Not my week

[924nutter]

Having had the headlight switch go intermittent is secondary to the check engine warning that was my original problem. This warning has started to flash momentarily (one or two seconds) then clear for a couple of months now. I had the fault codes read by a respected independent and it showed a fault on bank one and bank two which further down the tree had a third fault relating to "inlet charge" so the air mass sensor was swapped with a test sensor for me to test for a few days. This was Tuesday. On the way back from the OPC after picking up my new headlight switch today, the check engine warning came on again. Has my car eaten the test sensor or could this be something like a loose or corroded connection. With all this wet weather I have not been able to put the car away or cover it over because I cant get hood dried out sufficiently. Does this sensor have a current put through it to burn off deposits like the 928? If so it it at all likely that this circuit has broken down and that after two days the test sensor is sufficiently dirty for the engine management system to pick this up as a fault. At a steady 70 on the way back home I showed 23.9 mpg and the engine ran well but there seemed to be the slightest hesitation on hard acceleration. Any thoughts?

 

[Richard_Hamilton]

Do you have the fault codes that were displayed?

 

[924nutter]

No Richard unfortunately. The shame is it was at the end of the working day squeezed in due to absence of courtesy car. I only got a glimpse at the laptop screen. Currrently the specialist is reviiewing the codes to see if he can make sense of it as his apprentice wrote them down but out of courtesy (I haven't paid anything yet) I wouldn't dream of asking him to give me them. It isn't Northway, but someone close to me and of comensurate competence and reputation. I am just impatient as I have a 23,000 mile, £36k car sitting outside that I don't want to drive in case I damage the bores through bore washing because of an over rich mixture, or burn out a valve or piston because it is too lean.

I will just have to slum it and drive the 944T Cab to the Product Supply reunion tomorrow.

 

[Richard_Hamilton]

I guess Nettlebed isn't far from you?

It is a bit of a stab in the dark without the fault codes, but if it is recording misfires on both banks, then it is likely to be something which affects both banks. ie. the MAF or inlet manifold pressure sensor, rather than an O2 sensor, which would only affect one bank.

Could it have been P1101 or P1109? Input variables, charge measurement - above/below limit

Possible fault cause:
Heavily soiled throttle
Throttle adjusting unit faulty
Mass air flow sensor faulty

 

[924nutter]

Hi Richard thanks for trying to help. I think it might have been that, there was defiitely a phrase with the words inlet, charge and measurement.... and on what looked like an inverted family tree, above it were faults on both banks. As it affected both banks we opted to try his "known good" test MAF or that sensor that is attatched with two srerews/bolts on the LHS adjacent to the header tank and partially obstructed by what I guess is the hose from the LH turbo. There was some kind of readout which should have been a steady fifteen that was fluctuating up to seventeen. Since Tuesday evening when we put in the test sensor, until Thurs afternoon everything was looking fine. If I don't hear from him by lunch time Monday I will ring him and see if I can get the fault codes.

On a different subject the dual carriageway at Bix, on the way to Nettlebed had temporary road works last week. Region 19 used to meet at the Fox at Bix, and we also used to stop there on the way back from Silverstone, before the days of the M40, but it has reverted to a private property. The old landlord had a fair old stutter and used to tell this joke" HE WOULD ASK IF WE KNEW THAT THE FOX WAS THE LOCAL CENTRE FOR THE FOUR MINUTE WARNING, AND THAT HE WAS REPONSIBLE FOR BROADCASTING IT. Then he would say "FAT LOT OF GOOD THAT IS GOING TO DO WITH MY STUTTER, BY THE TIME I GET IT OUT IT WILL BE TOO LATE!"

 

[AlexBell]

9/10 times a bank failure is one or more failed coils. (in my personal experince)

For me the 10th was a catalytic converter that needed replacement.

 

[924nutter]

Thanks for your input Alex. Sorry to say the engine runs as sweet as a nut and there is no discernable misfire. Still pulls like a train as several slugs on the way back from Reading were passed with alacrity and a flat six howl from the tubi exhaust, although some twerp tooted me, and I have no idea why he did; straight road, broad daylight loads of space in front, 1/2 mile on the offside, probably had no idea a 911 could overtake so quickly, and was tooting as a conditioned relfex, but I digress. The car has stainless sports catalytic converters, and was indicating 23.9 mpg @70 on the M4. Just to be clear, there were identical fault codes on both banks on a tree, with the input charge measurement fault directly below it, which led us to conclude that the single inlet charge fualt was bringing on the other two. I must ring the garage as I havent heard from them.