Need a litte input on lift pump and glow plugs

[Trucker2k16]

Hey fellas so i had a issue with the fass lift pump not coming on with the key on so i tested to make sure i had power at factory lift pump plug which i did so i checked at fass harness at relay i had power there as well ok so bad relay so i thought.. I cone home today 11/17/22 plug in relay turn key on pump comes on ok wth so i drive it a hour round trip come home shut truck off turn key back on after 30 secs pump came on for a split second and heard the clock for glow plugs but no light is it normal once up to temp for the glow plugs to not cycle and lift pump to not run long if at all i cant remember it doing that in the pass 4 years but i dont drive it every day anymore so i forgot alot of things about it thanks and a new relay fixed my other issue

 

[ak diesel driver]

need to know the year of your truck to give an answer to how it works. the 94-95 won't run the LP until it sees oil pressure. The 96+ will run for a few seconds at initial key on. The glow plug light should at least come on briefly when hot

 

[Trucker2k16]

need to know the year of your truck to give an answer to how it works. the 94-95 won't run the LP until it sees oil pressure. The 96+ will run for a few seconds at initial key on. The glow plug light should at least come on briefly when hot

1997 i just cant remember for the life of me if that is normal when the engine is dully up to temp

 

[jrsavoie]

need to know the year of your truck to give an answer to how it works. the 94-95 won't run the LP until it sees oil pressure. The 96+ will run for a few seconds at initial key on. The glow plug light should at least come on briefly when hot

Depends on how it's wired also. I had mine wired to run when the glow plugs were on.

 

[Trucker2k16]

Once it sits and cools off i get one long glow plug light then a few short cycles likes normal and lift pump will run till light goes off but once fully warm lift pump might run a second or to and glow plug controller will click once then all turn off but once started lift pump runs like normal

 

[Trucker2k16]

Depends on how it's wired also. I had mine wired to run when the glow plugs were on.

Fass lift pump with its own harness a hot a ground and a plug that plugs into the factory lift pump plug

 

[Will L.]

The magic of a fuel pressure gauge...

 

[Trucker2k16]

The magic of a fuel pressure gauge...

13psi steady

 

[Trucker2k16]

The magic of a fuel pressure gauge...

Im just trying to find out if its normal that once fully at temp the pump dont run long on initial key on and glow plugs dont stay on long at same time.

 

[MrMarty51]

Im just trying to find out if its normal that once fully at temp the pump dont run long on initial key on and glow plugs dont stay on long at same time.

My 2000, when engine is at operating temp the GPs short cycle and the LP does too.

 

[ak diesel driver]

The LP short cycles hot or cold at least mine does

 

[JMJNet]

Here is the bottom line.
Does it have pressure when the truck runs? If yes, the prime before start duration really does not matter.

The problem is in 94-95 trucks when the LP is run by OPS when engine is running.
In this case, the Relay mod will be very important because there is really not priming without relay mod.

 

[jrsavoie]

The LP short cycles hot or cold at least mine does

I thought that was due to reaching pressure and shutting off

 

[ak diesel driver]

I'm under the impression the PCM does a time control vs a pressure

 

[Will L.]

Correct time. There is no pressure sensor.