Thanks Ginger, I didnt know the vac details but i do now
Iv been all over the vac side of things and happy they are all okay. I also followed a lot of the harnesses and they all seemed good. I did find box of 3 relays tucked down beside the battery that needed a bit of cleaning up and one of the earth points under the battery tray was re-done but no change.
The second MAF finally turned up but again no change. The second MAF was HASS im sure it was called which is a middle road MAF so I think ill bite the bullet and return this for the seimens one and pay the £120 (Tears)
On the plus side I managed to repair my chinese interface today by replacing the flash chip so at least I can talk to the car again. Ill post a dump from the flash chip in case anyone else gets the issue I had. Ill keep ya'll posted when the new MAF up (Tears again)
Hi, don't buy a replacement MAF just yet, if pp2000 is showing good readings for the new MAF then it should be okay....
£120 is a lot of money, wait for some sort of weekend offer, my new Siemens MAF was £78.. Didn't fix my car though.....
Can you describe how the car drives? Does it have flat spots, delays in boosting? Etc etc...
2003 2.2hdi estate - mine 1998 Volvo 940 auto estate - also mine 2019 Citroen C3 something - the wife's PP2000 user, can help with faults / diagnostics in the Bournemouth area.
I managed to get the car plugged in today and it still shows MAF fault (Permanent Fault, Airflow Meter signal open circuit or short circuit to earth. Flow too low). there are a few others but im sure i can sort them out. I'll upload another image of the screenshot.
The car idles fine but there is a very substantial lack of power and no boost. I can drive it okay(ish) and long as i dont intend to overtake or nip out at junctions.
The RPM's flatten out at 4000 (3500 when cold). Interestingly when I clear the codes, start the car with the pedal to the floor it seems to act normal until the engine management light comes on. i.e It revs to 2500, turbo kicks in and it shoots up too 5000, after a second at 5000 i hear the beep of the em light and the revs drop back to 4000.
When i put a test meter across the MAF plug I find there is 5v when its disconnected but this drops to around 3v when the MAF is hooked up. There are no other voltages present on the plug.
The original seimens MAF does appear faulty as when looking at the inside I can see the small black components still in place but on the other two rails where other components are supposed to live there is nothing. Iv noted the cheap replacements seem to have a resistor and something else strapped across these.
Driving with the MAF disconnected has no impact on the performance at all.
Okay, I'm a bit stumped by the Permanent fault, I would expect this if it was unplugged all the time...
If you have some carb cleaner or connector cleaner knocking around you can ( gently ) spray this onto the filaments in the MAF to see if it shifts any oily residue which may be affecting the readings - Don't use WD40 as it leaves a residue...
I don't really know much about the electrickery side of things, but if the replacement Siemens MAF also has a permanent fault when plugged in then maybe there is a bad connection somewhere?
Ignore the pre/post heating fault - they all do that and glow plugs are not required on these cars unless you live in Siberia.....
Sorry I can't really suggest anything else
2003 2.2hdi estate - mine 1998 Volvo 940 auto estate - also mine 2019 Citroen C3 something - the wife's PP2000 user, can help with faults / diagnostics in the Bournemouth area.
Cheers matey, I have a feeling it's summit to do with the 5 volt getting pulled to 3 volt on these cheaper replacements. The original definitely seemed to be missing a couple of components in there (blown apart I would imagine). I'm taking a punt on ditching the cheap MAF and just buying the original Seimens one. At very least I'll get to see the gubbins inside compared with the one I took out!
New Seimens MAF is in but although it seems the power has came up a little in reality theres still a very flat response, lack of power especially on a slight hill and no boost.
I have put a meter across all the MAF terminals and very possible found a short in one of the sensor returns. I bleeped this back to the ECU but seems the short is within the unit itself. My next question is, do we know the pin outs of this MAF, just to be sure it is a sensor return im looking at?
Okay well i finally got there, im rather ashamed to come clean on the final outcome but i guess it will help someone out at some point.
The original MAF was certainly blown as the hot wires were missing, the common issue I was missing with the cheaper replacements then the genuine replacement was I was assuming the 5v coming up to the MAF was the only supply. In fact after finding a schematic i realized i was missing a 12v supply also. Traced this back to a blown 10Amp fuse in the box under the hood. One of the smaller types. At the very beginning before ordering any parts I actually went through all the fuses and visually inspected them. It just go's to show, a visual is not enough!
If there is any positive I managed to fix a few niggling problems like split vac pipes along the journey!
