Vehicle jerks & Mysterious Tube

[Dmitry Tolstoy]

Greetings Viewers! 😉

WARNING: Newbie car owner with basic car mechanics knowladge.

I bought recently a Daihatsu Applause(97), Manual, 1.6L (Injected).
The car is in a very good condition considered to it’s age,
Yet it has one sickness that I’m looking to cure..

The problem:
When I release the gas pedal (sharply), the car start to jerk back and foward.
P.S. – It’s Idle Warm RPM is 1000 Steady. (Quite High?)

What have I done so far:
Quickly cleaned with Carb Cleaner the Throttle Plate. (like in Eric’s video)
Replaced the Ignition coil packs.
Checked the spark plugs. (Ok)
Checked the Air Filter. (Ok)
Replaced the Engine mounts.

Now I see that i’m on the wrong way.. Since nothing much changed.
I gave another look into the throttle area..
decided to follow one of the tubes that goes out of it.
What I had discovered kinda shocked me, so I took a few shots of the scene.
The tube supposed to connect to some sort of.. (another air filter?) but It’s plastic mount connection is Broken.
Overall to me looks like a Poor Zipping Job.

The ??? Tube & the zipper:

It’s the Middle small tube goes to the right top corner in the pict of the hrottle body:

Please Enlighten me with your knowladge and help me cure my car!

P.S. – The Engine is New with about 40’000KM on it.

Attachments:

• 999135_10202937521979459_1514546422_n.jpg
• 61461_10202937843027485_1824079975_n.jpg

Topic

[Dmitry Tolstoy]

I marked the tube, in case I confused you:

hope it helps!
if you need any further pictures just say and I’ll get them.

Attachments:

• tmp_PicsArt_1389914173196-2015265998.jpg

[Dmitry Tolstoy]

fix me if I’m wrong;
Could it be the vaccum line of the fuel pressure regulator?
and if so, could it lead to such a problem as described?

[Its me]

That certainly looks like a vacuum line and it should not be pinched like that…. I can’t tell where it goes though… Free that sucker and see what happens (if it goes to something)… If it is not connected (I think that is what you are saying) then make sure it is plugged off…

Edit: Look around the hood for a vacuum diagram, you make luck out and have one… If not get a repair manual for your car and that should let you know where it should go…

-Karl

[Dmitry Tolstoy]

I managed to get a decent shot of the whole area, and yep!
It’s the fuel pressure regulator!

And it’s mount is broken and dead dry. :blink:

I’m so much hoping it would solve all the gas pedal jerking..it’s very violent and annoying.

Attachments:

• tmp_20140117_044435-2015265998.jpg

[Its me]

I dont think that is the fuel pressure regulator… I dont see any fuel line near it… looks like something for holding vacuum/something to do with the EVAP system….this link is interesting as well…

http://en.bildelsbasen.se/?index=default&link=list&searchmode=3&query=7774087708

Still fix it and see what happens…

Karl

[Dmitry Tolstoy]

just before I check out your info I would point out that if you take another look at the very first pjcture that I posted, you’ll see a line that has w writing “Fuel..” which the vaccum line was aggressively attached onto.

Now I’ll gladly learn what’s EVAP system means, thanks for the info!

quick edit: look on the fuel line and follow it in the last picture.

[Its me]

If it is a carbon cannister it takes excess fuel vapor into the charcoal (carbon) to contain it. This is to prevent it from going into the atmosphere…

Just read a little on EVAP systems and on fuel pressure regulators…perhaps google a picture of one…

Cheers

Karl

[Dmitry Tolstoy]

I guess you are right about the EVAP cannister.
made me a bit sad..as I don’t see it affects the gas pedal leaving jerking.
I’m far from finding the source again.

Don’t want to throw money on every possible part..
What so you think can lead to my car issue?

shall I track the other vaccum lines?

[Wayne]

Have you checked for vacuum leaks? The high idle tends to lean that way. As it’s a 97, assuming you’re in the states you can also use a cheap live data scan tool to view the fuel trims and post the results.

Does it sound like a steady/normal drop off when you rev in park/neutral, then sharply let off the gas? How about just disconnecting the o2 sensor, and seeing if this condition is still present?

[Dmitry Tolstoy]

the engine sounds pretty clear to me, reving in neutral and dropping the gas cannot reproduce the symptom.
I can only reproduce it while driving in any gear.
(ofc lower gears would shake it very violently)

I’ll check for vaccum leaks, and try the sensors.. btw no check engine on.
The car is 97 but it’s engine is imported from japan.
atm supposed to stand at about 40,000km.
Besides unortunately I’m not from the states, it would be much easier with cars there..

edit: Which makes me think about possible transmission problem..
but on the other hand -why would it jerk on leaving the gas pedal?

[EricTheCarGuy]

Actually the first thing that came to my mind when reading your problem was a transmission issue. That said, the line you spoke of is likely the purge control solenoid line. I talk about evap systems in this article.

http://www.ericthecarguy.com/faq/finding-and-fixing-fluid-leaks

I would be looking into the transmission for the source of the problem you’re having. Here is another article that might be helpful.

http://www.ericthecarguy.com/faq/solving-transmission-problems

Good luck and keep us posted.

[Dmitry Tolstoy]

Thanks Eric!
I’ve just got back from a ride so here’s a quick update before I go to bed;

I’ve noticed that when the engine is warmed up enough, it’s hard to reproduce the issue.
Also I’ve tested the gear on 2nd while holding the breaks and leaving slowly the clutch pedal, the engine stalls like it should.

Tomorrow I’ll see some local mechanic..he has more testing tools and experience, hope he would have a clue.

Surely I’ll keep you informed!

[Luke]

Someone correct me if I’m wrong but that looks like the purge line for the charcoal canister. That would be cause a big vac leak as it appears to be connected to the intake on the engine side of the throttle plate. I’d be fixing that first and checking all hoses and connections for vac leaks.

[Dmitry Tolstoy]

After letting friends and mechanics to drive on my car.. none of them could reproduce it.
The problem was found: Me.

Im used to drive on Diesel/Turbo Diesel vehicles like M-35 and Ford Connect..
So my poor Daihatsu is going to pass trough hell until I get used to it.

Still it sounds to me a bit wierd why would a vehicle jerk on leaving gas at 2-2.5K RPM..
Time to get a few driving courses? =

[Tom]

The end of that line is disconnected, as the previous poster pointed out, that must be leading to a massive vacuum leak. Replace the charcoal canister, and connect that vacuum line like it should be, and see if that doesn’t make a difference in the way it runs.

[Author]

Replies