2G High idle

[98gstJames]

Alright so I wanted to start a new thread about the idling in my car. When I start the car it idles at about 1800 then shoots up to ab 2000 rpm’s once it’s warmed up, I checked my tps it’s getting 4.62 and 5.07 volts when it comes to pins 1,4 and then 3,4, when I got on my scanner app with the car running it says timing is at 31 degrees so I’m assuming that I need to retard the timing on it but I want other opinions. I’ve boost leak tested, replaced the maf, iac, replaced both inner and outer tb gaskets, and the fiav gasket and put a new biss screw in along with making sure the sas was set correctly.

 

[1990TSIAWDTALON]

Hose the engine at its intake mounting area with some water or brake parts cleaner and listen for the motor to go up or down in RPM's. If nothing happens, spray around any intake area/hose and see if the motor reacts to it at any time, signaling a vacuum leak. Not that you have one but its an easy check. Are you on a stock ECU?

 

[98gstJames]

Hose the engine at its intake mounting area with some water or brake parts cleaner and listen for the motor to go up or down in RPM's. If nothing happens, spray around any intake area/hose and see if the motor reacts to it at any time, signaling a vacuum leak. Not that you have one but its an easy check. Are you on a stock ECU?

I did a boost leak test last week and only one coming from my tb and it wound up being the fiav gasket causing the leak, it made the idle drop some but nowhere near where it needs to be and yes it’s the stock ecu.

 

[pauleyman]

It's not possible to idle above 1500 unless something is misadjusted. ECU cuts fuel based on throttle closed above 1500rpm. ECU doesn't know throttle is closed. Either it actually isn't, check the cable and the throttle body itself or TPS isn't adjusted so ECU doesn't know its at the lower limit.

 

[98gstJames]

It's not possible to idle above 1500 unless something is misadjusted. Ecu cuts fuel based on throttle closed above 1500rpm. Ecu doesn't know throttle is closed. Either it actually isn't, check the cable and the throttle body itself. Or tps isn't adjusted so ecu doesn't know the lower limit.

I’ve made sure everything on the TB is adjusted perfectly, it must be the TPS causing it to happen but I’m just unsure how to adjust it, I know it’s the two screw obviously but I’m not sure what I’m listening for when I turn it.

I also thought maybe it could be timing? Maybe it’s advanced? I’m just unsure right now.

So then, would that also explain why my car idles better when the MAF isn’t plugged in? It just drops RPM’s when I unplug it but doesn’t die

I read through the manual about the voltage drop and wasn’t able to get to the bottom bolt yet and dropped my wrench trying to get to it and it’s snowing so I just let it bet for now but I’ll go back out to check with the rotation.

I looked what it was reading where it sits now, I just wasn’t sure if when I moved it my RPM’s would drop or what it would do. In the manual it says with the car off but it didn’t know if there was any difference I could hear when moving it.

 

[1990TSIAWDTALON]

See if anything in this thread helps you out:

https://www.dsmtuners.com/threads/tps-voltage.203500/post-1693080

 

[steve]

Expect that once you have the TPS adjusted so the the Idle Position Switch (IPS) inside is working that you will start to see idle surging between 800 and 1500 RPM over ant over.

It will do so until you find the cause of excess air reaching the intake manifold.

Disconnected the MAF causes the ECU to enter a limp mode.

 

[98gstJames]

Expect that once you have the TPS adjusted so the the Idle Position Switch (IPS) inside is working that you will start to see idle surging between 800 and 1500 RPM over ant over.

It will do so until you find the cause of excess air reaching the intake manifold.

Disconnected the MAF causes the ECU to enter a limp mode.

Alright so the limp mode explains why it would sputter if it was unplugged, on the thread it says it needs to be 400-1000mv and it should says no more than 5 volts if I’m correct? I didn’t check the mv but I’m getting 4.62 volts from it so should I have the car started and adjust it to see the rpm’s drop or? I’ve read through the procedure through the manual over a dozen times and idk it’s probably a lot more simple than I’m making it seem.

I should be looking for a smooth voltage drop to check if it’s good and then look for non continuity and then set it there, what should my volt meter be reading when it’s at a point of “non-continuity”?

Exactly what do you mean excessive air? How could I check for this?

 

[pauleyman]

Exactly what do you mean excessive air? How could I check for this?

Post number 2.
Run another boost leak check.
Ensure fiav, isc are working properly.

 

[T Series Boost]

To add a bit of confusion when I had idle surge.. When it got hot under the hood, my throttle cable would tighten and pull the throttle open so make sure there is some slack in the cable. You also said your timing is 31 degrees? I believe that the ECU uses the timing to fine tune the idle, and usually it aims for 15 degrees. and like Pauleyman said, check to see you have the right voltage/set up with the throttle closed. The throttle cable and the closed throttle adjustment fixed my problems.

 

[1GAWD87]

Just found this new thread. I replied to the old not sure if it even relates at this point. I was hoping a Wiseman could give me some insight. Thanks

Have you set your base timing at 5°btdc with a timing gun,and timing connector grounded? Cam sensor 180° out? I understand that you want other options but your base timing is 5btdc 30° at idle doesn't seem outrageous

 

[98gstJames]

So I tried to adjust the tps that was in my car and I couldn’t get it to do anything it read the same way across the board so I got a new one put it in the car and boom that fixed my idle issue, I’m idling at about 800-1000 rpm’s now

But now I have another issue, I’m having fuel cut on wot. Once I get to ab 5k rpm’s I hit a brick wall, other than that my throttle is all there it’s just when I’m doing a pull then once I let off the gas the car comes right back.

I was thinking maybe change the fuel filter and check the plugs? I just wanted other opinions, thanks

 

[98gstJames]

Yup… gotta pull the motor out, got rod knock. Not too sure what my plans are yet, I’ll keep everyone updated

Im more than likely gonna get a new crank for the car and possibly pistons for it