cummins 4bt in m715 is running!

[LAlessi]

thanks steve!

1-1-03

had a small wrench o-thon today. around noon we got started. we got the tank mounted straight, the fuel line 5/16,return line1/4, and power steering and hydroboost hooked up. we did not get the hydro assist steering hooked up yet, and there is no steering wheel.



i put the stock radiator back in and used www.coolflex.com for the hoses. i looped the heater hose since i dont have the A/C plumbed yet. i hooked the taurus ($25) 2 speed fan up and mounted it against the radiator. we put 5 gallons of diesel in the thing and tried to fire it up.



no go. the starter barely turned it over with one yellow optima. hook up 2 to give me twice the amps and it turned over LAZY.



hooked up three and still no dice. took the starter off and ran it off the truck. sounded bad, but it did slowly start to speed up. put it back on the truck, and it still wouldnt turn.



hooked up 24 volts LOL, and it was NO better!!!!



i says to me "me, the starter is bad so... ... ... " i hooked up 36 volts! now were cookin, it wants to fling the motor out the truck!!!!!!!!!!! no start for HOURS. we crack the injectors... . blah blah blah. no dice.



then we take the rotary pump fuel solenoid wires (some cold start crap) off and hot wire it. no dice. we have fuel at the injectors , but it wont run.



we put either in it and it turns over but wont run. we later realize we disconnected and gutted the wrong part (after finally looking at a manual)

we put the wrong part back together and can hear the solenoid click.



fire it on 36 volts and it STARTS RIGHT UP! man it sounded sweet! its not as rough or as loud as i thought it would be!



now the kicker. i let it idle 1 hour before it hit 195 with NO FAN. it hits 205 so i hit the fan (high speed on) and the guage drops to 175 in less than 1 minute! yikes, the fan is too much on high at idle. outside temp was 65degrees.



man i need to get it running on the road!

 

[Forrest Nearing]

congrats!! I bet the ole adrenaline was FLOWIN' when that baby finally fired up! Oo.

 

[banzaitoyota]

Congrats

 

[Sled Puller]

Whats an M715?

 

[LAlessi]

click here to see what an M715 is!

 

[jayhawktrailers.com]

congrats. Can I borow some of your luck. My 4b has a weirder problem than yours. it will start ( after much effort ) and run on 3 cylinders but when you tighten down the fourth injector line it will die, it will alos die when you rev it up. it has new injectors and i tried an old one but no change. Any suggestions before I spend alot of money, by taking the pump into a shop. BTW mine is going in a 36 IH .

 

[LAlessi]

do you have the manual for it? i have it in pdf. format

 

[daveshoe]

South bend Clutch sells the brake unit as a pair. Check his price Vs. Mother Mopar

 

[jayhawktrailers.com]

I don't have a manual but realy need one. the Cummins parts man told me that my engine numberwas not valid when I tried to order one. I'm pretty much computer illiterate. What would I need to do to get the pdf formated manual? My 4b has a rotary pump. does your manual cover that pump? I got mine as an alegend rebuild incuding the pump was rebuilt and new injectors. thank you for the reply

 

[bmoeller]

stude- Is your 4B a Cummins or Case version? If Cummins said it was invalid, I would go to a Case dealer. They used them in some their equipment like backhoes and skid-steer loaders.



How is the fuel pressure?

 

[jayhawktrailers.com]

thanks for the tip, my 4b is a cummins, it came out of a step van, that appeared to be a 350 repower. The adapter let it mate right to a SM465. I then bought an adapter and it mated right up to an atlas II transfercase. Should be a great setup for my rock crawler.

 

[jayhawktrailers.com]

Fuel pressure seems great on the three cylinders that run, but not as well on the fourth injector. The fourth has decent voume of fuel but no real pressure. I still suspect the pump. Got frustrated and pulled the pump off the builder 4bt I have. It's going on today hope this does it. So I can get on with my other bugs in this truck.

 

[jayhawktrailers.com]

got the other pump on. It will now run on all four cylinders, but it will still die when you rev it up past idle. I have loosened every different connection in the return line, Jumped a hot wire down to the KSB valve that advances the timing. Always the same. does this give anyone a clue to my problem

 

[HoleshotHolset]

Sounds like a fuel delivery problem (before the injection pump)...



Have you checked the input fuel pressure at the injection pump?



Matt

 

[Steve Graham]

What about a fuel return problem from the injectors? If there is a pressure build up in the return line could this cause a problem?



Steve

 

[jayhawktrailers.com]

Thanks for the reply. After swapping injection pumps from the builder motor, it starts pretty good and will run on all four, but will die when you rev it up. I have cracked open the return line at every injector and at the back of the pump, I even have it running into a bucket to eliminate possible restriction at the tank. I have bypassed the mechanical fuel pump with an electric fuel pump which is almost new, by putting the hose onto the line that supplies the filter. Filter is a new fleetguard. Could it be that the electric pump doesn't have as much pressure as the mechanical is supposed to. This would explain alot. I think I'll go buy a new mechanical pump. It may be that simple. The motors have sat around for quite awhile. I'll kepp you guys posted if I make any headway.

 

[jayhawktrailers.com]

I got to thinking that maybe you guys could be right about the lift pump, so I bought one and stuck it on. It fired right up and ran for awhile then it died . I'm thinking it ran the filter out of fuel. I bled the lines again and it started , then died again. Now it won't start at all. It will act like its trying to start and then I crack one injector at a time trying to get all the air out. fter all that it act like it won't even try. My next thought is that the fuel shut off selinoid may be sticking. I took it out and tested it with a battery, seems ok. I decide to try it without the spring and plunger in the selinoid. I bleed the lines again. Nothing. any idea what to try next?

 

[Steve Graham]

Your engine is acting just like mine did when I had the injectors rebuild. I would bet you have air in the pump/lines or your sucking air from one or more of the fittings. It took me three days of bleeding the lines before I got the thing to run. Theres no easy way to describe the sequence of getting the air out, just work at it one injector at a time, two injectors at a time or bleed all 4 injectors at a time, it will eventually will fire on all four.



Steve

 

[JBurghard]

I'm looking at picking up a 68 M715 and was wondering how hard it would be to put a 5. 9 12v Cummins into it...



Thanks



James

 

[LAlessi]

3 inch body lift on the cab..... is how one guy did it. no aftercooler



if you run a mated auto with a lokar shifter it should work. i have just enough room to run a thin elec fan with a 4bt, and have the nv4500 shifter exit the cab in the correct location.



so far im happy with my 4bt.....



i also didnt want to hack the grill or radiator mounts up to put a 6bt.

the 4bt is the same weight of a stock 230 tornado motor, just better performance



i have 4 or so inches to the firewall with the 4bt, but remember, that will put the shifter that far back too