'88 XJ-S failed smog check spectacularly
#21
![Default](/forum/images/icons/icon1.gif)
Yes, but the FI system on this model doesn't rely on air metering for mixture control. Instead, it uses a baro sensor.
If there's an air leak of some kind the fuel injection system doesn't know where it's coming from. The baro sensor "sees " the leak simply as a throttle that is opened a bit wider (and, in fact, with an air leak the engine speed will increase) and responds to the extra incoming air by increasing the injector pulse width, thus keeping the mixture in balance.
Cheers
DD
If there's an air leak of some kind the fuel injection system doesn't know where it's coming from. The baro sensor "sees " the leak simply as a throttle that is opened a bit wider (and, in fact, with an air leak the engine speed will increase) and responds to the extra incoming air by increasing the injector pulse width, thus keeping the mixture in balance.
Cheers
DD
Thanks for all the input, everyone!
#22
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,817
Received 10,867 Likes
on
7,149 Posts
#23
![Default](/forum/images/icons/icon1.gif)
•ECU not adjustable from lean to rich-
•Fuel pressure regulator putting out fuel at 38 PSI instead of 29 PSI
and... the big one:
•The wiring harness in the V where the O2 heating elements ground, not grounded so the sensors were never getting up to their operating temperature.
When we first bought the car, I brought it to our regular mechanic who serviced my VW and works on my wife's Suburu. I asked them to have the XJ-S smog checked and it passed with flying colors.
They replaced the steering rack but felt they were out of their depth on most of the other repairs, so they outsourced the car to their local "Jag expert" who replaced the valve cover and cam cover gaskets which were gushing oil, overhauled the distributor because I insisted (per Kirby Palm's book) and overhauled most of the cooling system. Anyway, it would seem he left all of the grounding eyelets for one of the wiring harnesses disconnected and lying at the bottom of the V so my car has been gross polluting since he gave it back to me in December of 2012.
As soon as my current mechanic grounded the wiring harness, the sensors started operating properly and the emissions dropped back down to normal.
Now my ECU can be adjusted from lean to rich, the fuel pressure regulators are working properly and the 02 sensors are working efficiently- for the first time since I've had the car.
Last edited by Rhett; 02-18-2014 at 01:48 PM.
#24
#25
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,817
Received 10,867 Likes
on
7,149 Posts
#26
![Default](/forum/images/icons/icon1.gif)
If I take it up with my mechanic, I'd like to have some solid backup.
Cheers,
Rhett
#27
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,817
Received 10,867 Likes
on
7,149 Posts
#28
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,817
Received 10,867 Likes
on
7,149 Posts
The following users liked this post:
Rhett (02-20-2014)
Thread
Thread Starter
Forum
Replies
Last Post
VinnyT
XJ XJ6 / XJ8 / XJR ( X350 & X358 )
69
05-17-2021 09:30 AM
dragonfly777
Regional
0
09-08-2015 01:39 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)