85 ingnition question
Thread Starter
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Freshman User
Joined: Dec 2006
Posts: 34
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From: Alaska
85 ingnition question
Hello,
I was searching the forums and found a post by Canandianice from 10-24-07 that may be what I'm looking for, see below:
Okay this may be an old thread but the problem it talks about has been happening to my truck every day in the morning cold weather. The good news is I figured what the problem was. When the 85/84 bronco II's first start up in the morning in very cold weather the heater door in intake air cleaner must actuate in order for the motor to suck air that is flowing over the exhaust manifold. This allows the fuel to atomize properly as the engine sucks the warm air from over the hot exhaust manifold. The 84 and 85 systems are very different. My trucks heater door is actuated through a bimetal spring system attached to the bottom of the air cleaner. The 85 system actuates the heater door from a system on the passenger side Vacuum rail. Whatever year and system this is it does not matter as long as the door is functioning properly. If the system is not working right the ECM intake air temperature sensor will read that the intake air charge is to cold since its not getting the hot air from over the exhaust manifold. This throws the trucks computer into some kind of retard mode cause the truck to want to stall. So I got the heater door system working perfect on my truck and i no longer have this early morning cold air problem. I figured this out by testing if the hot air would make a difference by shooting warm air into the intake air stream Via a Blow dryer. So I hope this helps anyone who has been stumped by this problem, it only took me a year to figure it out.
What I'm wanting to know is how you fixed the heater dorr working, mine is inop and everyone I've found in the junk yard won't hold a vacume and forget trying to get a replacement.... Thanks in advance for any info.
I was searching the forums and found a post by Canandianice from 10-24-07 that may be what I'm looking for, see below:
Okay this may be an old thread but the problem it talks about has been happening to my truck every day in the morning cold weather. The good news is I figured what the problem was. When the 85/84 bronco II's first start up in the morning in very cold weather the heater door in intake air cleaner must actuate in order for the motor to suck air that is flowing over the exhaust manifold. This allows the fuel to atomize properly as the engine sucks the warm air from over the hot exhaust manifold. The 84 and 85 systems are very different. My trucks heater door is actuated through a bimetal spring system attached to the bottom of the air cleaner. The 85 system actuates the heater door from a system on the passenger side Vacuum rail. Whatever year and system this is it does not matter as long as the door is functioning properly. If the system is not working right the ECM intake air temperature sensor will read that the intake air charge is to cold since its not getting the hot air from over the exhaust manifold. This throws the trucks computer into some kind of retard mode cause the truck to want to stall. So I got the heater door system working perfect on my truck and i no longer have this early morning cold air problem. I figured this out by testing if the hot air would make a difference by shooting warm air into the intake air stream Via a Blow dryer. So I hope this helps anyone who has been stumped by this problem, it only took me a year to figure it out.
What I'm wanting to know is how you fixed the heater dorr working, mine is inop and everyone I've found in the junk yard won't hold a vacume and forget trying to get a replacement.... Thanks in advance for any info.
Post Fiend
Joined: Jun 2002
Posts: 13,873
Likes: 3
From: Atlanta GA
Switch over to a Duraspark II system and ditch the computer. On 1980s Chevys people ditch the carb for Holley and ditch the computer for a normal HEI distributor.
That being said, if you are talking about the one on the air cleaner intake neck, the Chevy setup is almost the same as the Ford. Drill out the two rivets in the Chevy system , remove it, and I bet it would fit the Ford.
That being said, if you are talking about the one on the air cleaner intake neck, the Chevy setup is almost the same as the Ford. Drill out the two rivets in the Chevy system , remove it, and I bet it would fit the Ford.
Thread Starter
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Freshman User
Joined: Dec 2006
Posts: 34
Likes: 0
From: Alaska
I would if I could but I can't. You know, not everyone lives in an area without emmisions. I'll check into Chevy parts though, thanks for the thought. I'd prefer to keep it original if I can.
