New TPS Problems

[99GSXblack]

About a week ago I got a new TPS installed by a friend of mine who is a mechanic. Cel light was on and the car would stutter and die after starting the first time then run good. He pulled the code for the cel and it said tps so time to get a $100 sensor...

Anyway with the old sensor it would idle steady at about 800 rpm... Now with the new sensor it will start the first time, but the idle bounces up and down about 50-100 rpm above or below 800 on the tach. Also when the car heats up the idle will go up to between 1200 and 1600 rpms. The car had no issues while driving once started before hand and has none now. Just the ridiculous idle. Is the TPS not adjusted correctly or what?

 

[TSiAWD666]

Did you just slap it on there? It's odd that you're asking if it's not adjusted properly because... if you adjusted it you should know whether or not it is. Check the voltages. I don't recall them unfortunately off the top of my head by if you do a search for tps adjustment you should find the specs here on the board plus instructions.

 

[99GSXblack]

My friend installed it not me. I did find voltages but for a 1g--between .48 and .52 at idle. Are these the same for a 2g? I'll also test both sensors to see if they old one was good. Time to be less lazy and do more work myself

I'll also checkout chiltons online manual.

 

[99GSXblack]

So lesson learned, do your own trouble shooting. I've tested the old tps and I get about 5.5k ohms between 1 and 3 which chilton says is good. However, when I rotate the sensor resistance doesn't change then suddenly spikes off my meter, chilton says that's not very good. So I have concluded that I did indeed need a new tps but could have got one for a lot cheaper.

Tomorrow I am going to make sure the new TPS is adjusted correctly myself and check the ISC while I'm at it. I will also be installing a new o-ring on the BISS and adjusting it properly. Do I need to go borrow my friends scanner or can I just disconnect the ISC? The scanner is used to keep the ISC at the basic step so would disconnecting it have the same effect? I think I read somewhere that it would. I've read so much crap trying to educate myself on this that it's all running together.

In addition the car still stumbles on startup when cold. I turn it back to off then turn it over again and it fires right up. Hopefully that will be fixed too.

The good news of the day is that I finally installed my upper ic with 1g bov. Boy were those bolts a bi*** to get off using a ratchet and standard wrench. It was all worth it though because the plastic 2g piece of shit was leaking like hell.

Sorry for the questions and wall of text. Thanks guys!

I adjusted the tps to the best of my ability per instructions using a feeler gauge and ohmmeter. I'm pretty sure it's right on. The idle is much more steady and controlled now, however when the car heats up the idle still creeps to 1k rpm then drops back down after sitting for a few minutes. The car also still stumbles on a cold start. I checked the isc and it's good. No boost leaks either. What could the problem be? Am I missing something incredibly simple and easy? One other thing yesterday the car decided to shift like crap, it didn't want to shift up but after the tps adjustment today it's shifting nicely (auto trans).

Thanks for any help you guys can give me.

 

[99GSXblack]

I adjusted the tps to the best of my ability per instructions using a feeler gauge and ohmmeter. I'm pretty sure it's right on. The idle is much more steady and controlled now, however when the car heats up the idle still creeps to 1k rpm then drops back down after sitting for a few minutes. The car also still stumbles on a cold start. I checked the isc and it's good. No boost leaks either. What could the problem be? Am I missing something incredibly simple and easy? One other thing yesterday the car decided to shift like crap, it didn't want to shift up but after the tps adjustment today it's shifting nicely (auto trans).

Thanks for any help you guys can give me.

Here's an update.

Drove the car around today and discovered that the biss is getting lose as I drive. Problem resolved.

 

[99GSXblack]

I'd rather keep my problem in one thread so here goes...

I guess I was wrong. It threw me a CEL today and decided to idle at 1400 rpms after I drove 30 miles shut the car down then drove another 30. The TPS is adjusted correctly, ISC motor is good, the BISS is fixed though I didn't set it with a scanner, and nothing is leaking. I still get the minor stumble on cold startup. A friend of mine will probably pull the cel code for me tomorrow. Any ideas what could be causing my issues?

 

[project_skyline]

How are you verifying there is no air leaks?
Its extremely common for DSM's to have leaks on the TB shaft seals, no one seems to think about it on a car thats 10-20 years old.

By minor stumble on startup do you mean while cold and idling or a stumble while trying to start the car cold?

 

[99GSXblack]

How are you verifying there is no air leaks?
Its extremely common for DSM's to have leaks on the TB shaft seals, no one seems to think about it on a car thats 10-20 years old.

By minor stumble on startup do you mean while cold and idling or a stumble while trying to start the car cold?

Stumble while starting the car cold. Did a boost leak test and no bubbles with soapy water. Sprayed carb cleaner too and no rpm change.

Update: After driving it today it's idling at nearly 800ish and going up and down slightly then it will spike to 1400 then back down. At this point I'm getting really frustrated and have no idea what the problem is.

 

[project_skyline]

Stumble while starting the car cold. Did a boost leak test and no bubbles with soapy water. Sprayed carb cleaner too and no rpm change.

Update: After driving it today it's idling at nearly 800ish and going up and down slightly then it will spike to 1400 then back down. At this point I'm getting really frustrated and have no idea what the problem is.

It could be a number of things. Have you checked your CEL?

 

[99GSXblack]

I had stupid attack and unhooked the battery to reset the ecu in case that was the problem, not thinking about the cel. I'm guessing it will throw it again in due time. I will update this if/when it does.

I readjusted the tps again yesterday even though it tested right on (3 and 4 pins have continuity at fully closed throttle and no continuity with a .0177 feeler gauge.) It seemed to help keep the idle steady (it's pretty rock solid now) but it still idles up slightly after driving for any period of time though it hasn't gone much past 1k.

What else could I check that I haven't without a code reader? Would leaking TB shaft seals cause the idle to creep like it is?

 

[TSiAWD666]

I've had idle creep when my throttle body cables weren't adjusted properly. I recently changed my engine, and with it I put in a new throttle body and intake manifold. Ever since my cruise control hasn't worked and would hunt around the desired speed. Due to the intake manifold and TB's new orientation, I had to relocate the cruise control so I thought that migration might have goofed up the slack in the cables. So I played with them, tightening up mostly the cable from the cruise control box to the cruise control motor/vacuum pump. If I did this enough, the car would start and idle as before, but after a bit of driving the car would idle at like 1500-1600. Turned out I just had the cable too taught, and releasing some slack allowed it to return to my set idle of 1100rpm.

I don't know if this possibly relates to your issue though, but thought I would share it in case it helps.

 

[99GSXblack]

The throttle return springs are about toast on my throttle body. I WD-40'ed them to death and the surge is nearly totally gone.

 

[RayBan GST]

what happens when you switch on your AC? have you checked all the vaccum lines on your throttle body? try to disconnect them and see if there is any difference in IDLE, which BOV are you running and how its connected is it recirculated? check also the throttle cable and the cruise control cables if you have one.


good luck

 

[99GSXblack]

what happens when you switch on your AC? have you checked all the vaccum lines on your throttle body? try to disconnect them and see if there is any difference in IDLE, which BOV are you running and how its connected is it recirculated? check also the throttle cable and the cruise control cables if you have one.


good luck

MY AC is dead--turn it on and it still runs nice warm air from outside in. I'm running a 1g (not crushed) bov and it's recirculated as it should be. The throttle cable is set right as far as I can tell plus I haven't messed with them since I've had the car. I will try pulling the vac hoses on the throttle body and see what happens to the idle.

 

[99GSXblack]

I went ahead and simply replaced all my vac lines and that fixed the problem.