Definitive Set Up / Tuning Process
Discussion
It's obvious that many (including me) have come across specialists that haven't a clue how to correctly set the EFI/mixture on a flapper type FI system.
Having searched previous threads there doesn't seem to be any definitive process stated, just bits in each or fault finding info.
The purpose of this thread is to provide for prosperity (and for me for Tuesday
) a point by point list of how to approach a basic set up on any flapper controlled system.
If I can start it off and hopefully others add their expertise and adjust as neccessary. If being followed it should be assumed that unless mentioned specifically all other parts / functions are in good working order.
1. Check fuel pressure - should be stable and 38 psi above manifold pressure at any one time.
2. Set throttle butterfly gap (3 thou as a starter) using the throttle stop allen head bolt.
3. Set throttle position sensor so that voltage between red and green cables is 325 mv with ignition on and throttle butterfly at idle position (undo sensor and turn and retighten when correct voltage measured).
4. Check AFM spring tension - should be 99.5% open at full throttle - adjust by removing clamp and turning the black cog clockwise to increase tension.
5. Turn idle mixture air bypass screw on plenum 2.5 turns anti-clockwise from the fully closed position.
6. Assuming all other sensors are reading ok/ AAV closing ok when hot / overun valve seating ok and cold start injector switching off after 60 seconds or so with no air leaks on hoses and the timing /plugs etc all ok (all described in the bible/ fault finding info) then run engine until warm.
7. Set full throttle CO to around 6 - 7% using air bypass screw on AFM - clockwise to weaken.
8. Set idle CO using idle mixture air bypass screw on plenum until idle speed ok (750 - 900 rpm) or around 2.5%.
9. If idle speed unduly affected by alternator or PAS/AC load (drops and stalls) then set higher (1000 - 1300rpm, however many revs are needed to stop it stalling) using the throttle stop screw. Adjust throttle position sensor back to 325mv at idle.
10. Check idle CO again and adjust as neccessary using mixture air bypass screw on plenum.
Obviously the above is less than complete and quite possibly all wrong - the hope is that if so someone who really knows what they are on about can re-write it !
I for one am sick of paying exorbitant amounts of money to muppets who profess to know these engines and FI systems inside out yet I find out afterwards they are totally wrong in what they have said / tried to do. It needn't be this way - anyone with a CO meter and multimeter should be able to carry out a set up or fault find. Of course, if something is awry it may take a specialist to diagnose it and to get a proper set up it should be on the rollers with Mark Adams burning the EEPROM but if this is not possible then the DIY'ers need some better info.
Having searched previous threads there doesn't seem to be any definitive process stated, just bits in each or fault finding info.
The purpose of this thread is to provide for prosperity (and for me for Tuesday
) a point by point list of how to approach a basic set up on any flapper controlled system. If I can start it off and hopefully others add their expertise and adjust as neccessary. If being followed it should be assumed that unless mentioned specifically all other parts / functions are in good working order.
1. Check fuel pressure - should be stable and 38 psi above manifold pressure at any one time.
2. Set throttle butterfly gap (3 thou as a starter) using the throttle stop allen head bolt.
3. Set throttle position sensor so that voltage between red and green cables is 325 mv with ignition on and throttle butterfly at idle position (undo sensor and turn and retighten when correct voltage measured).
4. Check AFM spring tension - should be 99.5% open at full throttle - adjust by removing clamp and turning the black cog clockwise to increase tension.
5. Turn idle mixture air bypass screw on plenum 2.5 turns anti-clockwise from the fully closed position.
6. Assuming all other sensors are reading ok/ AAV closing ok when hot / overun valve seating ok and cold start injector switching off after 60 seconds or so with no air leaks on hoses and the timing /plugs etc all ok (all described in the bible/ fault finding info) then run engine until warm.
7. Set full throttle CO to around 6 - 7% using air bypass screw on AFM - clockwise to weaken.
8. Set idle CO using idle mixture air bypass screw on plenum until idle speed ok (750 - 900 rpm) or around 2.5%.
9. If idle speed unduly affected by alternator or PAS/AC load (drops and stalls) then set higher (1000 - 1300rpm, however many revs are needed to stop it stalling) using the throttle stop screw. Adjust throttle position sensor back to 325mv at idle.
10. Check idle CO again and adjust as neccessary using mixture air bypass screw on plenum.
Obviously the above is less than complete and quite possibly all wrong - the hope is that if so someone who really knows what they are on about can re-write it !
I for one am sick of paying exorbitant amounts of money to muppets who profess to know these engines and FI systems inside out yet I find out afterwards they are totally wrong in what they have said / tried to do. It needn't be this way - anyone with a CO meter and multimeter should be able to carry out a set up or fault find. Of course, if something is awry it may take a specialist to diagnose it and to get a proper set up it should be on the rollers with Mark Adams burning the EEPROM but if this is not possible then the DIY'ers need some better info.
Its a very good idea of yours,I have also been ripped off by the so called experts,I took my car to have hunting problem sorted out and they mucked about for two hours ,trying to sort it out,but couldn't do it,but still charge me £70.00. All they could say its probley be a faulty air flow meter and they could get one for £160 and try it, but then it still may not be right and they would want it for whole day.
I have also ajusted tension spring in air flow meter and that made it a bit better (also new induction gasket,water temp sensor ect),not running to bad now,but I just wondered how do you ajust spring tension at full throttle,do you mean with engine running at 6000rpm.(hope this is not a silly question)
I have also ajusted tension spring in air flow meter and that made it a bit better (also new induction gasket,water temp sensor ect),not running to bad now,but I just wondered how do you ajust spring tension at full throttle,do you mean with engine running at 6000rpm.(hope this is not a silly question)
my 1p worth:
step zero : make a note of the current settings, so you can put it back if you make it worse (i.e you fiddle with it and can't start it the next moring)
step 0.5 : Might be better to warm the car up a bit before you start adjusting things, leastways thats what it says in all my other car books.
- jim
step zero : make a note of the current settings, so you can put it back if you make it worse (i.e you fiddle with it and can't start it the next moring)
step 0.5 : Might be better to warm the car up a bit before you start adjusting things, leastways thats what it says in all my other car books.
- jim
jchase said:
my 1p worth:
step zero : make a note of the current settings, so you can put it back if you make it worse (i.e you fiddle with it and can't start it the next moring)
step 0.5 : Might be better to warm the car up a bit before you start adjusting things, leastways thats what it says in all my other car books.
- jim
With your own car that's true, I was thinking of this as more of an approach on a car that's either not running at all or after some modifications.
dukeenfield said:
I just wondered how do you ajust spring tension at full throttle,do you mean with engine running at 6000rpm.(hope this is not a silly question)
I have no idea really - just repeating what Mark Adams has said in earlier threads. I assume someone sits in the car and gives if a bootful whilst backing of to ensure it doesn't over rev whilst someone checks flap position, either with a multimeter as suggested by Mark or, which I would think is easier, visually with the top cover off of the AFM.
The tension can then be adjusted so that it's fully open at full throttle at say around 4500 rpm. Mark suggests 99.5% open rather than 100% but I doubt it is possible to DIY set it at that level of accuracy.
Having had to alter mine after a specialist slackened off the tension to increase fuelling so that it was fully open at anything much above half throttle it will be interesting to see if this tactic has had to have been employed on many cars even with the AFM mixture air bypass screw fully closed.
If so this would indicate that really it needed higher fuel pressure and bigger injectors or there is another problem, especially as in my case it already runs Jag injectors - which leads to the possibility the ECU has previously been reburnt and injector firing time is now not long enough for a rebuilt engine with much improved breathing.
Trouble is - how can you tell without considerable expense ?
chunder said:
7. Set full throttle CO to around 6 - 7% using air bypass screw on AFM - clockwise to weaken.
Having read a bit more from some other sources this is wrong.
The air bypass screw on the AFM assists in setting idle mixture only and it is a balancing act using that and the plenum idle mixture screw to get the best idle speed / mixture setting.
Therefore without having someone reburn the EEPROM, the only way of adjusting mixture throughout the rev range is to play with the AFM flap spring tension. However, if the flap is then fully open before full throttle, it will probably be weak at this point.
I guess adjusting fuel pressure will also affect mixture but there's probably only +10% or around +4psi to richen with.
Seems like if you want to adjust part to full throttle fuelling then you either have to have the thing reburnt or fit a Tornado adjustable ECU or ditch Lucas altogether (knew I should have bought the Tornado in the PH TVR parts recently - anyone know of another one going cheap ?).
Top thread Chunder, hope it gets a result.
As for the AFM, most peoples advice seems to be "don't touch it"!! I for one will fiddle with just about any setting as long as i make accurate readings and notes of starting points (its too easy to forget what you've done and get totally confused if it goes t*ts up) The best trouble shooting guide that I have seen so far is here.......www.pixeltechnology.co.uk/wedge/maint_fuel_injection.pdf
Until Wedg1e gets his pen out and writes the definative version
As for the AFM, most peoples advice seems to be "don't touch it"!! I for one will fiddle with just about any setting as long as i make accurate readings and notes of starting points (its too easy to forget what you've done and get totally confused if it goes t*ts up) The best trouble shooting guide that I have seen so far is here.......www.pixeltechnology.co.uk/wedge/maint_fuel_injection.pdf
Until Wedg1e gets his pen out and writes the definative version
Hey Dicky, don't bring me into it! I'm just an enthusiastic amateur. Having said that I've stripped and rebuilt two AFMs now and they work fine (one had knackered bearings and on the other the shimming was worn allowing the flap to rub).
My car runs a rebuilt Jag AFM, but I suspect it leans-off at the top end.
I'm trying to get hold of spare ECUs to fiddle with, but on Ebay prices seem to be getting silly.
One guy is offering me a Twin Plenum ECU; nobody can tell me whether it was modified to give extra fuel to go with the extra air of the TP setup. One for Mark Adams perhaps?
I've seen a few TP setups for sale recently, but the sellers all seem to think they're worth their weight in gold. A few years back this may have been the case, but for the prices being asked now, I'm sure you could fit an Emerald or similar with more flexibility and probably better results all round. Having said that I'd still like a TP system to fiddle with, but not at those prices. Next option I suppose would be a hotwire setup, but IIRC someone on here said it improves driveability but at the expense of balls-out power delivery?
My car runs a rebuilt Jag AFM, but I suspect it leans-off at the top end.
I'm trying to get hold of spare ECUs to fiddle with, but on Ebay prices seem to be getting silly.
One guy is offering me a Twin Plenum ECU; nobody can tell me whether it was modified to give extra fuel to go with the extra air of the TP setup. One for Mark Adams perhaps?
I've seen a few TP setups for sale recently, but the sellers all seem to think they're worth their weight in gold. A few years back this may have been the case, but for the prices being asked now, I'm sure you could fit an Emerald or similar with more flexibility and probably better results all round. Having said that I'd still like a TP system to fiddle with, but not at those prices. Next option I suppose would be a hotwire setup, but IIRC someone on here said it improves driveability but at the expense of balls-out power delivery?
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