What I have:

1989 Mazda RX7 N/A

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The Problem:

Car does not start without a lot of effort when in my driveway which is very steep… Starts great anywhere else (so far)…

It idles erratically when coming to a stop but smoothes out when completely stopped…

It bucks or lunges when coasting at an idle…

It has begun backfiring occasionally when I am at high RPM’s and I release the throttle…

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What I Have Done Previous To The Issues:

I just put an aftermarket intake in... It is the modified prelude intake of course... Well I made my own little version since it did not seem to fit the way it was pictured in the previous threads... I added a crude Paint Brush illustration below…



[attachment=41438:attachment]



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The questions:

I have read that the AFM must be level in the car...

I thought this was only for the S4 "Door Type" AFM...

I have the S5 and it has the "Spring Loaded Cone" style AFM...

Does my AFM have to be level, and would this be the cause of the problems?

Does anyone have any other suggestions that would help?

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I hope I simplified this long drawn out thread and I thank anyone who is able to help…

 

I would say that yes.. gravity could affect it. Try parking the other way in your driveway. Like.. if you normally pull straight in... back in this time. See if that helps.



But according to your diagram, if you had the *** end of the car elevated, the AFM would be almost vertical. Parking the other way would make it almost level.



EDIT: Also.. You should probably try some common troubleshooting techniques as well. Like adjusting your TPS, checking the plugs, etc.

 

when you engauge the "start" position, the ecu ONLY looks at a couple of things, coolant temp and rpm being the important two. the car DOES NOT use the afm to start.

 

But if it was harder to open by pulling air past it (being pulled down by gravity). Wouldn't it restrict air flow considerably?

 

Just an update... I leveled the AFM and it has not had a probem with not starting since... It still floods 1 out of 10 starts but it always did that...

 

If the afm is anything like the Ford Probe GT - mazda V6 (the way you explain it sounds so "spring loaded cone" looks like an egg...) there have been people who have had the same issues when its not level. It is rediculously sensative, so much as pulling the dipstick can cause a stall on the PGT. The cone however isnt heavy enough to cause much of an air restriction though, atleast I wouldnt think so. Simply a bad measurement