lean cyLinder

Moderator: Tom Notch

Post Reply
User avatar
MinamiKotaro
Posts: 2071
Joined: Sat Aug 06, 2005 8:26 am

lean cyLinder

Post by MinamiKotaro » Wed Mar 01, 2017 8:55 pm

#2 cylinder is very lean. The header pipe is solid white, other three are black. Most likely culprit? My injectors are F.A.S.T., almost new, and supposedly flow matched.
'67 Beetle, 2276
MS-1 v3.57

User avatar
panel
Posts: 3623
Joined: Sun Sep 24, 2000 2:01 am
Location: Victoria B.C. Canada
Contact:

Re: lean cyLinder

Post by panel » Wed Mar 01, 2017 10:55 pm

Can you swap injectors around at all to see if it's the same scenario ? Can you pop them out and crank them into 4 jars and check the flow ?

mads b (dk)
Posts: 85
Joined: Fri Feb 08, 2013 2:48 pm
Location: Denmark

Re: lean cyLinder

Post by mads b (dk) » Thu Mar 02, 2017 11:03 am

I had lean 2 and 4 because off header design..... solved by adding 6% extra to injectors in 2 and 4

Tapatalk


User avatar
MinamiKotaro
Posts: 2071
Joined: Sat Aug 06, 2005 8:26 am

Re: lean cyLinder

Post by MinamiKotaro » Thu Mar 02, 2017 12:38 pm

panel wrote:
Wed Mar 01, 2017 10:55 pm
Can you swap injectors around at all to see if it's the same scenario ? Can you pop them out and crank them into 4 jars and check the flow ?
I can but it's a pain in the butt. Lol. Guess I'll just knuckle down and do it.
'67 Beetle, 2276
MS-1 v3.57

User avatar
MinamiKotaro
Posts: 2071
Joined: Sat Aug 06, 2005 8:26 am

Re: lean cyLinder

Post by MinamiKotaro » Thu Mar 02, 2017 12:39 pm

mads b (dk) wrote:
Thu Mar 02, 2017 11:03 am
I had lean 2 and 4 because off header design..... solved by adding 6% extra to injectors in 2 and 4

Tapatalk
Hmm. I believe that pipe had been leaking at the slip joint.
'67 Beetle, 2276
MS-1 v3.57

mads b (dk)
Posts: 85
Joined: Fri Feb 08, 2013 2:48 pm
Location: Denmark

Re: lean cyLinder

Post by mads b (dk) » Thu Mar 02, 2017 1:35 pm

There are no slip joint... it's a homemade header....

Tapatalk


User avatar
MinamiKotaro
Posts: 2071
Joined: Sat Aug 06, 2005 8:26 am

Re: lean cyLinder

Post by MinamiKotaro » Thu Mar 02, 2017 6:46 pm

mads b (dk) wrote:
Thu Mar 02, 2017 1:35 pm
There are no slip joint... it's a homemade header....

Tapatalk
I meant on mine. :D
'67 Beetle, 2276
MS-1 v3.57

User avatar
Piledriver
Moderator
Posts: 21748
Joined: Sat Feb 16, 2002 3:01 am
Location: Van Alstyne, Texas

Re: lean cyLinder

Post by Piledriver » Thu Mar 02, 2017 7:10 pm

Batch or sequential?
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

User avatar
MinamiKotaro
Posts: 2071
Joined: Sat Aug 06, 2005 8:26 am

Re: lean cyLinder

Post by MinamiKotaro » Thu Mar 02, 2017 9:27 pm

Piledriver wrote:
Thu Mar 02, 2017 7:10 pm
Batch or sequential?
Batch.
'67 Beetle, 2276
MS-1 v3.57

User avatar
Piledriver
Moderator
Posts: 21748
Joined: Sat Feb 16, 2002 3:01 am
Location: Van Alstyne, Texas

Re: lean cyLinder

Post by Piledriver » Thu Mar 02, 2017 9:52 pm

IIRC you can still use fuel trim if set for semi-sequential, but it effects 2 holes.

Semi-sequential doesn't need the extra sensor or a cam speed wheel, it just provides guaranteed injection timing, and should be IMHO default. Regular batch squirts when it gets to it.

Just enabling it and playing with the injection timing might have some positive effect by itself.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

mads b (dk)
Posts: 85
Joined: Fri Feb 08, 2013 2:48 pm
Location: Denmark

Re: RE: Re: lean cyLinder

Post by mads b (dk) » Fri Mar 03, 2017 12:01 am

Piledriver wrote:IIRC you can still use fuel trim if set for semi-sequential, but it effects 2 holes.

Semi-sequential doesn't need the extra sensor or a cam speed wheel, it just provides guaranteed injection timing, and should be IMHO default. Regular batch squirts when it gets to it.

Just enabling it and playing with the injection timing might have some positive effect by itself.
On vems you can trim fuel on every cylinder if its connected to its own driver, you don't have to run fully sequential

Tapatalk


User avatar
MinamiKotaro
Posts: 2071
Joined: Sat Aug 06, 2005 8:26 am

Re: lean cyLinder

Post by MinamiKotaro » Fri Mar 03, 2017 8:46 pm

Piledriver wrote:
Thu Mar 02, 2017 9:52 pm
IIRC you can still use fuel trim if set for semi-sequential, but it effects 2 holes.

Semi-sequential doesn't need the extra sensor or a cam speed wheel, it just provides guaranteed injection timing, and should be IMHO default. Regular batch squirts when it gets to it.

Just enabling it and playing with the injection timing might have some positive effect by itself.
I'd have to upgrade to MS2, wouldn't I?
'67 Beetle, 2276
MS-1 v3.57

User avatar
Piledriver
Moderator
Posts: 21748
Joined: Sat Feb 16, 2002 3:01 am
Location: Van Alstyne, Texas

Re: lean cyLinder

Post by Piledriver » Sat Mar 04, 2017 1:45 am

MinamiKotaro wrote:
Fri Mar 03, 2017 8:46 pm
I'd have to upgrade to MS2, wouldn't I?
My bad, I forget MS1 still works.
You are stuck with fixing the root cause, which is actually probably better anyway.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

User avatar
MinamiKotaro
Posts: 2071
Joined: Sat Aug 06, 2005 8:26 am

Re: lean cyLinder

Post by MinamiKotaro » Sun Mar 05, 2017 6:02 pm

Ok, I took #2 plug out and it was covered with white ash. I swapped #2 and #4 injector. We'll see if the lean condition migrates with it.

Also, two of my injectors measured 12.9 ohms resistance, the other two measured 13.5 ohm. Any cause for concern? Should I make sure to pair the two 12.9s and the two 13.5s on the same circuit?
'67 Beetle, 2276
MS-1 v3.57

User avatar
MinamiKotaro
Posts: 2071
Joined: Sat Aug 06, 2005 8:26 am

Re: lean cyLinder

Post by MinamiKotaro » Sun May 14, 2017 10:10 am

Update:

Cylinder #2 was still lean even though I swapped the injector. Cylinder #3 was also lean -- not as lean, but notably leaner than #1 and #4. #2 and #3 are on the same circuit. I got to thinking: a long time ago, one of the injector wires pulled out of the relay board and grounded against the case. Perhaps that injector circuit was damaged, somehow. I got a new relay board and this seems to have fixed the problem. Plugs #2 and #4 look exactly the same as #1 and #3. Also, my AFR has changed dramatically (richer) so I guess those injectors are firing better. Had to retune.

Edit: Did a compression test on #2 and #4 (easy to get to) and they were both with a couple psi. The valve clearance was also good.
'67 Beetle, 2276
MS-1 v3.57

Post Reply