OK, am I being stupid....?

[johnb]

2003 W210 I6 320 CDI

On going soft limp after a few miles.
Done all the standard things, reports boost error P1470.
Had some spare time today, ripped into the car and pulled both the vacuum valves EGR and turbo, notice that when not powered, ie on my bench they both pass vacuum....

Light bulb moment......DING.....I have the EGR shunt mod fitted, and have disconnected the power to the vacuum valve but not the vacuum lines themselves, so the poor old EGR valve has been held open all this time... no wonder a boost problem.

Haven't got time for a test drive.... but I'm hopeful that's sorted it.

What say the collective?

 

[renault12ts]

Mine works, only disconnected the power not the vacuum lines.

 

[johnb]

Maybe your EGR valve is blocked up or not working so its not responding to the vacuum passed by the control valve.

The EGR valve on my car works because I stripped it down and cleaned it out prior to fitting the diode resister mod.

Going to fit a blanking plate as well today, just to ensure that nothing passes thro the exhaust gas port.

 

[johnb]

Well it wasn't that then, still throwing P1470 codes.

New:
MAF
MAP
Glowplugs
Intercooler plumbing all OK
Vacuum pump output checked
Inlet port valves OK

That leaves:
Turbo itself
Turbo vacuum actuator

Anyone have any other ideas?

John

 

[johnb]

Before I set fire to this damn car.

Glow plug warning now come back on - been off for about 10 days - yippee. Do these engine eat glow plugs or what?

With egr mod fitted, blanking plate fitted and remembering to clear error codes out before going for a drive - doohhhhh!

Boost problem resolved no more P1470 codes - Yehhhhhhhh.

But now I have P0100 (Hot film mass air flow sensor) which is a brand new Pierburg one.

So, thinking that cant possibly be the problem, I have stripped out the egr resister diode mod, removed the blanking plate, reinstated the EGR vacuum valve control, cleared the ecu...and gone for a drive 1,2 3,4 .........Limp

Drive home connnect diagnostics, and I have P0100 Air Mass Sensor again.

WTF

So no boost errors, no egr errors, just Air Mass Sensor error.

Petrol can standing by.........................

 

[johnb]

While i was in there I checked the continuity on the wiring from the Air Mass Sensor to the ECU plug - all OK, Gnd, 12v and 5V and sensible looking signal - varying with revs on the yellow (pin5) wire at ecu end.