Author Topic: Uh oh....Fuel pressure issue (Read 12548 times)

wayneswirld2 · « **on:** February 18, 2010, 11:05:30 AM »

Hey y'all....now I've got a fuel pressure issue. Went to pick up the bus that I bought, can't get her started. If I spray ether, a NO NO I'm sure, the engine will start...briefly. Runs for about 5 seconds and the fuel pressure goes to about 10psi. If I continue to spray ether in the air cleaner I can get the fuel pressure to about 30 psi, but it still doesn't run on it's own.

Found that the previous owner had been running veggie oil with no extra filters and no heater. Replaced both fuel filters this morning...still won't stay running.

Now, since I really know nothing about running this bus...1988 GIllig Phantom transit with a 6V92T engine....I'm not completely sure that I've got the switches in the proper position.

Any ideas?

Wayne
Austin, Tx

DaveG · « **Reply #1 on:** February 18, 2010, 11:13:57 AM »

I'd make sure you are getting fuel to the filters, use the 5 gal bucket trick.

wayneswirld2 · « **Reply #2 on:** February 18, 2010, 11:15:03 AM »

Might be a dumb question, but what is the 5 gallon bucket trick?

Wayne

bigjohnkub · « **Reply #3 on:** February 18, 2010, 11:38:57 AM »

Wayne, call or pm rdbishop . He will assit you all he can. He is near you. That is the greatest thing about this board. You will get help if you ask.
If you don't know how to pm , go to your 1st post about buying bus, scroll
down to his reply and click on his name. Then click on his e-mail and go to town.
Big John

RTS/Daytona · « **Reply #4 on:** February 18, 2010, 11:52:03 AM »

How I PRIME A DETROIT DIESEL

First - here's the usual flow of Fuel in our buses

A - From the Fuel tank pickup to the "check valve" - The check valve is there to prevent fuel from running back to the tank on shutdown
"check valves can be anywhere between the pickup and the first filter - the usually places are the bulkhead - or at the first filter

B - the first filter in called the "PRIMARY" filter - that will be the one closet "in line" with the fuel tank - now it may not be the one that is physically closest
to the Fuel tank - just look at the lines coming from the fuel tank and follow it to the PRIMARY FILTER - now - there will also be a return fuel line going
back to the fuel tank - if you follow that path that will lead back to the engine and not a filter - so go follow the OTHER fuel line

C - now that you found the "PRIMARY Filter - most will have a THIRD PORT on the filter housing with a plug in it - the plugs are USUALLY 1/4" inch pipe
thread (commonly refered to as 1/4 NPT - national pipe tread) - don't be fooled the 1/4 refers to the APPROXIMATE inside diameter of that pipe - this
is where you would install a 1/4 " pipe thread to BARBED (Lowes / Home depot / Ace) fitting to attach the hose and of the garden sprayer full of fuel

D - from the primary filter - next is the FUEL pump - followed by the SECONDARY fuel filter - to the engine (sometimes left and right side split off

E - The overflow fuel (fuel not used by the injectors - about 90% is not used) will return back to the fuel tank thru a very important "RESTRICTOR VALVE"
The RESTRICTOR is there to help maintain fuel pressure (which is about a low of 15 psi at idle to a regulated (by the fuel pump pressure relief spring) to 50-60 psi at 1200 rpms and above - note the fuel pressure at the input side of the fuel pump and primary filter is about 6" to 12" of vacuum - that is the sucking power of the fuel pump - 6" indicates a clean filter - 12" could indicated a clogged filter.

Fill the filter (primary and secondary ) with fuel - fill the garden sprayer with fuel - remove the spray nozzle from the end of the sprayer hose -
attach the garden sprayer hose to the barbed fitting on the primary filter with a hose clamp and GENTLY pump at least ½ of the garden sprayers fuel into the engine -

IF a DETROIT DIESEL FUEL PUMP BECOMES AIR BOUND (no FUEL IN THE PUMP) THEY WILL NOT SUCK FUEL - this is why you need to push fuel into the primary - thru the pump and into the secondary and up to the engine to do a PROPER job of PRIMING YOUR DETROIT ENGINE

Pete RTS/Daytona

gumpy · « **Reply #5 on:** February 18, 2010, 11:58:11 AM »

Quote from: wayneswirld2 on February 18, 2010, 11:05:30 AM

I'm not completely sure that I've got the switches in the proper position.

That would be the first thing you need to do. Get your switches in the right position. Don't know anything about your bus, but if it has a rear run/stop switch that's in the stop position, it will probably act exactly as you describe. I would suggest you start it from the rear if possible, or have someone start it from the front, and watch the engine stop cylinder on the fuel cutoff. If it doesn't release, you'll never get fuel into the injectors.

This is not an uncommon problem for new bus owners. Not sure how long you've had it or what your experience level is here but most of us with a rear stop switch have done this at one time
or another.

craig

wayneswirld2 · « **Reply #6 on:** February 18, 2010, 01:52:35 PM »

Talk about a very helpfull bunch of people! Thanks so much for your input, especially that from RTS/Daytona. Man, what a detailed description of how to properly do this. I was over at the bus earlier this afternoon and was trying to bleed the system completely incorrectly. I was pushing fuel from the line that goes from the secondary fuel filter to the injector rail/head. No wonder I got nowhere. I'm guessing, from RTS's reply, that the fuel pump is air locked at this point.

This thing is being a beast to prime.

Wayne

DaveG · « **Reply #7 on:** February 18, 2010, 03:07:32 PM »

Usually if you can get fuel to the transfer pump, then it will go.

Jerry32 · « **Reply #8 on:** February 18, 2010, 03:28:03 PM »

PO might have been using a fuel boost pump on veggie too

RTS/Daytona · « **Reply #9 on:** February 18, 2010, 03:58:04 PM »

Wayne

Actually I seen the RE-PRIME question soooo many times in my 8 years on the boards - I took the time to write and hopefully spell-check a good reply - I keep it in a file - and just cut and paste it into replies

no big thing -- been there / done that

didn't want anyone else to fall down the same hole that I fell down ;-)

Pete

gus · « **Reply #10 on:** February 18, 2010, 04:47:51 PM »

As a second to what Craig said, if you have a rear shutoff switch and it is off and you have air pressure, it won't start on fuel.

If you don't have air pressure it will start and run fine until the air builds up, then shut off. I found this out the hard way when I first got my bus!

Obviously you won't have fuel pressure if the engine isn't running.

gumpy · « **Reply #11 on:** February 18, 2010, 07:31:37 PM »

Quote from: wayneswirld2 on February 18, 2010, 01:52:35 PM

I'm guessing, from RTS's reply, that the fuel pump is air locked at this point.

It may be now that you've messed with it, but it wasn't when you wrote the original post. You said you had fuel pressure to 30 psi. You won't have pressure if you have an air locked pump.

Check your switches....

Just Dallas · « **Reply #12 on:** February 18, 2010, 07:37:33 PM »

Removed

Chopper Scott · « **Reply #13 on:** February 18, 2010, 07:57:39 PM »

Beings Clifford is on the road I'll fill in for him. Pump the pedal 3 times and hold it to the floor.

PCC · « **Reply #14 on:** February 18, 2010, 09:16:32 PM »

If I may share a bad idea - when my 8V92 did the same thing (started on ether, but would not run), it was the ECM. I do not recall if you mentioned if the engine had a module?

I hope you are not experiencing what I have just been through.

If you open the fuel return line, and make sure you have fuel flow there, then you will know whether or not the problem is a fuel problem or something else.

Hoping for the best

wayneswirld2 · « **Reply #15 on:** February 19, 2010, 01:17:15 PM »

As for a module...there is a black box with connectors on the right side of it that is mounted sort of beneath and forward of the turbocharger, between the banks. Looks like a module of some sort. Smells like a module, tastes like a module...must be a module.

I'm guessing that this would be some sort of ECM for the fuel delivery system? Dagnabbit, am I gonna be looking for one of these in a bus boneyard?

Wayne

PCC · « **Reply #16 on:** February 19, 2010, 01:43:50 PM »

Do not presume it even could be the ECM until you have exhausted every other possibility.

Make sure that your fuel is running through the rack. Make sure you have everything else working. After looking at everything, find a dealer who can 'test' your ECM, before putting your millions on the table.

I was just mentioning that it might be an un-fuel related problem (one possibility).

It just happened to be my personal situation.

Keith
PCC

wayneswirld2 · « **Reply #17 on:** February 19, 2010, 03:50:28 PM »

I'm all too aware of ECM problems. Being a bonafied died in the wool ASE Master Tech, gas engines only, I've run into my fair share of "Oh hell it MUST be the computer" worries. I'll spend more time with the bus this weekend, AFTER the 'gathering' that Dallas and Cat are having.

Wayne

RTS/Daytona · « **Reply #18 on:** February 19, 2010, 04:15:07 PM »

If you have an AIR THROTTLE - then you will most always have a MUI (non-DDEC) D/D

IF you have a CHECK ENGINE LITE (CEL) you should have a DDEC - the CEL should blink a few times when the bus is first turned on
there should also be a momentary style bat switch up front to pull or down to blick out the DDEC error codes

here what a DDEC-II and DDEC-IV look like

RTS/Daytona · « **Reply #19 on:** February 19, 2010, 04:47:26 PM »

If you have an MUI (NON DDEC) DETROIT 6V92T

here another thing to check - if you hit the emergency shutdown switch by mistake - they have to be manually reset (i think - I'm a DDEC guy)

Just Dallas · « **Reply #20 on:** February 19, 2010, 04:55:22 PM »

Removed

wayneswirld2 · « **Reply #21 on:** February 19, 2010, 07:11:34 PM »

I've spoken to Mr. Bishop a couple times over the past two days, he's pointed me in some very RIGHT directions. AND with my almost negative amount of knowledge he's been very patient. I'll probably be calling him again, and damned soon, to ask very nicely for some more guidance. Either that or I'll burn the bus to the ground.....

Wayne

PCC · « **Reply #22 on:** February 19, 2010, 10:18:54 PM »

ASK - just ask

Ask has fewer letters than burn.

brando4905 · « **Reply #23 on:** February 20, 2010, 06:14:01 AM »

I'm not an expert on buses, but I did used to have a Dodge 2500 that was a veggie burner. If the PO was attempting to run a grease system with no extra filtering, no switches, and no heaters, then the entire fuel system could be restricted with hardened WVO.

luvrbus · « **Reply #24 on:** February 20, 2010, 06:17:29 AM »

Check you water level in the surge tank and fill it to the top

good luck

robertglines1 · « **Reply #25 on:** February 20, 2010, 06:26:18 AM »

2nd on surge tank...I know from experience...more often than not it's simple..

wayneswirld2 · « **Reply #26 on:** February 20, 2010, 06:32:32 AM »

To risk sounding like a complete dumb@ss....the surge tank is.........?

Wayne

RTS/Daytona · « **Reply #27 on:** February 20, 2010, 06:37:06 AM »

radiator water tank

MUST BE filled to the OVERFLOW PORT or SITE GLASS

wayneswirld2 · « **Reply #28 on:** February 20, 2010, 06:41:01 AM »

I sort of assumed that the surge was coolant related, but given that I'm in uncharted territory I'm not gonna assume ANYTHING....yet.

Thanks,
Wayne

RTS/Daytona · « **Reply #29 on:** February 20, 2010, 06:57:19 AM »

One of the first things that you may want to do is:

#1 - Make sure your batteries are charged - Make sure the oil and water and FUEL - is full !!!!!!

#2 - It's usually best to try start from the rear when your having a problem
   check the switchwes in the engine compartment - usually there are 2

   * ENGINE CONTROL (or something similar) - (NORMAL - OFF - REAR RUN)
   set it to REAR RUN
(when you are all done - return this switch to NORMAL after you fix the problem - or you will not be able to run the bus from the front)
   * START CONTROL (or something similar) - (NORMAL -OFF - REAR START
   REAR START is a momentary switch - push to turn over the engine (there is often a few second delay) -
(when you are all done - return this switch to NORMAL after you fix the problem - or you will not be able to start the bus from the front)

#3 - If the engine turned over but didn't start - The next thing THAT I WOULD DO is:

   Locate the secondary filter - they will usually have a 1/4 pipe plug between the inlet and outlet lines
   - remove the plug and install at least a 0-60 PSI pressure gauge - worst case get a schrader valve adater to screw in and use a tire gauge

   - With the engine turning over - you should get about 10-20 lbs of fuel pressure - if not re-PRIME from the primary filter

Pete RTS/Daytona

RTS/Daytona · « **Reply #30 on:** February 20, 2010, 07:06:40 AM »

call me three eight six - six seven two - zero five seven one

or email me at hawk_ii_mail @ yahoo.com with your phone# and I'll call you (I have unlimited L/D)

buswarrior · « **Reply #31 on:** February 20, 2010, 07:12:13 AM »

Yup, all bets are off when you said some DUMB A** thought he knew how to run veggie.

After those easy things listed above, switches and coolant tank, I'd be really suspicious that veggie is plugged up in it, and whatever fuel pressure you were generating was bypassing or not getting through.

Others are smarter than me on this topic, but maybe open a fuel line to an easy to reach injector and then hook up the garden sprayer as noted in Pete's priming directions and see if you get some fuel?

(Great job on that write up Pete, I wouldn't change a word)

Will diesel act as a sufficient solvent on veggie sludge, or will more extensive cleaning be required?

happy coaching!
buswarrior

expressbus · « **Reply #32 on:** February 20, 2010, 07:29:33 AM »

Second what RTS said about rear start. One more thing, I had a problem with the rear start switch. I toggled it down to rear start to work on some other problem. Solved it, returned the rear start to the run position, and dang thing would not turn over from the ignition key. Turns out these switches are so seldom used that simply going from run to rear and back can actually lose the electrical connection to start from the ignition key. Cheap but possibly temporary solution for me was to vigoriously exercise the toggle going from run to rear and back severasl times very fast. Kinda like, Take That, Take That ... You get the point.

As for the veggie oil, never tried it don't plan on doing it. Heck, I have not even tried bio and am not thinking on doing that either.

Good luck in running down your problem - or the PO!

RTS/Daytona · « **Reply #33 on:** February 20, 2010, 10:18:00 AM »

Time to re-group a little - 3 strings going about the same problem

Let's keep Wayne "NO START" problem in the "...Check Engine Light location.... " string

let this string die

CONDITIONS - I forgot he said he has 10-30 PSI at the secondary filter gauge - That's fine - he's primed and not air bound

But

Here's the problem so far:

#1 - DDEC-II - with no power on the INJECTOR CONNECTOR PINS A&B / E&F - this feeds BOTH banks of injectors

#2 - No CEL (CHK ENGINE LITE) double blink when bus turns on - probably related to #1 - but INJECTOR POWER IS USUALLY DIRECT FROM BATTERY NOT IGNITION

#2 - so Wayne needs to also check DDEC Ign Power to Pin B3 on J2 connector - sent Wayne the diagrams and pinouts for him to check

Pete RTS/Daytona

ANYONE KNOW WHERE THE DDEC GOES COMES FROM ON A ** GILLIG