Ok guys,

I know I have read this somewhere in here before, but I can't find it now. I have an 89 S5 TII conversion. I just rebuilt the engine and thanks to HAILERS got the thing running. Now when I start it (temperature in the garage is about 50 F) it runs smoothly and idles itself up to about 2000 RPM for about 15 seconds and then drops to 1500 or so and starts very steadily in a rythumic pattern bouncing up to 1900 with little popping noise in the intake as it starts to come down to 1500. It seems to be running very rich also. Any ideas?

 

TPS is out of adjustment

 

Thanks Ice I will adjust and report back.

 

The manual for the 89 says that there is an automatic self adjust in the ecu on this car for the TPS and that it is not adjustable. On the A-B terminals I am reading a slightly high 1.1 KOhms (spec is .9 Kohms. All of the other specs seem to be in order. Any ideas?

 

there is only a manual adjustment IIRC in the form of a screw on the throttle cam. You need a volt/ohm meter on the correct pins on the plug and a warmed engine to adjust the TPS.

 

Go to page F1-83 and do the Adjustment given there. Make your own light assy by getting two LED'S from Radio Shack and twisting both the positive wires of them together and putting a spade connector on the end of those two wires. Then put a spade connector on each of the other two wires.

Insert the spade with two wires in the TPS test connector (green, three sockets) and put the other two wires in the other two sockets on the test connector.

Then follow the instructions. This engine is several yrs old and needs this done.

A jpg of the LED's is attached. Sort of half assed looking but functions fine. Make sure the engine is HOT before doing this.

Once your done with the lights, you'll find an output from the narrow range will be approx 1vdc. You could check this at the ECU pin for narrow range TPS if you were curious. All your doing with the LED's and screw adjusting, is setting the TPS output to the ECU from it to be approx 1vdc. See the Fuel section of the FSM and a page called Control Unit (I believe) and it will show the output of the narrow range TPS and Full range TPS and the values. Sort of double check your work so to speak.

 

OK, I got the idle steady at 850 RPMs by turning down the idle screw (manual one near the cable) and disconnecting the TPS. With the TPS connected, the idle fluctuates even when warm. I will warm the car and adjust the screw just above the TPS with the car warm. I am getting proper OHM readings with the TPS disconnected, engine warm. But when I connect the TPS, it starts bouncing again. I will also check the wires back to the ECU again.

 

are there any blank spots on the sweep of the TPS sensors?

In otherwords, when you meter the TPS, there should not be any drops or sudden increases as you press it in.

 

I am using a needle type OHM meter. I very very slowly opened the throttle and did not notice a blip in the sweep. It did however show that when I was checking it from 0 throttle up that I did not have to have it in WOT position to get the max ohm reading. In other words about half way on the throttle, it maxed in proper range on the meter.

 

The Narrow range is full open at approx 18% of throttle travel. Or another way to put it, it's open fully Just as the secondary throttle plates Start to open. I said Narrow, not Full range.

 

OK, I just made up the little light thingy and used it to adjust the tps. At first, both lights were on. I back counter-clockwise the screw out until it went off. Tried it again and to no avail. It is still surging with the TPS connected and not when it is disconnected. It was strange however one time after I had warmed the car up, let it sit for a few minutes and started it again (the TPS was disconnected on start. I plugged it in and it surged twice and then went to a perfect idle at 800 rpm without a popping noise. I let it idle this way for 10 minutes figured I had somehow magically solved the problem, put the IC back on. Turned it on and back to the surging idle. This was before I adjusted the TPS.

 

Anybody awake this morning. I tried to put my NA TPS on the car last night. THe bracket is different, so I just took the sensors off and moved them to the turbo bracket. It solved the bouncing idle problem, but now it sounds like it is running on one rotor. I am not sure if the NA sensors themselves will be able to be adusted or not. They may be entirely different calibration.

 

This will sound dumb, but.......take your bac plug off. Look into the plug and see if both contacts on the end of the wires are at the same height. In other words make sure one or both are not pushed back inside the plug possible making intermittent contact with the pins in the bac plug. Also make sure the bac plug is connected to the bac good.

Sort of off the wall, but it's happened to me with a bac plug that was not connected solidly to the bac and making intermittent contact.

 

Just looked at the bac plug and everything seems to be in order. CHecked it back to 3Q on the EGI and everything is good there. I pushed on the pins to see if they might be pushing back on insertion of the plug and they are good. What do you think about the Idle leveling out on the NA TPS? They only problem is that with the engine cold, I checked the OHMs on the NA TPS and it is not in spec.

There is also a screw on the back side of the TB on top that I don't know what it does. I was trying to adjust this to fix the high idle. I may have it out of wack now. Remember this is a JSPEC and it does NOT seem to have the AWS system on it. Could this be a conflict with the ECU being an N370 vs 374?

 

In the attached jpg, can you tell which one of the screws you've been fiddling with? Pay NO attention to the RED marks in the second jpg, just the blue arrows pointing to screws.

And about the TPS narrow range....I'm sticking with my story. If the green/red wire at the TPS connector is outputing 1vdc approx at idle, then the TPS is set. Engine HOT. Everything connected up when checking it. Or check it at the ECU by backprobing the narrow range TPS wire there. Still a green/red wire.

I'm looking for a better picture of the throttle body of a turbo. Later.