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

[sergio]

I don't like the fact that many often OPs leave their thread without an epitaph.
So I'm going to write one for mine

This saga started, more than 3 months ago, when I took apart a working engine to clean the PCV -because the car had 170k miles on it- and since I'm there, why not the throttle box as well.

I spent +- 10 hours to do the job. I was somehow supervised by a real mechanic.
Once this was done, the engine went on an oscillating idle.
I bought a Dice/Vida to see why.
Fingers started pointing to MAF and ETA.
It was suggested that I change MAF. I did, no change in the idle.
Then ETA, I did that one too. Again, no change.
Now, the battery would read 12.something Volt, but after a single ignition it would go down to 10V.
I had the 2 year old battery checked, it was dead and replaced with a new one at no cost.
Now the engine would start but would die right after.
I noticed a small box left in the DIM preventing me to see that I was out of gas.
Put 2 gallons of gas in.
Now the engine would crank with a big bang noise. I was told forget the noise read the codes!
I checked and rechecked everything, wire continuity etc etc. Same codes, same thing.
I was told ECM might have gone bad. I built a tool to remove it.
I realized I was about to double the book value of the car by renovating it part by part.
And then one day the starter began making the sound you hear when applying power to a small electrical motor you buy at RadioShack; Whoooshhhhhh.
I decided to call a towing company and take it to an independent (but Volvo specialized) shop.
They could not pull the car out of garage, the rear wheels were locked. Playing with the hand break didn't help.
They used skids to pull the car on the truck.
The guy in the shop said the starter is dead. He replaced it.
He also said that the oscillating idle is gone too! But I had to replace the fly-wheel.
He replaced that too. He showed it to me; several teeth were gone. (the reason for / or result of those bang booms?)

Now the car runs the way it ran before this Ralph Kramden tried to clean PCV. The book value of the car is went up 2k above what it was 3 months ago.
It would have taken less time had I not had to go through the long planned foot surgery and wear a cast for 7 weeks +.

Now I can drive AND walk.

Cheers

.

[precopster]

WOW.

I don't know how cleaning a PCV can go to broken flywheel (actually flywheel is the wrong word unless it's a manual car, it's called a driveplate for auto cars) It has notches on it that the crank sensor references as normal engine rotation and therefore gives pulse to injectors, etc. Perhaps with the areas that were read by the crank sensor being damaged it was giving poor pulse to injectors resulting in varying idle and backfires.

But why no 12V to ETA? Perhaps the flywheel was resting at an area that it couldn't reference at the time and this was cutting power to ETA? Perhaps if the engine was rotated by hand it would have provided power to ETA? Who knows......

The main thing is that you didn't give up on your Volvo and handed it to someone with the specialised equipment to diagnose.

From all of us here at MVS: Well done!!

[draser]

Last time I'm bumping this post, I promise. Hey Sergio, I'm glad your car is fixed and you're back in the saddle. Thank you for posting back with the solution, I learned something. Happy driving!

[E Showell]

So all of this was due to a bad starter?

[EngineeringBloke]

I suspect the main cause was a bad battery. Even if the engine was not running optimally, the alternator should keep it healthily charged but it had to be replaced.

Once it was replaced other issues had already arisen - out of gas, and damaged starter.