Too lean, Adjust air fuel mixture |
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Too lean, Adjust air fuel mixture |
57lincolnman |
May 2 2013, 05:58 PM
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#1
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Member Group: Members Posts: 174 Joined: 14-September 10 From: Los Angeles Member No.: 12,175 Region Association: Southern California |
I have 75 1.8L with L-jet FI. We have completed an engine rebuild and determined that it is running to lean. A:F ratio of 17. We are trying to get it in the 13 or 15 range to make it fatter. I have replaced the AFM with a NOS unit. Any suggestions?
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Porschef |
May 2 2013, 06:04 PM
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#2
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How you doin' Group: Members Posts: 2,165 Joined: 7-September 10 From: LawnGuyland Member No.: 12,152 Region Association: North East States |
The AFM is adjustable. It's pretty easy, the hardest part is getting the cover off. There's a great tutorial available..
Here... http://forums.bimmerforums.com/forum/showthread.php?t=489885 |
57lincolnman |
May 2 2013, 06:38 PM
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#3
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Member Group: Members Posts: 174 Joined: 14-September 10 From: Los Angeles Member No.: 12,175 Region Association: Southern California |
The AFM is adjustable. It's pretty easy, the hardest part is getting the cover off. There's a great tutorial available.. Here... http://forums.bimmerforums.com/forum/showthread.php?t=489885 Not sure what this link is for...it talks about tranny swaps for BMW's. Can you be more specific? Thanks. |
914itis |
May 2 2013, 06:43 PM
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#4
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Advanced Member Group: Members Posts: 2,892 Joined: 9-October 10 From: New York City Member No.: 12,256 Region Association: North East States |
Are you drinking again Joe?
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Porschef |
May 2 2013, 06:47 PM
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#5
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How you doin' Group: Members Posts: 2,165 Joined: 7-September 10 From: LawnGuyland Member No.: 12,152 Region Association: North East States |
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57lincolnman |
May 2 2013, 07:05 PM
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#6
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Member Group: Members Posts: 174 Joined: 14-September 10 From: Los Angeles Member No.: 12,175 Region Association: Southern California |
Perfect. I shall read this carefully and have a go at it in the morning. I'll let you know how it turns out. Thanks. |
Dave_Darling |
May 2 2013, 11:48 PM
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#7
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914 Idiot Group: Members Posts: 14,990 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
Mucking with the air flow meter is very very very hard to un-do. I wouldn't try it as the first step.
In fact, the first step should be to find and eliminate any and all vacuum leaks. When un-metered air gets into an L-jet intake, the FI doesn't "know" about it so it cannot add fuel to go along with it. Which results in a lean mixture. Also check the fuel pressure. Is it in spec? (I forget the spec for the 1.8s, sorry!) --DD |
Cap'n Krusty |
May 2 2013, 11:53 PM
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#8
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Cap'n Krusty Group: Members Posts: 10,794 Joined: 24-June 04 From: Santa Maria, CA Member No.: 2,246 Region Association: Central California |
Mucking with the air flow meter is very very very hard to un-do. I wouldn't try it as the first step. In fact, the first step should be to find and eliminate any and all vacuum leaks. When un-metered air gets into an L-jet intake, the FI doesn't "know" about it so it cannot add fuel to go along with it. Which results in a lean mixture. Also check the fuel pressure. Is it in spec? (I forget the spec for the 1.8s, sorry!) --DD Not adjustable. If it's not right, you have choices. Pump, fuel line path, regulator, vacuum supply to regulator. Of course, if the cam profile has been "Upgraded", there's always the ol' "split the case and put in a stock cam trick". As with D-jet, L-jet is intolerant of camshaft changes. The Cap'n |
ChrisFoley |
May 3 2013, 10:49 AM
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#9
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I am Tangerine Racing Group: Members Posts: 7,927 Joined: 29-January 03 From: Bolton, CT Member No.: 209 Region Association: None |
As with D-jet, L-jet is intolerant of camshaft changes. The Cap'n I guess I'd better tell Andy (Scarlet75) he needs us to install a stock cam in his 2.2L. (IMG:style_emoticons/default/blink.gif) (IMG:style_emoticons/default/biggrin.gif) |
57lincolnman |
May 6 2013, 09:06 PM
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#10
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Member Group: Members Posts: 174 Joined: 14-September 10 From: Los Angeles Member No.: 12,175 Region Association: Southern California |
As with D-jet, L-jet is intolerant of camshaft changes. The Cap'n I guess I'd better tell Andy (Scarlet75) he needs us to install a stock cam in his 2.2L. (IMG:style_emoticons/default/blink.gif) (IMG:style_emoticons/default/biggrin.gif) Previous owner installed a 73 grind. Is it that much different than stock? We've checked for leaks and fuel pressure is in spec. Just put the engine back in car after rebuild using the 73 grind. |
timothy_nd28 |
May 6 2013, 11:35 PM
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#11
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Advanced Member Group: Members Posts: 2,299 Joined: 25-September 07 From: IN Member No.: 8,154 Region Association: Upper MidWest |
What RPM does your tach show when at idle?
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AndyB |
May 10 2013, 03:38 AM
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#12
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The Governor is watching me Group: Members Posts: 1,115 Joined: 10-April 10 From: Philadelphia New York Member No.: 11,595 Region Association: North East States |
As with D-jet, L-jet is intolerant of camshaft changes. The Cap'n I guess I'd better tell Andy (Scarlet75) he needs us to install a stock cam in his 2.2L. (IMG:style_emoticons/default/blink.gif) (IMG:style_emoticons/default/biggrin.gif) I will never go back to stock (IMG:style_emoticons/default/drunk.gif) |
Bleyseng |
May 10 2013, 08:44 AM
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#13
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Aircooled Baby! Group: Members Posts: 13,034 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
Its pretty easy to adjust the AFM once you open it up. You need a A/F meter to tell you the mix as you do the adjusting inside the AFM. If you are at 17 to 1, what rpm is this at?
You want to be running the test at 2500 rpms up a slight long slope so the engine is under load not coasting. Read the AF meter and then adjust the wiper like in Colin's article. Check the WOT and then set the idle mix. With a Web 73 you will have to run 1000 rpm idle speed. |
Dave_Darling |
May 10 2013, 10:05 PM
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#14
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914 Idiot Group: Members Posts: 14,990 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
That may just be mis-adjusting things to cover up a more basic problem. I still say that there's a good chance of vacuum leaks.
--DD |
Bleyseng |
May 11 2013, 07:55 AM
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#15
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Aircooled Baby! Group: Members Posts: 13,034 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
That may just be mis-adjusting things to cover up a more basic problem. I still say that there's a good chance of vacuum leaks. --DD Dave, he says he is running a Web73 which takes a richer mixture to run right so you have to adjust the AFR. There is no vooddo just a little work. |
Drums66 |
May 11 2013, 12:54 PM
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#16
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914 Rudiments Group: Members Posts: 5,321 Joined: 15-January 03 From: Coronado,Cali Member No.: 151 Region Association: Southwest Region |
Mucking with the air flow meter is very very very hard to un-do. I wouldn't try it as the first step. ....Strictly voodoo, unless you" know" what you are looking for?(readings) (IMG:style_emoticons/default/idea.gif) (IMG:style_emoticons/default/bye1.gif) (IMG:style_emoticons/default/popcorn[1].gif) |
markyb |
May 11 2013, 03:59 PM
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#17
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Member Group: Members Posts: 100 Joined: 27-November 11 From: Rochester, Michigan Member No.: 13,823 Region Association: None |
do you still have your decel valve hooked up? mine gave me plenty of trouble trying to get idle down and A/F ratio under control. try blocking the vac line to it if you have one and see how she goes, those are some big ol' vacuum lines and contribute a lot of air to the system.
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