fuel pump working?

[dieselturbo]

when on the highway with a/c on my check engine light came on on long upgrades. i thought my fuel filter might be clogged. i changed the fuel filter - then it would not start. opened up fuel filter and filled with fuel - then put in filter and it started. my question is about the little fuel pump on the frame rail under drvers door. should it be on/ running when key is on /but engine not running. mine seems not to be on. when the engine is running i cant tell if fuel pump is on - too noisy down there. 1995 suburban 4x4 diesel with 146,000 miles. thanks. i need to know if i should replace the fuel pump as i am going on a roadtrip pulling camper in 2 weeeks' thanks andy

[SCREAMINXL]

grab it while the engine is running, should feel it pulsing. Proper test would be done using a fuel pressure gauge. Connect at T valve by T stat housing. Looking for a min of 3psi.

[grancito]

it won't run until there is engine oil pressure, stupid, but a safety feature to stop fuel flowing after a crash.

[dieselturbo]

OK how did you know my real name???? . yes while it is running if i put my hand around the pump i can feel it vibrating a little. and it starts up immediately with no hesitation. i admit to not being an expert thats why i ask questions - remember there is no such thing as a stupid question! my next one... i am probably not installing fuel filter correctly. i just read on another thread.. after i put in new filter.. whats next.. do i open the valve on top of filter and turn key on to fill up filter and get air out??? i did not do this. maybe thats the problem. what is the proper procedure for this. thanks andy.

[grancito]

I didn't say that you were stupid, it is the system that is stupid, other vehicles have a shock sensor to stop the fuel pump. On the passenger side fire wall there is a plastic cover, someone may need to correct me I am talking about 94 95 years don't want to loose this to check your year. remove it and there is a fuse there. If you pull the fuse and connect one side to one of the threaded things above, the fuel pump will run and so you can bleed the air out of the system instead of cranking the engine.
P.S. I like your sense of humour

[AGNSCODY]

I had the same problem you are describing. and the problem existed for about 6 months. Until one day the damm thing just left me stranded. turned out to be the PMD the whole time. I bought a new PMD and it cranks right over. Now I am waiting for my FSD Cooler that I ordered here from walter. When i was haveing problems. I realized there are three componts that would cause you not to get fuel. 1. Oil pressure switch clogged up and not showing safe pressure (then truck will not turn on fuel pump under drivers door frame mounted unit) 2.) Fuel pump realy. located in the fuse box. 3.) BAD PMD.....

I thought I was haveing problems with frame mounted fuel pump. So I ran wire from it to the inside of my truck. I then drilled a hole in my dash and put a little light that connects to the ground and positive wires that plug into fuel pump. When I crank my truck the light comes on, indicating that I have fuel pump working. While my truck is on, light is on, indicating fuel pump is getting power and should be working. If light goes out, I know I have a problem. So just a thought. I used a small light fixture for like and ashtray light bout it at auto-zone for like $2.00 and it just provides a sense of security to know my pump is working.

Steve Cody
Agnscody@aol.com

[w_huisman]

Pull codes with a paper clip. Check out Walt's website for details. You don't have a clue what your truck is complaining about until you get the codes.

[jifaire]

PMD won't stop your lift pump from working ... it WILL stop your Injection pump from working, though.

I agree with w_huisman ... always check your codes first, unless you just LIKE changing parts.

If you change enough parts, you're bound to hit the problem, sooner or later.

[dieselturbo]

no stalling problems or codes. just me not knowing the proper way to bleed the air out after installing new fuel filter.

[grancito]

Thanks for the feed back.