Bench testing a Diesel injector pump

mrfxit, Nov 12, 8:54pm
Mechanical pump/ early Surf

Whats the average price to get an injector pump bench tested & re-calibrated,.
Got a spare low-ish km'spump here but not wanting to put it on without knowing more about it.
Who's reliable & at a reasonable price (north island/ Hamilton)
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Oh yea & do you know if theres any mechanical difference between non turbo & turbo injector pumps.

intrade, Nov 12, 9:02pm
they want about 380$ but the job is only taking about 1h .
I had one done in the early 90s by a old german guy for 180 german mark and german mark was about the same what nz$ are . They usually try to tell you they need to strip it down first and alsorts like they tryed to tell me in switzerland and it be 1000$ + . i said i had it apart and just need it timed correct.the german guy just done what i wanted and it was fine .
There is a guy Akfuel he sounds like he knows about diesel.

intrade, Nov 12, 9:08pm

trader_84, Nov 12, 9:30pm
Yep agree. They will try the 1k thing on ya as soon as you walk in. Mrfixit . is this on a 2L series! I'm interested in this sorta stuff also. Your mission is to determine 1. What the task involves and 2, See if what a pro diesel shop does can be replicated in a shed with a 'work around' or two. See - I know squat about them other than have been fed the line about it costing over 1K before . and have settled on buying a good running one instead of paying a shop to fix the leaky/faulty one. How hard can it be or is it truely rocket science!

mrfxit, Nov 12, 10:05pm
Yea 2l-t 88 2.4 mechanical pump.

Yea interesting stuff all right. 1st diesel EVER & still loving most of it.
3 years now but at this age (Me & the 88 Surf) we both need a fair dose of TLC to keep us going.
Pumps been leaking for 2 years now but not badly, a hose wash cleans it up ok for a new wof each time but it's more of a concern about the inside pump wear/ pressures etc.
Hence getting a spare pump last month thats spose to only have 160k's on it.
But you know how it is, it's a lot of time to swap them over so want to make sure the pump won't be an issue (just me)

mechnificent, Nov 12, 10:34pm
They are a piece of cake to strip and reseal. There are articles online explaining it all but you shouldn'tneed that if you are a careful worker and lay it all out on a bench carefully.

There is one special tool, a three sided socket, which you can make by carefully filing a single hex socket to suit. You just have to file/dremmel a bit off three of the flats so they clear the rounded parts of the three sided bolt head.

There is no setting up to be done if you put it all back together just as it came apart. They don't have to be calibrated and balanced like old inline pumps.

My son was doing them for the boss where he works when he was still in his apprenticeship, cause he'd done them on his own vehicles.

intrade, Nov 13, 3:02am
not quite if its absolut fully stripped then you got to get it set and checked on that machine.
https://www.youtube.com/watch!v=2haN3XkTxz8

mechnificent, Nov 13, 3:17am
No you don't Intrade.
In the old days you had to calibrate each plunger to be the same as the others. that isn't necessary any more.
The only useful job that tester does these days is check for leaks, and, I have not ever had one leak after I've had it to bits.

Once it's back together, if there is a faulty delivery valve, or the revs are a bit out at full revs, or idle, or the amount of fuel being delivered is too high or too low, you can fix or adjust it from the outside with it fitted to the vehicle.

chebry, Nov 13, 4:17am
Google can help you Ive seen a step by step for a 2l pump while I was searching 2C pump info that one was easy as half an hour and ready to go back on

trader_84, Nov 13, 6:29am
Yeah . a couple of quid short of $750. They'd find some reason why they had to up their estimate to close on a grand and still come out looking like good pricks to you. You are onto it Mrfixit . you'd have more nous than most on here. Have a look at some of the articles . check out the cost of the seals and have a go yourself! It sounds like there are posters around that are reasonably familiar with stuff. Good luck!

trader_84, Nov 13, 6:34am
When they say 'bench run' . what does that mean exactly! Is it the same concept of bleeding/purging a M/Cylinder prior to installation!

mechnificent, Nov 13, 7:45am
All they check on the test bed these days is that none of the seals are leaking after they have worked on the pump. In theory you could test that just by pumping diesel in under about forty pounds of pressure, without even spinning the pump.
I have done dozens of pumps though, stripped right down to the tiniest part, and have never had a leak. I've fixed heaps of leaks in place on the vehicle too. About the only thing that gives trouble is the cold start idle-up on the side, the big spring causes the spindle to wear the housing. The housings are seven hundred dollars, and since we don't need the idle up, most diesel specialists say to discard the whole housing and all and fit a blanking plate off a different model pump. I've done that and you can't tell the difference if you put your foot on the throttle to start them.
Most of the seals are common O rings or copper washers, the only tricky one is for the top cover and that is about thirty dollars.
In the old days of inline pumps you had to use the test bed to set the governor and adjust each individual plunger so they all pumped the correct amount of fuel and exactly the same amount as every other plunger. Now one plunger does all the cylinders, and all the adjustments are external. If you take them apart carefully, and note how many turns you wind out the adjusting screws, you will have no trouble.

mrfxit, Nov 13, 7:50am
"bench run" = tested on a bench mounted pressure tester & fully plumbed in
They don't temperature test the choke/thermostat system but instead bypass it & have a set of spec's to guide them as to how it should react when off & on.

Personally I would set it up with a small heated radiator system to get the full picture (couldn't be that hard would it.).

mrfxit, Nov 13, 7:52am
Would that also apply to the 2L-T mechanical pump.

Garage that did the injectors has offered to bench test my spare pump for $120.

mechnificent, Nov 13, 7:59am
The temp sensor is only for a faster idle at start, as soon as it's started, that system does nothing. The temp sensor only decides whether it should use the idle up or not. It doesn't enrichen the fuel, it just runs the fuel pressure a bit higher which advances the timing. as soon as the motor runs, the timing is advanced anyway and the cold start is doing nothing.

They don't pressurise the pumps, the pumps pressurise themselves when they spin. If you wanted to pressure test it before refitting, you could block off the return and feed pressurised diesel into the pump.

mechnificent, Nov 13, 8:14am
Yes, the turbos have some extra adjustments but if you take note of where the diaphragm on top is facing in a rotational sense as you take it apart, then no problems. The diaphragm can be rotated. as you rotate it, it moves an oval stopper that sets the maximum fuel flow when there is boost. The adjustment can be done as a hot-up/tune-up at any time, as can the normal/ non-turbo fuel stop setting.

On some models, under the diaphragm there is also a star shaped wheel which adjusts the spring pressure against the diaphragm. you need to take note of the star wheels adjustment if you take that apart, but it can be left alone.If you want to adjust the star wheel you pull out a bolt at the back and lever the wheel around with a screwdriver. that setting affects how it runs at part throttle with boost. The diaphragm adjustment affects how it runs at full throttle under boost. There is a screw and locknut at the back of the pump, that affects how it runs at full throttle without boost. Of the three adjustments, only the bolt and locknut one is critical, an eighth of a turn makes a big difference to that one. In makes more power, and smoke, and out does the opposite.