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90 xj
November 15th, 2004, 13:07
does anybody know what the tps specs are for a 1990 4.0 i think i have mine set too high. alldata said the operating range is from 1 to 5 but diddnt give a set idle or a wide open throttle spec
jake

Matthew Currie
November 15th, 2004, 14:28
The TPS setting is done not by a specific voltage setting, but by a percentage of the input voltage, which can vary from one vehicle to the other. For this test you should use a high-impedance voltmeter (digital multimeter, FET VOM or VTVM if you're old enough to know what that is).

I finally got smart and wrote it down in text form, so I can paste it in to posts like this:

For an 87-90 4.0:

Test is done with throttle closed, connectors connected. Insert probes through back of connectors to make readings.

For manual connect + probe to terminal A, and - to B. Take a reading, which should be in vicinity of 5 volts but probably lower. Note the reading well. Now move the positive probe to terminal C. The reading should be 16 percent of the previous reading.

For Automatic, use the square, 4-terminal plug. Connect probe + to terminal A, and - to D. Note reading, which should be in vicinity of 5 volts. Now move probe + to terminal B. This reading should be 82 % of the first.

5-90
November 15th, 2004, 15:29
For this test you should use a high-impedance voltmeter (digital multimeter, FET VOM or VTVM if you're old enough to know what that is).


Damn, yer old! I didn't think anyone else around even knew what a VTVM was!

If you want me to prove it, I'll PM ya - I think I might even have one in "cold storage" somewhere that I built years ago...

5-90

jldiaz
November 15th, 2004, 16:06
Heeey!!! Just last year, I garbaged the Heathkit VTVM that I'd put together.

dizzymac
November 15th, 2004, 17:22
sheesh....Heathkit...now wer'e really "dating" ourselves.....lol

old_man
November 15th, 2004, 17:37
Who here remembers how to grid leak bias a tetrode?

94XJ4x4
November 15th, 2004, 18:13
I dont know about other people reading this post, but you guys definatly confused me.

jpdriver1
November 15th, 2004, 20:32
grid lead bias on the tetrode? come on give us a tuff one --- like recalibrating the tube 6Meter with the vtvm !!! KD6lfo here