CarlSimo

Well I have had a new MAF installed, Fuel Pump, Turbo valves.. The Engine has been dropped (which cost me a lot in man hrs out here) to check hoses etc. Now may have to be dropped again to go over wiring... The one thing that phases me is the lack of power every now and then the car limps, has no power and is nearly stalling on take off.. And other times its fine.. But ultimately the lights come on eventually and I lose boost and it drives horribly again. Must illuminate some mechanical things due to its inconstancy?!

Will see what he comes up with the next couple of days before he feels we need to drop the engine..

"02996ttx50

welcome to "limp mode" a condition the ecu creates that limit the cars ability to exceed 4k rpm or whatever it is. to save itself from your as yet, undiagnosed issue(s).

jeanmarcboilard

Your ecu is receiving a signal from somewhere telling it something is wrong. It then cuts back on your throttle position to protect the motor "limp mode". That's why you're only getting 0.4bar. Get yourself a Durametric cable and get some readings from your ecu to see what's going on. If you can't get the cable, start by doing a pressure test on your intake and look for leaks. A visual check won't cut it, do a pressure test and listen for leaks. Your MAF fault code is telling you that your MAF is sending the ecu a reading that doesn't correspond with other signals it's getting. So if your MAF is functioning correctly then you know that there is a discrepancy between the amount of air entering your intake and the other variables your ecu is reading. I might be wrong but all your fault codes seem to be related to air issues, MAF, O2, boost.

dc3843

Check your knock sensors...

Mine was doing the same thing, throwing all sorts of weird codes, running fine then falling on its face. We went to replace the knock sensors, a rat had chewed up 6 wires going to the sensors. once we fixed them it was fine. (Previous owner let the car sit outside a LONG TIME. I just bought it.)

CarlSimo

Thanks guys I am going to take these suggestions to the garage tomorrow. Been faulty for well over 2 months... Replacing bits and getting nowhere! Just want it fixed already

wross996tt

Here are your faults and possible causes:

P0103: 115 Mass Air Flow Sensor - Above Limit
Possible fault cause
♦ Intake air system on pressure side (between turbocharger and
engine) leaks
♦ Short circuit to B+
♦ Mass air flow sensor faulty
♦ Throttle jacking unit faulty

P1107/08: Oxygen Sensing Adaptation, Lower Load Range, Bank
1/2 – Below Limit
Possible fault cause
♦ Incorrect signal from MAF sensor
♦ Fuel pressure too high
♦ Fuel injector leaking

P1109: Input Variables, charge measurement - above limit
Possible fault cause:
♦ Heavily soiled throttle
♦ Throttle adjusting unit faulty
♦ Mass air flow sensor faulty

P1250: Boost Pressure Control Deviation - Above Limit
Possible fault cause
♦ Bypass flaps incorrectly adjusted
♦ Turbocharger faulty

So there may be more than one issue, when was the last time you cleaned the throttle body? Still MAF issues (I would get the voltage reading on the MAF...0.9-1.1V ignition on, 1.2-1.5 at idle). Lastly, check the wastegates.

Load values of the 911 Turbo (996)
Mass air flow ML in kg/h CLV in %
Idle speed 16 - 20 1.45 - 1.82
No load, n=3,000 rpm 60 - 80 5.45 - 7.27

CarlSimo

Thank you appreciate the detailed advice, we checked the throttle and that seemed to be ok. We did the MAF readings, no obvious pressure leaks either so we are replacing the Wastegates.. I did ask them to check the Knock Sensors so hopefully they did that too...

drh

Excuse my ignorance, but how could your turbos "not work". I would think if low boost is occurring with turbos that are a manual device, then one might consider looking at the boost hose to see if it came loose slightly (perhaps by the intercooler) or above.

I had a hose come loose because I didn't secure it properly while changing plugs and the MAF and I got the ABS/PSM waring.

But what do I know...

CarlSimo

lol funny enough there was a loose hose, but we attached it reset the computer and still the same issue occurs. So we did a pressure test and the next step they say is the wastegates... So let's see 😌

Kevin

If the turbocharger wastegates doors are corroded shut you typically get a overboost limit CEL. As a result the car will go into limp mode. If the gates are corroded in an open state, the turbochargers will not have enough exhaust energy available at the turbine wheel to make boost. The car will be laggy and poor on performance.

If your car was stored outside, I would look at the knock sensors, and the connections. They sensor if NOT working will put the car into limp mode.

CarlSimo

Thanks Kevin, they seem to be ok I have been told. Wastegates are on order from Germany so it's the waiting game for me for about 10 days to find out if this is the issue.