FI 16V Sidekick Idle Issue

[jaime]

Hi.  My 16V FI motor has been working fine. 

Recently my 16V FI motor has been acting weird.  It starts and drives fine but sometimes after parking for a while and then starting up again or (engine warm but rested) the idle goes very low or it falters forcing me to re start and use my foot on the accelerator pedal to keep it on.  Driving at some speed for a good length of road makes engine stop doing that and the issue might not happen again until later or another day  

It is not something that happens all the time but it is getting more frequent

Any ideas what to look for ?

 

[IanL]

It is probably the waxstat in the throttle body.  For a fuller explanation, see here.  My guess is that the stat is sticking in the hot position instead of contracting as the engine cools, until it is so cold that the force overcomes the stiction.

What can you do about it?  Not a lot, as the stat is not a spared item.. You could try another throttle body, or just try adjusting as per the linked post,  Try a quarter of a turn - with luck, it will set the bypass air high enough to overcome the stalling, but still keep matters within the IAC control range when hot.

The other suggestion is a sticking EGR valve.  Maybe it needs a cleanout.

 

[jaime]

It is probably the waxstat in the throttle body.  For a fuller explanation, see here.  My guess is that the stat is sticking in the hot position instead of contracting as the engine cools, until it is so cold that the force overcomes the stiction.

What can you do about it?  Not a lot, as the stat is not a spared item.. You could try another throttle body, or just try adjusting as per the linked post,  Try a quarter of a turn - with luck, it will set the bypass air high enough to overcome the stalling, but still keep matters within the IAC control range when hot.

The other suggestion is a sticking EGR valve.  Maybe it needs a cleanout.

 
    Hi  
Any photo/ close up of the part we are talking about ?   The Waxstat ?

 

[k29349]

Now I'm worried about my aging waxstat. Wondering if it could be replaced if you have machine shop access?

 

[txgocart]

One option is to contact National Carburetors and see if you can get a Suzuki friendly tech, preferably one that deals with Toy250 carbs.

He will know how thrifty we are and see if they have a source for the rebuilding of the trackick TB.

Ray

 

[IanL]

    Hi 
Any photo/ close up of the part we are talking about ?  The Waxstat ?

Sorry, don't have the truck any more  Did you try the adjustment?

 

[IanL]

Sorry, don't have the truck any more  Did you try the adjustment?

 
 


From memory, the adjuster is a small brass-colour screw under a neoprene bung, on the top of the TB.

 

[Rasmei Nhem]

The battery gets near the end of the life also cause the car runs like crap!! 

 

[WarTowels]

From memory, the adjuster is a small brass-colour screw under a neoprene bung, on the top of the TB.

 
 

That is the Hot Idle Adjustment Screw and it won't help cold starts, starting, etc. It's only purpose (afaik) is adjusting the idle when the engine is at full operating temp.

It sounds like to me, you may have an issue with the ISC (where the wax pellet is, I believe).

This device is the cylinder looking tumor on the throttle body. It has a cover on it that has three screws, and it's facing forward in the engine bay when you are viewing the engine. This controls (in part) the cold idle. It's job is to make the idle about 2,000-2,500 during starting, in conjunction with the dashpot. As the coolant warms up the valve inside the ISC should close, the dashpot vacuum retracts, and your idle drops. If the ISC is out of whack, you could have a hard time maintaining idle if the engine is cold. I would expect this behavior anytime the engine is cold, though. So if your issue is only after it's run, then cooled some, then tried to run again, perhaps this is not the issue.

However, it's easy to adjust, so may be worth a try:

Remove the three screws. Get a 12 sides 17mm socket, insert it into the ISC.

Clockwise will REDUCE the cold idle RPM.
Counterwise will INCREASE the cold idle RPM.

Hope that helps,

 

[IanL]

That is the Hot Idle Adjustment Screw and it won't help cold starts, starting, etc. It's only purpose (afaik) is adjusting the idle when the engine is at full operating temp.

It is not.  Its job is to set a value for bypass air which allows the Idle Air Control valve (IAC) to control the idle revs under control signals from the ECU.  However, as I explain in my linked post, it has been found to be effective in overcoming the deficiencies of a fatigued waxstat.  It does not set the hot idle rpm - that is done by the ECU to a programmed value (850 rpm).  The warmup rpm is also controlled by the IAC according to the coolant temperature, but the waxstat is fitted to increase bypass air to allow that control over a higher rpm range.  There is no dashpot involved.  This information is directly from the Suzuki FSM for the 16-valve engine.
When the waxstat is so fatigued that it no longer flows sufficient bypass air to maintain revs during warmup, the idle adjust screw can compensate for that, and still allow the hot idle to be correctly controlled.

Btw, the ISC (which does a similar job to the IAC) on the 8-valve engine also does not incorporate a dashpot, but there is a vacuum-operated throttle opener (controlled by the ECU) which controls warmup rpm, instead of the waxstat in the 16-valve.  Perhaps that is what you meant by a dashpot, but, in any event, it does not apply to the 16-valve.

 

[jaime]

Sorry, don't have the truck any more  Did you try the adjustment?

 
 
 
 

Hi
I will look into it this weekend
Been having relatives for the past 3 weeks and all my favorite things did take the back seat
If in need of a new throttle body ,  is there a better part I could use ?  Aftermarket or perhaps a TB from another SUZUKI model (Swift) ?

Will check the EGR valve as well

 

[IanL]

 
If in need of a new throttle body ,  is there a better part I could use ?  Aftermarket or perhaps a TB from another SUZUKI model (Swift) ?

Aftermarket - perhaps, but you would probably need an aftermarket ECU which you would have to program - $$$ and time.  Big effort and probably more than the truck's worth.

 

[jaime]

Just re appearing here at the forum

Will tackle right now the idle issue

Not a big issue but could have something to do to with what I mentioned here above .

For a long time I have experienced every now and then a surging idle. Could be several things like the EGR valve and related smog parts malfunctioning or a simple vacuum hose (s) leaking

Will change the hoses and go from there

Will do that, then check the check engine light which turns on ... by using the clip trick on the plug in the engine bay (found the plug that was covered in plastic wire insulation ... for a while I thought this 1.6 16V did not have that darn plug) after changing the hoses and see what it shows.

Before doing anything with the adjustment as explained above (thanks guys) will eliminate the more obvious things that came along like vacuum leaks and /or EGR system issue

Need to smog my car as well so need tackle the engine check lamp issue ... it is all fun times to work on my own Suzuki !