I have a 1984 XJ6 that I've owned since 1995. I was a Jag tech from 1980-1992 and am aware of the gremlins that come with these rides. I had the engine rebuilt 10K miles ago, replaced all injectors and wiring harness, cold start sensor, O2 sensors, fuel pump and change over switch and so on. It always ran well for me over the years but about a month ago, she started to sputter and stall out at an idle and eventually while driving, which was kind of scary. Once I got it back home I checked out the fuel pump which was working intermittently. Upon checking wire connectors at the pump relay, I found them loose on the spade connectors. After adjusting the connectors to fit more snugly, turned on the ignition and opened the air flap on the AFM. The relay clicked on and off as I opened and closed the flap but then it became intermittent. I swapped out the relay with a new one but ended up with the same result. On a hunch I decided to open the AFM. I know this may be taboo for some techs out there, but this little unit had been operating for 38 years, 266,000 miles, parts do wear out, wouldn't hurt to check it out. The AFM flap is attached to a resistance "wiper". Attached to that is a stem that actuates a switch to the relay. With ignition on, flap open, applying a little pressure to the copper arm of this switch manually, the relay clicked on and the pump worked continuously. After cleaning the contacts with electronic contact cleaner and ever so gently bending the copper arm for better contact, the intermittent problem was gone. After startup, idle was ok (a little lumpy but did not stall out), but had an off idle stumble. Applying a little pressure to the resistance "wiper" with a Q Tip, the stumble went away as I opened the throttle. On the resistance wiper itself, I cleaned the board with contact cleaner and a Q Tip and gave the copper wiper a couple of swipes with 2000 grit sandpaper and a bend ever so gently (and I do mean gently, these are fragile as is the board so just the slightest amount of increased pressure need be applied) for better contact between the wiper and board. After this, the lumpy idle went away as did the off idle stumble. Idle stays at a smooth 800rpm without a bump. I only had to make one major adjustment and that was to the stem that actuates switch to the pump relay. It would bounce back after revving the engine and turn off the fuel pump causing a stumble. Once adjusted properly, stumble was gone and pump would shut down when ignition off. All in all this was a simple fix. Just have to be very careful when manipulating these little copper pieces around. After driving for a few weeks now, she drives better than ever. These Jags always had an idle issue from brand new and I wonder if weak contact settings in the AFM's were the problem. Factory would void warranty on AFM if we opened one up and that was always a taboo issue. I wish I would have done this 10,000 miles ago.

 

Great writeup!! I watched a YouTube video on cleaning up an AFM and now with your description I believe I will try my hand at it. I have a spare AFM from a junkyard car so easy to refurb and swap into my car.

Thanks. Randy

 

vickxxx: thanks for taking the time to document your experience and resolution. i would imagine your topic affects most of us on this forum. i know i will do as randy did and get a spare at the local yard and experiment following your instructions. thanks again for documenting a solution. too often members post their problem but not enough post a solution. i'd like to see an enhancement made to this forum whereby the author of a post could check a box indicating their problem was resolved after posting their solution. we could then search on topics with solutions. it's irritating to read a long thread and never discover the answer. nice job. ren

 

Glad you enjoyed the topic Ren. When you do go to pick up another AFM from the yard, best find one that has not been opened. At least you will know the settings are still set to factory specs and hasn't been tampered with.

 

I have a 1984 too and have not had to mess with anything

 

I have an 83 and messed with it big time!!!

Carl

 

vickxxx, This is more than worthy, especially as these cats age so gracefully. If you could find it in yourself to do a video as to how you did this, I for one would be immensely grateful. Perhaps it could be a sticky! Ian