Help Tuning a 2.5na - I dont mean power tuning!!!
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flat
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err its been over the course of about 8 months with a 5 month break due to a busted leg let me remember.
Ok
I did the pump body tweak thing to get it running right and smooth, but then it was quite smokey so if you look at the pump body from the timing case end, on the right hand side about half way down is the fuelling screw, it might be under a plastic cap, i fiddled with that a lot.
Pump body tweaking:
- set revs at around 600-800 ish
- with engine off slacken the fuel pipes at the pump (or they could fracture)
- mark the pump body relative to the timing case so you have a known setting to return to if you over do it.
- slacken off the pump body securing
- gently rotate the pump body 1 or 2 mm towards or away from the engine (this changes the fuel timing relative to the cylinder timing)
- retighten everything and start the engine, take it for a drive and listen for knocks under load. If it knocks you have gone to far so back off the rotation of the pump a bit. you will know if it is knocking, it will be clattery as hell.
repeat the above to get a good compromise between power/lack of knocking.
once you have 'narrowed' the pump adjustment down to a couple of millimetres you can tighten the fuel pumps and there is 'just enough' room to move the pump about 2mm either way. Be careful though it doesnt take much to damage the fuel pipes. I fopund i got more movement in them if i took off the supports temporarily.
My fuel timing seemed best when the pump was rotated towards the engine about 2mm.
At first i move it about 8mm and it was like a bag of nails
Mine was then quite smoky (black smoke so unburnt fuel) so i did this
Fuel supply adjustment (be careful with this its easy to cock it up)
on right hand side of the pump body looking from the timing cover end is a bolt with a locknut, it might be covered with a plastic anti-tamper cover.
Before you go any further measure accurately the distance of the bolt head from the fuel pump body so you can return to this setting if needed.
i then wound the screw out a few mm, test drove and looked at smoke (had someone following me), screwed it in, drove again etc and repeated till i had got it smoking as little as possible. To far either way causes over or under fuelling noticeable by a massive smoke screen or lack of power. this was the bit that toooks me ages and ages to get right, i think my screw ended up about 3mm screwed further in. Its a trial and error thing.
I did this whole process twice, narrowing it down more each time to the optimum setting. End result is engine is a bit quieter, better MPG and seems happier at faster speeds (lol)
Ed
Ok
I did the pump body tweak thing to get it running right and smooth, but then it was quite smokey so if you look at the pump body from the timing case end, on the right hand side about half way down is the fuelling screw, it might be under a plastic cap, i fiddled with that a lot.
Pump body tweaking:
- set revs at around 600-800 ish
- with engine off slacken the fuel pipes at the pump (or they could fracture)
- mark the pump body relative to the timing case so you have a known setting to return to if you over do it.
- slacken off the pump body securing
- gently rotate the pump body 1 or 2 mm towards or away from the engine (this changes the fuel timing relative to the cylinder timing)
- retighten everything and start the engine, take it for a drive and listen for knocks under load. If it knocks you have gone to far so back off the rotation of the pump a bit. you will know if it is knocking, it will be clattery as hell.
repeat the above to get a good compromise between power/lack of knocking.
once you have 'narrowed' the pump adjustment down to a couple of millimetres you can tighten the fuel pumps and there is 'just enough' room to move the pump about 2mm either way. Be careful though it doesnt take much to damage the fuel pipes. I fopund i got more movement in them if i took off the supports temporarily.
My fuel timing seemed best when the pump was rotated towards the engine about 2mm.
At first i move it about 8mm and it was like a bag of nails
Mine was then quite smoky (black smoke so unburnt fuel) so i did this
Fuel supply adjustment (be careful with this its easy to cock it up)
on right hand side of the pump body looking from the timing cover end is a bolt with a locknut, it might be covered with a plastic anti-tamper cover.
Before you go any further measure accurately the distance of the bolt head from the fuel pump body so you can return to this setting if needed.
i then wound the screw out a few mm, test drove and looked at smoke (had someone following me), screwed it in, drove again etc and repeated till i had got it smoking as little as possible. To far either way causes over or under fuelling noticeable by a massive smoke screen or lack of power. this was the bit that toooks me ages and ages to get right, i think my screw ended up about 3mm screwed further in. Its a trial and error thing.
I did this whole process twice, narrowing it down more each time to the optimum setting. End result is engine is a bit quieter, better MPG and seems happier at faster speeds (lol)
Ed
flat
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How DFNL did you manage to remember that lot??
Good job, well done!
I am a complete anal retentive when it comes to things like that, and as i only get landy tinkering time every couple of weeks, it sometimes is in bits for a while. I learnt from restoring VW's that taking photos and keeping a notebook is never a waste of time!!
Pump body tweaking:
- set revs at around 600-800 ish
- with engine off slacken the fuel pipes at the pump (or they could fracture)
- mark the pump body relative to the timing case so you have a known setting to return to if you over do it.
- slacken off the pump body securing
- gently rotate the pump body 1 or 2 mm towards or away from the engine (this changes the fuel timing relative to the cylinder timing)
- retighten everything and start the engine, take it for a drive and listen for knocks under load. If it knocks you have gone to far so back off the rotation of the pump a bit. you will know if it is knocking, it will be clattery as hell.
repeat the above to get a good compromise between power/lack of knocking.
once you have 'narrowed' the pump adjustment down to a couple of millimetres you can tighten the fuel pumps and there is 'just enough' room to move the pump about 2mm either way. Be careful though it doesnt take much to damage the fuel pipes. I fopund i got more movement in them if i took off the supports temporarily.
My fuel timing seemed best when the pump was rotated towards the engine about 2mm.
At first i move it about 8mm and it was like a bag of nails
Mine was then quite smoky (black smoke so unburnt fuel) so i did this
Ed
Did this to mine and it didn't make any difference, I moved the pump then timed it to 40mph then moved it again and timed it to 40mph. Did this several times and it didn't make any difference to the times. It did smoke a bit more or les depending on the position of the pump but even moving it a quarter of an inch didn't alter the up to 40mph time.
Don't know why so just set it so it sounded right and upped the fuel a bit
flat
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Yeah mine didn't make it accelerate quicker. It just made it a bit smoother and I gained about 10-15 mph in the top end
flat
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no worries, post back here if you need any more help. its a bit fiddly but was fine to do, just took a while to find the sweet spots
took it out laning today, some quite technical stuff, 65miles in total. Performed aswell off road as the TDi and V8 motors, its actually a lovely engine off road imo
flat
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Took it on a long run yesterday, 2 hours on the motorway. After all the work I am pleased to day it is now no longer borderline dangerous to drive on the motorway.
I was overtaking lorries. Used my garmin etrex to track speed and it will happily sit at 60-65mph now (it just takes an age to get there!).
Still gutless on hills but not as much as before, this engine is very sensitive to inappropriate gear selection - wrong one and your floundering at 30mph.
Very happy.
PAS kit all fitted now apart from the belt and the steering box
I was overtaking lorries. Used my garmin etrex to track speed and it will happily sit at 60-65mph now (it just takes an age to get there!).
Still gutless on hills but not as much as before, this engine is very sensitive to inappropriate gear selection - wrong one and your floundering at 30mph.
Very happy.
PAS kit all fitted now apart from the belt and the steering box
Taffy
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Mine is ffr (fitted for radio). The throttle it has two cables. One for the foot and the other is hand operated to increase revs to supply power for radios etc via the 24 volt generator I thought I has a strange one until I realised it was FFR etc.
FlyingPete
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I guess the process would be similar for a TD? There's the extra degree of freedom from the boost compensator, but I'd assume you'd adjust that last after the pump timing adjustment and max fuel. Don't want to blow it up so won't be fiddling with the wastegate...
