Official Engine Stalling Thread

Andrew · Post by **Andrew** » 17 May 2005, 12:36

Guest again wrote:Anyway, I didn't get to the dealer in time due to unusually heavy traffic, hello Mr. Murphy!, so I settled on the "quickie" clean again that is, just cleaning the outboard side of the TB accessed after removing the black hard-plastic elbow that also houses the FT assembly. Sure enough, the car is running OK again this moring, but since the last partial cleaning of this type only lasted about 9 days, I'm sure it (the deceleration stalling) will be back.

Question, why do you think that cleaning works temporarily at all but fails rather quickly? Is it those 2 little holes that are temp. unclogged allowing better circulation to the 2 vacuum lines that appear to be connected there? Actually I don't even know if the "holes" do go all the way thru the cylinder as I didn't try to poke a pin or what-have-you thru the tiny holes, 1 bigger that the other, but instead sprayed the h*ll out of them with bolt lube and wiped dry. The black flexible hose from the elbow to the Air Filter also had another split in it so I duck-taped it some more, does that play a role? Odd...

Any theories?

Yes, the 2 little holes are different sizes and do go all the way through the TB. Disconnect the vaccuum lines on the other end and do run a pipe cleaner or a toothpick through to make sure they are unclogged.

Also, the flexi tube having splits is not a good thing as there is pressure that builts inside the housing which allows for 4 vaccumm hoses to run. Loss of pressure could have strange effects including the starvation of the engine from air resulting in a shutdown. That is not the root of your problem but it does contribute.

My guess for the partial cleaning is that the TB fly (the moving disk inside the housing) has collected a bunch of goo around the edges and on the back which makes it stick. Also, I would expect that once you get the chance to get the TB out, you will find the EGR hole (discussed earlier) to be pretty much clogged up. Cleaning the outside of the TB would cause a little more pressure to be available until the clog settles again.

Finally, I did mention it before too; consider changing the Fuel Pump Relay. It is a 60 second job and as someone said, they are only $49 at autozone. A big percentage of people that I have read having this problem online, cured their troubles with that.

So, if I was you, I'd try taking out the TB and cleaning it and if it still comes back, drop the $50 for the FPR.

____________

There are other ways to reset the computer codes on the car. Shorting the power cables although should have the same effect, has the disadvantage that you could blow your ECU off! When you short the cables all remaining charge in the system (and there's enough) will flush through the system which could very well blow up the ECU resulting in a high $$$ bill.

The process of clearing the codes is very simple and takes only a couple of minutes. Why even chance it?

Guest · Post by **Guest** » 17 May 2005, 13:26

Andrew said:

"...Also, the flexible tube having splits is not a good thing as there is pressure that builts inside the housing which allows for 4 vaccumm hoses to run..."

That makes sense and seems to explain the new splits in the flexi-hose wherever there is not duct tape already. I guess the rubber/plastic gets too brittle to flex due to the heat eventually.

I'll clean those holes really good 1 more time, then rip out the TB for the thorough cleaning and the EGR hole while in there and replace the FT assembly too, and then the relay switch in that order, cost impact.

Thanks again.

P.S. and yeah, that touching the battery terminals together sounded a little odd/dangerous to me too but then it seems like 95at seems to know what he's talking about most of the time but that caution about destroying the expensive part is appreciated so I don't think I'll be clearing codes that way if I ever do.

95autoturbo · Post by **95autoturbo** » 17 May 2005, 15:56

I have re-edited the tip, to make a clearer understanding for you, that I do not intend for anyone to connect positive and negative while they are attached to the battery!

Thanks Team.......... for reminding me that I have horrible writing skills. My only goal is to make sure we have great running Volvo's!

Andrew · Post by **Andrew** » 18 May 2005, 10:40

95autoturbo wrote:I have re-edited the tip, to make a clearer understanding for you, that I do not intend for anyone to connect positive and negative while they are attached to the battery!

Thanks Team.......... for reminding me that I have horrible writing skills. My only goal is to make sure we have great running Volvo's!

Lol, no problem but that was not what I was talking about. I have a couple of degrees in electrical and electronic engineering. ANY system connected to a battery, will still have a charge accumulated when the battery is disconnected. Unless the charge is cleared or 'drained', there can be enough charge in the system to short almost anything electronic.

That is the reason shorting the cable would clear the ECU but also the reason why it could blow it resulting to a nice $500 bill

95autoturbo · Post by **95autoturbo** » 19 May 2005, 23:16

Andrew..........do you think that by keeping the ignition on then disconnecting the cables would drain enough of the power from all the main points of the car? since they are grounded it should seem safe enough. It is a critical point to leave the key on, if you did not-the left over current from the battery could cause damage. I talked with Sam over at Auto Evaluators in St. Louis, he has been working on Volvos for over 14 years, he says he has done this thousands of times and has never had any troubles.

Guest too · Post by **Guest too** » 20 May 2005, 07:30

The classical dilema

Book smarts vs. real world experience

Being an engineer myself, although not electrical, I think the book learning teaches that theoretically it could happen on that 1001st time...

But you know the old saying, "I'd rather be lucky than good".

Any other electricians, electrial engineers or seasoned auto mechanics want to weigh in on this topic?

Andrew · Post by **Andrew** » 24 May 2005, 11:40

95autoturbo wrote:Andrew..........do you think that by keeping the ignition on then disconnecting the cables would drain enough of the power from all the main points of the car? since they are grounded it should seem safe enough. It is a critical point to leave the key on, if you did not-the left over current from the battery could cause damage. I talked with Sam over at Auto Evaluators in St. Louis, he has been working on Volvos for over 14 years, he says he has done this thousands of times and has never had any troubles.

Nope, it would not. The principle is quite simple. While the battery is connected, current is flowing to the system. The instant the circuit is broken (i.e battery disconnected) there is no more current flowing to the system but you still have what's stored there. Only way to get rid of that is ground the car.

In most European countries that would not be much of an issue since they use those funky mudflaps with a little strip inside which always grounds the car.

Now, Sam your mechanic friend is in a bit of a uniqie situation: being a mechanic it means that 99% of the time the car will be on jacks if not on the lift. That will ground the car so the system is drained. Someone working in their garage/driveway is not in the same situation.

Again, this is only a very small chance. True, 99.9% of the time nothing will happen, it is that 1 time that will hurt you.

Obviously some times the chances are higher. Remember those days that it feels like whatever you touch you get a static shock?

True, chances are slim but still there. All I am saying is, why take the chance?

The amount of times I had something fry on me the most inopportune time......

Andrew · Post by **Andrew** » 24 May 2005, 11:49

Forgot to say that it's now been 3 weeks and the stalling problems have not returned

Guest · Post by **Guest** » 24 May 2005, 12:33

Checking in, on day 10 of the second "quickie" TB cleaning (w/o removing TB from engine). First time after the quickie clean, stalling came back on day 10. Will see what happens in the next few days.

Guest · Post by **Guest** » 01 Jun 2005, 06:46

Day 17 of 2nd "quickie" TB cleaning. Still holdiing...