Does anyone know the fuel pressure spec on this machine? I suspect i have a bad lift pump. Im getting 5 lbs FP but i cant find anywhere what the spec is.
5 psi is correct..
Ok so I have 5psi, a freshly rebuilt injection pump. But this motor is extremely sluggish and weak. It takes almost 5 seconds to rev up to peak rpm. As soon as you go to move the sticks it acts like the flywheel is the only thing pushing it. You can easily stall it out yet it doesn't blow any smoke at all. I'm stumped.
Does the fuel pressure drop under a load? Check the turbo? If it's not getting boost the pump won't fuel up.
No smoke.?? I was leaning towards timing.. but it would white smoke.. usually.. You could hook up an air tank and regulator and feed about 17 psi to the aneroid on top of the pump to see if its a boost problem.. Did the problem start when you changed the inj. pump.??
The problem existed when I bought the machine. I had the pump rebuilt because I thought that was the problem. It acts the same now as it did before. I will try hooking up a regulator.
Is it reasonably possible that the spring or linkage between the governor and the metering valve(or what is in this pump that actually controls injection volume) is broken or disconnected? That's the only thing I can think of that would cause it to run like this and blow no smoke at all, even when stalled out. I haven't checked the afc with compressed air yet for several reasons but I will shortly.
Does a spring belong there?
Some do and some don't.. if it did and it fell, it should be right there.. It cant fall out when assembled.. so no, it probably doesn't have one..
I SURE HOPE you marked the throttle lever BEFORE you removed it from the shaft..
Ok. I'm stumped. Putting air to the afc did nothing, adding a spring there did not give it any power. Is it not standard practice to bench flow a pump when it is rebuilt? It starts and runs fine just has less power than it normally would at idle. What else can I do?
I remembered that as soon as I took it off. I got it back right now.... I think
A "rebuilt pump" is bench tested, calibrated, 100% of the x, in my world.. Especially THAT PUMP.. and depending on where you got the rebuilt pump, it may or may not be calibrated correctly.. OR you may be chasing ghosts and the pump isn't the problem at all.. Heres a little test you can do as long as the top cover is off.. Look at the under-side of the cover.. where the spring hooks up.. You see the small pin behind the swivel bracket, for the boost diaphragm.?? THAT PIN WILL get stuck in the "no boost" position.. Push IN on the bracket and at the same time, put air to the boost hole on the cover.. IF the pin is FREE.. it will move the bracket with you finger holding it in.. let off on the air and the pin should go back in its hole with a little pressure from your finger.. IF its stuck, it wont do anything.. THAT WOULD explain the low power and no smoke..
i took the cover back off and the pin you mentioned seemed to be stuck as you said, i pulled the diaphragm off and tried working it back and forth with a pick. it didnt really loosen up. putting air too it only barely moved it (~1/16 at the foot of the bracket)after playing with it.. i got in touch with the company that rebuilt it and was told that it was certainly benched and tested to bosch spec. I reinstalled the pump and i have more power now. Instead of approximately 20 hp i had before i have close to 40 hp now. But thats still not the 78 im supposed to have. I have 3-4 psi of boost at WOT with no load. Im still trying to eliminate boost issues causing my problem. I still think that the stiffness in the pin that rides on the diaphragm shaft is my problem.
YUP.. more than likely its the pin, stuck in the no-boost position.. Did you notice on the leg/shaft of the diaphragm, where the pin rides.. a wear mark?? The diaphragm MUST go back in the same position..
It still wont act any different. I took the pump back to the pump shop and they ran it on the pump stand again and the tech said that everything was right. I then took the injectors and had them pop checked and they are ok. (250 bar) It has a new lift pump. I have bottle fed it out of a jug, and i have ran it with 17 psi or air to the boost reference. It does run up close to full rpms, but its so week it boggs even just putting the boom DOWN. I have no clue what else to check.
Im at a complete loss. What else can i do?
Im about to go buy a new injection pump. I dont know how they could have put it on the stand and it still be wrong but i think it has to be.
I suggest you send THAT pump out for a second opinion, it probably just needs a slightly more professional touch. Be sure you send it with the backstory though.
IF I was on my feet, I'd gladly have a look at it, but as luck would have it, I'm flat on my behind, stuck in a chair.. That pump is going to cost around 2k.. Might I suggest Diesel Equipment Co. in Greensboro.. for another calibration check.. They are a member of ADS and so is Greensboro/Atlanta.. SOOOOO, if anything is "wrong" w/ the pump that the previous shop "overlooked".. it will be an inter-office warranty.. and be billed to Atlanta..
Just an update. The machine is now running as good as can be. I changed the injectors and the problem vanished. I suspect that it had the WRONG injectors in it.
I guess its possible.. but the no smoke thing is alittle baffeling.. I've seen the holes equded and the holes get carboned up and that cuts the fuel delivery WAY WAY down.. that could explain it.. Just curious.. why didn't you START THERE..??
Trust me, im asking myself the same question. I just have never seen injector issues cause a loss of power without smoke. It cranked and idled so good just had no power. I did have the injectors pop tested and they popped off a touch low but nothing that would cause this kind of loss in power. I have not ran the tip numbers to see if they were the original injectors or not. I suspect that when i had them pop tested no attention was given to the spray pattern, and not all 6 holes were clear. They were not professionally tested. If i had started there it would have saved me several thousand dollars and an enormous headache.
I know what you mean.. Stuff like that has bitten the best of us atleast once.. Glad you got it straightened out..