89fastlookinRS

My idle went alittle high all a sudden the other day. I went ahead and replaced the IAC and it helped some, but it's still alittle high. So I tried to test the TPS voltage with a voltmeter. The back two wires gave me a voltage of 4.37 at idle???? And moving the throttle to wot it went down to .13???? This is way off from what the tech article says ".054-.075 @ idle to over 4 volts @ wot. Am I missing something here?

I went ahead and adjusted my minimum air anyway so idle is back down, but I would like to figure out why the tps voltage is weird. I also tested the tps off of my stock tbi unit and it read the same.

Benm109

When you say "back two wires", what color wires are you using to test the TPS? You should be hooking your DVOM on the blue wire and the black wire (or a good ground). That should give you 0.54volts +/- 0.75volts at closed throttle and over 4.5volts at WOT.

orangetang

I replaced my TPS a few days ago because the old one packed it in and my fuel economy went to hell. Once installed, the SES light wont come on anymore, the engine runs great and it idles normal. However, my fuel economy is still horrible. I've since replaced the stock snorkel/cleaner with a 14x3" open-element, replaced the plug wires with MSD heli-cores, replaced the cap and rotor with MSD parts and still, the engine runs well, but consumes a ridiculous amount of fuel. Just for an example, I usually get between 400 and 550km out of the ~65L tank, depending on how much time is spent in the city or on the highway. Lately I've been getting around 280-350km out of a tank.... I picked up some Autolite Platinum plugs a couple days ago, but I'll probably end up waiting a couple days before I actually gap and screw them in... That EGR/AIR system is a really bitch to work around. I've never needed to climb under a car to install/remove plaug wires before...

Any ideas on what the problem is? This new TPS is adjustable. If you guys havn't ever seen an adjustable one, I can post some images. Basically, the two screw holes are elongated to allow about 20 degrees rotation. I've tried the sensor in a few different positions, then eyeballed it with my old sensor and tightened it up. Sadly, in any position, the engine appears to perform the same and I'm stumped on what is causing all this excess fuel burn...

PLEASE help me if you can!

Thanks,

Landon

~ for those of you considering an open-element... I picked up an Edelbrock #1207 and it fits my 91 L03 very well. The TBI spacer needs to stay though, otherwise you won't be able to clear the coil or distributor. ~

Here are a couple pics from my website showing off the new ugly chrome

orangetang

Benm109,

I suppose that's what I could do right there... Take a multimeter to the TPS and calibrate it for ~0.5V at an idle... Any specific number I should aim for? Less the better or anywhere between lets say 0.2-0.5V?

89fastlookinRS

Cant really tell the dark colors on mine. They're alittle faded and dirty. But if you look at the 3 wires, the back two meaning towards the back of the car are the ones i got an actual movable reading.

orangetang

Since 'help' is totally out to lunch on the topic of TPS sensors, this week... I went ahead and bought a shiney new AC Delco brand TPS today, which will replace the 'adjustable' Niehoff sensor I installed last week. Considering these sensors are not meant to be 'adjustable', and my fuel consumption (possible fuel/spark tables?) is still out to lunch, I've concluded the Niehoff brand TPS to be a complete POS. I'll try out the Delco in a couple of minutes and if it works the same or better, the Niehoff will find it's way back to Lordo later on today. If not, I'll be completely confused, lost and angry with everyone and everything until someone here gives out some advice

Cheers,

Expect some pretty pictures of the sensors and perhaps a more detailed explanation of the problems I've been having with the TPS. Maybe it'll deserve a sticky, and maybe I'll send off that e-mail of pics/write up I havn't been able to post in the TBI/open-elements thread, since it's so conveniently been locked...........

orangetang

Here are some pictures... It seems that this board has somewhat limited options for uploading. I'll just add them in sequence, and leave a description in order... May need to edit

This be the three sensors... From left to right, the new AC Delco, the Niehoff, the original GM or Delco?

orangetang

Same Order

orangetang

And finally... installed! Fired up the engine and all seems well. It even sounds the same. I'll get back to the thread after a couple days of fuel burn to let you all know weather or not the problem is cured.

My oppinion: Please stay away from the Niehoff sensors becuase a TPS really shouldn't be adjustable, plus Delco makes stuff specific for our cars and in this case it cost $2 dollars less.

89fastlookinRS

My TPS is a different style. It has two bolts spread apart, with the plug in the middle.