Throttle body cleaning issues EPIC Volvo saga...RESOLVED!!

[bags519]

One of these days Alice! Straight to the moon. Lol

Everybody has a Ralph moment.

[precopster]

Most indies would have told the customer they don't have the test equipment to get to the bottom of this. AND you would have already paid over $1,200 in inflated parts prices and labour.

Apart from your time this exercise doesn't owe you that much yet and you have new parts which will last at least another six years. It's time to step up and finish what you started.

Take those voltage readings at ECM connector with ECM removed. Draser already gave you the pin positions. If voltage DOESN'T drastically drop with ECM removed that is about as conclusive a diagnosis as you'd want that the ECM is at fault.

[sergio]

Mike what you say is true and there is something else too, the challenge. I love taking the challenge of doing something myself. When a friend says "why don't you pay someone to do it and be done with it", I think "pay someone to have fun in my place?"

Any ways here some developments;
The battery, I toot it back to the store where I bought it, had it tested. It was dead!
It was 26 months old. I came out with a brand new, and free, replacement.
I still can't understand how it happened. Curiously, the previous one died the same was (reads fully charged then dead after couple of cranks) but that one was the original (2002)?

Too late to work tonight.

Tomorrow morning I should have 12V for longer then few seconds !

Now testing the voltages
You said [ "Take those voltage readings at ECM connector with ECM removed." ]
If the ECM is removed, all connectors going out to ETA, MAF etc would show 0V ? No?
My understanding is that ECM transforms the 12V to 5V and back.
I will try a voltage reading with ECM attached. Then a Vida scan.


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[precopster]

We ALREADY know that ECM doesn't provide voltage to drive MAF and ETA. If it did you would have measured 10V at least.

The test without ECM is to determine if the ECM is loading/killing output to ETA and MAF.

I work with electronics all day; it's my profession. This is a way to test the system without any more guesswork

You are looking for INPUT of 12V to ECM. Forget OUTPUT for now

[sergio]

Testing fuses and input to ECM

Battery brand new/12.45V
ECM removed
Key on 2
multimeter black on car chassis

ECM
On pin A17 (black connector female) 12V confirmed
On pin B11 (white connector female) No juice = 0V

Fuses are removed reading on both slots (fuse female???)
B11/23 12V on one slot 3V on the other one
B11/6 0V on either side
B11/8 0V on either side

Relay

I measured the two small poles, the magnet juice, they register 12 volts each. So current IS passing trough when key on position 2
On the two larger poles (the switch) one has 12V the other one none.
When the key goes from 0 to 2 there is no sound /vibration whatsoever.
And the ECM is removed.

Is this the good news? That the relay is kaput?



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[draser]

You'll need the ECM back in for the relay to work. I'd plug ECM back in (batt off), key on 2 after, and measure 11B/6 with fuse pulled. If relay works you'll have 12V on one side of fuse.

[precopster]

I just read this entire thread and we may have missed on checking the engine management relay completely.

If I'm not mistaken you should find the same relay in other places. Swap it and put everything back together. Don't forget to connect battery LAST.

If the lack of power ceases to MAF for example there's your red herring.

[sergio]

Followed meticulously the instructions
ECM back on its seat, key on 2 , battery connected, waited 30 seconds
Fuse 11B/6 12V on one slot 2.6 on the other
Power measured on MAF sensor 12V on pin 2 and 5V on pin 4

Then started the engine
Went on idle with a different oscillation cycle then before. after 30 seconds engine stopped.
There is a lot of smoke and smell in the garage.

Reading on Vida haven't change. Although I have clicked on update at "read vehicle".


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[precopster]

What circuit did you transfer the problem to or did you use a new relay? So you have 12V at MAF? Do you have 12V at throttle connector?

Remember the throttle needs adaptation as it never had voltage.

Did you clear codes?

[draser]

Not sure how to explain the 12v on MAF - but I'm glad it's there. For completeness sake I'd measure the MAF signal wire on pin 3 (some 0.015V) and ground on pin 5 - this is easy, just stick the needle in the back of connector. Everything is plugged in (MAF, ECM, ETA), key on 2.
Then, like Mike says, I'd measure the ETA - I had 12v on pin 1 (BL/R), 0.08v on pin 2 (GRN/YL), 5v on pin 3 (WT) and 10.5v on pin 4 (GRN). I could not get to the last 2 pins with my needle.
When you measure ETA pins 1 and 4 you'll see a switch from about 12v to 3.2v and hear a click (relay?) in sync with the voltage change - key on 2 again.
If all this checks I'd do the fault erase, adaptation, etc - see Mike posts.
I just wanted to bring this up - since you did a pretty big job with cleaning the ETA and PCV, removing manifold and TB - I'd retrace all the components to make sure you did put gaskets for manifold and TB, all the screws are tight, all air ducts are connected and clamped, and any other stuff that I may miss but it was touched is in place and tight. It does not hurt to 2-check stuff even if you're sure you did it right.