Alright everyone, need some help with this.

S5 turbo motor, no emissions, stock ECU. No BAC.


I've already killed two turbo's in the car because something with the Timing/TPS is off. Last time the turbo caught fire!!

So this time around after a motor rebuild with help from ArmyofOne, I started up right away, i got it to idle around 750. Sweet. Black and Green wires on the TPS read 1.00k ohms and Blue and Yellow wires on the TPS read 1.37k ohms. Those are both spot on.

Now, when it comes to timing, if I rev the motor, then slowly let it down, it'll be spot on. But then either the motor will pulse slightly, or **** (I have no ******* clue what) happens and it's completely gone. As in I can't see the mark anywhere on the pulley. So then I'll rev the motor up, and help it come down slow then I'll see the timing mark come back under the pin.

My AFR seems to jump around with the motor from 14-15-16 but when I adjusted the idle from 850 to 750 it seems to go from 14-15. It's still a bit lean at idle. When I rev the motor up it gets more and more rich. Coolant (distilled water for now) temp is around 180-195*

I know that when you have the idle above 1k that timing will start to adjust.

What else will cause timing to change? Why is it off in no man's land?

 

After making the first post, I tested it for vacuum leaks. I hear a lot of hissing under the intake manifold, and I found that the bolts holding one of my block off plates were very loose. So I'm going to address these in the morning and go from there.

 

Anyone?

I started her up today, when it was cold, the timing was perfect. Then when it warmed up all the way, the idle went down a few hundred rpm and then timing when out the window again. I can't figure this thing out. I'm trying to make it to a bbq this weekend. Any help is appreciated.

 

It sounds like part of the problem is you still have an vaccuum leak. Are you running any accessories when the idle changes etc..A/C ? Also, have you checked the following; Water thermo sensor on the back of the upper intake, the variable resistor and compression of the motor?

 

The motor is a fresh rebuild. I did my best to get all of the vacuum leaks taken care of. There are some places like the throttle butterflies which I can't do anything about. It's where the bar that holds the throttle plates goes through the throttle body.

I don't have any accessories on the motor.

The water thermo sensor is on the back of the water pump housing correct? There's a green sensor and a black sensor - it's one of those two? I don't know how old they are but I can get new ones.

I'll have to look into this resistor as well. Just searched and I don't have one.

 

Um I might be wrong, but I didn't see anything about you properly setting the timing, If you haven't done it yet.

 

Not sure if S5 Turbo have 'em, but on my S5 NA, I took SATCH's advice and saw that my High Idle Cam screw wasn't set properly.

I came across that after determining there were no vacuum leaks (used every trick I read on the forums to hunt for a vacuum leak), even replaced the hoses. Figured the only thing to check was somewhere in the Throttle Body, and it turned out to be the High Idle Cam wasn't set according to FSM.

 

On S5 cars the ecu will also use the timing advance to help hold the idle stable. When are setting timing are you grounding out the initial set coupler?

 

I have no coolant running to my throttle body, so I removed all of that.


As far as timing being set, as far as I can figure out, it's set correctly. The gun I used was malfunctioning. I would have it set right, then found that there's a short in the cable and that's why the mark would completely disappear.

But now my idiot lights don't work, the oil pressure gauge goes all the way up and the coolant gauge doesn't work. I checked the 7.5 room fuse in the footwell, along with others in there and they're all good. Same with the fuses under the hood.
When it rains it pours I guess.

 

Either the oil pressure sender wire is grounded or the oil condenser wire is grounded. And what makes you believe the idiot lights don't work (examples?).

 

the fact the oil pressure gauge works sais they all should, but a short to ground would cause it to read a max value. it is also killing that gauge.

 

So when the car first keys on, the idiot lights should turn on. They don't.

When I pull the parking brake, the light should come on. It doesn't.

I thought they were completely dead, but last time I drove it the air bag light came on.


I'm pretty sure that the timing is set correctly. I have yet to find a timing gun that I know is operating at 100%.

 

Is the whole car an S5 or just the motor?

 

Whole car is s5

 

One of the two wires plugged into the back of the alternator is White/Black. W/key to on it should have a ground to it (or very close to 0 volts). This wire ends up at the warning light cluster where the alternator warning light relay is situated. Thus you can check this wire w/key to on to verify if it has very low voltage or not.