 psi as an example- are really minor gains in power. But that gain is also the efficiency so it MIGHT help mpg- rare but might.
If you did all this - the start time will not improve by 1 second crank time, maybe 1/2 second. This is for long term health of the rig.
Your problem sounds like glow plug issues. It wont save you time because the best plugs require longer glow times to get to heat.
Best thing for faster starting in your case long term is a Powermaster 9052 starter.
You need to ensure battery cable conditions and size. Ensure battery condition and size. Ensure clean connections.
GM didn’t care when the liftpump dies because the engine still starts and runs. The majority of owners don’t notice the longer start times, the loss of performance going down the road. So they profit the difference.
It is only from fleets that own huge quantities of these rigs and owners that have a descent mechanical ability (many are mechanics as a day job) that it is learned how bad underperforming the factory lift pump is.
The injection pump is ballpark $1000 plus labor- so a really expensive lift pump becomes hard to justify. Newer diesels where parts and labor run around $15,000 the price makes sense.
6.5 pickup guys choke on the idea of $800 for a lift pump- especially considering resell value of the rig. But when the rig has value of $40,000-$100,000 like a Hummer… and you ever have a breakdown, tow bill, or even think about it again- many hummer owners easily justify it. An RV… very situational. It might be a $150,000 rv, but if it is only driven 2,000 miles a year and a HUGE FACTOR is how much labor to replace the injection pump - makes the difference.
I once bought an RV just for the engine. It had a bad waterpump- the weep hole was dripping. The nose of the rv had to be literally cut off to gain required access. Estimated repair cost back in 2002 was $24,500 average- he had 4 quotes and all were within $1100 of each other. It sat for 5 years before he gave up and sold it to me for a couple grand - I removed some of the interior stuff = tv, 2 recliners and delivered them to his house. I took a forklift and ripped the body to shreds and into a dumpster. Chopped the frame with a torch to roll out the engine and transmission. Everything else went into the roll off dumpster.
Some RVs are easy to work on.
Labor for replacing an injection pump is double to triple on a hummer vs a pickup.
Van labor is triple a pickup, if it has 150,000 miles it goes to a junkyard, regardless of condition.
Some people keep buying the poor working factory lift pump and just replace it every year. My hummer is the older injection pump that only needs 5psi- so I replaced my lift pump about every 1.5-2 years. But the lift pump used to be $40.
Now $110 is about right. But the diesel fuel now has ethanol in it. Look at your gas station for the word OXYGENATED that is ethanol. It shortens the life of these pumps, and higher percentage does it faster. 10% means about 1 year- and it doesn’t matter how many miles. Once the fuel soaks into the plunger of the pump it is eating it slowly. Taken apart and soaked in the fuel you cant tell the difference until you use a magnifying glass to see the edges getting messed up. It simply rots it away.
If you dont measure the pressure AT THE INJECTION PUMP - you wont know what is really happening. I have had the argument with literally hundreds of people over the decades. But I am the guy that the dealership and small shop mechanics called and paid a consultation fee to when they could not fix a 6.5 rig. I was once flown to Texas from Nv where they paid their mechanics and had 8 trucks still under warranty all set up in the mechanics bays. I wlaked through one at a time and did the diagnostics on trucks they took back in on trade and lost money on each one. I told them over the phone what I am repeating to you & many others here. Then when I got there, they finally did what I said. Half of them were fixed and on the lot for sale that day as good reliable trucks- they others took a week for parts to get there.
I’m not being picky. I don’t care when people don’t listen. But I tell the same lessons to people over and over again. Eventually some listen and are happy. Those who don’t can just keep throwing money at it and sell it later in disgust.
To be clear- I don’t think your hard start will be fixed by improving the incoming fuel pressure at this point. I think your injection pump has already suffered some internal wear it shouldn’t have. You can slow that progression by putting on a Fass or equivalent pump and getting the pressure adjusted to higher pressure meausred at the pump never exceeding 14 psi, never below 8. The wear on yours will determine where the best exact level is. But adjusting and testing as something most dont do. Adjust, test, record results. Repeat. Examine the numbers and make the final adjustment. Once in the 8-14 range, the gains to get it exactly at say 11 psi as an example- are really minor gains in power. But that gain is also the efficiency so it MIGHT help mpg- rare but might.
If you did all this - the start time will not improve by 1 second crank time, maybe 1/2 second. This is for long term health of the rig.
Your problem sounds like glow plug issues. It wont save you time because the best plugs require longer glow times to get to heat.
Best thing for faster starting in your case long term is a Powermaster 9052 starter.
You need to ensure battery cable conditions and size. Ensure battery condition and size. Ensure clean connections.
