S4 AFM problem (too much g force)
11-30-02, 04:52 PM
#1
No longer cares
Thread Starter
Join Date: Apr 2002
Location: just a bit north of your business
Posts: 1,345
Likes: 0
Received 0 Likes
on
0 Posts
S4 AFM problem (too much g force)
So I have a healthy monster ported n/a and it runs great with the exception of a very lacking stock fuel system (I'm working on it!) but I have this little annoying problem....
When I connect on launching hard 1-2 and 2-3 shifts I can actually slap the flapper door in the AFM wide open and it reads 100% on the s-afc. This occurring at 4K rpm or so obviously causes the engine to flood (seeing as I normally hit 61% or there abouts) and then the car chokes and spits out the black nauxious fumes and then she runs fine again.
I tested the AFM in the car by prying it open while the car was off and it reads up to 62% when completely opened UNLESS you slap the thing against the housing (full travel) and then it'll read 100%. I tried the same tests with another spare AFM hooked up and got the same results.
Other than transversely mounting the AFM back by the TB what can be done to correct this situation and has anyone else experienced it?
I'm running little shitty tires untill I can afford my new rims and tires, so the problem will only get worse in the future. I need some help on this one.
When I connect on launching hard 1-2 and 2-3 shifts I can actually slap the flapper door in the AFM wide open and it reads 100% on the s-afc. This occurring at 4K rpm or so obviously causes the engine to flood (seeing as I normally hit 61% or there abouts) and then the car chokes and spits out the black nauxious fumes and then she runs fine again.
I tested the AFM in the car by prying it open while the car was off and it reads up to 62% when completely opened UNLESS you slap the thing against the housing (full travel) and then it'll read 100%. I tried the same tests with another spare AFM hooked up and got the same results.
Other than transversely mounting the AFM back by the TB what can be done to correct this situation and has anyone else experienced it?
I'm running little shitty tires untill I can afford my new rims and tires, so the problem will only get worse in the future. I need some help on this one.
11-30-02, 06:59 PM
#2
Rotary Enthusiast
Join Date: Aug 2001
Location: Tallahassee, FL
Posts: 1,402
Likes: 0
Received 0 Likes
on
0 Posts
Time to upgrade to an S5 unit. 
With the correct wiring harness diagrams it's easy to do. In the mean time, make sure that your AFM is mounted completely flat and level.
Brandon
With the correct wiring harness diagrams it's easy to do. In the mean time, make sure that your AFM is mounted completely flat and level.Brandon
11-30-02, 09:46 PM
#4
No longer cares
Thread Starter
Join Date: Apr 2002
Location: just a bit north of your business
Posts: 1,345
Likes: 0
Received 0 Likes
on
0 Posts
I've looked into the S5 swap, but the impedence is not the same between the units. I'd be more interested in making something that converted it to a hotwire maf.
The wiring diagrams are in both of the FSM's availible over on fc3s.org's site.
My afm is straight and level mounted off one of the original air box mounts. Some form of viscous mounting could potentially eliminate the impact which causes the eratic reading going from 60's to 100%. I just don't want to waste my time with band-aide's on this thing. For the money I'd spend swapping the S5 unit I could have a megasquirt.
The wiring diagrams are in both of the FSM's availible over on fc3s.org's site.
My afm is straight and level mounted off one of the original air box mounts. Some form of viscous mounting could potentially eliminate the impact which causes the eratic reading going from 60's to 100%. I just don't want to waste my time with band-aide's on this thing. For the money I'd spend swapping the S5 unit I could have a megasquirt.
11-30-02, 11:14 PM
#5
Rotary Enthusiast
Join Date: Aug 2001
Location: Tallahassee, FL
Posts: 1,402
Likes: 0
Received 0 Likes
on
0 Posts
You can straight wire in an S5 AFM into an S4 car - the impedences are very much the same. I've seen it done and the car ran fine (it's Dale Clark's car).
Brandon
I've seen it done and the car ran fine (it's Dale Clark's car).Brandon
12-01-02, 01:49 AM
#6
No longer cares
Thread Starter
Join Date: Apr 2002
Location: just a bit north of your business
Posts: 1,345
Likes: 0
Received 0 Likes
on
0 Posts
My car runs fine too... with the exception of hard shifts. 
S5's are in short supply around here for parts.
I'm really thinking of just dealing with slipping the clutch untill I go stand alone at this point.
Anyone else have this problem before?
S5's are in short supply around here for parts.I'm really thinking of just dealing with slipping the clutch untill I go stand alone at this point.
Anyone else have this problem before?
12-01-02, 02:03 AM
#7
Senior Member
Join Date: Nov 2001
Location: Spearfish, SD
Posts: 725
Likes: 0
Received 0 Likes
on
0 Posts
could you not some how rig up your intake to allow it to go sideways? I have a tII and I am thinkin that would solve your problem but maybe you cant w/ your intake setup.
Trending Topics
12-01-02, 02:34 AM
#8
No longer cares
Thread Starter
Join Date: Apr 2002
Location: just a bit north of your business
Posts: 1,345
Likes: 0
Received 0 Likes
on
0 Posts
I actually mentioned that option in the initial post here. I have a buddy who owns a speed shop and he's got a bunch of cold air kits that might have a 3" sleeve i could rig up to the afm and move it back to the TB area. I'm not positive it'll even fit back there though. I'd really like to not mess with it unless I'm improving the whole setup. Lots of fab time that could be better used to further my new plenum or large single TB ideas.
the more I mess with it the more I realize what a pile of crap our stock ecu's really are...
the more I mess with it the more I realize what a pile of crap our stock ecu's really are...
Thread
Thread Starter
Forum
Replies
Last Post
Jeff20B
1st Generation Specific (1979-1985)
73
09-16-18 07:16 PM
