 L-jet help needed |
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| wanchaiwarrior |
 May 2 2010, 01:48 PM
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#1
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Newbie  Group: Members Posts: 21 Joined: 16-January 10 From: Los Angeles Member No.: 11,242 Region Association: Southern California  |
74 1.8L L-jet was running well before I decided to give the engine a good cleaning and replace all the old vacuum lines. Now it idles great, but as soon as I go beyond 1/10th throttle it just losses all power. At low throttle it will run all the way to 4,000+RPM. But beyond a certain throttle position, regardless of RPM, it just goes limp.
2 months ago I performed a full tune, including valve adjust, pertronix, plugs, rotor, cap. I have triple checked my vacuum hose connections and electrical connections. I even pulled the throttle body off and checked the TPS operation, which appears to be operating properly. Oddly, my throttle body only has one port that goes to the back side of the vacuum advance diaphragm leaving the port on the front of the vacuum advance open. It definitely seems to be related to throttle position. Not sure where to try next. Any suggestions would be greatly appreciated. |
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| wanchaiwarrior |
May 2 2010, 06:31 PM
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#2
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Newbie Group: Members Posts: 21 Joined: 16-January 10 From: Los Angeles Member No.: 11,242 Region Association: Southern California |
I opened up my air flow sensor and discovered the problem. The center tab connection had somehow twisted to the side and was no longer making contact with the center pole. If you look closely you can see the arrow pointing to the copper tang.
Now the car is running like a top!! I'm so happy (IMG:style_emoticons/default/cheer.gif)  |
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| Brando |
May 3 2010, 12:26 AM
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#3
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BUY MY SPARE KIDNEY!!! Group: Members Posts: 3,935 Joined: 29-August 04 From: Santa Ana, CA Member No.: 2,648 Region Association: Southern California |
To address this issue later on in Motronic cars, Bosch ran a ground wire from the wiper bridge to the wiper. It prevents issues like this from happening.
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.efinnegan.com-2648-1272868011.1.jpg) More info on AFM rebuilding & diagnostics here. QUOTE(wanchaiwarrior @ May 2 2010, 04:31 PM)  I opened up my air flow sensor and discovered the problem. The center tab connection had somehow twisted to the side and was no longer making contact with the center pole. If you look closely you can see the arrow pointing to the copper tang. Now the car is running like a top!! I'm so happy (IMG:style_emoticons/default/cheer.gif) |
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| zonedoubt |
May 5 2010, 02:34 PM
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#4
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Canadian Member Group: Members Posts: 668 Joined: 14-May 03 From: Vancouver, BC Member No.: 696 Region Association: Canada |
QUOTE(Brando @ May 2 2010, 10:26 PM) Great resource. I haven't seen that one before. QUOTE(wanchaiwarrior @ May 2 2010, 04:31 PM) I opened up my air flow sensor and discovered the problem. The center tab connection had somehow twisted to the side and was no longer making contact with the center pole. If you look closely you can see the arrow pointing to the copper tang. Nicely done. I had a problem with one of the other contacts. It was getting snagged on the rotor and would cause the engine to lose power under load. |
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Posts in this topic
wanchaiwarrior L-jet help needed May 2 2010, 01:48 PM
jsayre914 the port should not be open to air.
check for a n... May 2 2010, 02:08 PM
wanchaiwarrior I prepared a detailed diagram before I started dis... May 2 2010, 02:24 PM messix
I prepared a detailed diagram before I started di... May 2 2010, 03:09 PM wanchaiwarrior I actually removed the air box before cleaning, so... May 2 2010, 03:53 PM MrKona
74 1.8L L-jet was running well before I decided t... May 2 2010, 03:51 PM wanchaiwarrior Are you referring to this port?
[/quote]
Yes, tha... May 2 2010, 03:57 PM computers4kids Did you remember to plug the harness back into the... May 2 2010, 04:30 PM wanchaiwarrior
Did you remember to plug the harness back into th... May 2 2010, 04:33 PM computers4kids
Did you remember to plug the harness back into t... May 2 2010, 10:00 PM messix thats were i thought you might have had the proble... May 2 2010, 09:32 PM Cap'n Krusty
74 1.8L L-jet was running well before I decided t... May 2 2010, 10:50 PM wanchaiwarrior '74s have both an advance port and a retard po... May 3 2010, 09:51 AM zonedoubt
'74s have both an advance port and a retard p... May 5 2010, 02:35 PM Drums66
'74s have both an advance port and a retard ... May 5 2010, 03:54 PM charliew Nice engineering change to know about. At first to... May 3 2010, 08:34 AM ClayPerrine I normally agree with Cap'n Crusty, but on thi... May 3 2010, 01:07 PM Drums66 I'm surprised no 1 told you not to go inside t... May 5 2010, 01:37 PM wanchaiwarrior
I'm surprised no 1 told you not to go inside ... May 5 2010, 02:16 PM |
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