can anyone tell me where the mixture/co adjustment is on the fuel injection system?
co adjustment
co adjustment
hi dudes,i have a 1971, 411,
can anyone tell me where the mixture/co adjustment is on the fuel injection system?
can anyone tell me where the mixture/co adjustment is on the fuel injection system?
Some have a small grey knob on top of the 'brain' - something like 40 clicks I've heard - but not the early ones.
Don't do it at random - get a CO meter.
Otherwise, do not play with the setting on the manifold pressure sensor - it is a dual concentric screw and will be very hard without factory equipment to get back again.
Usually it's fuel pressure or timing adjustment that's wrong - there's not much else to change!
And do check the voltage output - should be around 14 volts at mid-RPM. A low charging rate is a very common problem which makes it run too rich - you may simply need a new voltage regulator. (And there are a few mechanics who've said 'rubbish', then eaten their words later!).
Don't do it at random - get a CO meter.
Otherwise, do not play with the setting on the manifold pressure sensor - it is a dual concentric screw and will be very hard without factory equipment to get back again.
Usually it's fuel pressure or timing adjustment that's wrong - there's not much else to change!
And do check the voltage output - should be around 14 volts at mid-RPM. A low charging rate is a very common problem which makes it run too rich - you may simply need a new voltage regulator. (And there are a few mechanics who've said 'rubbish', then eaten their words later!).
The brain is usually in the rear wing (fender) I think (I know Type 3 better than Type 4). Just look for where the mass of white wires go to the brain and you will find it. May need to remove an access panel on the rear luggage compartment left side. Make sure you replace the cover properly or it will leak - there are lugs on the bottom which go behind the wall so the seals are compressed.
Have you checked the voltage and for vacuum leaks yet? Wrong mixture is not usually a problem, but a symptom of something else wrong.
Sadly lots of these D-Jet systems have been messed up by inadequately trained mechanics treating them like any other fuel system. The circuit in the (normally very reliable) brain makes the injectors squirt the right amount of fuel in depending on engine and air temps, manifold pressure and throttle position.
Type 3s had no mixture control at all (same system) but some Type 4s had a small grey knob with a cross slot on the top edge of the brain (metal box 10" x 5" x 2").
What is it doing wrong that makes you think it needs the mixture adjusted?
Have you checked the voltage and for vacuum leaks yet? Wrong mixture is not usually a problem, but a symptom of something else wrong.
Sadly lots of these D-Jet systems have been messed up by inadequately trained mechanics treating them like any other fuel system. The circuit in the (normally very reliable) brain makes the injectors squirt the right amount of fuel in depending on engine and air temps, manifold pressure and throttle position.
Type 3s had no mixture control at all (same system) but some Type 4s had a small grey knob with a cross slot on the top edge of the brain (metal box 10" x 5" x 2").
What is it doing wrong that makes you think it needs the mixture adjusted?
OK.
1st check that voltage output. At idle it will drop, and that reduces the spark strength too, as well as making it over-rich. I mean this seriously. Bet you it's the problem!
Don't mess with the injection mixture yet.
2nd Look at the large vacuum pipe from the big central air intake box to the pressure sensor at left of engine bay. Make sure it's not split and holds firmly.
3rd If it's been standing for a long time, maybe the injector seals have dried up and they're leaking - they may cure themselves now fuel is reaching them.
4th If the voltage is fine, check the fuel pressure. The book says 28 - 30 psi.
5th Check you are timing the spark correctly. Check the manual for how to do it. It's critical.
6th Check the valve adjustment. They are also critical in an air-cooled engine.
7th Check the compression - you may have a damaged valve.
Let us know what happens. Please do not mess with the mixture control - it probably isn't wrong!
1st check that voltage output. At idle it will drop, and that reduces the spark strength too, as well as making it over-rich. I mean this seriously. Bet you it's the problem!
Don't mess with the injection mixture yet.
2nd Look at the large vacuum pipe from the big central air intake box to the pressure sensor at left of engine bay. Make sure it's not split and holds firmly.
3rd If it's been standing for a long time, maybe the injector seals have dried up and they're leaking - they may cure themselves now fuel is reaching them.
4th If the voltage is fine, check the fuel pressure. The book says 28 - 30 psi.
5th Check you are timing the spark correctly. Check the manual for how to do it. It's critical.
6th Check the valve adjustment. They are also critical in an air-cooled engine.
7th Check the compression - you may have a damaged valve.
Let us know what happens. Please do not mess with the mixture control - it probably isn't wrong!
