Digifant timing |
Post Reply | Page <123 |
Author | |
SebRogers
Vanorak Joined: 07 Oct 09 Location: Somerset Status: Offline Points: 1676 |
Post Options
Thanks(0)
|
Shame really, because if you could switch the lambda via a relay I would've thought you could wire it up to the fuel switch so it'd be automatic...
|
|
'85 T3 Doka EJ22
'94 T4 Westy Cali Club ABT 2.4td |
|
..lee..
Vanorak Joined: 14 May 08 Location: llanelli swales Status: Offline Points: 1420 |
Post Options
Thanks(0)
|
seb i think you have got it the wrong way around. the lambda influences the afr according to what is already pre programed in to the fuel map in the ecu. its an add on. and not the main controll. oxygen in the exhaust gas is dependant on how complete a burn the combusion chamber produces. the oxygen content in the exhaust gasses varies very slightly even without a closed loop lambda system its just with that type of system there is no lambda correction.
if you connected a lambda probe to a non lambda system you would see it vary voltage as the oxygen left over from the burn varies.
it should do the same with gas i belive. the posts on you tube seem to confirm this.
if the afr is optimsed on the gas and the oxygen levels in the exhaust gas are correct i can see no reason why the lambda should not behave and produce a variable voltage of between 0.1v and 0.9v. if the oxygen level goes outside of the lambda`s tolerance then it will flatline. thats what will cause the fuel system to play up when you switch back over.
i dont think it should flat line on gas. "again i`m no expert but the video`s on you tube show voltage variance on gas. check it out"
i think if you hanen`t allready done it check the lambda readings on petrol and also as you switch over to gas and let us know what the readings were at idle and at say 2500 rpm.
|
|
SebRogers
Vanorak Joined: 07 Oct 09 Location: Somerset Status: Offline Points: 1676 |
Post Options
Thanks(0)
|
Quite possibly! However, this is what happens from cold startup on petrol: the lambda output at idle is essentially steady for, I dunno, a while (Aidan reckons 30 seconds but it seemed a bit longer than that to me, though I didn't time it) until the engine starts 'listening' to the lambda and cycling the afr to keep the exhaust somewhere between just lean and just rich. At that point the lambda output suddenly changes to the curve you'd expect. Of course the afr will vary a bit anyway, but surely it can only cycle between 0.1 and 0.9v if the fuelling is actively being changed, whether that's because of throttle position off idle or because the ecu is varying fuelling at idle? If there isn't that constant cycling of afr then the output voltage from the lambda will be a steady 0.x v, where x varies according to throttle position and engine load. My lambda changes output voltage with afr as you'd expect. But it only cycles when it's running on petrol. That seems right to me. At least, that's how I understand it. But I could well be wrong Will look into it some more...
|
|
'85 T3 Doka EJ22
'94 T4 Westy Cali Club ABT 2.4td |
|
..lee..
Vanorak Joined: 14 May 08 Location: llanelli swales Status: Offline Points: 1420 |
Post Options
Thanks(0)
|
ooooooo. ive had an idea.
tdi
.
|
|
SebRogers
Vanorak Joined: 07 Oct 09 Location: Somerset Status: Offline Points: 1676 |
Post Options
Thanks(0)
|
Thanks! Nah, I like the 2.1WBX, despite its various quirks. If I wanted a cheap to run, reliable and practical van I'd buy a T4
|
|
'85 T3 Doka EJ22
'94 T4 Westy Cali Club ABT 2.4td |
|
Baxter
Admin Group Scruff Daddy Joined: 29 May 04 Location: Huddersfield Status: Offline Points: 8060 |
Post Options
Thanks(0)
|
The bastard, he always has the best ideas.
|
|
..lee..
Vanorak Joined: 14 May 08 Location: llanelli swales Status: Offline Points: 1420 |
Post Options
Thanks(0)
|
|
|
Post Reply | Page <123 |
Tweet |
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |