This has happened once before, about 2 months ago and I thought I'd fixed the problem by jiggling the flywheel position sensor leads...

Today I took the 951 out for a short drive after fitting a new rear sway bar from Lindsey. At about 7km from home and going down a hill at 60km/h, the car started missing and surging. Hitting the throttle had no effect and it was obvious that the engine was going to stop as soon as I chose neutral. Coasted to a halt off the side of the road, popped the bonnet and looked for loose wires/hoses etc. All OK. Replaced the DME relay (of course). The engine would catch, rev to 1500, then immediately die. Wiggled the FPS wires and tried to start again. No change. This was quite repeatable for some time, but with some throttle applied, would JUST continue running, with clouds of black smoke emanating from the exhaust. Just wondering if there might be a fault with the 3bar FPR causing over-fueling... Rang my wife to come and collect me so I could return with another FPR. 10 min later, she arrives. I gave the ignition one more try, and it started and ran normally. Drove home and parked it in the shed. I hate intermittent faults.

Car has Rogue A-Tune, Fabspeed turbo-back exhaust and a Tial wastegate. Your advice would be most welcome...

Rob

 

Sounds like what I had. It was a sticking AFM - do you still have the stock one? If so, worth checking it out, and while you're there, pop the top off and check the wiper contacts aren't worn (if it's original they probably will be) - if so you can adjust the wiper arm slightly to a new contact area. There are You tube videos on this.

 

Sounds logical. Car still has the standard AFM although there is some silicone sealant visible at the joints. I've only had this car since January and am still getting to know it and tune it to my liking.

I'll have a look at the You tube videos and give it a go.

Thanks for the advice.

Rob

 

Today, I pulled the AFM and observed a slight ridge in the AFM floor at 30 degree opening angle of barn door, but no other signs of stickiness. Used 400# wet & dry paper on the ridge, then tested the operation of the resistor strip as per Clark's Garage procedure - all good. Re-assembled AFM and engine started as per normal. Took it for a short drive. I don't know if it's the power of suggestion, but off-boost performance seemed to be smoother and more responsive. As for the fault, it didn't recur, but of course it's an intermittent one and only time will tell.

However, if anyone has any similar experiences that haven't been AFM-related, let's hear about them.

Thanks

Rob

 

Bruce had a similar problem with his AFM. his flapper was getting stuck. causing a rich condition and for the car to stall, hesitate ect.