November 11, 20186 yr comment_561416 3 hours ago, Pochie45566 said: I should also mention that the EGR and BCDD valves have been deleted but it did not impact this issue. Both the EGR and the BCDD can be vacuum leak sources. Check the PCV hose under the intake manifold too. Link to comment https://www.classiczcars.com/forums/topic/60983-rough-idle-when-cold-running-rich/?&page=3#findComment-561416 Share on other sites More sharing options...
November 11, 20186 yr Author comment_561420 I am going to arm myself with a can of carb cleaner and go vacuum leak hunting. I have replaced the PCV valve and hose, the old hose had cracked and was falling apart. If I'm correct, a vacuum leak after the throttle body causes low and lumpy idle. Before it causes a high idle. So I am most likely looking at oil pan gasket, dipstick, front seal, stuff like that. Also going to check out the charcoal canister. Would the carb cleaner trick work down on the oil pan? I don't see why not just making sure. Link to comment https://www.classiczcars.com/forums/topic/60983-rough-idle-when-cold-running-rich/?&page=3#findComment-561420 Share on other sites More sharing options...
November 11, 20186 yr comment_561424 If the AAR valve is only open a sliver when cold then it is not working properly. The thermotine switch is a ground for the AAR so it has to work correctly . Do not put AAR in any water . The AAR should be fully open when cold and close slowly with voltage . Ohms tests with the EFI bible will show this. Sounds like you also have a vacuum leak Link to comment https://www.classiczcars.com/forums/topic/60983-rough-idle-when-cold-running-rich/?&page=3#findComment-561424 Share on other sites More sharing options...
November 11, 20186 yr comment_561426 5 minutes ago, Pochie45566 said: I am going to arm myself with a can of carb cleaner and go vacuum leak hunting. I have replaced the PCV valve and hose, the old hose had cracked and was falling apart. If I'm correct, a vacuum leak after the throttle body causes low and lumpy idle. Before it causes a high idle. So I am most likely looking at oil pan gasket, dipstick, front seal, stuff like that. Also going to check out the charcoal canister. Would the carb cleaner trick work down on the oil pan? I don't see why not just making sure. Disconnect your brake booster and purge canister also looking for vacuum leaks Link to comment https://www.classiczcars.com/forums/topic/60983-rough-idle-when-cold-running-rich/?&page=3#findComment-561426 Share on other sites More sharing options...
November 11, 20186 yr Author comment_561427 1 minute ago, madkaw said: If the AAR valve is only open a sliver when cold then it is not working properly. The thermotine switch is a ground for the AAR so it has to work correctly . Do not put AAR in any water . The AAR should be fully open when cold and close slowly with voltage . Ohms tests with the EFI bible will show this. Sounds like you also have a vacuum leak It runs the same without the thermo time switch plugged in. The switch doesn't seem to be working anyway, the contacts are quite corroded and every sensor in that housing is new except the switch. But wouldn't that only prevent it from closing not opening? The problem here seems to be not enough air at idle. On the average morning when I pull the AAR out it is only a sliver open. Once I throw it in the freezer it is about half open. My AAR reads 60 ohms for the heater, which is what is labeled on the unit itself Link to comment https://www.classiczcars.com/forums/topic/60983-rough-idle-when-cold-running-rich/?&page=3#findComment-561427 Share on other sites More sharing options...
November 11, 20186 yr comment_561428 Be careful with the carb cleaner. It's a powerful solvent and will eat paint and swell seals. Link to comment https://www.classiczcars.com/forums/topic/60983-rough-idle-when-cold-running-rich/?&page=3#findComment-561428 Share on other sites More sharing options...
November 11, 20186 yr comment_561429 The thermotime switch is on the circuit for the cold start valve. But the AAR shows a ground through the ECU, pin 34. 1 minute ago, Pochie45566 said: On the average morning when I pull the AAR out it is only a sliver opoen. Once I throw it in the freezer it is about half open. Both madkaw and myself have mentioned that the AAR should be more open than a sliver. I can't remember what it looks like but Nissan provided a drawing. Pinch that hose when it's cold. If it splits fix it with a piece of heater hose. Then you'll know. But you still have vacuum leaks. Link to comment https://www.classiczcars.com/forums/topic/60983-rough-idle-when-cold-running-rich/?&page=3#findComment-561429 Share on other sites More sharing options...
November 11, 20186 yr comment_561431 12 minutes ago, Pochie45566 said: On the average morning when I pull the AAR out it is only a sliver open. Once I throw it in the freezer it is about half open. Per the instructions I copied, your AAR is out of adjustment. Adjust it so that it is open on the average morning. It moves, which is good, but it's starting from the wrong spot. And you still have vacuum leaks. Link to comment https://www.classiczcars.com/forums/topic/60983-rough-idle-when-cold-running-rich/?&page=3#findComment-561431 Share on other sites More sharing options...
November 12, 20186 yr Author comment_561440 I followed adjustment instructions from this website, http://www.hiperformancestore.com/Ljetronic.htm, and put it back on the car, idled much better but idle got too high after a while because it was not closing. I had my idle sitting at about 1000 when cold which is where id like it if not a bit high. But once I was up to temperature, the AAR was still open about half way. Going to apply 12 v I know is good then see if it closes then. Edited November 12, 20186 yr by Pochie45566 Link to comment https://www.classiczcars.com/forums/topic/60983-rough-idle-when-cold-running-rich/?&page=3#findComment-561440 Share on other sites More sharing options...
November 12, 20186 yr comment_561442 Weird stuff. I'd go to a local auto parts chain and get a loaner vacuum gauge. Partial from Blue's tech tips https://www.classiczcars.com/forums/topic/50850-no-vacuum-at-throttle-body-ports/?do=findComment&comment=462594 Link to comment https://www.classiczcars.com/forums/topic/60983-rough-idle-when-cold-running-rich/?&page=3#findComment-561442 Share on other sites More sharing options...
November 12, 20186 yr comment_561443 16 minutes ago, Pochie45566 said: Going to apply 12 v I know is good then see if it closes then. The AAR has 12 volts at all times when the engine is running. You could put it on a switch if you want to test it as it's supposed to work. Have you tested for continuity to the AAR plug from pin 34 at the ECU? Maybe the ground circuit is missing. Link to comment https://www.classiczcars.com/forums/topic/60983-rough-idle-when-cold-running-rich/?&page=3#findComment-561443 Share on other sites More sharing options...
November 12, 20186 yr comment_561453 I think you need to just open your wallet and get another AAR valve. I didn’t know you could adjust them, but yours does not seem to be working correctly. It sounds like there isn’t proper movement of the valve - as in , not enough, which might not be adjustable . 1000 rpm cold is not too much- if not enough really. Link to comment https://www.classiczcars.com/forums/topic/60983-rough-idle-when-cold-running-rich/?&page=3#findComment-561453 Share on other sites More sharing options...
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