Strange idle (Common '90 issue)
#1
Full Member
Thread Starter
Join Date: Jan 2008
Location: Calgary,AB
Posts: 91
Likes: 0
Received 0 Likes
on
0 Posts
Strange idle (Common '90 issue)
I have a 90 FC and it has a strange idle. When stopped and no pedals depressed, the idle will fluctuate slightly from 400-700 rpm. I did a little research and I heard this was a common problem for the '90 model only and it requires placing an orifice in the Idle Air Bypass Valve. Anybody have any idea what this means or has anyone done it themselves? Any help would be greatly appreciated. Thanks.
#2
Former Moderator. RIP Icemark.
uh, yeah right a orifice on the idle air bypass value... who is feeding you that crap?
The 89 though 91 used the same everything as far as the motor is concerned... so saying it was a '90 only problem would be wrong.
It sounds like you have a TPS that is out of adjustment. Not some made up missing orifice.
The 89 though 91 used the same everything as far as the motor is concerned... so saying it was a '90 only problem would be wrong.
It sounds like you have a TPS that is out of adjustment. Not some made up missing orifice.
#4
Full Member
Join Date: Oct 2007
Location: I-55 @ I20
Posts: 152
Likes: 0
Received 0 Likes
on
0 Posts
When I got my 87 back it would do that jumping mess. It didn't seem to hurt anything but wasn't cool.
Besides adjusting the TPS (which didn't help my case). But first I adjusted the TPS blindly and it solved the fluctuation, but that caused the TPS to probably be way out of adjustment which caused the engine to stall at WOT above 5k rpm.
So, spend the three bucks on a TPS tester.
And something else I haven't figured out was the 10mm adjusting nut on the throttle body. My neighbor did this and was much better afterwards. He told me not to ever mess with it, so I assume you can do some harm if you do it wrong.
Besides adjusting the TPS (which didn't help my case). But first I adjusted the TPS blindly and it solved the fluctuation, but that caused the TPS to probably be way out of adjustment which caused the engine to stall at WOT above 5k rpm.
So, spend the three bucks on a TPS tester.
And something else I haven't figured out was the 10mm adjusting nut on the throttle body. My neighbor did this and was much better afterwards. He told me not to ever mess with it, so I assume you can do some harm if you do it wrong.
#5
Full Member
Thread Starter
Join Date: Jan 2008
Location: Calgary,AB
Posts: 91
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for the input people. The orifice idea came from carreview.com I believe. I found it a little strange too that they said it was a '90 only issue because all S5 engines should be the same.
Thread
Thread Starter
Forum
Replies
Last Post