DFlintstone

Yea, I'm thinking of the Ford yellows also...Maybe a vendor will give me something for my 703's in the deal. I think my slow to warm was the combo of the 703's and my 02 sensor being stone dead. Got under 11 on one tank!
Got over 20 on a highway trip after the new 02 sensor..still sucks bad on short trips though, 13-14....<16

Heres the link to "that other thread" (A-haem) https://www.cherokeeforum.com/f2/ren...ce-rms-133153/

Which has the NAXJA link with EcoMikes info right on top. In case you are interested.

Well after the new sensor you can come back at the idle. EGR or IAC sticking? (I did see you cleaned it) I haven't done mine, torx issues.

hankthetank

yeah, i'm not sure its that either. but since its most likely original, i'll start there anyways. To my knowledge none of the sensors have been changed on the old girl since new...

hankthetank

EGR is deleted, IAC, throttle body and intake manifold are cleaned (inside and out)...

This morning on the way to work, it would not come down at all. Stayed around 1000rpm at every light, even if I tried to 'make' it come down...gonna check for vacuum leaks again before i install the sensor.

DFlintstone

Makes sense....I sort of screwed up. I found the leak with quick start, then while changing the manifold gasket found one lower injector O ring boogered up. Waz so close to the gasket I missed it. I needed the gasket anyway because of exhaust leaking at #6, but it wasn't my vac leak.

If I found a couple of easy to reach manifold bolts were loose, I'd pull the air cleaner and tighten them all. Guess you know that movie.

I wonder if the TPS adjustment could do that.

cruiser54

Absolutely could, does, and will.

hankthetank

i'll dig my meter out this weekend...again! i do have a slight exhaust leak rearing its head again too. welding the manifold definitely didn't work for me...grrr so many things to do to it, with so little time on my hands. i'm on the second of three weeks straight right now for work...

DFlintstone

cruiser54

Don't start drinking and posting!! I've gotten those emails. LOL.

5-90

TPS adjustment should be verified with a digital voltmeter.

TPS operation is to be verified using an analogue ohmmeter or voltmeter - digital DMMs have buffer circuits that delay response, and you can't see what you need to see.

Bear in mind that TPS adjustment is a static reading, and doesn't verify TPS operation. It can happen that a TPS (it's a carbon-track potentiometer) can get a "flat spot" on its track, which manifests as a "skip" or "drag" as the wiper arm sweeps. You won't see this with a DMM, due to the buffer circuits. Analogue (sweep needle meters) don't have those circuits.

Verification would be done by either backprobe the same point on the TPS as for adjustment, and slowly and smoothly operate the throttle valve and watch the needle - movement should be proportional to the motion of the wiper arm.

Or, you can disconnect the TPS (engine side) and take a direct reading.

If you backprobe the pins to read voltage, set your meter to read up to +5VDC (usually a 20V scale.)

If you take a direct reading, set it to the lowest resistance scale (usually 200 ohms.) You may need to adjust upwards.

The actual reading isn't critical at any point, once you've verified adjustment. It is the change in reading (delta-R or delta-Volts) that is important - it should move smoothly, and in time with the wiper arm on the sensor. It should not pause anywhere while the wiper arm is moving, it shouldn't drop to "zero" or "full scale" while you're moving and back down to where it was, or anything like that.

I have had TPS units read good at adjustment, but fail a function test or "sweep test" - the most common symptom that would lead to such a test would be a "flat spot" in throttle response - the engine drops out at part-throttle, or engine speed doesn't keep pace with throttle opening (accelerator pedal movement) briefly. This most often happens at the most common cruising range; while the spring tension on the wiper arm (internally) is very mild, it still ends up compressing the carbon track - which changes the resistance characteristics of the track at that point (compressed graphite exhibits different resistance characteristics than uncompressed graphite - I believe it's lower when it's compressed.)

hankthetank

^^^Thanks for the info! My analogue is at home, i'll bring my dmm from the shop and i'll post my findings on monday!

ekim3708

Watch your video. What happened to the exhaust reading

hankthetank

update: Adjusted tps (had 4.877 volts ref and .677 out)to .829 volts out. Sweep test was perfect - no hiccups. Ground test good too...

i'll drive around some more before i change that o2 sensor...