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:

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Topic

[Dmitry Tolstoy]

Update:
Seems like im having trouble with the gas pedal itself..
I’ve read around the web that there could be a problem with a worn pedal spring that supposed to pull it back up..

I’ve checked it and it seems like what I got here..
I can move the gas pedal at some interval without actually activating the gas..so I think what happends is thst it jumps freely back and forth and causes the throttle go crazy..

Also I’ve checked the throttle cable tension, its maximum screw tensioned but still I can move the cable pretty freely inside the line.

Any thoughts on that one?

Edit:
here’s a topic with pictures from another forum about the issue

[Dmitry Tolstoy]

Update:
I was wrong about the cable;

And still unable to find the source of the problem..
Meanwhile the steps I’ve done:

1)Got used Carbon cannister from a scrap car, cleaned it a bit with air pressure and connected to the lines.
1)Used K44.
2)After finishing the gas tank filled with K44, refueled and Changed the Fuel filter.
3)Listened with a Flat screwdriver to the Fuel Injectors. – all working.
4)Changed the Spark Plugs (NGK) & Cleaned the Distributor Cap (unable to find a fitting new).
5)Cleaned most of the wires from oil and corrosion, fixed some connections which broke in the process.
(due to dry plastic & overly corroded wires & ofc too much force used)
6)Cleaned most of the Vacuum lines & the Sensors which were connected to them.
7)Adjusted the Idle speed (Idle screw), Runs slower and smooth, around 800 stable warm.(lower would cause vibrations in the cabine)

Besides the moment when I realized that now I got a check engine light and my engine chokes and lowers from 3k to 2k RPMS suddenly when pressing the gas pedal.. (forgot to connect a sensor) :pinch:

Idk to tell if the engine runs smoother now or it’s just me happy that I’ve done something. B)

Inspected the problem Furturer, Reproduced it at a big parking ground.. decelerated accelerated, turned fully right and left circles (No clicking from CVs, CV boots look good)

Conclusions:
Very noitcible when playing with the gas pedal at 2K at 1st & 2nd gear – Decelerating and Accelerating (!)
Car jumps back and forth. (no rpms change)
Sometimes when I reverse and suddenly stop, I hear a Bang, like a brick moved inside.
Wierd, But I replaced an New Engne mounts, few weeks a go. 2 out of 3 (the right seems to be ok).

So what could it be?
Transmission problems? some kind of Torque converter In manual car?
Ujoints in daihatsu applause? =

Please help me at least diagnose the problem..
I can’t trust in my area at any mechanics, they want too much money for cheap parts and easy work which I could make myself like all above.
I’d better diagnose it with you and if I see I can’t handle the task, I’ll go to one mech and say exactly what I want to change so he wouldn’t throw in unneccery new parts that were working well as old.
Some say the fixing price on fly before even touching the car / looking under the hood! 🙁

[EricTheCarGuy]

Most idle adjustments require a special procedure. It’s often not a good idea to just adjust the idle screw, in fact, it’s often the last place to go when trying to deal with issues like this.

I don’t recall reading anywhere that you checked for vacuum leaks. Vacuum leaks can cause all kinds of issues and should be at the top of the list of things to check. In addition, if you have a MAF sensor in the intake, it’s very important that there aren’t any holes in the tube that runs from the sensor to the throttle body. If there are any holes here, it can cause serious performance issues.

More info, tests, and videos about solving performance problems can be found here.

http://www.ericthecarguy.com/faq/solving-automotive-performance-issues

http://www.ericthecarguy.com/faq/solving-automotive-idle-problems

Keep us posted.

[Dmitry Tolstoy]

Yesterday I washed out the Tap Water (!!) which filled the pervious owner.
I’ve Cleaned the thermostat housing, Installed a new Thermostat, Which for some reasone I’ve been told that it was removed.. (But surprise, it was tere!)
poured some local green “ready to use anti rust mixture”, Bled the air out of the cooling system, cooling fan kicked in properly.

Now the engine is heating well up to the middle, and the heat gauge stays in the middle during all the drive time outside and inside of the city.
(perviously outside of the city the engine was “freezing”)

Meanwhile It seems like the problem is much less pronounced if at all, when the engine work at it’s normal temperature range.

Today i’ve checked for leaks with a carb cleaner, sprayed it like you’ve shown in your video, no RPM change, engine sounds good, about 800 RPM steady warm Idle.

[Dmitry Tolstoy]

Update:
I’ve gone mad with my multimeter, tested valves and sensors..
Guess what I found out?
The IACV is dead closed!
Changed it today, it seems to smoothen the ride even on cold engine.
Now I have to try harder to make the car jerk.

[Dmitry Tolstoy]

Although the serial number leads to some MAP sensor..it’s not, confused me at first.

Attachments:

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[Dmitry Tolstoy]

After almost two years of trying almost everything.. now I can call it a FIX!

Reminder:
The Original problem was jerking hard when taking the leg off the gas pedal around 2K – 2.5K RPM, especially when vehicle was cold.

The so what went wrong?
A series of problems:

1) The original IACV was busted ( so replaced with Junk yard part)

2) The Ingnition timing was overly advanced and when I tried to set it by the factory timing makrs, the car would ping hard and won’t accelerate.
(I’ve bought a timing light to set properly and disabled the ECU, by shorting two connection terminals on the obd port)
Which made me suspicious about the third thing: The Timing belt alignment! (why else would a car run like crap by the factory marks??)

3) Timing belt marks.. discovered the Camshaft was 1 tooth off.

4) That one was actually hard to find.. A TPS Sensor Connector had an abrupt contact, so I’ve bent a bit the “legs” of the connector and worked like a charm.

That’s it!

Extra info:

Important extra about OBD 1 and this antique TPS sensor:

Why I couldnt read that I had a tps code fault from the beginning? (code 12 here)
[u]for some weird reason that the ECU dosen’t store this specific code in the system!
All my pervious code tests were made when the engine was shut off.[/u]

Discovered the code by pure luck when I adjusted the ignition timing (disabled the ecu – runs it in code read mode) and in the same moment the connection of the tps was bad.
Another symptom was that the engine ran “almost smooth” just a very slightly unstable rpm (not enough to show it on the rpm panelboard)
Which made me wonder back then, why it does it when it has 0 vacuum leaks + correct ignition timing + correct camshaft marks.
the lucky TPS code explained it all. :woohoo:

Had a great battle over this one, now its over and im kinda bored.. but satisfied 😆 .
This case teached me so much about car mechanics and diagnostics, so it’s my duty to share this info here.
Thanks a lot to Eric The Car Guy, guys on this forum and many other Mechanics and Technicians over youtube and the web!
Also to BIG Thanks to good friends that helped me to get the job done.

Every mechanic I had met with said it’s easier th throw it off the cliff than try to find the problem, or they just couldn’t reproduce it, or said something like “yeah it’s an old car and this is how they act, get used to it.” :blink:

[Author]

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