Fuel pump tests?

[JDMills]

I was out and about yesterday, and noticed that my truck did not seem to pull quite as strongly in the upper gears after accelerating from a stop, no smoke, not the usual thrust in third and forth gear.

Time to check the fuel pump pressure, was my thinking. Is there a way to test the pump on the truck? would a volume test be advisable as well or is it a case of volume makes the pressure?



Just drained and cleaned the fue tank, and the fuel filter only has about 1500 miles on it.



Thanks

Jason

 

[1stgen4evr]

fuel pump tests

Just some observations from 40 years with diesels. As the injection pump wears, the primary trouble shows as poor LOW speed and cranking problems. As rpms go up, the pump will overcome some of the wear that has occured from service. So if it has the ability to push the fuel at cranking speed, it usually will do a good job at full throttle. Nothing is absolute however, so consider the injection pump but look and be sure of the other things first.



You mention that you have just been doing some cleaning to the tank. You may have stired something and plugged the filter. Or sent some trash to the flow valves in the lift pump. The miles you mention on the filter are not reason to suspect filter trouble but make sure that is not the case. You mention 'no smoke', that would indicate poor fuel supply.





A good many owners have a fuel deliver pressure guage to know if that part of the system is as it should be. If you don't know what the fuel pressure is, you have no idea if it is good or bad. You might find that the lift pump is getting weak or crudded up as I mentioned and not keeping fuel to the injection pump as it should be. That would be more likely than the injection pump is my guess.



1stgen4evr

James

 

[JDMills]

James,

My mistake for not being more clear. I dont even want to suspect an injection pump. I was woundering how the fuel pressure supplied by the lift pump can be tested. Anyone ever put a inline fuel filter before the main filter. I saw one on a mercedes diesel the other day and thought it might be a good idea. may be that is overkill.

Jason

 

[tugboatphil]

JD,



I have no help for your question, but wanted to ask one. I'm considering dropping my tank this summer to see what's inside. I really want to look at my sending unit, as my gauge is very erratic.



Do you think that cleaning your tank was worth it, having seen what had accumulated? Any snags to look out for?



Thanks.

 

[JDMills]

Tugboat,

I guess it was worth it as I have some peace of mind, and that is worth a fair bit. I did not see a huge amount of sediment come out, but then my inspection process of the removed fuel was not scientific.

I took my muffler off to make getting at the upper fuel tank straps easier. That may have been unnessary, but it was also a good excuse to put a better muffler on the truck. In retropstct, the straps on the outboard frame rail would be all that need to be removed. I used some 6x6's and such to keep the tank from falling out then removed the blocking a bit at a time. It was easer than expected which was a nice plus. at the time it had about 5 gallons of fuel, and was still manageable.



Next time:



I would try and get a new filler neck to tank gromet (sp?) as mine was a bit cracked and I will end up taking the filler neck apart again to replace that. The inside of the tank did not seem to be as full of crud as I expected, used a siphon to get most of the fuel out and cleaned up the exteror. then put a gallon or so of fuel back in, sloshed it around and tried to dump it out while still having the grit (if there was some) suspended in the moving fuel. my best idea at the time, but it could be improved upon. I did not remove the fuel sending unit. that was a can of worms left unopened. Oh and I ended up cutting the rubber fuel line so as not to break the plastic elbow where the fuel return/ supply lines come out of the tank. lot easier to play with and replace that stuff when not on my backside under the truck. all in all it was start to finish about 4 hours or less. Thus I would be willing to do it again if the situation arises. a lift may make it even easier.



Also pull the metal fuel filler tube out of the tank while it is still in the truck, as it makes getting the tank down past the frame rail a lot easier. that is about all I can think of off the cuff.



Jason



Oh and have a can of primer/sealer for the frame rail, as it may be a bit rusty behind the tank.

 

[1stgen4evr]

inline fuel filter before the main filter.

I have seen some very sophisticated fuel filters on the bigger trucks. There are kits that you can install more filteration on your truck. Because of the trash coming from the tank, I would think it should be before the lift pump. That of course would mean that it would be underneath somewhere.



It would need to have a remote drain to be most effective. Small airplanes have such a system and there must be something like that. Had an International cotton picker that had a system like that. Maybe some other owner has such and can tell you where to find what you want.



One thing I know for sure is that you get dirty fuel from time to time. I was down to ten miles an hour on 70 between Kansas City and St Louis a few years ago. Pretty sure I got the crud from Flying J. I still fuel there and that has been the only time. Now I always carry an extra fuel filter for such occasions.



As to checking the fuel pressure, get a pm off to Dpucket. I bet a buck that he can tell you where to tap it in. I do not have one.



1stgen4evr

James

 

[John - K5AWO]

Fuel tank cleaning / sending unit rejuvenation:



About 3 weeks ago, my son PJ and I had to clean up the fuel tank on a 1985 Honda Goldwing. The bike had been setting on the kickstand for over 4 years. The reason it was parked was the owner couldn't keep it running. Wide open throttle, it would sputter, cough, etc...



After getting access to the tank (taking it off is a 7 hour job requiring removing the engine from the frame), we could see inside from the top, middle (filler neck) and rear (sending unit). This thing was full of rust. Obviously a lot of moisture over the years.



PJ bought a gallon of CLR cleaner at Lowe's. Hardware stores, etc... have it. (Phosphoric Acid). We first dumped the sending unit in a quart of the stuff. After about 30 minutes, it came out clean as a new nickel and worked perfectly. The rust was gone (after water flush) from the frame, and the varnish on the resistive coil contact surface disappeared. surfaces were bright as new. An ohm meter test proved it to be good as a new unit.



This will probably fix your sending unit tugboatphil. In our case, we needed to clean the tank. This we did by dumping the full gallon in the tank constantly stirring the stuff and splashing it up on the top and sides. We then used a small inline fuel pump purchased from the auto store with an inline pre-filter (Ford fuel injection type) and pumped the liquid out of the tank. That filter had to be back flushed several times.



Lots of water hose flushing followed. We used a wet-R-dry vacuum cleaner to pull the water from the tank by taping a 3/4" radiator hose to the nozzle of the vacuum hose. Worked like a champ. Repeated that process about 4 times, acid in, boiling the rust, inline pump that out back into the original container. Then the water flush process.



The vacuum hose did a wonderful job of drying the tank. Could have used the exhaust air too.



PJ and his wife rode that bike on a 3 day ride through the mountains of northern Arizona returning today. Not one minute of trouble from the bike.



Hope you fair as well.



Here is one link on the subject:

http://www.morrowmarsh.ca/concours/techpages/rustremoval.htm



PS: flushed the inline pump with oil after we were done...



John

 

[CGauthier]

I second the suggestion of a secondary fuel filter--before the lift pump. I always fill up at the same place, at an esso where alot of big trucks go and its cardlock. But, one time on my Ford 7. 3l I was stuck a little low in the winter so I figgured to put $40 in tha tank at shell for this ONE time I should be alright. I wasn't... there must have been water in there crystallizing, cause in my secondary fuel filter has a site glass at the bottom... and i could see ice particles floating around... this was after I was stranded on the road. I had a spare fuel filter, I changed it and i got where i had to go... but i ended up having to put some methyl hydrate in the tank to keep the flow going. Unbelievable, how can they sell that cr@p? But, what would have happened had i not had that 5 micron (very fine) fuel filter? I'd imagine I would have had to spend alot of $$.



Carl G