740 poor running and stalling

[Beadybc]

Originally Posted by Laird Scooby

Sounds like #3 plug lead is either defective or not making proper contact or #3 plug is defective.

The fuel pump whine will disappear, it's probably been a while since the pump could actually move at a sensible speed.

Ordered new leads as well as a new cap and rotor arm just in case, I'll update date in a few days as to whether anything changed.

[Beadybc]

I have now replaced the spark plugs, distributor cap and HT leads and it is still not running properly. If the engine is warm/hot it will only fire if I pump the accelerator whilst turning the key, otherwise the starter motor just turns over endlessly. Once it starts it dies instantly unless I keep the revs up with the throttle.

Could these possibly be symptoms of a faulty Fuel Pressure Accumulator? = https://www.skandix.de/en/spare-part...upply/1029873/

It's the only part of the under-car fuel supply system that hasn't been replaced yet. I can't test fuel pressure but would these symptoms not indicate that there is no fuel pressure at start-up? Also now that the fuel pump is whining I am noticing that it is not producing one tone of noise, every second or so there is a quick jump in pitch as it is working harder for less than a second.

[Laird Scooby]

Originally Posted by Beadybc

I have now replaced the spark plugs, distributor cap and HT leads and it is still not running properly. If the engine is warm/hot it will only fire if I pump the accelerator whilst turning the key, otherwise the starter motor just turns over endlessly. Once it starts it dies instantly unless I keep the revs up with the throttle.

Could these possibly be symptoms of a faulty Fuel Pressure Accumulator? = https://www.skandix.de/en/spare-part...upply/1029873/

It's the only part of the under-car fuel supply system that hasn't been replaced yet. I can't test fuel pressure but would these symptoms not indicate that there is no fuel pressure at start-up? Also now that the fuel pump is whining I am noticing that it is not producing one tone of noise, every second or so there is a quick jump in pitch as it is working harder for less than a second.

Did you give it the meths treatment as i advised and if so, how much meths into what quantity of fuel?

[Beadybc]

Originally Posted by Laird Scooby

Did you give it the meths treatment as i advised and if so, how much meths into what quantity of fuel?

Yes I gave it the meths, 2L to 18L of fuel. Left it to idle for half an hour, had moments where it idled nicely but ultimately ended up the same as before. Tried the throttle response after about 20 minutes of idling and was the same, revs drop but climb after and get stuck up there for a bit.

[Laird Scooby]

Originally Posted by Beadybc

Yes I gave it the meths, 2L to 18L of fuel. Left it to idle for half an hour, had moments where it idled nicely but ultimately ended up the same as before. Tried the throttle response after about 20 minutes of idling and was the same, revs drop but climb after and get stuck up there for a bit.

Aah - yes, i remember now. Did you check the throttle adjustment and the cable has some slack in it at idle? Do you have an idle bypass screw on yours? Usually a knurled head with a hole for a large (8 or 10mm) Allen key in it?



That's the one there, ringed in cyan. It's possible that is partially blocked. Also have you checked for a +12V feed to the warm-up regulator?

[Beadybc]

Originally Posted by Laird Scooby

Aah - yes, i remember now. Did you check the throttle adjustment and the cable has some slack in it at idle? Do you have an idle bypass screw on yours? Usually a knurled head with a hole for a large (8 or 10mm) Allen key in it?



That's the one there, ringed in cyan. It's possible that is partially blocked. Also have you checked for a +12V feed to the warm-up regulator?

I do have that idle screw, should I take out and clean it?

By warm up regulator do you mean the air auxiliary valve or something else?

[Laird Scooby]

Originally Posted by Beadybc

I do have that idle screw, should I take out and clean it?

By warm up regulator do you mean the air auxiliary valve or something else?

Yes, and the drillings in the throttle body too. Before you do that though, screw it all the way in, counting the turns accurately. Then unscrew it all the way and squirt carb cleaner into the hole it came from and on the end of the screw which should be pointed.
When refitting, screw all the way in then screw it out the same number of turns as you counted from where it was to all the way in.

When i say warm-up regulator, i tend to be fairly specific about things so no, i don't mean the auxiliary air valve. Haynes refer to it as a control pressure regulator, i've always known it as the warm up regulator - arguably both terms apply as it serves both purposes. This is the wee beastie in question :



Often i will also use TLAs such as CPS, CTS, FPR etc which can cause confusion so clarification is always good if you're unsure.

In theory, if your AAV is getting a feed and closing as it warms up then you should have a feed at the WUR but it might pay to unplug it, check for corrosion/cleanliness on the contacts in the plug and socket and spray both with contact cleaner then refit/unplug several times and give a final spray of contact cleaner before refitting a final time.

I don't suppose you have (or have access to) a gas analyser/ CO meter at all? Also are you able to see the mixture (pressure) adjustment screw in the top of the fuel distributor?

Also when cold, what rpm does the engine idle at?

[Beadybc]

Originally Posted by Laird Scooby

Yes, and the drillings in the throttle body too. Before you do that though, screw it all the way in, counting the turns accurately. Then unscrew it all the way and squirt carb cleaner into the hole it came from and on the end of the screw which should be pointed.
When refitting, screw all the way in then screw it out the same number of turns as you counted from where it was to all the way in.

When i say warm-up regulator, i tend to be fairly specific about things so no, i don't mean the auxiliary air valve. Haynes refer to it as a control pressure regulator, i've always known it as the warm up regulator - arguably both terms apply as it serves both purposes. This is the wee beastie in question :



Often i will also use TLAs such as CPS, CTS, FPR etc which can cause confusion so clarification is always good if you're unsure.

In theory, if your AAV is getting a feed and closing as it warms up then you should have a feed at the WUR but it might pay to unplug it, check for corrosion/cleanliness on the contacts in the plug and socket and spray both with contact cleaner then refit/unplug several times and give a final spray of contact cleaner before refitting a final time.

I don't suppose you have (or have access to) a gas analyser/ CO meter at all? Also are you able to see the mixture (pressure) adjustment screw in the top of the fuel distributor?

Also when cold, what rpm does the engine idle at?

1) I don't have a gas analyser / CO meter at the moment but I could probably get one. There does seem to always some liquid coming from the exhaust.

2) This one?




3)The engine; if it starts and runs like in the videos from cold, will go up to about 1400-1500 then after a while drop down to 700-1000. It's usually after it drops down where I play with that adjustment screw on the throttle body or turn the distributor to get it to sit at 900.

Which leads me onto the fact that I had it running yesterday whilst I had my dad using a strobe light to check the timing and according to him it was way off, probably as a result of us playing with the distributor and other things?

[Laird Scooby]

The timing is non-adjustable, you can't alter it by moving the distributor. It's all controlled by the EZK ignition ECU so will alter by itself.

The pic didn't come out on Photobucket, been moved/deleted allegedly.

Which screw are you touching to change the idle speed?

Shame you weren't closer, i'd come and have a look.

[Beadybc]

Originally Posted by Laird Scooby

The timing is non-adjustable, you can't alter it by moving the distributor. It's all controlled by the EZK ignition ECU so will alter by itself.

The pic didn't come out on Photobucket, been moved/deleted allegedly.

Which screw are you touching to change the idle speed?

Shame you weren't closer, i'd come and have a look.

Sorry, were you referencing this screw?



The screw I was changing the idle with was the one you circled on the throttle body.