How much cranking is necessary for starting?

[oifvet]

My 1971 M35A2 w/ Hercules multi-fuel seems to take more cranking than I think it should.
I'm on the starter button at least 15-20 seconds in two attempts usually before it fires. This occurs after setting for the better part of a day or longer. Not a problem if I go to re-start after fueling or a quick pit-stop. The truck runs great once it's up. Idles fine, everything. NOW, just yesterday, it started quick! Two-second crank! The only thing that is different is that I had just topped the tank off the day before. I don't know what difference that would make, but all other times, CRANK! There has never been less than 1/4 tank of fuel during my ownership. Another issue I've seen occur is suddenly dropping from 60 mph to 48 mph and no power This happens after about 100+ miles of steady driving or 2 hours, whichever comes first. Pull over and take a short break, and I'm back to full power for the same range. I have yet to change fuel filters if that is an issue. Also, is there a small filter for the "cold start" on this engine? One about the size of one of those "cute" (as my wife calls them), 7 oz. soda cans you see now days? I see one on the left (drivers) side of the engine. I was told that is a fuel filter for "cold start." ????? I don't want to suck battery life and/or burn up a starter. Thanks!

 

[mangus580]

RE: how much cranking is necessary for staring?

Your in-tank pump is dead. This is exactly what mine does. Been like that for some time now too.

 

[oifvet]

O.K., but let me add this... When the truck was idling once, I opened the fuel cap , pulled the strainer and could see the fuel "churning." I'd say the tank was about 1/4 full (3/4 empty for the pesimists). Would the in-tank pump be causing that?

 

[jasonjc]

RE: how much cranking is necessary for staring?

I would check/change all 3 fuel filters and check for leaks. You could have an air leak and be loseing the prime. Also check the in tank pump. My pump has not work in the 2 year that I've had the truck but it fires right up. 1-5 sec at most on the starter. And yes there is a cold start filter on the top or left side of the eng. It is for the manifold flame heater.

 

[oifvet]

Roger! Good copy! I had planned to do the fuel filter change in the next week. I'll do the leak check as well. Now, about this in-tank pump... Is that an easy part to get/replace? Where is a good source to get a new one? Can it be re-built? Is this an item that fails often? And could it be as simple as an electrical connection to that pump?
Over.

 

[mangus580]

O.K., but let me add this... When the truck was idling once, I opened the fuel cap , pulled the strainer and could see the fuel "churning." I'd say the tank was about 1/4 full (3/4 empty for the pesimists). Would the in-tank pump be causing that?

This could be caused just by fuel circulation.


I have done all my filters twice now, and it still bleeds down.


As far as fixing the pump.... the usual cause, is a bad fuse under the cover. Check that out first.

 

[jimk]

RE: how much cranking is necessary for staring?

Inspect the fuel in the filters. If it is black it is contaminated. Look for water, too. JimK

 

[oifvet]

Wilco! Tango Yankee! I was also advised that the primary fuel filter is/was often neglected at some locations and that they can be prety nasty. I'm looking forward to the fuel filter change-out and tightening a few things up. I'll check the fuse and all. Sounds like it might not be too hard. Really, this has been my only frustration. My deuce was a G-L purchase. I know many have had bad experiences there, but this was my first truck and my first truck through them. I picked it up in VT and drove it back to OH with no problems other than the intermittent power loss. On a happiness scale of 1-10, I'm at a 9. After some minor cosmetics and fresh paint, I feel a 10 coming on!!

 

[houdel]

You should be able to hear the in tank pump run if it is working. I can hear mine in the cab with the engine off (and air buzzer off, of course). Next run, after you shut the engine off but with the accessory switch on, go to the fuel tank and listen for the pump. It makes a noticeable hum. Of course, the motor could be running but the bottom fell off the pump (a common problem). If the pump hums, take a container and crack the drain valve on the primary fuel filter, fuel should gush out. No hum at the pump, either a bad fuse or shot pump motor. Hum from the pump but only a dribble of fuel from the primary fuel filter drain, time to repair the pump. Plenty of fuel from the primary fuel filter drain, your pump is OK, time to search for an air leak.

 

[nf6x]

My first shop van would bleed down if it hadn't run for a while. It would take a similar amount of cranking after sitting for a day or more. One thing that helped a bit was to wait 30 seconds or so between turning on the master switch and hitting the starter button, so the in-tank pump could push out some of the air.

My second shop van would start in less than one engine rev, every time, even after sitting for months! So, that's how good it can be when everything is in top shape. The only fail-to-starts were from a slightly sticky bendix gear that would occasionally fail to engage the ring gear, and once the batteries went dead after a very long sit. The engine would always start almost instantly once it turned, though.

So, I'd see if the in-tank pump is running (as mentioned, you should be able to hear it with the master switch on and the low air buzzer unplugged), replace the three fuel filters and all associated seals and clean their sealing surfaces well. If it still takes significantly longer to start after sitting for a while (particularly if running the in-tank pump for a while before starting helps), then continue looking for a tiny leak somewhere!

 

[acetomatoco]

The drain back is typically in the see thru return lines on the injectors unless someone has painted them OD... you shut everything off and watch the bubbles form inside the return lines...then you tighten the fittings or look for abrasion on them... usually nothing comes out the primary drain cuz it is clogged with crud... the place to check for volume and pressure is the vent over the secondary and final...should spout like a baby boy laying on his back just as you are changing the diaper....

 

[oifvet]

O.K., the fuse is open. It was pretty dirty under that cover. A little rust and some moisture. I'm hoping that was what contributed to the fuse blowing. I'm off to get a replacement. The fuse that was in there is (white ceramic, not clear glass), rated 250V, 20A, #314. Again, hoping that is what belongs in there and not just a slop job from someone before. Any problem with putting a jumper lead across the fuse holder for a few seconds to see if the pump runs? What is the mechanism of that pump? Do they seize easily? I'm thinking that if it's stuck a little and just needs a bump, the fuse may pop again.

 

[jasonjc]

I think its take a 2A or 5A not 20A. The thinking that if the fusse blows put in a bigger one untill you find one that does not blow. Is common BUT NOT RIGHT. If the fusse is too big it will not blow but some thing else will. The in tank fuel pump is not cheap.

 

[CanonNinja]

I can say when I had my in-tank pump fuse blown, my truck still started fine, after about 5-6 seconds at most... it wasnt until I went to change my filters that I found out I had a blown fuse.... I'd do what the others here say and check/replace your filters.


And last I remember, when I swapped my fuse, I replaced it with a 5A

 

[houdel]

Depending on which TM you read, the in-tank fuse is specified as either 2 amps or 3 amps. I couldn't find 3 amp fuses so I used a 4 amp fuse. 20 amps is way too much, you run the risk of damaging your pump motor using a 20 amp fuse.

 

[67Cougar]

My Deuce is a little funny, if I just push on the accelerator pedal it fires almost instantly, but if I don't touch it, she will crank for some time. Don't have to move it much, just a little, and instant life every time.

 

[houdel]

My Deuce is a little funny, if I just push on the accelerator pedal it fires almost instantly, but if I don't touch it, she will crank for some time. Don't have to move it much, just a little, and instant life every time.

Try increasing your fuel delivery adjustment a bit. When I first got my deuce, it would not start unless I held the accelerator pedal to the floor. I cranked up the fuel delivery about 1/2 turn (3 flat on the adjusting nut) now it starts immediately with my foot off the accelerator pedal, driveability is also much improved. Do NOT go more than 1/2 turn unless you have a pyrometer installed, increasing fuel delivery increases turbo boost but also increases exhaust gas temperature (EGT). If the EGT gets too high, >1250F, you run the risk of damaging/melting your turbo.

See http://www.steelsoldiers.com/index.php?name=PNphpBB2&file=viewtopic&t=6629

You have to remove the safety wire and cover over the fuel adjustment screw (see my photo in the first posting) then adjust the delivery screw at the very bottom of the FDC (shown in Fig. 199 as posted by cranetruck)

 

[CCATLETT1984]

I'd be more worried about melting a piston top, before doing any damage to the turbo itself. the turbo can stand temps much higher than the rest of the engine components can.

 

[oifvet]

Well, the 5 amp fuse blew. I got all 10 screws to back out w/o rounding out. As soon as I know it's not going to rain, I'll pull the pump and take a look at it. Before I do, one question. Does the in-tank pump run continuously? ...or is it pressure regulated some how so it shuts off when it doesn't need to "push" fuel? I'm not hearing it run with the fused block jumpered. Lately (with the tank topped off), a two-second crank is about all it takes. I'm thinking the lines are staying full and primed, or at least the mechanical pump isn't having to lift much. (Filling it up the other day didn't help me in the trouble-shooting of this little matter). But anyway, I put a little higher current rated fuse in for now. If the TM says 5A, then O.K., but a motor, especially a pump motor that has a little work to do, I would think is going to draw a lot more current than that, especially at start-up (surge). If I can't do anything to repair this pump, I'll probably put a new one in. I know they're big money, but I won't consider it a waste. I've wasted money before, and it wasn't on anything this worth-while.

 

[mangus580]

Its supposed to be a 'slow blow' fuse. IIRC Kenny says its a 2.5 amp? Be careful putting a large fuse in, as you could melt down a wire...