Hello guys
I am based in Germany and currently struggling with emission problems with my ‘94 5.0 SN95.
I am not familiar with other emission checks but for us the car has to run with Lambda 0.97 - 1.03 during the emission control procedure.
My first try ended because Lambda was ~1.8 - so too lean.
The car idles good and also feels as if it’s not lacking any power.
I checked for vacuum leaks with a smoker and got rid of all the visible leaks.
2nd emission checked unfortunately had the same results.
After treating the exhaust and its leaks I checked again with no success.
While desperately trying to solve this issue I unplugged the vacuum hose of the Smog Pump bypass valve which lead to lambda dropping down to 1.04.
You can feel constant vacuum on the mentioned hose when unplugged.
Checking with a manual vacuum pump I was able to find out that the diverter valve can change between its two outputs.
I took off the hose that is connected directly to the Air Pump and attached my smoker.
I was then seeing smoke being vented to the atmosphere as expected. However when vacuum is applied to the valve (which should - as far as I know - direct all the air to the second valve) there was still smoke leaking from the bypass valve.
Also when triggered the diverter valve was leaking smoke out of the small holes in its casing.
My EGR valve has been deleted by the former owner just to mention.
Sometimes the engine stalls while maneuvering.
Maybe these problems have something in common.
I’m desperately looking for a solution so that I can finally have my SN95 registered and on the road again after almost 20 years.
Thanks for any advice in advance.
I am based in Germany and currently struggling with emission problems with my ‘94 5.0 SN95.
I am not familiar with other emission checks but for us the car has to run with Lambda 0.97 - 1.03 during the emission control procedure.
My first try ended because Lambda was ~1.8 - so too lean.
The car idles good and also feels as if it’s not lacking any power.
I checked for vacuum leaks with a smoker and got rid of all the visible leaks.
2nd emission checked unfortunately had the same results.
After treating the exhaust and its leaks I checked again with no success.
While desperately trying to solve this issue I unplugged the vacuum hose of the Smog Pump bypass valve which lead to lambda dropping down to 1.04.
You can feel constant vacuum on the mentioned hose when unplugged.
Checking with a manual vacuum pump I was able to find out that the diverter valve can change between its two outputs.
I took off the hose that is connected directly to the Air Pump and attached my smoker.
I was then seeing smoke being vented to the atmosphere as expected. However when vacuum is applied to the valve (which should - as far as I know - direct all the air to the second valve) there was still smoke leaking from the bypass valve.
Also when triggered the diverter valve was leaking smoke out of the small holes in its casing.
My EGR valve has been deleted by the former owner just to mention.
Sometimes the engine stalls while maneuvering.
Maybe these problems have something in common.
I’m desperately looking for a solution so that I can finally have my SN95 registered and on the road again after almost 20 years.
Thanks for any advice in advance.
