air/fuel mixture tool
01-08-2011, 03:27 PM
#1
Rennlist Member
Thread Starter
air/fuel mixture tool
I would like to make an mixture adjustment tool for my 82 928 has anyone made one or know how it works or what it looks like so I can get an idea of how to make it
01-08-2011, 03:41 PM
#2
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Do you have a Euro with CIS or US car with L-Jet?
If CIS - here is what an adjustment tool can look like:
http://www.928motorsports.com/parts/cotool.php
What exactly are you trying to fix? What are the symptoms? Where are you located?
Oh yea - welcome to Rennlist!!
If CIS - here is what an adjustment tool can look like:
http://www.928motorsports.com/parts/cotool.php
What exactly are you trying to fix? What are the symptoms? Where are you located?
Oh yea - welcome to Rennlist!!
01-08-2011, 03:55 PM
#3
Rennlist Member
Thread Starter
mixture
The car is running rich I think it has a strong exhaust smell and getting terrible gas mileage around (13 mpg) I do hear a loud hiss on pass side of engine not sure if this is normal or not all hoses are on and in good shape so I'm thinking the mixture is off!
01-08-2011, 04:19 PM
#5
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
The only "adjustment" for an L-Jet car is the barn door bypass:
https://rennlist.com/forums/8162988-post6.html
Problem is, even cranked down for full rich isn't going to cause your issue.
Back to basics. Make sure your fuel pressure regulators are working and getting vacuum (could be the hissing). The gas smell could be them leaking.
If the regulators are not working and you are getting full fuel pressure at cruise, your gas mileage will be terrible.
The regulators will also be at "wide open" all the time if they are not seeing vacuum.
The only way to accurately test the regulators is with a fuel pressure gauge.
It's not a bad idea to have a fuel pressure gauge on the rail with these cars. Easy way to quickly diagnose issues down the road.
"Poor mans" test is jumper the fuel pump relay and apply vacuum to each regulator with a MightyVac and listen for the pump to strain a little as pressure increases. Not accurate, but it can at least tell you if they are doing something
Also, with the pump jumpered, you can sniff around the regulators for leaks.
The AFM could be worn or broken in some way. Injectors could be leaking / stuck etc..
L-Jet brain could be doing weird things.
Long list, but as I said above. Start with the basics.
Lot's of experts in NorCal too.
https://rennlist.com/forums/8162988-post6.html
Problem is, even cranked down for full rich isn't going to cause your issue.
Back to basics. Make sure your fuel pressure regulators are working and getting vacuum (could be the hissing). The gas smell could be them leaking.
If the regulators are not working and you are getting full fuel pressure at cruise, your gas mileage will be terrible.
The regulators will also be at "wide open" all the time if they are not seeing vacuum.
The only way to accurately test the regulators is with a fuel pressure gauge.
It's not a bad idea to have a fuel pressure gauge on the rail with these cars. Easy way to quickly diagnose issues down the road.
"Poor mans" test is jumper the fuel pump relay and apply vacuum to each regulator with a MightyVac and listen for the pump to strain a little as pressure increases. Not accurate, but it can at least tell you if they are doing something
Also, with the pump jumpered, you can sniff around the regulators for leaks.
The AFM could be worn or broken in some way. Injectors could be leaking / stuck etc..
L-Jet brain could be doing weird things.
Long list, but as I said above. Start with the basics.
Lot's of experts in NorCal too.
