V6 Idle Issue - Mazda MX-6 Forum
 
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post #1 of 7 (permalink) Old 10-20-19, 18:32 Thread Starter
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V6 Idle Issue

Hey everyone.

I just joined the MX-6 Forum looking to seek some assistance with my car. About a month back I was driving down the highway and all of a sudden out of nowhere my car dies. It just stalled out and I went to crank it over and nothing. To make a long story short I determined that my distributor and my crankshaft position sensor were dead. So I replaced them and now the car is running, but not great. When I crank it over it usually takes around 5 seconds for the engine to start up and when it's running it's not a steady idle. It is surging from around 500-1000rpm. This car ran completely mint before all of this started happening it would start up immediately and idle very smooth but now it's acting up for some reason. I've done a little bit of research around the internet and I'm thinking it may be either air related or timing related. I also had the work done on the car at a local mechanic so it wouldn't surprise me if something was done incorrectly. I just recently, after these problems started happening put in new NGK Platinum plugs, but they didn't seem to do much. I'm thinking I should maybe throw in some new plug wires and maybe a MAF. But if anyone can give me a little bit of guidance as to why I may be having these issues, that would be greatly appreciated. 🙂
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post #2 of 7 (permalink) Old 10-21-19, 19:08
 
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Welcome to the board!

My guess is that one of the vacuum lines got disconnected, or a vacuum leak between the VAF meter and the throttle body, when the distributor and crank position sensor were changed. These cars are very sensitive to vacuum leaks. Does it run OK at higher rpm (when a small vacuum leak won't matter much)?
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post #3 of 7 (permalink) Old 10-22-19, 15:23 Thread Starter
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Quote:
Originally Posted by NickR View Post
Welcome to the board!

My guess is that one of the vacuum lines got disconnected, or a vacuum leak between the VAF meter and the throttle body, when the distributor and crank position sensor were changed. These cars are very sensitive to vacuum leaks. Does it run OK at higher rpm (when a small vacuum leak won't matter much)?
Thank you for the quick reply! I went out today and had a look to see if there were any vacuum lines that were disconnected and I disconnected then reconnected one of the vacuum lines at one of the valves, and the car started idling completely normal. However the idle was a bit high so I turned it down a bit with the idle set screw on the throttle body. Do you happen to know what these cars should idle at normally? Mine is idling at about 1200rpm right now, just wondering if it should be any lower. Once again, thank you for your help 🙂
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post #4 of 7 (permalink) Old 10-22-19, 19:58
 
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That's good to hear!

Just to be sure: you adjust the idle with the big Phillips (X) screw that is embedded in the top of the throttle body. Don't touch the tiny little screw that is near to where the throttle cable ends (if you did touch it, try to put it back to where it was originally).

With a fully warmed up engine (it's set to idle much higher when cold), the idle should be 700rpm +/- 50rpm.
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post #5 of 7 (permalink) Old 10-22-19, 20:12 Thread Starter
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Quote:
Originally Posted by NickR View Post
That's good to hear!

Just to be sure: you adjust the idle with the big Phillips (X) screw that is embedded in the top of the throttle body. Don't touch the tiny little screw that is near to where the throttle cable ends (if you did touch it, try to put it back to where it was originally).

With a fully warmed up engine (it's set to idle much higher when cold), the idle should be 700rpm +/- 50rpm.
Yeah I adjusted it using the big phillips screw and it seems to be running really well now and starts very easily compared to before which is great! It's funny how much a single vacuum line can throw everything off on these cars, but I'm just glad it's running good again! 🙂
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post #6 of 7 (permalink) Old 10-22-19, 20:19
 
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Just for a laugh, remove the oil dipstick when the engine is idling normally. It should create enough of a vacuum leak to stall the engine.
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post #7 of 7 (permalink) Old 11-2-19, 10:43
 
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If I recall, recommended idle is 750. I never really got that to work that well, because when it is in gear and idling, it drags down the rpm from when it is in neutral. If 750 is the recommended idle when in neutral, it doesn't work for me. I set mine to 1300 at neutral, then when in gear, it idles at 750. Talking about an automatic. I even think that may be helpful for longer engine life, as you always want the oil circulating at a good rate.

They say vehicles run on the highway all the time have only 10% of the wear that vehicles that stop and go do.

Last edited by Goodbar; 11-5-19 at 8:40.
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