850R with intermittent engine mgmt light but no codes
 

Hi, I have an intermittent problem on my 850R Estate/Wagon and thought I'd join this site to see if anyone can shed some light on possible cause. The problem I have is the engine management light (green triangle in red square) comes on intermittently and when it does come on I notice that the turbo doesn't kick in. Even under load the needle on the turbo gauge only goes to the half way mark and not in the zone to indicate turbo boost. However, either in the same journey or a journey or two down the line the turbo is back in action but the management light stays on. If the turbo keeps kicking in for a few more outings/journeys the engine mgmt light eventually goes out but it's not long before it's back on again and the turbo boost doesn't kick in. Just a few weeks ago everything ran as it should for three weeks with regards to the turbo boost and no sign of the engine mgmt light only to start playing up again.

My mechanic can't get any stored codes out of the ecu as he thinks his ODB II reader has had updates and for some reason can't communicate with my 1996 850R ecu. I have called in when the light has just come on and when it has been on for a while to no avail. I have tried the hack with the switch and LED which canget codes from the ECC pin 6 and traction system (I think) pin 13 but nothing from pin 3 which again implies no codes !?

I have just bought a Streetwise ODB II reader from eBay which seems to connect to the ecu as I get a reading status but again no codes !!?? I'm really at a loss as I'd rather have an error code to point to the problem rather than start replacing things as a process of elimination. My guess is that a sensor might be on it's way out, working one minute and not the next - perhaps the MAF sensor ??

Any help would be much appreciated :-)

not having boost gives you a starting point - check the actuator rod to the waste gate and see if its able to move freely. Also check vacuum lines and intake air path for leaks as this can cause the boost to drop out.

Thank you for the pointers. I will take a look.

When I bought my 850R it came with two ECU units, one mapped and one standard. I had the mapped ECU in when the boost started to intermittently work and fail along with the engine management light coming on. As I had no luck reading the codes I swapped the ECU's around and have been using the standard one. Initially no engine management light for a few days which was wierd as the turbo definitely isn't boosting any more so I would have thought the engine mgmt light should have come straight on?? When an ECU relearns the car does it take it's current status as the default? in my case without the turbo working? The engine management light has come back on and I was actually able to read the code (only one) which was 2-3-1 Long term fuel mixture too lean or too rich in part load stage - is this likely to be the original code when the turbo was on and off or do you think this code likely relates to the effects now of the turbo not kicking in (boosting) - prior to getting this code my mechanic suspects the actuator arm has come loose but hidden behind heat plate.

heat plate is held on by 3 bolts - easy removal, then check the waste gate rod - it can be adjusted as well - check around for the recommended adjustments