Discussion
Syncrometer to balance the throttles first. Do them in banks of three ie 1-3 & 4-6. I set to 6kg/hr air flow.
Set the idle last then use the software to re-set the throttle position and adaptive maps.
Oh and don't wind the grub screws all the way out because when you drop 'em they are a b
h to find.
Shep
Set the idle last then use the software to re-set the throttle position and adaptive maps.
Oh and don't wind the grub screws all the way out because when you drop 'em they are a b
h to find.Shep
Edited by shep1001 on Sunday 14th August 00:21
This started when you changed the clevis pin on the throttle assembly didn't it?
Sounds like the throttles (although balanced) are simply too far open for the ECU to correctly fuel at idle.
You need to shut the throttles down with the idle screw, then reset the pots.
If you have the software running as you're adjusting, you'll see that the lambdas start switching correctly at the correct opening, and the engine note will change and start idling much more smoothly.
Once roughly set, you can fine tune each body with the synchrometer, and reset the throttle pots to save the settings once done.
Sounds like the throttles (although balanced) are simply too far open for the ECU to correctly fuel at idle.
You need to shut the throttles down with the idle screw, then reset the pots.
If you have the software running as you're adjusting, you'll see that the lambdas start switching correctly at the correct opening, and the engine note will change and start idling much more smoothly.
Once roughly set, you can fine tune each body with the synchrometer, and reset the throttle pots to save the settings once done.
The most reliable way (IMO) is to adjust the throttle stop (outwards) until all the butterflies are really shut, then loosen off the balance screws so that all the butterflies are 100% shut (push them with your finger). Now (engine off) starting with the throttle stop adjust until the #3 butterfly *just* moves off of shut (tiny amount, perhaps 0.5 to 1thou feeler guage past butterfly...just!). Now adjust each balance screw working outwards to just take out any mechanical slack. When you just touch the throttle actuator all butterflies should begin to move almost without any slack/delay. Its a very fine judgement.
The engine should run in this state albeit with about the lowest air flow (6 ish perhaps).
Now run the engine, reset the pots in the s/w asap and then use the synchrometer and throttle stop screw to get 8 to 9 ish flow on #3. Reset again. Now adjust outwards from #3 using balance screws, get about 8ish on each one, reset after each adjustment and then do next one further out. You can reset the adaptives to if you like but it takes a little while for those to settle so not critical.
Work back along all 6 and recheck all flows. It can take some to-and-fro to get a proper balance. Also recheck as it warms up. It all changes like the weather.
You are far better off keeping the throttles more closed that more open. Expect to get very hot CATs if you go too far open, and lots of pops and flashes in the bodies. Too lean is bad.
Remember there is no idle screw as such, the engine idles at its natural rate for the ECU timing advance etc as set by the pots and this resets to 15% when you start the engine (so dont push the throttle while twisting the key!). The pots are the weakest part of the system really . There is some mechanical slack in them, so you can find they dont start to change evenly bank-to-bank. That can cause a nasty hesitation on light throttle...revs actually drop if the pots lag each other by 2-3% reading. And i've found that changes too depending on engine bay temp, driving style (i.e. after mway cruising it seems worse than hooning)
hth
The engine should run in this state albeit with about the lowest air flow (6 ish perhaps).
Now run the engine, reset the pots in the s/w asap and then use the synchrometer and throttle stop screw to get 8 to 9 ish flow on #3. Reset again. Now adjust outwards from #3 using balance screws, get about 8ish on each one, reset after each adjustment and then do next one further out. You can reset the adaptives to if you like but it takes a little while for those to settle so not critical.
Work back along all 6 and recheck all flows. It can take some to-and-fro to get a proper balance. Also recheck as it warms up. It all changes like the weather.
You are far better off keeping the throttles more closed that more open. Expect to get very hot CATs if you go too far open, and lots of pops and flashes in the bodies. Too lean is bad.
Remember there is no idle screw as such, the engine idles at its natural rate for the ECU timing advance etc as set by the pots and this resets to 15% when you start the engine (so dont push the throttle while twisting the key!). The pots are the weakest part of the system really . There is some mechanical slack in them, so you can find they dont start to change evenly bank-to-bank. That can cause a nasty hesitation on light throttle...revs actually drop if the pots lag each other by 2-3% reading. And i've found that changes too depending on engine bay temp, driving style (i.e. after mway cruising it seems worse than hooning)
hth
spercy said:
Mine struggles on tick over when cold, and only 750-800 revs when warm. Was looking at doing this myself, but afet this thread i'll just ask Str8six to do it for me at the next service
It isn't that bad really! The oil pressure will be very low so my advice would be sooner rather than later. It is a bit fiddly though and sometimes you make it worse than better. The slack in the pots is PIA, and the adjustment isn't the most user friendly either.Thanks Pete, did it yesterday no problem, just needed a clear head.
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