Help! I fiddled with something I shouldn't...

[Dr. Robotnik 0]

Hey, right, my car had been running a little bit lean for a while and I remember reading about adjusting the fuel mixture with the screw on top of the metering head

Now after that I've read that the 9a's motronic shouldn't be messed with because, and as I am testament to this, you'll break it :) However, mine was missing the tamper resistant seal, so felt I had to investigate :D

 

I've been fiddling for the past couple of days with varying success, until today when I decided to see if I could get the head apart at all to see if I could put the screw exactly where it was before, it didn't give me any indication of where it was previously (it was equally caked in dirt) so I put it back together, defeated.

At first I was getting problems where it'd stutter up to about 2500 rpm and then rev freely after that (not nice trying to cross a dual carriageway like that! Kinda like having ignition timing way out) but now there's a different problem, in that it'll rev better than ever up to about 4000rpm and then suddenly stop, not a gradual loss of power, sorta like a rev limiter kicking in but a bit more angry sounding. Fiddling with the mixture further makes no difference to this behaviour, and I am lost for ideas other than to replace the whole metering head (So if anyone has one cheap, intact, and unmolested, I will happily take it off your hands :D)

 

Lesson learned I guess. If it ain't broke, don't fix it.

 

Anyway, I look forward to your replies.

Cheers!

[kerrly 0]

what condition are the igntion components in eg HT leads, DIzzy, Rotor arm, Spark plugs etc?

 

Removing the spark plugs and inspecting them can tell you a lot about how the engine is running be it too rich or too lean.

 

In the past i had a similar problem where the engine felt lame above 4k, a new rotor arm and dizzy did wonders as did makng sure the HT leads were correctly seated, my king lead from the Coil to the dizzy wasnt on properly and tbh it felt like gaining 30+ HP straight away once it was on.

 

Oh and since you have been tinkering it is best to go to someone who has a gas analyser now to correctly set the CO2 emmissions back to 2% ish.

 

dave

[Dr. Robotnik 0]

what condition are the igntion components in eg HT leads, DIzzy, Rotor arm, Spark plugs etc?

 

Removing the spark plugs and inspecting them can tell you a lot about how the engine is running be it too rich or too lean.

 

In the past i had a similar problem where the engine felt lame above 4k, a new rotor arm and dizzy did wonders as did makng sure the HT leads were correctly seated, my king lead from the Coil to the dizzy wasnt on properly and tbh it felt like gaining 30+ HP straight away once it was on.

 

Oh and since you have been tinkering it is best to go to someone who has a gas analyser now to correctly set the CO2 emmissions back to 2% ish.

 

dave

 

Yeah thanks, I was considering going to a garage today and asking to use their gas meter, but they'd probably tell me that only they can use it and I must pay them many hours labor to do the job for me :)

 

And I thought it could well be ignition components, though they're all in good condition and were absolutely fine before I started fiddling.

 

However, it seems that if I gradually open the throttle it'll rev all the way to the redline, it's only at wide open throttle that it backs off at 4k, you really feel a jolt when it happens while driving!

I'll check out my leads and dizzy etc anyway though! Thanks!

[Dr. Robotnik 0]

Hmm also it seems other people have had the same problem with WOT, something to do with the lambda sorts out the fuelling until wot, but at wide-open it's entirely down to the CO potentiometer so still seems fuelling problems :/

[Dr. Robotnik 0]

Shameless Thursday self-bump :)

[Dr. Robotnik 0]

Okay never mind, I dismantled the metering head and put all back together as accurately as possible, now it's fine high end but there's a massive flat spot at about 2800 now :/ Still thinking just replace and be done is probably the best way.

[pumbaa 0]

Having very similar problems to you, i took apart and changed everything! No luck. Waiting on a new lambda now. I have a fully functioning 9a metering head spare if you want but like you i have played with the mixture screw. Can only suggest checking timing, leads, dizzy and arm, throttle body switches/potentiometer and metering head. Try unplugging things like the plugs on the throttle body or lambda or metering head to see if is any difference.

 

Hope this helps

 

Kunaal

[The_Dude 0]

I was really disappointed as I was expecting some kind of superglue/hand/kn*b problem. :)

 

Hope you get it sorted soon matey.

[pumbaa 0]

pmsl

[Dr. Robotnik 0]

Having very similar problems to you, i took apart and changed everything! No luck. Waiting on a new lambda now. I have a fully functioning 9a metering head spare if you want but like you i have played with the mixture screw. Can only suggest checking timing, leads, dizzy and arm, throttle body switches/potentiometer and metering head. Try unplugging things like the plugs on the throttle body or lambda or metering head to see if is any difference.

 

Hope this helps

 

Kunaal

 

Yeah cheers. I just cleaned up the contacts on my rotor arm/dizzy cap after leaving the battery off for an hour and so far it's looking alright.

I've got a new metering head on the way from Matty123 if I can't get this working, if I can, oh well it's always good to have a spare!

I tried unplugging the throttle switch plug thingy and it wouldn't start or anything then, quite worrying.

At first I thought it was to do with the WOT switch but after sorting out the head a bit I'm now left with just an annoying flat spot!

What I did was loosen the screw at the back of the flap arm thingy on the pivot to see if i could get it off and see if there were any dirt marking on the mixture screw, but no such luck, it does't come off like that But the pivot arm seems to be connected to some sort of potentiometer that probably went out when I fiddled with it. I put it back to closed position earlier and sorted it luckily, but it still aint perfect!

 

Regardless, thanks for your input :D

[Dr. Robotnik 0]

I was really disappointed as I was expecting some kind of superglue/hand/kn*b problem. :)

 

Hope you get it sorted soon matey.

lmao thanks, I chose such name to try and get more people to look at it.

Plenty of views but I reckon they're all like you, after some taboo story!