1360Cc Tu3 High Idle

[pyrrhic 14 2 Cars]

I am not well versed on the TU3 engine management system on my winter beater 309 as I am with the one in my 205 CTI. The 309 right now has a high idle, I have looked for vacuum leaks but haven;t detected any. The car idles as high as 2000 rpm when cold, settles to 1500 rpm after warm. On a few times the idle will go down to 1000 rpm, and very rarely below that. Can someone help me get the idle back to normal?

[trogboy 17]

Hi,

 

Is this a single point injection engine, or a carburetted model?

 

Ad

Edited March 25, 2014 by trogboy

[pyrrhic 14 2 Cars]

I am fairly certain it is single point. I'll take a picture of the engine.

[pyrrhic 14 2 Cars]

I just verified it, the car has fuel injection, no carbs.

[sickomotorsport 4 2 Cars]

M.a.p sensor faulty or vacuum hose split? Check throttle cable isn't too tight

[pyrrhic 14 2 Cars]

I really need to educate myself on the TU3. This car has been dead reliable to me, only boring to drive, so I never really learned the ins and outs of the TU3. The XU5 on my CTI on the other hand... everyday I learn something new on that car! Where is the MAP sensor located on the TU3?

[pyrrhic 14 2 Cars]

OK, reading through the Haynes for this car, it says that idle speed is controlled by the idle speed motor and is non adjustable. Does that mean that perhaps the idle speed motor is bad? What controls the idle speed motor?

[RossD 44]

The ECU!

 

I would suspect an air leak before the expensive task of starting to swap out components. Make sure the SPi unit is tightened down onto the manifold properly and that the inlet manifold bolts on to the head are tight too.

 

The start checking all of the hoses coming off the manifold, including the one to the brake servo!

 

There were 3 types of injection fitted to these, Bosch A 2.2, Bosch MA 3.0 and Magneti-Marelli G6. If you can find out which one is fitted I might be able to help further

 

(Bosch A 2.2 had a distributor, whilst the others had coilpacks and no distributor)

Edited March 27, 2014 by RossD