injection pump going bad?

[brainsboy]

1968 M35a2 non turbo

I read here about how to turn up the fuel on the injection pump. I noticed on my truck that someone has already maxed it out. The only thing is that my truck doesnt smoke at all. Does this mean that my injection pump is worn out and its not supplying enough fuel? It runs fine but In 5th gear is slows down alot while going over hills, I would like to get just a hair more power out of it if possible. Not sure if this matters but the guy who owned it before me must of been running used motor oil because all the filters were clogged and gas tank was black. I just put in a new fuel pump and all new filters a month ago and been running straight diesel. I have ran the truck through about 3 full tanks since then., and just wondering if the used motor oil may have damaged the injection pump? I dont usually work on diesels so Im somewhat lost if this is normal or if I need to rebuild the IP.

 

[wreckerman893]

The first thing you should do is change all the filters again (or at least check them for clogging).

Excessive smoke can mean several things to include too much fuel. Since yours is not smoking excessively the air cleaner is prob OK (restricted air flow can cause poor performance).

Deuces were underpowered from the get go so pulling down on hills (especially loaded) is normal.

If your fuel is turned all the way up (are you sure of this) you would be wise to install a pyro to keep track of excessive heat on the turbo side. Keeping your foot in the fuel on a hard pull can cause severe damage due to heat buildup.

A deuce with a stock multi-fuel engine is always going to be a toad in the road. If you can't adjust to it you might consider other options.

 

[Ford Mechanic]

How do you check for fuel filter clogging?

 

[patracy]

How do you check for fuel filter clogging?

Fuel pressure gauge or visibly inspect.

 

[Ford Mechanic]

Do you think a pressure guage mounted on the engine would hold up as a permenant mod for quickly checking fuel pressure for those of us that run WMO? Or would vibrations be too much and a remote mounted guage be a better choice?

 

[gimpyrobb]

Have you replaced the air filter? My multifuel wrecker was a dog till I replaced the air filter. It is no speed demon, but it travels comfortably now.

 

[Floridianson]

Do you think a pressure guage mounted on the engine would hold up as a permenant mod for quickly checking fuel pressure for those of us that run WMO? Or would vibrations be too much and a remote mounted guage be a better choice?

Put the gage right where the bleeder is, think a T so you can still bleeed. The gage should be higher end scale. You would need a lower end scale to check the intank pump so just high end for now.

 

[svd dragunov]

Put the gage right where the bleeder is, think a T so you can still bleeed. The gage should be higher end scale. You would need a lower end scale to check the intank pump so just high end for now.

Pics?

 

[m-35tom]

OP says non turbo, so it would be a slug anyway you do it, but no smoke on non turbo means it is getting very little fuel. fuel pressure gauge should be 0 - 100 psi, at max rpm should get around or past 70 psi

 

[Ford Mechanic]

OP says non turbo, so it would be a slug anyway you do it, but no smoke on non turbo means it is getting very little fuel. fuel pressure gauge should be 0 - 100 psi, at max rpm should get around or past 70 psi

Would this be the same for the LDT? Wow 70 psi is alot for a 40 yr old designed lift pump. This sounds like something I might try in the future for ease of mind between maint. Thanks!

 

[gimpyrobb]

The in-tank pumps supplies 5-7psi and the gear pump on the IP gets up to 85psi if I remember correctly. It is rpm dependent.

 

[m-35tom]

Would this be the same for the LDT? Wow 70 psi is alot for a 40 yr old designed lift pump. This sounds like something I might try in the future for ease of mind between maint. Thanks!

It is not the lift pump, it is the engine driven, gear type, booster pump that pressurizes the HH. Yes this can be used as an indicator of the filter condition, but I use clean diesel only and never have I replaced or even checked the filters. They only get dirty from dirty fuel.

 

[brainsboy]

Air filter is fairly clean.

If I take fuel pressure readings on the motor and they are low, then this would mean that I need to rebuild the injection pump, correct? Can I rebuild the injection pump myself or does it require hard parts? As for pressure 85psi seems low, shouldnt a diesel have 1500psi?

 

[cranetruck]

Didn't think they had hills in Florida

 

[m-35tom]

Air filter is fairly clean.

If I take fuel pressure readings on the motor and they are low, then this would mean that I need to rebuild the injection pump, correct? Can I rebuild the injection pump myself or does it require hard parts? As for pressure 85psi seems low, shouldnt a diesel have 1500psi?

We are talking about supply pressure TO the injection pump. Actual injection pressure is way more than 1500 psi, almost double.

 

[brainsboy]

We are talking about supply pressure TO the injection pump. Actual injection pressure is way more than 1500 psi, almost double.

Am I missing something? Where does the 85psi come from? My lift pump is listed at 5psi

 

[gimpyrobb]

The IP, as I said, has a geared fuel pump built into it. You can follow the fuel line from the primary filter, under the rad, and connected to the fuel pump on the IP. From there it goes to the secondary filters, and to either the FDC or the Hydraulic head of the IP. The HH is where pressure jumps WAY up.

 

[M543A2]

Another thing to check is that the fuel shut-off, when pushed in to the dash in run position, is fully traveling the shut-off on the side of the pump to the run position. If it is not opening the fuel shut-off valve all the way, you are not getting full fuel. Sometimes the clamp that holds the outer jacket of this cable becomes loose, or just adjusted wrong.
We use this to limit the power on our trucks that are fully turned up. We replaced the stock pull cable with a micrometer adjustment locking pull cable so we can, by pulling the shut-off lever back a bit from full open, limit the fuel supply. We set it for normal use to give us around 10 PSI boost at floored pedal, which prevents engine damage if one forgets and floors it at floored pedal too long. We release it and shove it in to the full fuel position for the short times we want full power, watching exhaust temp closely to prevent damage.We have done this with fully turned up trucks for many years with no problems.
Regards Marti

 

[Ford Mechanic]

I've not gotten around to installing a guage yet but I've run into a problem.

I've heard ya'll talk about fuel filters stopping up causing high EGT's and low power, so I think that might be what's happening. I've got really high EGT's, 1150*F in 4th! And it's taking forever to get to 45 indicated by the speedo due to having to keep my foot out of it because of the temps. This started last week when I hit a 1/4 tank so I pulled the in tank pump. Replaced pick-up hose and correctly adjusted pump depth(it was too short). Pumped the tank to check it for trash and it was shockingly clean, nothing but some varnish. Made a new batch of fuel at 60%WMO to 40% diesil since I have added 5 more gallons diesil and 3 gallons gas. This batch has more diesil content that I normally run so I was hoping to have more power and great smoke. I had truck pull quality smoke almost, it was just a little too much! So I added 3 gallons gas which has cleaned it up considerably. It idles at 350*F, the air filter has not been changed but the indicator has not shown yet either. The fuel filters were changed 1500 miles ago. And my truck is sitting on 395's so the temps runn a little hot anyway.

Any input, or is this text book filters clogged?

 

[Ford Mechanic]

Got around to checking the truck some during lunch. Drained about a 1/2 qt from each filter, all had some big pieces of trash floating around in it and a minute amout of water in the primary. I also jacked up the front axle to check for any rotation problems and found my left front I was barely able to turn! Backing off the brake adjustment didn't help. So I reckon I'll run it home and start tearing the front axle down to see why. Any one remember the name of the member here that sold the front axle seal set that included the A3 style silicone boots?