" how to adjust throttle position sensor?"

[sxyvet]

hi there guys,
just wandering please as i dont yet have a corvette repair manual yet on how to adjust throttle position sensor for 1991 l98 engine?

it looks like the sensor is adjustable as i did loosen the sensor and you can move side to side and up and down a little!

i do have a digital multi meter!

can some one please give me a run down step bye step on what,how to set the throttle sensor please?

where do i put the leads from the multi meter?

in which order?

what do i set the multi meter on in settings?

any info would be greatly appreciated!
thanks heaps
from glen
sxyvet
Australia

 

[tomtom72]

Hi Glen, The reading is in volts, on a 90 LT5 the reading at the factory idle speed is .46 volt to .62 volts up to about 5 volts @ WOT. On mine there three leads, but I have an LT5 so I'm not sure if the L98 is the same.

452 black = sensor ground one VOM lead here?
417 dark blue = TPS signal one VOM lead here?
416 Grey = SV reference

Don't know if this helps??? I have a 1990?

Tom

If you have a scan tool the work is easier, I used dress pins to go in thru the back of the connector the first time. Then I bought a used snap on 2500 & it's sooo much easier as you just plug into the ALDL connector. Corvette Central sells a set of connectors to make it easy to connect a VOM. They are sold as a set or separately.

 

[MBDiagMan]

TomTom told you how to connect the meter, but I guess he assumed that you know what to set the TPS to. The setting is .54 +/- .08 volts. I have found that setting it a little on the high side of .54 gives a little better throttle response. I usually look for about .56 to .58 and lock it down. Recheck the voltage after you have tightened it down.

Good luck,

 

[sxyvet]

r.ethrottle position sensor!

TomTom told you how to connect the meter, but I guess he assumed that you know what to set the TPS to. The setting is .54 +/- .08 volts. I have found that setting it a little on the high side of .54 gives a little better throttle response. I usually look for about .56 to .58 and lock it down. Recheck the voltage after you have tightened it down.

Good luck,

hi there tomtom72 and mbdiagman,
thanks for the reply back guys,
which leads from multimeter do i connect where?

i also have three leads too,black,grey,blue!

on the multi meter what setting do i switch it too?
volts is it?

i was looking at buying a "auto xray-scan 3000" for $299.00 u.s from zip products!

are the auto x-ray scanners any good?
thanks guys
have a great day
from glen
sxyvet
Australia

 

[speedmaster4]

91 vette ecm "auto-zeros" tps input. l98 is non-adjustable but must signal .3-.9 vdc at idle . lt5 is adjustable but must range .46-.62 at iidle.
assume u have -727 ecm,speed dens (no maf) same as usa.
earlier -165 ecm (1986-1989) must adjust with multi step procedure or eng perf will not be satifactory. if u need this i will post.

91 ecm 1227727 (and prob 90-havent seen) used on l98. any tps signal betw .3 and .9 vdc idle condition is processed by ecm as 0% throttle open and fuel curve reset accordingly...tps signal above or below .3-.9 vdc turns on MIL....so u cant "tune" -727 ecm like -165, the -727 will just offset any signal in normal range to 0% throttle

 

[Vettefan87]

If it is the same one that is in my 87 you put it in the top two, the A, and B holes. A is black and B is dark blue. C is grey which is the 5v reference. You are supposed to have .58 volts with just the key on and no throttle depressed, and 5v at WOT, which I have never seen happen. Play around with it and you can bump up the voltage, but if you set it to high your idle will be high as well. Good luck.

 

[MBDiagMan]

Put the meter in DC Volts position. If it is a digital meter, it will work with either lead in the black wire and the other lead in the blue wire. Leave the grey disconnected.

If it is an analog meter, I think the black lead will go on the black wire and the red lead on the blue wire. You also will have to select the range on an analog meter. Choose the smallest range that is 5VDC or greater.

Good luck,

 

[sxyvet]

hi there mbdiagman,vettefan87,speedmaster4,
thank you kindly for your info and help!
much apprecated!
cheers
glen
sxyvet
Australia

 

[EOLIVER]

I thought I read somewhere that the L98 TPS is not adjustable?

 

[Vettefan87]

I thought I read somewhere that the L98 TPS is not adjustable?

Nope it is, it is just like a variable resistor.

 

[bossvette]

the early ones had slotted holes with more adjustment then the later ones

 

[Vettefan87]

You just loosten the two screws and move it up or down till you reach the voltage you want, then tighten it back up and you are done.
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