I've never heard my lift pump, until I jumped the relay and stood next to my beautiful Red '95 2-Door SLT Z-71 4x4 6.5 Turbo Diesel Yukon and listened for it. The SLT has a lot of sound insulation I guess, or it's not working?! LOL It died in a puddle so I'm glad I don't have to crawl under there. I've got a relay and a pressure switch coming today and if that doesn't fix it I'll replace the PMD.
Friwnd had a very hard starting 6.5. Turned out she put a non vented fuel cap on her. Now she mostly starts everytime. Runs mostly good. She does sputter every so often. Im going to test the LP to see if this could be the culprit
READ THIS; In the service manual it states to check pressure at the inlet fuel line behind the filter. Checking the pressure at the water drain valve as you did makes no difference when the truck is not running. When the truck is running, the pump will not build the pressure as it’s consuming fuel and the shutoff solenoid is disengaged. This is what I’ve gathered for a 1993 DB2.
The key is on so the fuel shutoff solenoid is open. You’ll see less than .5-1psi pressure difference with it on or off and if it’s running. This is more of a test to verify you have pressure, because if you don’t it will cause hard starts and lazy throttle response.
GSC so I did this and determined my switch was garbage. Bought a new one and installed and my lift pump turn on without the key in the ignition. I had to unplug it in order for it turn off. Only thing I noticed is the angle of the valve the ops plugs into moved a bit when removing the old one. Any ideas of what I can do to fix this issue? Please and thanks!
If you had to unplug it to shut it off that new sensor is also bad. The 92-95 use one style sensor and I get a lot bad out of the box. 96-00 have them prime feature and I’ve found those are a bit more hardy. Check the ground on the passenger rear intake runner and make sure the little relay on the fire wall is good. Assuming it’s a 92-95.
@@gingersnapcustoms Yeah my truck is a 93. I checked the relay last night and fuse was good. I’m going to go double check grounds and maybe sure wire is good. now in the day light. On the old switch my lift pump would never come on unless the truck was cranked over, once I put the new switch in now the lift pump won’t turn off unless I unplug it. Idk we’ll see.
Will a bad ops not allow fuel at injector? Have fuel at filter bleed, T valve and IP return but no fuel at injectors. ?? Cranked with injector lines off several try’s no fuel. Batteries on charge now
@@briancifreo3214 you can ohm it out or pull it from the pump and have someone turn the key on and off. If the plunger doesn’t fire. That’s most likely the issue.
@@briancifreo3214 haha I can’t blame you. Check the ground on the PMD harness as well to the top of the injection pump. If that’s damaged it can cause a crank No start.
Hey bud. I put in a new standard ops, ac Delco lift pump and new fuel filter. No leaks along the fuel anywhere from the tank to where it goes from metal to rubber at the back of the engine. And still getting 3-4 psi. What do ya think. 94 k500. 6.5
That’s normal for a new out of the box lift pump. They are kind of terrible. Which is why I suggest doing upgrades like a fass or raptor from Leroy diesel.
I have the same problem with a hard start. Made the same setup, opened the T valve and have 0 psi running. Oil pressure gauge on the dash reads 7-10 psi at operating temperature.
@@gingersnapcustoms no I didn't jump the ops plug in end, but the other day I replaced my fuel filter and primed the housing unit to get the air out. Lift pump worked just fine.. btw great videos man. Very informative and straight to the point. I have a 94 suburban k2500 6.5.
Also There's 378k on the odometer. Has developed a hard and uneven idle and lots of white smoke on the first cold start. 6 out 8 glow plugs are newer. I'm thinking it's a combination of things. Maybe fuel shut off solenoid is bad or injector issue. Also the the other issue with the ops. What are the symptoms of a bad or dead ops? Thanks for your videos and time.
@@timux6024 the rough idle and shake is due to air in the fuel system or a lack of incoming fuel pressure. These are designed to run with a lift pump. So take that away and they begin to shake and have issues.
@@gingersnapcustoms 10-4. What're some lift pumps you recommend? I don't use the truck for hauling.. just a daily driver. I'm in Minnesota and run it in the winter as well.
I got a 6.5 motorhome... I know lucky me! Put a new lift pump in new ops wont turn on still, I can jump the terminal and hear the pump turn on but 4 different new ops units still nothing while running. What can I be missing?
I just got a 6.5 and been following all of your videos question for you, my air box filter all that looks brand new just picked up a clean 400kkm 6.5 all basically stock other then the previois owner has the boost hose i believe for the turbo just sitting there and a cone and small pipe coming off the turbo is this problematic? He said its suppose to be for mileage havent found any info, also pmd hasnt been relocated so i plan of "bulletproofing it" but the pmd already has a 2 fan cooler attached have you ever seen such a thing ?
I can say the air intake thing is kind of a myth. If you run a stock turbo a stock intake is really the best way to go. I’ve seen a few guys put a PMD on a heat sync and add cooling fans but I’ve never actually seen the trucks run with said fans hooked up.
@@gingersnapcustoms it honestly really blew me away im trying to locate a way of redoing it to the stock filter the only place i could see have a cone for the turbo would be by the front bumper personally, and the pmd if probably my first task as previous owner keeps a backup in the backseat but its just weird to me looks like a computer fan ontop of a heatsync, i paid 1500$ so dont expect much of it but its clean of rot and with the dual 5" stacks it sounds mean i just want it to last
@@itsnegl3ct341 you can always look at getting an S&B intake or see what other cheaper aftermarket’s are out there. As for the PMD. If it works let it be.
So, my truck stalls when I crack the T-Valvle with it running. I have a 94 k2500. It's got a sputter when getting into higher speeds and hard acceleration. I'm trying to figure it out but I don't have a whole lot of resources available to me. I'm thinking it's either the lift pump or ops. I'm hoping it's not an issue with the injection pump. It's got 289k miles.
@@pozzymoto2385 that’s a dead lift pump if it stalls with the T handle open. The oil pressure gauge will always read. So don’t be shocked if the OPS is junk too.
I have 93 6.5 and it starts when it is cold or cool out and will restart after driving. But when it is 70 degrees or more it will start when cold but after driving it 6 blocks or more and I shut it off it won't start until the engine cools down. About 4 to 6 hours. Live in rural area, had a mechanic try to fix it twice but it still won't start after engine runs and is shut down. Installed aux fuel pump, glow plugs and elect pod have about 3,000 miles on them. Any ideas what I can do? Thank you.
I don’t think it’s worth the money. All it is is a 92-93 lift pump. That’s all they’ve been for years. I’d rather see a Carter, Fass, air dog/raptor on these.
Going from a 24 valve cummins and common rail cummins to trying to figure out a 95 6.5 is something else . $500 bucks and a week after buying it she starts bucking under acceleration then just dies . Won't start for nothing. Fuel filter wad changed . I see fuel after manual running the pump but no start still 😫
Well an update I bought a new pmd and installed it . Also new fuel filter . primed the system got all the air out . Still just cranks . I need a new fuel pressure gauge my old one is bad. Can u check for fuel at the injector lines like a cummins or no ? I have fuel at the petcock or whatever u call it
I had the truck running before this video. Oil pressure was still primed. So I apologize for it seeming in accurate. Or as if it was not as it should have been.
Which AirDog lift pump did you get? I’ve seen a couple different options for the 6.5 with AirDog. I also was considering a FASS. I currently have a Carter and it’s going out.
Thanks for the Video. Not sure what year your working on but my 94 6.5 needs to be cranking and oil pressure reading on the gauge for it to kick in. I want to wire it to turn on when the key is on like my 98. but not sure if it will turn off when pressured up or just keep running ?
@@gingersnapcustoms in the morning it starts within half a second like it's just waiting to start but once driven it takes longer to start,is that possibly a faulty lift pump?
@@gingersnapcustoms in the morning it starts within half a second like it's just waiting to start but once driven it takes longer to start,is that possibly a faulty lift pump?
@@gingersnapcustomspersonally I think you know more about these trucks than anybody else I'm on the opposite end of that so what do you want me to test? fuel pressure?
how many gallons per hour does a lb7 duramax injector pump pull? how many gph does the 6.5 flow? I don't know of anybody going through a tank of fuel in an hour.@@gingersnapcustoms
@@gingersnapcustoms I got a bad oil pressure sensor mines a 1996 chevy k2500 5 speed I have oil pressure at my cooler the gauge checked good in cluster so pretty sure my switch is bad
@@devoncole5789 so the OPS will always read on the gauge. The lift pump portion of the switch is what burns out with no real “failed” symptoms. Sounds like an OPS and a relay harness would fix it up.
I put a video up of a cold start on my truck if you want to check it out. Let me know what ya think is going on. You tube channel is timu x. Video name 94 Chevy k2500 6.5 diesel cold start.
So looks like you still have zero fuel pressure from the lift pump. Which isn’t right. You need to have lift pump pressure when the engine is running. It isn’t just a primer feature.
Hi. You can Google the oil pressure switch harness for a 6.5 and find what you are looking for. It’s back by where the OPS is on a TBI small block Chevy. Sorry for being awful. Good luck.
I've never heard my lift pump, until I jumped the relay and stood next to my beautiful Red '95 2-Door SLT Z-71 4x4 6.5 Turbo Diesel Yukon and listened for it.
The SLT has a lot of sound insulation I guess, or it's not working?! LOL
It died in a puddle so I'm glad I don't have to crawl under there.
I've got a relay and a pressure switch coming today and if that doesn't fix it I'll replace the PMD.
Thanks homie, gonna try this out
My LP don’t come on until the engine has made 1-2 revolutions. Even if I just shut it off. So I’d always crank it for a second to perform this test.
Friwnd had a very hard starting 6.5.
Turned out she put a non vented fuel cap on her.
Now she mostly starts everytime. Runs mostly good. She does sputter every so often. Im going to test the LP to see if this could be the culprit
READ THIS; In the service manual it states to check pressure at the inlet fuel line behind the filter. Checking the pressure at the water drain valve as you did makes no difference when the truck is not running. When the truck is running, the pump will not build the pressure as it’s consuming fuel and the shutoff solenoid is disengaged. This is what I’ve gathered for a 1993 DB2.
The key is on so the fuel shutoff solenoid is open. You’ll see less than .5-1psi pressure difference with it on or off and if it’s running. This is more of a test to verify you have pressure, because if you don’t it will cause hard starts and lazy throttle response.
Just installed a seachoice marine lift pump in my 94 burb advertised at 9-12 psi , I’ll have to try this to see if that’s what I’m actually getting
Let us know what you find! The important thing is to get above 50gph and be around 12psi.
I couldn't see what pins you jumped on the OPS plug. Is it the left and right pins??
It is the left and right pins straight across from one another. Hope that helps
GSC so I did this and determined my switch was garbage. Bought a new one and installed and my lift pump turn on without the key in the ignition. I had to unplug it in order for it turn off. Only thing I noticed is the angle of the valve the ops plugs into moved a bit when removing the old one. Any ideas of what I can do to fix this issue? Please and thanks!
If you had to unplug it to shut it off that new sensor is also bad. The 92-95 use one style sensor and I get a lot bad out of the box. 96-00 have them prime feature and I’ve found those are a bit more hardy. Check the ground on the passenger rear intake runner and make sure the little relay on the fire wall is good. Assuming it’s a 92-95.
@@gingersnapcustoms Yeah my truck is a 93. I checked the relay last night and fuse was good. I’m going to go double check grounds and maybe sure wire is good. now in the day light. On the old switch my lift pump would never come on unless the truck was cranked over, once I put the new switch in now the lift pump won’t turn off unless I unplug it. Idk we’ll see.
@@SWBjr15 it should work when the engine is running and after you’ve cranked it up and have oil pressure.
Will a bad ops not allow fuel at injector? Have fuel at filter bleed, T valve and IP return but no fuel at injectors. ?? Cranked with injector lines off several try’s no fuel. Batteries on charge now
No. That’s a PMD failure or a dead injection pump typically. Verify the fuel shut off is working on the injection pump as well.
@@gingersnapcustoms new PMD but could be bad out the box, I’ll change it. To check the fuel shut off do I need to remove it from IP or can I ohm it?
@@briancifreo3214 you can ohm it out or pull it from the pump and have someone turn the key on and off. If the plunger doesn’t fire. That’s most likely the issue.
@@gingersnapcustoms thanks. I’ll ohm it to keep anymore fuel in my eyes lol.
@@briancifreo3214 haha I can’t blame you. Check the ground on the PMD harness as well to the top of the injection pump. If that’s damaged it can cause a crank No start.
Hey bud. I put in a new standard ops, ac Delco lift pump and new fuel filter. No leaks along the fuel anywhere from the tank to where it goes from metal to rubber at the back of the engine. And still getting 3-4 psi. What do ya think. 94 k500. 6.5
That’s normal for a new out of the box lift pump. They are kind of terrible. Which is why I suggest doing upgrades like a fass or raptor from Leroy diesel.
Thanks man
I have the same problem with a hard start. Made the same setup, opened the T valve and have 0 psi running. Oil pressure gauge on the dash reads 7-10 psi at operating temperature.
Time to change the oil pressure sensor. Did you jump it to see if the lift pump runs?
@@gingersnapcustoms no I didn't jump the ops plug in end, but the other day I replaced my fuel filter and primed the housing unit to get the air out. Lift pump worked just fine.. btw great videos man. Very informative and straight to the point. I have a 94 suburban k2500 6.5.
Also There's 378k on the odometer. Has developed a hard and uneven idle and lots of white smoke on the first cold start. 6 out 8 glow plugs are newer. I'm thinking it's a combination of things. Maybe fuel shut off solenoid is bad or injector issue. Also the the other issue with the ops. What are the symptoms of a bad or dead ops? Thanks for your videos and time.
@@timux6024 the rough idle and shake is due to air in the fuel system or a lack of incoming fuel pressure. These are designed to run with a lift pump. So take that away and they begin to shake and have issues.
@@gingersnapcustoms 10-4. What're some lift pumps you recommend? I don't use the truck for hauling.. just a daily driver. I'm in Minnesota and run it in the winter as well.
I got a 6.5 motorhome... I know lucky me! Put a new lift pump in new ops wont turn on still, I can jump the terminal and hear the pump turn on but 4 different new ops units still nothing while running. What can I be missing?
The wrong OPS will prevent the lift pump from kicking on. I would suggest getting the relay harness from PTwiring solutions
@@gingersnapcustoms thank you exactly what I did!
@@dreammoney4227 did that fix it?
I just got a 6.5 and been following all of your videos question for you, my air box filter all that looks brand new just picked up a clean 400kkm 6.5 all basically stock other then the previois owner has the boost hose i believe for the turbo just sitting there and a cone and small pipe coming off the turbo is this problematic? He said its suppose to be for mileage havent found any info, also pmd hasnt been relocated so i plan of "bulletproofing it" but the pmd already has a 2 fan cooler attached have you ever seen such a thing ?
I can say the air intake thing is kind of a myth. If you run a stock turbo a stock intake is really the best way to go. I’ve seen a few guys put a PMD on a heat sync and add cooling fans but I’ve never actually seen the trucks run with said fans hooked up.
@@gingersnapcustoms it honestly really blew me away im trying to locate a way of redoing it to the stock filter the only place i could see have a cone for the turbo would be by the front bumper personally, and the pmd if probably my first task as previous owner keeps a backup in the backseat but its just weird to me looks like a computer fan ontop of a heatsync, i paid 1500$ so dont expect much of it but its clean of rot and with the dual 5" stacks it sounds mean i just want it to last
@@itsnegl3ct341 you can always look at getting an S&B intake or see what other cheaper aftermarket’s are out there. As for the PMD. If it works let it be.
@@gingersnapcustoms appreciate the input is the hose sitting loose a concern ? Or for the time being not big of a deal ?
@@itsnegl3ct341 I would snug it up the best you can and just check it often to make sure it doesn’t loosen up
Where do you stick that barbed nipple to check that pressure?
The water drain on the factory fuel filter head.
So, my truck stalls when I crack the T-Valvle with it running. I have a 94 k2500. It's got a sputter when getting into higher speeds and hard acceleration. I'm trying to figure it out but I don't have a whole lot of resources available to me. I'm thinking it's either the lift pump or ops. I'm hoping it's not an issue with the injection pump. It's got 289k miles.
Oil pressure is fine on the gauges. Reads around 30-40 psi at idle.
@@pozzymoto2385 that’s a dead lift pump if it stalls with the T handle open. The oil pressure gauge will always read. So don’t be shocked if the OPS is junk too.
@@gingersnapcustoms that would cause the stuttering as well correct?
@@pozzymoto2385 yes it causes the shutter and loss of power.
@@gingersnapcustoms sweet. I just picked up a new one. Gonna get it installed tomorrow
I have 93 6.5 and it starts when it is cold or cool out and will restart after driving. But when it is 70 degrees or
more it will start when cold but after driving it 6 blocks or more and I shut it off it won't start until the engine
cools down. About 4 to 6 hours. Live in rural area, had a mechanic try to fix it twice but it still won't start
after engine runs and is shut down. Installed aux fuel pump, glow plugs and elect pod have about 3,000
miles on them. Any ideas what I can do? Thank you.
Injection pump is worn out.
@@gingersnapcustoms Thank you for your expert advice. I wish I could find someone
like you that knows what they are doing. God bless you.
How do you feel about the Heath/dieselsite heavy duty factory lift pump upgrade?
I don’t think it’s worth the money. All it is is a 92-93 lift pump. That’s all they’ve been for years. I’d rather see a Carter, Fass, air dog/raptor on these.
Going from a 24 valve cummins and common rail cummins to trying to figure out a 95 6.5 is something else . $500 bucks and a week after buying it she starts bucking under acceleration then just dies . Won't start for nothing. Fuel filter wad changed . I see fuel after manual running the pump but no start still 😫
It’s a 95? Change the PMD and prime the fuel system with a jumper wire. That should get you going again.
@@gingersnapcustoms nice ! I'll give it a try ! Thanks brotha
@@pipelinecowboy keep me posted!
@@gingersnapcustoms you got it 👍🏼
Well an update I bought a new pmd and installed it . Also new fuel filter . primed the system got all the air out . Still just cranks . I need a new fuel pressure gauge my old one is bad. Can u check for fuel at the injector lines like a cummins or no ? I have fuel at the petcock or whatever u call it
3:32 Turtle Power!!!
What can cause hard start once it's warm new lift pump pmd all new lines pickup etc
Warn out injection pump most likely. That’s the number one cause of hot start issues in these.
You didn't crank the truck the first time so that was inaccurate. 95 and earlier only energize the pump while cranking/running. Key on gets nothing.
I had the truck running before this video. Oil pressure was still primed. So I apologize for it seeming in accurate. Or as if it was not as it should have been.
Currently running an airdog lift pump set to 15psi and this thing has never started easier
Which AirDog lift pump did you get? I’ve seen a couple different options for the 6.5 with AirDog. I also was considering a FASS. I currently have a Carter and it’s going out.
@@SWBjr15 the airdog fp150 the part number is A4SPBC087
@@austinfouts9139 much obliged brother
Thanks for the Video. Not sure what year your working on but my 94 6.5 needs to be cranking and oil pressure reading on the gauge for it to kick in. I want to wire it to turn on when the key is on like my 98. but not sure if it will turn off when pressured up or just keep running ?
Leroy diesel and other guys online sell a harness that runs the pump before you start by running it off the glow plug relay, it uses that for signal.
Thanks
I've got no flow from ffm it's a 93 Silverado 6.5 gsn help do I just replace ops and lo?
Just replace the OPS and add the relay harness from Quadstar or Leroy diesel when doing the job.
@@gingersnapcustoms in the morning it starts within half a second like it's just waiting to start but once driven it takes longer to start,is that possibly a faulty lift pump?
@@gingersnapcustoms in the morning it starts within half a second like it's just waiting to start but once driven it takes longer to start,is that possibly a faulty lift pump?
@@stevebuttrum you’ll need to test pressure at idle and see what it’s putting out.
@@gingersnapcustomspersonally I think you know more about these trucks than anybody else I'm on the opposite end of that so what do you want me to test? fuel pressure?
What year??
This works for all 92-95. 96-00 does the same.
why wouldn't one these make a good lift pump for a duramax?
The Carter pumps don’t move the volume a common rail requires. Works great for older mechanical jobs but that’s about it.
how many gallons per hour does a lb7 duramax injector pump pull? how many gph does the 6.5 flow? I don't know of anybody going through a tank of fuel in an hour.@@gingersnapcustoms
Guilty. We have two...three if you count the swapped motor...lol
I have a 97 chevy 6.5 diesel i have diesel on the pump and the return line too but no diesel on the ingectors what can i do my friend ???
You can change the PMD with a new extension harness from Leroy diesel. Many times the PMD fails and the pumps won’t operate correctly
I still own a 6.5😂 339,000 on second motor
They will run and run and run when taken care of.
@@gingersnapcustoms I got a bad oil pressure sensor mines a 1996 chevy k2500 5 speed I have oil pressure at my cooler the gauge checked good in cluster so pretty sure my switch is bad
@@devoncole5789 so the OPS will always read on the gauge. The lift pump portion of the switch is what burns out with no real “failed” symptoms. Sounds like an OPS and a relay harness would fix it up.
I put a video up of a cold start on my truck if you want to check it out. Let me know what ya think is going on. You tube channel is timu x. Video name 94 Chevy k2500 6.5 diesel cold start.
So looks like you still have zero fuel pressure from the lift pump. Which isn’t right. You need to have lift pump pressure when the engine is running. It isn’t just a primer feature.
@@gingersnapcustoms ok. Do you know if the AC Delco lift pumps are any good.
@@timux6024 they are what came on them stock. So they are ok
Lo?
Lp
Your cameraman is awful. Where exactly is that plug you jumpered and the pinout please?
Hi. You can Google the oil pressure switch harness for a 6.5 and find what you are looking for. It’s back by where the OPS is on a TBI small block Chevy. Sorry for being awful. Good luck.