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[Engine] 5 clean starts, ECU question
#1
Checking the EGR threads and generally reading old threads on this forum I have seen sometimes guys mention that "5 clean starts" is needed to reset the computer, or as I understand it, to "convince" the computer that the new data from the MAF sensor etc is the "real" data and then the ECU adjusts accordingly.  Correct me if I'm wrong. 

Anyway - what I don't know is - what exactly constitutes 5 starts?  
Sitting there parked, turn on the ignition, turn off? 

Each time after fiddling with my EGR blanking plate, or EGR vacuum lines or whatever, I do five starts sitting there with the Lingo parked.  No change.  (maybe no change because I haven't fixed the problem).  

But I begin to wonder - does a "start" require "start + drive + stop," and if so, how much time/distance?

Also - I've got no MIL (check engine light) now while driving - but while switching on the electrics, all the lights illuminate (to show the lights are working), and then most of them switch off - except the engine light, the "exclamation point" light, and one other (I forget).  Those three lights stay on until I ignite the engine.  Is that normal/ok?
[Image: 177657.png]   2004 1.9D DW8 WJY with black spray paint on wheels instead of flimsy plastic wheel covers.
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#2
If the lights go out when running then no problem, it's when they flash on or you get beeps that you have problems in my experience. If I adjust my drivers seat I get the air-bag light and beep till I fiddle with the connector under the seat. If the car is running alright and the lights are not ABS or air-bag I would not worry about it.
So where does this bit go then ?
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#3
Hi ffrenchie, thanks for your reply. Ok with the lights, however I am trying to diagnose a problem with lack of power ever since reconnecting EGR vacuum tube and "cleaning" the MAF sensor. Hence my question about the 5 starts.

For my airbag warning, I unclipped the connector under the seat and sprayed some electrical contact cleaner in there. Made that problem go away even if I adjust the seat.

I suspect that that same electrical cleaner *caused* a problem with my MAF sensor in the air intake tube (after the air filter).

Reason being: my spray can of electrical cleaner actually contains some solvent and lubricant. Never seen that before. Solvents are not good for MAF sensors (that's why we don't use brake cleaner or carb cleaner on that).

I'm now trying to get ahold of some isopropyl alcohol to clean it again, since "MAF cleaner" is not sold in Israel, evidently. I tried denatured alcohol but it made no difference. However, now my brittle plastic electric harness to the MAF sensor is not connecting with a "click" anymore so something else now to troubleshoot.

At the same time I had used the electric cleaner I also connected the one vacuum line I found. Less power ever since. Later another disconnected vacuum line I found).

Since then I've removed EGR blanking disk, reinstalled it, unplug MAF sensor, removed both vacuum tubes running to the EGR/butterfly valve area, reconnected them, all these changes and never any change in the engine running for better or worse. Never any "check engine light" so far either.

So either the ECU is completely confused or I'm not doing it right.


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[Image: 177657.png]   2004 1.9D DW8 WJY with black spray paint on wheels instead of flimsy plastic wheel covers.
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#4
Hi have you tried running the car with the Maf Sensor unplugged but everything else connected as normal to see if it regains power.

As you may well know maf sensors are quite temperamental when it comes to cleaning etc, regarding the 5 starts I usually start engine then turn off wait a few seconds then start engine again and repeat.

hope you sort it out.
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#5
Got a multimeter on it and figured out the five wires:

Pins 3 (green) & 6 (purple) are ground. 

Counted from the left:
1 beige - 
2 white - 14.30v idle to 14.50v Max
3 green - ground
5 yellow - 2.6v idle to 4v 80% and 4v max 
6 purple - ground

So I guess pin 5 yellow is the signal from the MAF sensor. And to me, it doesn't seem right that there's a steady voltage increase from idle up to around 50-70% throttle, and then it stays stuck at 4 volts all the way up to max throttle. 4.1v at max.

So that there may explain the fault with this sensor.

I will also see what driving is like with the sensor electric unplugged but just a little bit of driving on that.


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[Image: 177657.png]   2004 1.9D DW8 WJY with black spray paint on wheels instead of flimsy plastic wheel covers.
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#6
Plugged or unplugged, can't tell any difference at least not in 1st, 2nd or 3rd gear.


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[Image: 177657.png]   2004 1.9D DW8 WJY with black spray paint on wheels instead of flimsy plastic wheel covers.
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#7
OK, thanks so much for the comments; here's the conclusion:
1. Turn the car off, unplug the MAF sensor electrical harness.
2. Start the car, notice the Check Engine light is on.
3. Test drive the car - I did not notice any difference.
4. Shut off the ignition, replug the harness.
5. 5 starts: Start, run motor a few seconds, shut down. Repeat.
6. After 5 starts, the Check Engine light is off again, which confirms that BerlingoHDI's advice was correct; and now I know what it looks like.
7. Thanks!

I still need to track down the proper voltage range for these MAF sensors; it seems it should be around 1v at idle and 4.5-5v at Wide Open Throttle (WOT) instead of what I got: 2.6v (idle) and 4.1v (WOT).
[Image: 177657.png]   2004 1.9D DW8 WJY with black spray paint on wheels instead of flimsy plastic wheel covers.
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#8
So are you suspecting a faulty maf sensor?

Can't help you with the correct readings unfortunately, I know when my sensor was playing up I unplugged it and it ran perfect but the engine light was on but didn't put it in limp mode or anything.
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#9
Well I kind of suspect a faulty MAF sensor. But it's not totally wonked, therefore if I unplug it there's not a noticeable difference really.

I know some folks say it's either working or broke, but this might be an odd case.

Now I know--don't ever clean the MAF sensor on the car. I did that at the same time as 1 vacuum line reconnect and I can't isolate which of those two actions caused the power loss at high RPMs.

I've searched the googles and downloaded 2 manuals in mht format and nothing publishes the correct voltage range.

http://www.berlingoforum.co.uk/showthread.php?tid=11522

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[Image: 177657.png]   2004 1.9D DW8 WJY with black spray paint on wheels instead of flimsy plastic wheel covers.
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#10
B HDI, did you replace with a 3rd party brand or a PSA part for that MAF sensor?


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[Image: 177657.png]   2004 1.9D DW8 WJY with black spray paint on wheels instead of flimsy plastic wheel covers.
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