Davedownunder

Hey guys good news ....

On the advise of another pump man I put a non-return valve in the line between the green filter and the fuel pump. It has started with no problems for 2 mornings now.

Fingers crossed this is the solution.

Thanks for all input and advise.

DAVE

Hey guys good news ....

On the advise of another pump man I put a non-return valve in the line between the green filter and the fuel pump. It has started with no problems for 2 mornings now.

Fingers crossed this is the solution.

Thanks for all input and advise.

DAVE

On my old V8 it was 17 Degrees

Paul - Thanks for the diagrams.

The differences I have are

1. The pump is a full Bosch not an Ambac therefore there is no Puff Limiter

2. I have an air start which I put a tap on before the lubricator too eliminate any possible leaks here. It made no difference. I had this problem on a previous V8.

3. There is no tube in the tank for the return line. Fuel just goes into the tank through an elbow and splashes into the tank.

I have taken the return line off the pressure relief value on the pump overnight and placed a funnel and cup underneath - nothing was captured - I assume from this that nothing was leaking or draining back through the pressure relief valve back to the tank.

In what your saying, I don't know if it will suck back through the pressure relief value back into the pump in the opposite direction. Though this direction may need more investigation. Maybe I could put a one way valve (I have here) in that line to stop any possible sucking of air back through the pressure relief valve.

Working today the truck was stopped for 2.5 hours and it wouldn't fire without priming. It is Pissssssssssssssing me off.

DAVE

Paul (Mrsmackpaul)

A diagram of your explanation would be appreciated.

Thanks

Dave

The change of position of the fuel line to the pump made no difference at all. There really was only 1 drop of fuel in the container under the pressure relief valve indicating there isn't a leak here.

Back in the shed today for me ........

It was suggested I look at the F.A.S.S Fuel System. I have started another thread on here inquiring of you my fellow trucking compatriots, to get any info on this product. see forum entry in "Engine and Transmission" section titled "FASS Fuel System"

DAVE

Thanks for your insight guys.

My inquiry on this product is related to the problem I have starting my E7400 Mechanical in the morning as in the tread I have also running here in "Engine and Transmission" forum called

The saga thickens .....................

It has been suggested to me that I look into the Fass Air Separation System for Macks.

Has anyone any experience with these?

Their website states some great things but would like to know if anyone has actually tried one of these and would they pass on some comments.

http://www.pittsburghpower.com/product_info.php?products_id=264

OK bad news - the problem is still there. Had to prime it up the last few mornings.

Trying now by rerouting a fuel line to eliminate a potential problem from the line creating a vertical uplift into the pump. Probably not the answer but I am clutching at straws at the moment and it was suggested that the fuel line might be better to have a straight run all downhill to the fuel pump then that setup I had - see photos

Also tonight I have disconnected the return line and placed a container under to see if any fuel is leaking this way.

So far so good .......... Truck started up after a 6 hour period from replacing the grommets in the crossover tubes on the heads.

It also started OK the next morning after 12 hours . Here's keeping fingers crossed

The engine is a 1993 EN7-400 Mechanical 11GBA78090

The pump no is 0402746619 - the pump is opened up 10% currently.

Turbo is a 470 - part no = 1748288 Serial No = 03A219120050

BWTS = 174828

Thanks

Dave

I am looking to buy a 18 Speed Mack Gear Shift Knob. New or near new. Thanks

I put a one way valve in the suction line from the tank before the primary filter yesterday. Hoping this would elevate the "air in the system" possibility - but this morning the problem is just the same. Looking like injector tube not sealing on the injector problem may be the answer. Removed the crossover tube this morning and replaced the 2 grommets (they looked fine but replaced them anyway) Just now awaiting a time period of a few hours to see if it starts.

Still need to know the optimum pump timing to ensure this is set correctly.

Glen

I just tried your suggestion of removing the injector return line and fuel was spurting out of the line comping from the pump end. This was not what I was expecting - now I am totally baffled.

This is doing my head in - and today in Sydney Australia it is 37 Degrees Celsius (98.6 in your scale) way too hot to be working in the driveway.

Dave

When I first installed the pump I had the timing set to 23degrees and it wouldn't pull the skin of a rice custard. The rocket cover says to set at 23 degrees BTD. Then the setting was altered to 18degrees - pulls a lot better but I feel it should go a lot harder.

Does anyone know the correct setting or has a reference guide for this area.

DAVE

Thanks Guys

I have only just rebuilt this motor 48k ago and the injectors where serviced, however this is an area to investigate. I have not as yet noticed any fuel in the sump, or smokey exhaust, so was not looking along these lines. Will now investigate.

Dave

My E7 Valueliner has this issue that it wont start in the morning (or after about a 6 hour rest) without the fuel being primed up. Once the truck is going throughout my work day, it will restart OK. I have been living with this problem for a few months now and have tried many things to overcome this issue.

Initially suspecting there is "air in the system" I have replaced practically all fittings and hoses to eliminate any intake of air.

All hoses have been replaced

All fittings have been replaced

The pressure relief valve has been replaced

The Primary Filter head has been replaced. When I removed the old one I did find 3 fractures in the threads and was excited that this might be the answer - however it proved not to be so and the problem remains.

A new fuel pump has been fitted -

Another suspicious clue is that there appears to be excessive vaporization in the fuel tank. this excessive vapour will be present as soon as the fuel starts returning to the tank from the engine. How much vapour is normal? Is this a related problem to my fuel for starting issue?

I have noticed that the suction line from the tank to the Primary filter is empty and even the Primary filter having about an inch at the top empty on inspection after a period of a few hours. The lines from this filter to the lift pump and then subsequently to the next filter on to the fuel pump are full.

Any Clues

DAVE