I've searched through many many threads on tps problems, still have a few questions.

The car is a 90 na. It starts up completely fine, has idling problems. Pulsates like a bad bac, but not only from ~1200-1700, it does it at about 500-800 as well. I still need to pull it off and clean it/ohm it out to see if its good. The car has the idle problem as well as a very bad 'buck' when letting off or pressing on the gas, it is not rpm dependent

I went to adjust my tps today, and have seen 2 different methods. Ohm's and volts. I fully warmed it up and set the narrow range to 1k ohms closed, but it's at 7.5k fully open. Fsm states around 4-6k correct? So I assume it is bad? I backprobed the green/red at the tps and am getting .5v fully warm key in on position.

My other question is about the initial set connector being a 2 wire plug. I've read about how you're supposed to jumper it when setting idle. I have 2 green connectors by my primary coils, one 6 plug and another a single plug. I know the single is for pulling codes. So where is the initial set plug on a s5 na?

So, basically I'm looking at:
Check bac
Unplug tps/jumper initial set plug and set idle
Replace/set tps
Check timing

Sound about right?

 

Green/Red wire should read 1 volt w/key to on and the engine as hot as it can possibly get. (warm is not good enough-a twenty minute drive should do it). The Orange wire is your Initial Set Coupler. Not really required to set the TPS though.

 

Warm was the wrong word to use, the engine was hot as can be, 45 minute drive.

So, how do I go about getting 1v from that wire?

I was asking about the initial set for doing my idle, since it will allow me to adjust it without other sensors effecting it, per the fsm. If it is just the one wire do I ground it?

 

You set it the same way you would set it using the ohming method, which would be w/the TPS adjustment screw.

 

Okay thank you. What do you think of the high ohm's with the narrow range? It's at 7.5k+ 'full throttle'. Fsm states 4-6k. As far as I know you can't adjust that range, so I'm assuming replace it?

 

If your problem were to go away by setting the device to 1 volt as suggested then it's probably not necessary to replace it. You would think if it were a little out of spec but at the same time that the car operates properly that you could ignore it for now. And it also depends on whether you replace it with a brand new out of the box unit or another used one which might be worse than the original one.

 

the S5 has a one wire plug that you ground. its in the same place, close to the battery, in the same branch as the 6 pin green plug.

 

Thank you, I will be adjusting it again today using the volt method and report back

And thank you as well. I had a feeling it was that one. The same one for pulling codes.

Thanks again

 

Adjusted tps to 1v. Helped somewhat but problems still exist. Idle is on/off with the surging, sometimes will be steady and sometimes jump up to ~1300-1700. Still bucking coming on/off the gas, but it is slightly better then before.

I did notice with the key on my BAC is CONSTANTLY clicking quite loud and repeatability. Unplugged it and not all that much changed with how it runs, still surges on and off and just didn't effect much. I have a feeling it is playing a role in how it's at least idling. And since the tps didn't change much I guess I will replace it with another(used) one to see if it helps.

I'm going to do a leakdown test to make sure I don't have any vacuum leaks

 

The BAC vibrates after the car has been run for a while before it eventually shuts off. The BAC is mainly used to prevent the idle from falling below 750 rpm so unless it is stuck open your problem probably lies elsewhere. Does your idle problem occur only w/the engine cold or does it still occur w/the engine fully warmed up? A rough idle could also be caused by the Water Thermosensor too. Has this problem sprouted up out of nowhere or has it occured since you purchased the car? And have you checked for error codes.

 

The BAC is clicking just about all the time, and very loudly. The idle has dropped to about 400 rpm a few times. The idle problem is occurring all of the time. It did it when I first bought the car but only when it was cold, and once it warmed up it smoothed out. It has gradually gotten worse up to the point where I'm at now.

I have checked for codes and it is not throwing any, even with the BAC unplugged.


I did want to add, I recently had a bad MOP(code 27). That was swapped out with a new(used) one and my CEL/limp mode problem went away. But I did notice the idle/running has slightly deteriorated since then.

 

So the BAC clicks even if the engine were stone cold? Have you tried to physically pull codes? There is a single Orange wire in a Green check connector near the leading coil. You ground this wire like to the negative battery terminal and w/key to on the codes should be displayed if there are any.

An OMP code can damage the ECU when it occurs so maybe this is playing a role in your problem.

 

Yes it has done it with it cold, not every single time but it has done it.

I have tried to pull codes to no avail, did not get anything from it.

 

I was just out there poking around in the bay, I noticed the nipple on the solenoid valve(relief: blue, per Haynes manual) is broken clean off. Now I'm SURE that will have some effect, but could it cause all my problems? Or do you think there's some other things still going on.

I will be putting an ad in classifieds tonight for a replacement.


I'm aware about the MOP taking out the ECU when it goes. I pulled the ECU and checked all the chips, capacitors, resistors and tracers when I did the mop..everything looked fine, but I DO realize shorts can happen internally and even micro cracks I can't see with unmagnified eyes. Replacing it is hopefully my last resort, would be nice to find someone local with one so I don't have to aimlessly buy one if it's not my problem(I'm quite poor)

 

All those solenoids are identical, so you don't specifically need the "blue" one.
They are configured for each application by simply placing the filter on a different port (so if the one you get looks different, just move the filter and hook it up like the original).

 

If the nipple w/the hose connected to it is broken off then it could cause a vacuum leak perhaps. If you cap the hoses then see if the idling problem disappears or not.

 

Good to know, clokker. Thanks a lot. I'm sure it won't be hard at all to find one

Satch - it broke off clean at the base of the solenoid so I can't cap it there. I threw a cap on the other end of the line, I think it's the purge control valve. Running conditions did not change.

 

If the solenoid is Blue then it should be the Relief Solenoid. And doesn't the solenoid have two hoses running to it?

 

Yes it is the blue one and yes it has 2 lines running to it. I will cap off the other line running to it which will completely bypass the solenoid. What is it[solenoid] used for if you don't mind me asking. I'm just wondering if running with it out of the equation will have any side effects ie. idling/running problems

 

The air pump sends air to the ACV. When the air arrives at the ACV the air goes to one of two places. Either the air is allowed to enter the ACV or it is directed to a relief hose that runs under the air box and is vented to the atmosphere. The Relief Solenoid dictates where the air pump air goes.

The ACV will at times require this air pump provided air to help the cats burn off excess emissions. W/o this air the emissions would be above established limits.

 

Went out for another long drive and checked tps again. It was not idling at all dropping to 300rpm. Tps was back at .5v so I set it back to 1v, it did help it idle better, still surging though. Bac failed resistence test so that will be replaced. Ordering a new solenoid tonight.

Will a bad tps not hold/drop voltage or would it be a wiring problem?

I have a feeling a big part of the problem has to be a vacuum leak somewhere since it will not hold idle no matter what. I will be pressure testing it in the next couple days.

 

Sometimes the adjustment screw is not tight and can loosen some, but then there's always other issues such as the TPS itself or too much resistance in the wiring. The voltage on the G/R wire is an output signal.

 

I made sure the nut was tight and it was still tight when I went to readjust it. It took a good 1.5-2 full turns to get it back to 1v

 

If that's the case then the TPS is bonkers or the wire connected to the G/R wire of the TPS is pulling down the voltage for some reason. If it drops to .5 volts again you could measure the Br/W wire w/key to on and it should be 4.5 to 5.5 volts (powers the sensor) and the Br/B wire is a ground.