Karl, I'm starting this new thread to talk about the double Groove TB I did for you for your Mazda truck.

Maybe the high idle issue w/ the double Grooved TB isnt a bad TPS- maybe I did something wrong on this one. I'm not perfect, nobody is... I just went into my pic's on my computer and had another look at the Groove job I did on this TB. I can see both the normal underside Groove and the top side "double" or second Groove, and the IAC restricttion I did.













I remember the TPS screws were stuck buggers. If the TB could be secured like in a vice carefully, the screws could be loosened w/ an old-style impact driver w/ the proper phillips bit in the screws. The kind of impact tool you strike on the end w/ a hammer. I think I may have tried this, but I lacked a proper heavy bench vice to hold it. Tricky business, to break the screws loose without breaking anything else.

what I don't remember and can't see in my pics, is an idle stop screw, it does have one right? Tried adjusting it? I know that will mess up the TPS setting, bringing the TPS screw deal right back...

I believe I would have "checked my work" w/ a flashlight. Try shining a flashlight into the bore see how much light shows around the throttle plate, and verify there are no pinholes in the TB from bit breakthrough. If you switched back to your other TB, and the idle RPM issue goes away, then obviously something is wrong w/ this TB. Maybe the two Grooves, and any abrasions on the throttle plate, have increased the amount of air getting 'round the plate at idle. Somehow too much air is entering at base idle throttle position. It WAS more difficult to do the upper Groove in this one, with the deep throttle body casting...

over...

Tracy G

The TB worked for a while with no issues.
It was around December before Christmas that the idle went nuts. Had it off since January since I had to pass inspection and could not get rid of problem and code so had to wait till I got back to NY to change TB.
Got an IAC code(dont remember #)and replaced IAC with a new autozone one.
Didnt make a difference. The high idle stops only when I smack the TB a few times but next time in neutral or shifting and it comes back.
Read some online about issues with idle being connected to TPS. One was the sensor is not turning smoothly and gets stuck. So tried to remove to see if there is an issue there is how I found the screws too tight to remove.
Dont have an impact tool, just a hammer which I would like to use on the whole truck.
The plate does stick a little when I go to turn the spring to open but dont know if the old one does the same.
If it was a hole in the area letting too much air in, then why would tapping resolve the issue?
Sounds like its something sticking and tapping resolves that so I am guessing the sensor sticks.

well, I'd say simply try to replace the TPS. Lotsa parts stores nowdays rent tools or even have loaner program. I think I tried to loosen those screws w/ my hammer-operated impact driver, but while holding the TB. So I couldn't get much of a whack on the screws. I'd shoot 'em w/ Pb Blaster penetrating oil several times, get the thing in a good vice, and use the manual impact driver, trying not to break anything.

Kinda weird it ran OK for a month then went south. that tells me the Grooves and my work musta been OK. I'd check the edge of the throttle plate to see if it's binding though, THAT also could be the issue-- I don't remember if I did throttle plate shaping on this TB, though the upper plate side next to the upper Groove looks shiny in my pics. If it feels at all bind-y when opening/closing then it's a good bet the plate edge has a tiny burr on it, If the dang thing was here I'd have it figured out, and either fixed (Or broke from impacting the TPS screws) in short order. I haven't yet seen a TPS bind or go out to lunch so bad to cause throttle sticking.

Actually this is all part of my evil plan to ruin the world- I'm just sorta slow at it!

Tracy G

I tried working with the plate to see if there was something sticking when it first started seeing I had to fix it for inspection. Ran some fine sandpaper over it I think but I didnt feel any burs.
Also worked with the idle screw to let it bump the plate so as to not make the throttle plate stick closed.
If I could have removed the TPS I would have checked to see if rotated smoothly as my next course of action in finding the problem.
The TB was a junkyard special($80)from a 2000 Ranger and it did work for a while.
Guess I could deal with the high idle but I do coast much with the stick to save gas, brake and tranny so that is what would bother me when in idle.
At least I have the original to use and not stuck with the issue now.

That IAC code would've come in handy. Should've tracked that down rather than throwing parts at it; if you still have the old one, put it on the TB and see if you get a code again. Perhaps the code was to trigger an IAC re-calibration.

Another thing to consider, due to issues seemingly being sensor and ECU related, is grounding. Karl lives at or near sea level, miles from a large body of salt water; burnishing those connectors and applying some dielectric might help return accuracy and reliability to the system. Same for chassis grounds...a few ounces of preventative maintenance bringing pounds of cure at the gas pump.

You're right, Karl, TPS and IAC are closely related from the ECU's perspective; if one is bad or off, it will make the readings from the other make no sense to the ECU and funny things will happen. Ford's TPS needs to deliver 0.1-ish VDC to the ECU for closed throttle, which is in the 10% open range; when that's triggered at cold idle (meaning the engine coolant temp sensor hasn't seen whatever temp it needs to trigger closed loop fuel delivery), the IAC opens to some degree to compensate for the fuel being dumped in....thinking about what i just wrote here, how's your ECT sensor's health? not the one wire sending unit that's connected to the temp gauge in your instrument cluster, but the actual 2 wire sensor the ECU uses?

It may not be a maintenance related vacuum leak after all...maybe it's a computer logic issue at play here!

Another thing to consider in tracking down the problem points back to the IAC and its calibration - in these Rangers, I've learned that the MVAC compressor is engaged in most cases, which makes the ECU open the IAC so the engine doesn't bog under the added load. again given your coastal location Karl, is it possible that you're driving around with your heat/defog on? (no doubt you were: you said it was January). No doubt the engine was warm from driving, but was the ECU getting the correct coolant temp info? and further, if it wasn't, was the IAC valve actuating CORRECTLY for conditions and status? again, if ECU doesn't see closed loop/warm idle, that IAC will open (further!) to prevent bogging/stalling...so back to ECT sensor.

Just some second cup of coffee thoughts for you to consider and track down, giving Tracy's work the benefit of the doubt, and possible computer/sensor gremlins to slay! Hamster-wheeling on vacuum wasn't getting you anywhere, so a different approach might help. I really hope this is the right track finally for you Karl, and that you can return to chasing 50+ MPG, zero emissions and a wallet that stays fatter longer! Don't forget your PCV re-route and then moving those spark plug wires around If I'm right...You deserve a eureka moment after all this time.

Wow- some beautiful insight there 'dude... I mean I vote to give Heysoundude Dr. status, as in Doctor of Remote Diagnostics. Hey now, Greg, you can start adding letters in Caps after your name, IMHO. Or even give yourself another handle- like Dr Dude. We all and poor Karl have been trying to pin the tail on this Donkey for quite some time now, longer than a lot of major Events in history have taken...

for Gosh sake Karl, locate the 2 wire ECT sensor, and check the connection, maybe clean the terminals on the wooly-bugger. there HAS to be a spec on this sensor, it's going to be a variable resistor across the 2 wires. There has to be spec's on the Ohms reading at different temps-- or maybe, just maybe- the wire plug or even the wires themselves are corroded. Ford has always been pretty good about putting dilectric grease in their electrical plugs to guard against this, but...

This darn Mazda has provided food for thought for me for over 2 years now, or is it 3? And Karl is about ready to blame excess sunlight on Pluto for all the trouble (I'm not far behind) Man oh Man, it's a good thing we are working on vehicles and not reactors...I'm spoutin' off here, otherwise un-justifiably, except it has gone on for so long now. Even Ron never suggested THIS idea! If this isn't it-- well try the trip to Hunza, maybe ( I heard the yaks there prefer a certain Mountain-grown carrot...)

As for myself, well you see, I never got to work at NASA in Mission control, probably a Good Thing.

Tracy G

Another thing to consider, due to issues seemingly being sensor and ECU related, is grounding. Karl lives at or near sea level, miles from a large body of salt water; burnishing those connectors and applying some dielectric might help return accuracy and reliability to the system.

I did that after trying everything else back in January and found no cure. Even though the wires/connectors were clean, I lubed them anyway.
When I put the old one on when I got back home, it worked fine so that ruled out the connections for me.

Same for chassis grounds...a few ounces of preventative maintenance bringing pounds of cure at the gas pump.

I found one huge ground broken of that connects I believe the engine with the firewall last year. A pretty large flat weaved ground wire and put on a new connector and reattached it to the firewall. Got exited to think this was the problem but between fixing that ground and fixing 4 vacuum leaks I thought "problem solved" but all this fixing did zero to the performance.
To think fixing 4 vacuum leaks did zero, I wonder how can fixing so many leaks not affect performance?
Talk about frustrating!!!

.thinking about what i just wrote here, how's your ECT sensor's health? not the one wire sending unit that's connected to the temp gauge in your instrument cluster, but the actual 2 wire sensor the ECU uses?

That I will have to do some Youtube searching on.
The doctor is giving the patient possible causes but the patient is not absorbing the doctors lingo.
Will do some research.

Thanks for the info Dr. Dude

Update:
Found the ECT I believe. If we were talking thermostat temps, I monitor this on my Scangauge and its usually 184 plus or minus 4 degrees.
The two sensors look almost the same right next to each other.
Both sensors seem to have good wires and connection after inspection.
Plus, if this wire was the problem, then the problem should still be there when I changed over the TB to the old one. Doing the change solved the problem so the ECT should not be a problem. Pic #1

Did find what looks like a loose ground that has a connector plate that is not connected to a bolt but laying on the base that the bolt connects to but I dont think this is an issue since its still grounded by making contact. The loose ground plate is below the copper tube resting on the base and the bolt where I think it should go is above the tube.
Pic #2

yo Karl! I'd check a wiring diagram to identify that loose wire. color codes should tell the story. caveat: Fords, at least the older ones from the 80's- speaking of emissions controls anyway- and possible corresponding wire harnesses- had MANY different emissions diagrams, to an exasperating degree. When looking at wire diagrams, just be sure you are checking the right one for your exact truck. Often there can be different diagrams, but I would infer the right one by checking for engine size, year, model, and then options etc. Might be differing diagrams for Ford vs. Mazda. If it IS a ground wire, make sure it has a really secure connection, just touching metal isn't good enough. One more thing to look for, is if insulation shrinks back from a wire plug, corrosion can get in the wire. Use Napoleonic Justice, guilty until proved innocent type thinking.

but at the bottom of this-if by replacing the TB from the double Grooved one to the present one- the entire idle RPM issue went away, then obviously it is to do with the double Grooved one. Captain Obvious here- remember I wasn't this old this morning, and I DID just have a b-day!! It's not early Alzheimers, it's just delayed Learning syndrome, for me,right?

Tracy G

hey, that's perfect; the ECT IS usually right near the thermostat housing.

Don't dismiss the sensor because the wiring and connector look fine, though.

it's a simple swap that doesn't require draining/refilling the cooling system: if your engine is cool and the system is de-pressurized (hint- take the rad cap off), you might "lose" an oz or 2 of coolant at most. the sensor itself is not an expensive part...under $20 i would think. I can look up colour codes for you in my Haynes manual if you want to be 100% sure you're pulling the right one. I would think that it would take ~20 mins, out and in, once you have everything in place.

Grounding- I may have posted this elsewhere on this forum before, but seeing as we're talking about sensors it can't hurt to post this again. what this video suggests is the factory wiring for the grounding system is adequate, but misses a key link for efficient charging and power transfer, and it makes perfect sense to me so I agree with it and suggest anybody with an automobile of any kind consider making the upgrade. as far as our trucks, Karl, I'd re-do the whole scenario entirely with no less than 4 GA wiring, which i believe twice as large as factory, so there should be a gain in efficiency from that somehow. anyway, check this:

Grounding Video


EDIT: Karl (and Tracy and whomever else is following along at home), check out what 1983-2011 Ford Ranger 4-Cylinder Engines - The Ranger Station says under Porting, almost all the way down the page; it might be another factor in not realizing gains post-groove (the airflow/waveform/turbulence is disturbed). It's also recommended for the 3.0 V6 that I have, but it's probably solid advice for any engine to have done to correct for differences between design and manufacture.

EDIT 2:Karl, I found Ping, surging, revving? | The Ranger Station

And one more, a bit easier to read/follow:
coolant temp sensor, sender questions | The Ranger Station

So Karl, any update? I'm going a bit crazy waiting to see if this could be the solution for you. (hopefully you're out establishing new mileage benchmarks with your grooved TB)

Still haven't changed the TPS since time and other things like finding a vac leak.
Have the gauge reading 0-10 STFT and 25 LTFT so something is leaking somewhere.
Did the old brake cleaner everywhere I know with no results. Even the HCS is not giving any results lately and I can only surmise a vac leak is part/all of the problem.
Amazing though how I can take out a vac hose where I can feel the vacuum on the hose coming from the intake manifold(with a valve on it just letting in 20% of total vacuum from manifold) and it doesn't register any larger numbers on the STFT or make the engine to stumble.
You would think that letting in that much air would register at least but not according to the gauge. I have an 02 extender on my upstream sensor that is not seated correctly and wonder if that is messing with the LTFT numbers. Have it wrapped with foil and fiberglass to seal until I can remove it.
So until I find the reason for the large LTFT numbers, I will not mess with the TPS. Finding the leak is much more pressing.
PS...I can also smell my exhaust, not as clean as before. Must be the unburned fuel being dumped into the cylinders due to the leak.