ak diesel driver
6.5 driver
Try hooking it directly to the IP with the jug gravity feeding it.
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Eratic behavior from an 85' 6.2 (more below) requesting help please (Two vids in one)
- Thread starter nycxjeremyy
- Start date
nycxjeremyy
Active Member
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nycxjeremyy
Active Member
New video by Jeremy
photos.app.goo.gl
nycxjeremyy
Active Member
New video by Jeremy
photos.app.goo.gl
nycxjeremyy
Active Member
We're fairly certain it's the LP that failed,
nycxjeremyy
Active Member
nycxjeremyy
Active Member
nycxjeremyy
Active Member
Started up without any struggle, has not reved inexplicably since
There is no signs of air bubbles in the hose
I think we got it
photos.app.goo.gl
There is no signs of air bubbles in the hose
I think we got it
New video by Jeremy
photos.app.goo.gl
Will L.
Well-Known Member
Most likely it, hope so.
Now check the engine oil for signs of diesel fuel. If there is any feel, thinner oil, smell of diesel in the oil- do an oil change before starting or driving it again.
The reason GM went away from the mechanical lift pump is they can fail and have diesel get into the oil. You have to be super observant of oil pressure if you keep it. When pressure drops, check for diesel in the oil. Obviously be cautious whenever a bad lift pump is found like this.
If not then you’re ok.
If you ever have air coming out the ip and can’t find the source, then put clear line going into the ip also. No air in but air. Coming out is a bad ip. But that is incredibly rare.
Glad you didn’t swap the ip- seen that too many times.
Now check the engine oil for signs of diesel fuel. If there is any feel, thinner oil, smell of diesel in the oil- do an oil change before starting or driving it again.
The reason GM went away from the mechanical lift pump is they can fail and have diesel get into the oil. You have to be super observant of oil pressure if you keep it. When pressure drops, check for diesel in the oil. Obviously be cautious whenever a bad lift pump is found like this.
If not then you’re ok.
If you ever have air coming out the ip and can’t find the source, then put clear line going into the ip also. No air in but air. Coming out is a bad ip. But that is incredibly rare.
Glad you didn’t swap the ip- seen that too many times.
ak diesel driver
6.5 driver
Do yourself a favor and buy an assortment of sizes of clear tubing. Makes diagnosis much easier and faster. I have a hard time believing you had trouble finding it. Home Depot, Lowe's, just about any small town hardware store carries it.
dbrannon79
I'm getting there!
Glad you found it. on my 93 I have a fuel pressure gauge tee'd into the line going into the IP under the hood. it only tells me I have pressure at idle, but this is something you might consider so to see what the LP is doing as well as the assortment of clear hoses.
keep the clear hose on the return, don't remove it. just get you a couple of clamps or do like I did and put zip-ties on it to help hold it in place. you can also install a clear hose on the LP where the rubber is so you can always see what goes in the LP and see what comes out of the IP.
later down the road and as funds allow, plan to invest into a electric lift pump and an electric fuel pressure gauge. mount the electric LP on the frame near the tank and have it powered by key on with a relay. remove the mechanical LP and use a block off plate or use that for the turbo oil drain / oil catch can drain.
going to electric will eliminate the possibility of getting fuel in the oil as well as getting better pressure to keep the IP happy. look into the air dog lift pump. you'll buy once and cry once ($$$) but your rig will thank you for it.
keep the clear hose on the return, don't remove it. just get you a couple of clamps or do like I did and put zip-ties on it to help hold it in place. you can also install a clear hose on the LP where the rubber is so you can always see what goes in the LP and see what comes out of the IP.
later down the road and as funds allow, plan to invest into a electric lift pump and an electric fuel pressure gauge. mount the electric LP on the frame near the tank and have it powered by key on with a relay. remove the mechanical LP and use a block off plate or use that for the turbo oil drain / oil catch can drain.
going to electric will eliminate the possibility of getting fuel in the oil as well as getting better pressure to keep the IP happy. look into the air dog lift pump. you'll buy once and cry once ($$$) but your rig will thank you for it.
MrMarty51
Well-Known Member
I too vote on the electric lifting pump.
There are pumps on the market that will pump good for a while. I think I got two or maybe three years out of the lift pump/harness kit from Leroy Diesel.
It too failed and I am happy I had a fuel pressure gauge set up when it did fail.
I had spent several hundred on various brands and styles of lift pumps and on this last LP failure asked Myself, how long am I going to keep this truck, then cough, cough, coughed up and went with the Air Dog complete system.
@ak diesel driver suggests going with the Raptor pump and using the factory, or whatever filter system You currently have installed.
Like @dbrannon79 suggests, buy once cry once.
There are pumps on the market that will pump good for a while. I think I got two or maybe three years out of the lift pump/harness kit from Leroy Diesel.
It too failed and I am happy I had a fuel pressure gauge set up when it did fail.
I had spent several hundred on various brands and styles of lift pumps and on this last LP failure asked Myself, how long am I going to keep this truck, then cough, cough, coughed up and went with the Air Dog complete system.
@ak diesel driver suggests going with the Raptor pump and using the factory, or whatever filter system You currently have installed.
Like @dbrannon79 suggests, buy once cry once.
MrMarty51
Well-Known Member
I see that Quadstar tuning is out of stock on the Air Dog, but, they still have a couple of the Raptor systems available.
MrMarty51
Well-Known Member
Oh yeah.
One other handy permanent tool for diagnostics.
Get a fuel pressure gauge installed on that unit.
@Will L. suggests, when making the gauge purchase get an extra sending unit for that brand of gauge.
Install one sending unit near the lift pump on the pressure side. Install the other sending unit post the filter system, near the IP.
Install a three way toggle switch in the cab and then wire the switch to the gauge.
That way You can monitor the fuel pressure pre and post of the filter system at the flip of the switch, and have a good idea if a plugged filter is creating a problem or if it is a bad lift pump.
One other handy permanent tool for diagnostics.
Get a fuel pressure gauge installed on that unit.
@Will L. suggests, when making the gauge purchase get an extra sending unit for that brand of gauge.
Install one sending unit near the lift pump on the pressure side. Install the other sending unit post the filter system, near the IP.
Install a three way toggle switch in the cab and then wire the switch to the gauge.
That way You can monitor the fuel pressure pre and post of the filter system at the flip of the switch, and have a good idea if a plugged filter is creating a problem or if it is a bad lift pump.
dbrannon79
I'm getting there!
I know pressures are different spec for the db2 and ds4 IP's I assume you use the same air dog LP kit for both and just set the regulator for the right pressure? I have been told 9-10 psi is too much for the db2. I have a Facet dura-lift style lift pump on both of my trucks that run 9-14 psi. I have not seen any ill effects running one on the db2 yet.
Here is the lift pump I have...
Here is the lift pump I have...
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MrMarty51
Well-Known Member
Best to contact quadstar.com and notify them what You are needing the pump for.
The will set it up for the proper year, injection pump and etc.
I believe that the raptor base has similar functions as the Air Dog, just without the filters, but with the pressure regulator screw.
Maybe @ak diesel driver can fill in the blanks with how his system is set up, and, if it is pressure adjustable.
Nice thing about the Quadstar kit, it comes with the relay harness plus all the hose sizes needed and the hoses are diesel rated.
The will set it up for the proper year, injection pump and etc.
I believe that the raptor base has similar functions as the Air Dog, just without the filters, but with the pressure regulator screw.
Maybe @ak diesel driver can fill in the blanks with how his system is set up, and, if it is pressure adjustable.
Nice thing about the Quadstar kit, it comes with the relay harness plus all the hose sizes needed and the hoses are diesel rated.
smokymtn65
Well-Known Member
If you don't go through it all the way, I have a friend that does gears, he told me to mark the pinion and nut, then carefully remove the nut and count the number of turns and position of the mark on nut when it comes off. Replace the seal, put a dab of lock tight on them replace the nut exactly, do not torque. I have done this twice both times successfully.
Will L.
Well-Known Member
Db2 should have 5psi lift pump feeding it. Never ever over 8psi (unless the pump was modified for high performance and the timing advance feature is defeated).
iirc when over 6psi it forces the timing advance.
Personally, I support electric lift pump over mechanical because of the tremendous amount of engines ruined by the failed mechanical ones. If i was ever convinced the fuel leaking into the oil issue was resolved- I would have preferred it for my db2, or even modified gasser units that can support high performance db2 and ds4 pumps because there are aftermarket ones that produce that pressure and volume range.
I believe the camshaft failures related to them was a temporary issue in producing the pushrod and was corrected. I also believe with the oiling corrections made in an engine rebuild and the updated cam bearing position that the cam issues from the mechanical pump can be eliminated.
Almost no one puts a fuel pressure regulator on the mechanical ones- because most never get the pressure tested and don’t find out the new design ones since the mid 80’s produce too much pressure and force the advance all the time. Not enough to properly feed the ds4, but more than the db2 handles. Same for the low cost electric pumps where the high end electric pumps can create so much that it’s obvious but most come with adjustable design built in.
I really like the simplicity of a mechanical pump when it works properly, the issue is these have a sorted history of failures in various ways which all require engine rebuilding or replacement when it goes wrong.
The electric pumps have short lifespans if they are affordable, and are painfully expensive if made really well.
I don’t tell people what they have to do, I just want to give them as much info as I know so they can choose what is right for them.
In honesty for years my db2 equipped hummer- just watching the gauge and swapped the AC Delco ep158 each time it failed. Usually 12-15,000 miles.
iirc when over 6psi it forces the timing advance.
Personally, I support electric lift pump over mechanical because of the tremendous amount of engines ruined by the failed mechanical ones. If i was ever convinced the fuel leaking into the oil issue was resolved- I would have preferred it for my db2, or even modified gasser units that can support high performance db2 and ds4 pumps because there are aftermarket ones that produce that pressure and volume range.
I believe the camshaft failures related to them was a temporary issue in producing the pushrod and was corrected. I also believe with the oiling corrections made in an engine rebuild and the updated cam bearing position that the cam issues from the mechanical pump can be eliminated.
Almost no one puts a fuel pressure regulator on the mechanical ones- because most never get the pressure tested and don’t find out the new design ones since the mid 80’s produce too much pressure and force the advance all the time. Not enough to properly feed the ds4, but more than the db2 handles. Same for the low cost electric pumps where the high end electric pumps can create so much that it’s obvious but most come with adjustable design built in.
I really like the simplicity of a mechanical pump when it works properly, the issue is these have a sorted history of failures in various ways which all require engine rebuilding or replacement when it goes wrong.
The electric pumps have short lifespans if they are affordable, and are painfully expensive if made really well.
I don’t tell people what they have to do, I just want to give them as much info as I know so they can choose what is right for them.
In honesty for years my db2 equipped hummer- just watching the gauge and swapped the AC Delco ep158 each time it failed. Usually 12-15,000 miles.
nycxjeremyy
Active Member
Well yall, i suppose a conclusion is in order.
Thank you all so much for your help through this, ever sinfe changing out the Lift Pump, the 6.2 has been running smoothly (https://photos.app.goo.gl/D4kWrNc3Bo1zSFUFA) with no issues as of yet, I am forever thankful to you all
Next up on (mechanical) work that id want to do is adding a Transmission Cooler and Transmission Temperature Gauge to said 6.2, i currently have a 4L60E behind it (https://gearstar.com/4l60e-transmission-with-torque-converter-level-3) that has a US Shift Kit 4 control unit with it.
The cooler going behind it will be a Hayden Rapid Cool Transmission Cooler (https://photos.app.goo.gl/g33Vsuku1qKgb7wLA) which would greatly help the transmission stay cool behind the torque monster known as the 6.2, that and having a Temp guage would greatly help in knowing if it is overheating or not.
I will consider adding a Fuel pressure guage aswell, since, why not at this point, as i already have a Pyro Meter and Boost Guage installed by the prevhous owner, having another 2 would compliment it well.
I've been looking at these as possible guages:
Transmission Temp Guage:https://www.autozone.com/gauges-and...mperature-gauge/131376_0_0?cmpid=OSA:US&gQT=1
Fuel Pressure Guage: https://www.autozone.com/fuel-deliv...-pressure-gauge/131382_0_0?cmpid=OSA:US&gQT=1
Aside from installing the Transmission cooler and the guages, all I have left is cosmetics, please let me know what you all think, and if my choices in gages are okay or not, your help seriously goes a long way.
(The radiator I'm currently running on the 6.2 btw: https://a.co/d/6qL4Z1W )
Thank you all so much for your help through this, ever sinfe changing out the Lift Pump, the 6.2 has been running smoothly (https://photos.app.goo.gl/D4kWrNc3Bo1zSFUFA) with no issues as of yet, I am forever thankful to you all
Next up on (mechanical) work that id want to do is adding a Transmission Cooler and Transmission Temperature Gauge to said 6.2, i currently have a 4L60E behind it (https://gearstar.com/4l60e-transmission-with-torque-converter-level-3) that has a US Shift Kit 4 control unit with it.
The cooler going behind it will be a Hayden Rapid Cool Transmission Cooler (https://photos.app.goo.gl/g33Vsuku1qKgb7wLA) which would greatly help the transmission stay cool behind the torque monster known as the 6.2, that and having a Temp guage would greatly help in knowing if it is overheating or not.
I will consider adding a Fuel pressure guage aswell, since, why not at this point, as i already have a Pyro Meter and Boost Guage installed by the prevhous owner, having another 2 would compliment it well.
I've been looking at these as possible guages:
Transmission Temp Guage:https://www.autozone.com/gauges-and...mperature-gauge/131376_0_0?cmpid=OSA:US&gQT=1
Fuel Pressure Guage: https://www.autozone.com/fuel-deliv...-pressure-gauge/131382_0_0?cmpid=OSA:US&gQT=1
Aside from installing the Transmission cooler and the guages, all I have left is cosmetics, please let me know what you all think, and if my choices in gages are okay or not, your help seriously goes a long way.
(The radiator I'm currently running on the 6.2 btw: https://a.co/d/6qL4Z1W )
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ak diesel driver
6.5 driver
There's a reason GM went to the 4l80e when they turboed it