Small Block Mount Injection Pump General Questions

[Birken Vogt]

TPG I am sure you will be the one to respond to this but others may want to also....

I work on the full range of small Japanese diesels and they rarely have injection problems but they have me curious.

They all seem to have their own injection setups.

Isuzu likes to use individual pumps.

Mitsubishi, Kubota, and Perkins/Shibaura all seem to like some kind of inline pump but they all are shaped different from each other.

Are these just different mountings of the same thing? If they were all from Zexel for instance would they all have similar inner workings?

 

[thepumpguysc]

They all LOOK the same & same working principals.. But the parts are different in sizes & fuel displacement.
NOT ALL Zexel pumps are the same, not all Bosch pumps are the same, THATS WHY I insist on the #'s off the name plate..
I could set up 10 different Zexel pumps side by side & each 1 will have different internal parts BUT they ALL look the same..
As far as different manufactures go.. its whoever bid the contract the lowest & wanted to take the time to engineer the fuel system to meet the OEM's specs..
Another factor is territory/country of origin.. Japan uses Zexel, China uses Nippondenso, Yanmar uses Yanmar.. Germany uses Bosch.. they keep it, IN THEIR COUNTRY..
THEN the NAFTA crap started.. JD started using japanees/Yanmar.. God only knows what you'll find when you lift the lid on a Cummins, most of their engines have Bosch/German fuel systems on them..

 

[Birken Vogt]

So why do they sometimes use the simple block mounted pumps and sometimes use the A-pump? I am guessing the A-pump has the capability for more advanced features such as variable timing and turbo boost sensing?

 

[thepumpguysc]

Exactly.. when your putting around at 5 mph w/ a 25-35 hp machine theres not much need to control the
speed.. and the torque can be controlled by a single stop screw & spring.. & they put out very little fuel.
Then you get into the 150-200 hp range & the speed increases & the demand for a variable speed governor comes into play.. hence the A-pump w/ an RSV or RQV governor.. and the fuel increases by 10 X.
Where a single cylinder PFR pump will put out 12 cc of fuel.. an A pump will put out 120 cc of fuel.
So basically.. it boils down to HP > bigger pump.. and the need to control the speed of the machine> type of governor system..
An injector is an injector.. altho there are different types of nozzles/tips depending on application..
Some have holes drilled into the end & varying #'s.. 2-6 holes in each one.. & some just have 1 large hole that sprays in a cone shape.. THATS WHY the #'s are SOOO important..
If I had a dollar for every time I found a machine w/ the wrong pump or injectors in it.. I'd be rich..
Hell, I'v gotten in a set of injectors w/ 5 of 1 tip & 1 of another.. THAT HAPPENS ALL THE TIME since the invention of the internet..
Someone diagnoses a skip on 1 cylinder.. buys an injector off the internet, not knowing there are 6 different tips that could go into that injector.. cuz it doesn't tell you that on the web page.. they put it in & still have a skip on that cylinder.. SOMETIMES they tear the engine down, don't get the injectors checked.. put the injectors BACK IN the engine & the skip has moved to another hole.. because they bought the wrong injector to start with..
THEN.. I get the call & their pissed.. after spending 2000.00 on an O/H they still have the same problem but it moved.. AND.. I NEVER get the full story behind it, so I have to work my ass off to find the problem. Only to find that a 65.00 injector would have fixed the whole thing.. Rant over [for now]

 

[Tinkerer]

thepumpguysc ;
Good grief Mike ! I'm thinking that your user name should have the replaced with Dr. Like a person would have after getting a doctorate degree from an advanced collage education. hence----> Dr.pumpguysc
Your knowledge of fuel injection systems appears to be endless !

 

[thepumpguysc]

ha ha ha.. I WAS offered a teaching position but turned it down.. I'm a "hands on" kinda guy..
I had several positions sitting behind a desk, but found myself staying after hrs building pumps or mopping the floor after the guys went home.. sometimes till midnite.. lol
After doing nothing but injection pump work for 35 years, you kinda pick things up.. lol
The industry is changing rapidly tho.. its all electronic & hi pressure systems now & they're JUNK. & you need a computer & 2000.00 worth of connectors to do ANYTHING..
I found out early this week that Bosch is pulling our certs.. in 2018.. BECAUSE we wont buy a 1/2 million dollar electronic injector tester.. WE HAVE 3 but they aren't BOSCH testers.. nice huh??

 

[Brodiesel]

Glad this was brought up, I was also curious about those Zexel pump cartridges and why you only see them on small engines, makes sense now, used for low HP ranges. I still don't quite understand the pump shims though, gasket kits will come with different colored or thickness shims, I figure it affects the pumping stroke of the plungers? I could never figure out which shim to use.

 

[Brodiesel]

thepumpguysc ;
Good grief Mike ! I'm thinking that your user name should have the replaced with Dr. Like a person would have after getting a doctorate degree from an advanced collage education. hence----> Dr.pumpguysc
Your knowledge of fuel injection systems appears to be endless !

If you put Dr. in front of your name then you also have to turn into a total A-hole like Dr. Diesel from Foley engines who hangs up on you usually within the first 30 seconds of your phone call.

 

[thepumpguysc]

Your correct Bro.. you raise or lower the pump, changing the effective stroke.. which inturn determines the "time" it takes to inject the fuel into the cylinder.. easy as that..
Each pump is set internally & has a spec.. then you take a depth mic & measure the pump cam lobe at the bottom of its stroke called "base circle" then at the top of the lob.. subtract the 2 and then subtract the pump timing spec.. that must meet the book spec.. if not you add or subtract shims under the inj. pump.
I have heard of the diesel dork.. I haven't had the pleasure myself.. I cant think of ANY situation where I would ever need his "experience"..

 

[Birken Vogt]

OK, I am starting to see the pattern here with your assistance. #1 now I know the name for these little things, they are PFR.

So it seems they are good for up to about 8 HP per cylinder? Then the A-pump takes over.

I have seen A-pumps on older engines that were at the small end of this range also, looks kind of ridiculous because the pump is half the size of the engine it is mounted to.

Now most of the PFR and A-pumps are Zexel but I saw one on a Mitsubishi that is Denso. Does that mean the Mitsubishi engine is made in China? It is a bare power unit engine built with a Chinese generator head by some hillbilly outfit so it would not surprise me.

 

[thepumpguysc]

Don't quote me on the HP ratings, that was just an example.. but you get it..
Mitsubishi is Japanese also.. I get confused with all the "overseas" stuff.. I forget weather Denso is Japanese or China..
Like I said before.. its whoever has the lowest bid on the product.. they don't care weather it black or white, just so long as it saves them money & they can make a profit.. and to be realalistic, they don't care weather it works or not..
Look at the God Almighty John Deere.. USA, USA, USA.. putting Japanese motors in their equipment.. they buy it for pennies on the dollar & if they have a problem w/ it, they send it back at a "slight" cost to the customer.. BECAUSE, they PAID FOR the warranty..
I'v typed this before.. A dealer brought in a brand new zero turn mower in the shop that wouldnt start.. the pump pumped, the timing was right, the injectors were at spec and pumped outside the engine.. but it didn't sound right.. it spun over TOOOO FAST.. not normal..
I did a compression test & it was Z E R O psi.. they forgot to put rings on the pistons..
IT came ALL THE WAY FROM JAPAN.. PASSED ALL the quality checks {yeah, right} Installed in a mower, left the factory here in the USA and was sitting at a dealers lot.. LOL

 

[Birken Vogt]

Great info. I saw pics of a Honda diesel today that had an instantly recognizable PFR pump on the block too...now it is all starting to make sense to me.

Now for a little side track...newer Yanmar built (and Isuzu rebadged Yanmars) 3 cylinder seem to have a quite different rotary injection pump mounted sideways in the block pointing mostly upwards. Also has a coolant hose running to it. What is the deal with those? I think you mentioned they are built by Yanmar in house? I don't think I have seen it on a different make. Also Yanmar used to use a PFR IIRC.

 

[thepumpguysc]

a little history lesson for ya.. BOSCH invented the diesel, so they say.... google it..
80% of the injection pumps are licensed thru Bosch.. Its THEIR design & they[Bosch} lets the other manufacturers put their spin on it.. The Denso pump is Bosch's, the Zexel pump is Bosch's..
IF you look very closely at the name tag on the pumps, it says, in small print Bosch.. I think yanmar bought the license outright, but its still Bosch's design..
When I look up parts for a Zexel pump, I can cross it to a Bosch # BUT.. Bosch wont sell it to me because of license agreements.. AND the Zexel part is CHEAPER than the Bosch part.. SAME FRIGGIN PART, SAME FRIGGIN MANUFACTURING PLANT.. its the difference between Japan & Germany.. and the almighty dollar..

 

[thepumpguysc]

That coolant hose, I'm guessing, is for a water temp switch for the timing.. Toyota used it for years & years in their diesels.. VERY GOOD design.. It has a "wax motor" that heats up when the coolant temp comes up & advances the timing once the engine it up to temp. Once the engine cools, say overnite, the wax hardens & it retards the timing for easy starts in the morning..

 

[thepumpguysc]

That Yanmar ROTARY IS JUNK w/ a capital "J".. OMG..
Its an INLINE pump w/ rotary internals.. Biggest POS to hit the market in 100 years..

 

[Birken Vogt]

This is the pump I am referring to...not sure whether you are saying it is good or bad in the last two posts? Have not seen another one on any other type of engine besides the Yanmar 3TNx or Isuzu 3CE1.

 

[thepumpguysc]

RUN, RUN AWAY FAST.. The slightest bit of water will shut it down & it costs BIG dollars to fix.
It LOOKS impressive tho doesn't it..??

 

[thepumpguysc]

THAT ONE.. is strictly a Yanmar design. I can hear Bosch laughing all the way from Germany.
Theres ONLY a few standards in life.. and THAT is a Frankenstien..
Theres an INLINE PUMP & a ROTARY PUMP and never the two shale meet.. until now..

 

[Birken Vogt]

Glad this was brought up, I was also curious about those Zexel pump cartridges and why you only see them on small engines, makes sense now, used for low HP ranges. I still don't quite understand the pump shims though, gasket kits will come with different colored or thickness shims, I figure it affects the pumping stroke of the plungers? I could never figure out which shim to use.

Per the service manuals I have read, you time them by using the "spill method" and selecting shims. Sounds like a messy and time consuming process.

 

[Birken Vogt]

If you put Dr. in front of your name then you also have to turn into a total A-hole like Dr. Diesel from Foley engines who hangs up on you usually within the first 30 seconds of your phone call.

I have wondered about them in case a Hoof belt drive governor ever needs repair/rebuild, now I think I know, found a different guy who charges about 25% what they do for the same service but I would also be strongly tempted to replace them with an electronic governor if this is the kind of service people get.