There has been some interesting discussions about the Bosch pumps recently and it seems a few have taken them apart and rebuilt them, probably with a much better understanding of how they work and (certainly in my case) that knowledge helps eliminate fear of the unknown, especially when things aren't going quite right!
So, I wanted to share a couple of minor problems I have experienced in putting a 1.9td pump on my 1.7td. I have a few hunches about solutions, but thought I'd discuss them here first...
The reason I've put a 1.9td pump on the 1,7td is not necessarily more power, but more torque. The 1.9 injectors lift at 170 bar, whereas 1.7 injectors lift at 130 bar. So I figured better atomisation, better burning, better economy and more torque.
Certainly torque is up and economy, by 5mpg without trying! But......
She's a little smokey. I have moved the max fuelling screw back a bit, but the majority of the overfuelling (black smoke) occurs when accelerating on low revs (i.e. before any turbo pressure kicks in).
I can only think of the governor spring assembly having different ratings (so more or less sensitive acting against the governor weights) or the governor shaft preset screw (above and in line with the pump drive shaft) or even different governor weights themselves. Any thoughts?
My other query relates to the injectors. I disassembled them to have a clean up but they were spotless inside. I did all four and put them back on the car. One 'appeared' to be leaking so I whipped it off and tightened it up a nudge.
This got me thinking that not only have I done this injector up more tightly than the others, but the likelihood is they are all tightened to varying torque settings. I didn't use a torque wrench, but then what is the correct torque setting? Additionally, don't injectors need re-calibrating after so many thousand miles? Do they simply re-tighten the injectors or are the springs replaced? Would an extra lb ft of torque of tightening the injectors equate to a 'calibration' or even better result in a slightly higher lifting pressure?
Sorry for the long winded post and million questions!
Bosch VE 1.9td pump on 1.7td
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Geoff Lebowski
- Posts: 114
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Black smoke off boost is normaly to much base fuel.
Try backing it off a bit more and see what it dose.
I know people have used the 1.9 XUD9 pump on a 1.8 XUD7 (sometimes known as 1.7) without changing setings so it may not work but it's quicker and cheaper than messing with injecors, just make a note of the present setting.
Try backing it off a bit more and see what it dose.
I know people have used the 1.9 XUD9 pump on a 1.8 XUD7 (sometimes known as 1.7) without changing setings so it may not work but it's quicker and cheaper than messing with injecors, just make a note of the present setting.
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99 C250TD sport estate
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MikeT
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Hi Geoff, I applaud your efforts and you're right things can go wrong if you don't fully understand how they work but taking risks can be very rewarding as you've discovered on the power and economy front.
I'm not sure but I believe you change the spring tension (therefore the break pressure) the injector will break at when you alter the torque between the nozzle holder and the injector body. What you will need is a pop tester to reset them properly. It's the shims that give the adjustment required, not the springs.
But I do believe that tuning starts at the injectors and without a clean spray pattern and proper break pressure, there's no point making other fuelling adjustments.
Additionally, the nozzles are designed such that they function as intended at the correct pressure. You may have inadvertantly altered the timing, the delivery rate and more. I would be more inclined to fit 1.9TD injectors as they are designed to work at 175-180Bar.
Having said that, regards the soot, have you tried adjusting anticlockwise the "smoke screw"? It's the adjuster found on top of the LDA. I wouldn't advise you alter the governor settings at this point.
I'm not sure but I believe you change the spring tension (therefore the break pressure) the injector will break at when you alter the torque between the nozzle holder and the injector body. What you will need is a pop tester to reset them properly. It's the shims that give the adjustment required, not the springs.
But I do believe that tuning starts at the injectors and without a clean spray pattern and proper break pressure, there's no point making other fuelling adjustments.
Additionally, the nozzles are designed such that they function as intended at the correct pressure. You may have inadvertantly altered the timing, the delivery rate and more. I would be more inclined to fit 1.9TD injectors as they are designed to work at 175-180Bar.
Having said that, regards the soot, have you tried adjusting anticlockwise the "smoke screw"? It's the adjuster found on top of the LDA. I wouldn't advise you alter the governor settings at this point.