 Cold idle issue, Rough cold idle after initial |
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| Charpe197 |
 Jun 20 2018, 08:31 PM
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#1
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Newbie  Group: Members Posts: 8 Joined: 5-June 18 From: RI Member No.: 22,197 Region Association: None  |
1972 1.7 d jetronic runs great when hot. At startup, runs great at about 1500-1700. But when steps down about 2 minutes later, rough idle. Once warmed up, 10 min of driving, perfect idle of 800-900. Any advice?
Thanks, Charpie |
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| BeatNavy |
Jun 21 2018, 05:01 AM
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#2
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region 
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QUOTE(Charpe197 @ Jun 20 2018, 10:31 PM)  1972 1.7 d jetronic runs great when hot. At startup, runs great at about 1500-1700. But when steps down about 2 minutes later, rough idle. Once warmed up, 10 min of driving, perfect idle of 800-900. Any advice? Thanks, Charpie My first thoughts are: 1. Your AAR is not operating properly - sounds like it's closing too quickly. In my experience they close more gradually - more like 5 minutes from total open to total close. I don't know how often this is a problem, though. Normally they just fail to open or close. 2. More likely, your mixture is just too lean during warm up. Could be your CHT is not functioning correctly (or maybe not correct CHT), or perhaps your fuel pressure is too low in general. Some people run Brad Mayeur's "spacer" that slows down the CHT warm-up, effectively giving you a richer mixture longer during the warm-up process. More info on D-Jet: https://members.rennlist.com/pbanders/djetp...htm#Drivability You can troubleshoot your CHT by checking resistance values between the lead and ground during the warm up process. There's more info in that link. |
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| Charpe197 |
Jun 21 2018, 12:37 PM
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#3
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Newbie Group: Members Posts: 8 Joined: 5-June 18 From: RI Member No.: 22,197 Region Association: None |
QUOTE(BeatNavy @ Jun 21 2018, 07:01 AM) QUOTE(Charpe197 @ Jun 20 2018, 10:31 PM) 1972 1.7 d jetronic runs great when hot. At startup, runs great at about 1500-1700. But when steps down about 2 minutes later, rough idle. Once warmed up, 10 min of driving, perfect idle of 800-900. Any advice? Thanks, Charpie My first thoughts are: 1. Your AAR is not operating properly - sounds like it's closing too quickly. In my experience they close more gradually - more like 5 minutes from total open to total close. I don't know how often this is a problem, though. Normally they just fail to open or close. 2. More likely, your mixture is just too lean during warm up. Could be your CHT is not functioning correctly (or maybe not correct CHT), or perhaps your fuel pressure is too low in general. Some people run Brad Mayeur's "spacer" that slows down the CHT warm-up, effectively giving you a richer mixture longer during the warm-up process. More info on D-Jet: https://members.rennlist.com/pbanders/djetp...htm#Drivability You can troubleshoot your CHT by checking resistance values between the lead and ground during the warm up process. There's more info in that link. Where do you buy the spacer? |
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| BeatNavy |
Jun 21 2018, 12:54 PM
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#4
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region
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http://914ltd.com/store.php?c=1384303079
The CHT extension. May help, but make sure you read up on DJet too. |
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