Lankan

Read "4crawlers" thread and did some tests. Here are the results:

- Test 1 & 4 passed.
- I can't get any readings for tests 2 & 3 (failed these tests).

In another section of the "4crawlers" thread says: "And it is this very simple test that can be the ultimate test of the idle circuit of the TPS. If the ECU responds to the timing test jumper as it should with your TPS connected, it is "good" per your ECU." I'm FAILING this test also, as when the TE1/E1 are "jumped", there's no change in the idle at all.

This makes it seem like only parts of the TPS are working properly. Because it fails tests 2&3 above, is it a good assumption to say that it needs to be replaced??

ChefYota4x4

iTrader: (5)

Alright, now we're getting somewhere TANGIBLE! (not cheering at your misfortune, lol... You KWIMean, yeah? lol)

Well, that depends... usually you can set the first setting and the rest should be in line(the first one is VERY wide range and sensitive... and if you ever set one, you'll see how sensitive I mean! lol)... I'm curious as to whether this one is just out of adjustment... might be worth a shot to try and 'adjust it', as it's free! lol...

Also, asked ya "Did you ever soak that thing with solvent on accident/on purpose/while cleaning the throttle body?"... I ask because YOU DID take it down SOME to do timing belt swap, etc., right?

Also, as I said about the 'timing kit install'... I have NO IDEA on the belt driven one if having something 'OFF' can create dead spots in the TPS, etc., ya know?( I doubt it as you're only looking for resistance readings).. I guess slapping a new TPS on and setting it properly in every way would conclude that, either way, right? Might be easier than getting in and doing a full on inspection of 'timing belt/tensioner settings'??? I have, again, no idea. (DID A FEW belts on a Cressida, Camry, etc., ...but never on this V-motor... So not sure).

Interesting findings, to say the least, Lankan! I actually, last time, bought a throttle body at Pick-Your-Part with the TPS on it..... didn't change the price at all, 40$! lol. I inspected it and the thing was set DEAD On still... so I just cleaned the TBody carefully and installed the whole thing. You COULD test one at the yard you use, just ask them("can I run a multi meter test on yours, the one on the t-body still, just to see/confirm mine is fubar?") ???

Keep me updated, and NICE FISHING, man! You're persistent, I like it! lol(I know, sometimes we're more PANICKED than 'persistent' or 'persevering'... In other words, "When our motives are purely out of 'HOLY CRAP I HAVE TO FIX THIS FAST, IT'S ALL I GOT' ", lol... That's a bit different, but I appreciate your efforts. Just do me a favor, ok? Answer EVERYTHING I ask, there's a reason I ask it, ok?

Lankan

Chef, the feelings mutual when it comes to actually being happy to find something wrong! Ironic how I sometimes feel that you and other members on here are more persevering than myself... your support is much appreciated!!

Didn't even go near the throttle body during my timing belt replacement. I'm pretty sure that the timing is set okay, but can never be 100% I suppose.

Funny thing is, I had an appointment this morning at a Gold Shield smog station, but cancelled it as I have done so much up to this point and would feel like an idiot if it was something simple wrong with it. And finally I MAY be onto something!! Will take a look now to see if it's out of adjustment.

Lankan

Update... I removed the TPS and tested it for resistance (tests 2&3) as it's much easier to get to the sensor leads when it's out. It actually works, but not sure if it works properly. The test says that it should read anything under 2300 ohms. With the sensor on the table and the multimeter hooked up to IDL & E2, untouched it read @7 ohms. When turning it clockwise to find the point where it goes to open/infinite, that occurred at @18 ohms. Does it sound right that these numbers are so low, as technically, it's still within spec?

ChefYota4x4

iTrader: (5)

Hey Lankan,

I've never tested a TPS without it being attached to the throttle body. In fact, the precise settings determined by the throttle plate stop screw create the 'range of motion/or lack of' that's supposed to be reading certain resistances, etc. Ya know? Even when you install it on the Throttle body, then adjust it to specs, it's not necessarily like it would be with the TPS on a bench, standing alone(spring relaxed all the way, etc.). Usually you just remove the throttle body with the TPS still attached(plugging the coolant lines as you disconnect them), then test/adjust it on the bench.

Could you clear this up?(exactly what you did to test it? Was it removed from the throttle body, etc.) K?

As Roger says in his tutorial... "It's good to shoot for somewhere close to the middle of acceptable range"... Not sure which portion of the testing that is on, and I'd have to read it again to figure that out. I'll leave that to you, had a really long day(19 hours hahaa)

(My personal feeling is that; If you'd removed it from the T-body to test... You need to re-attach it and retest with the throttle stop screw set first, etc.... You might have to remove the t-body to more easily test it... But remember, once you set it on the bench, you can button that TPS back down tight and call it a day/Or wait for the new part if it tests "out of acceptable range" or "TOAST")

Lankan

Chef, sorry for the confusion. On my 94 3VZE you don't need to take the throttle body off or drain the coolant to take the TPS off. It was a bit difficult due to the placement of the screws, but I managed.

I only took it off to get a feel of how it works. I did all the tests that are recommended on the "4crawler" section called "How to tell if the TPS is good or not", and it passed all five tests. The only thing I was questioning was the transition point between test 2&3 (<2300ohms & open/infinite). This transition was occurring, but at a very low number (@18 ohms as I mentioned). I would think that it's supposed to be somewhere in the middle.


Once I figures out it was working, I followed the instructions on "Throttle Position Sensor IDL-E2 Adjustment Procedure (courtesy of Frankenyota)". However under the "Troubleshooting" section, the only symptom it's showing that makes me think that it's abnormal is that after warming up the engine, the idle does not change at all when the timing check connector is jumped. Got an appointment at the Gold Shield smog station tomorrow. If I can't figure this one out today, I really feel it's time to take her in. All my time is consumed trying to find this gremlin! Looking for a job at the moment (Manufacturing Engineer), so it doesn't help that I'm obsessed with getting to the bottom of this problem.

ChefYota4x4

iTrader: (5)

Ahhhh, ok. Well, IIRC, it does NOT HAVE TO be where you think it should be(what would SEEM more logical)... As long as it's within that range.... it's likely fine, ya know? It might have been right on in adjustment, too... That's why I was wondering why you took it off... But I see now

Can you give me a quick list again of what you've verified to be 'JUST FINE'?

When you remove the TPS, I believe it IMMEDIATELY goes back into "open loop" cycle, where it's just a pre-set ECU setting/cycle that The ECU runs to avoid 'DAMAGE TO THE MOTOR', ya know? I'm really curious about things like the Coolant Temp Sensor... But I seem to remember you saying "I tested it at 165*F and it was dead on"..........Or was that someone else? lol. Mixing you and "Skinny" up on occasions here! lol. Both have later model 3.0's.

I seem to remember some guys with "AUTOMATICS" having Throttle/Drive-ability issues. Not sure at Idle, but bogging and surging, ... I DO remember reading that. Just can't remember where it was.

Anyway, yeah, throw up that 'LIST OF SUSPECTS'/CODES; For code '26'???? And a list thereafter of what you've tested? I don't mean to be lazy, but I'm telling ya.... Fresh perspective comes more often with LISTS OF YOTA-STATS! lol. So far you're doing a great job man.... don't quit!

BTW, BEST WISHES ON THE JOB HUNT!!!!

PS> I know exactly what it's like to run down to the wire on the registration/testing due dates, etc... And even though I could have got an extension so I could drive without having passed... I DID NOT WANT THAT PAPER STICKER OF SHAME! hahahaha. Nah, I wouldn't have cared AS much about that, as I would care about having to go down and file for temporary stickers, etc., etc. YUCK! hahaha.

ChefYota4x4

iTrader: (5)

PSS> I know you didn't have to drain anything or remove the TBody to test the "dead or not" readings on the TPS.... BUT, I just didn't want you to have to 're-set' the thing if you didn't have to. WIMean is, 'it could have been set dead on spot(they usually are, MORE often than not, ya know?).

Lankan

Is it correct to say that the only time the throttle opener spring/vacuum shaft touches the plate of the TPS is when the engine is off? This may sound like a stupid question/comment, but on mine, whenever the engine is on (idling, accelerating, or decelerating), the throttle opener is always retracted, as there's always vacuum on that line. I thought maybe the vacuum lines may have accidentally been switched, so I tried the furthermost one from the front of the engine... the one seen on this link (with the plugged port):

http://www.google.com/imgres?q=3vze+...r:0,s:15,i:108

That seems more logical in how it works, as it's touches the TPS plate during idle and decelerating, and backs away when accelerating. But the pictures in the FSM and others I came across show that the throttle opener vacuum line from the throttle body is the one as seen on the picture. Is this correct??

Chef, I haven't forgotten to recap everything I've tested/replaced thus far. Working on that! Just wanted to make sure that the correct vacuum port was being used.

ChefYota4x4

iTrader: (5)

WOW, looking at that picture(and some diagrams I've seen), I can confirm that your TPS/EGR/TBody and otherwise vacuum realm is LORD OF THE RINGS compared to my "Goonies", hehehe. I have no clue which one actuates what... BUt whatever the FSM says GOES, period! Right? You've looked on your hood? The vacuum diagram?

Lankan

The diagram on the underside of the hood is contradictory to what's in the FSM, as it does not show two of the five vacuum ports that are on the throttle body. The under-hood diagram shows only the three inline vacuum ports from the throttle body, and the one closest to the firewall is split and used for the throttle opener and the charcoal canister. That would actually make sense, but the FSM shows something different!

Same with the adjustment of the TPS. The FSM says to check the resistance while vacuum is applied to the throttle opener (see step 2 on the first page):

http://www.ncttora.com/fsm/1990-1995...e/throttle.pdf

While the 4crawler thread says to check the resistance when the engine is off... first paragraph under TPS Adjustment:

http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

This maybe obvious to some, but can someone please clarify as to which way it should be adjusted and which vacuum port is the correct one to use??

ChefYota4x4

iTrader: (5)

Trying to get some input for Lankan... PLEASE, any 3VZE Guru's... give the guy some input? I'm just very slim on time to try and 'learn 94 specific 3VZE Emissions, etc., ya know?

Thanks guys, in advance!

Gonna throw it up on my Build thread, ..but not sure that'll help much any more as I'm not getting nearly as much traffic as previously(obviously cuz I'm somewhat at a standstill, etc., etc., lol).. But I'll try anyhow, ok? lol.

ChefYota4x4

iTrader: (5)

I see, .... must be a difference in "production date" and ACTUAL year of yours. Have you called the dealer and asked them with your vin#; "IS THIS A 94 OR 95 SYSTEM?"

I posted your thread on my build, not sure it'll bring a single homie, lol... but worth a shot, right? I would do a nice summarized post, cleanly laid out, like you've been doing, with everything that's wrong/all you've tried/results, etc., ok? (Just in case)

PS> DO NOT feel bad about taking it into that Gold Shield shop for diagnosis... THEY DO THIS EVERY DAY! lol.... And, well, you're out of time, right? So keep at it as long as you can and then just get it in there, ya know?

scope103

18 is less than 2300, so you're good. All you're testing is whether a switch closes or not; it's not a rheostat. So you "should" get zero ohms, but anything under 2300 is good enough. http://www.ncttora.com/fsm/1990-1995...e/throttle.pdf

Correct; the throttle opener holds the throttle valve open when the engine is OFF (no vacuum), otherwise it does nothing. http://www.autoshop101.com/forms/h21.pdf

I know that it is an article of faith that the idle shifts when you jumper the diagnostic connector, but mine does not do that. And I've heard from others with the same experience (I think MudHippy may be one.) I can't explain it. Since you've actually checked the TPS and found it working, I think you don't need to worry about the idle speed shift.

Lankan

Chef, thanks for all the continued support!

scope103, thanks for chiming in! At least I have adjusted the TPS correctly then. Since we have the same production year vehicles, can you do me a favor and post a picture of the top of your throttle body where all the vacuum lines are. Please make sure you capture the throttle opener in the picture as I want to see how it was done by the factory. Before I got it, mine's been messed around with a lot, so I want to make sure that everything is connected properly.
You would agree that the TPS outputs should be checked with NO vacuum applied to the throttle opener right? Assuming it's a typo in the online FSM that I'm referencing.

abecedarian

Pardon me if I step out a little....

Logically, one would assume that if the resistance of the TPS, or any other sensor for that matter, is within the spec's you would get from 4Crawler (yes, he's a guru if you ask me), or anyone else, everything should work properly.

But don't forget that the ECU doesn't measure resistance from a sensor, but rather the voltage. Translation: the ECU puts volts on a wire and if the sensor isn't getting the correct voltage from the ECU, the result will be an error, even IF the sensor passes any and all other tests.

Summary: check that wiring- make sure you're getting the proper reference voltage to the sensor.

ChefYota4x4

iTrader: (5)

WOOT! lol... NICE, my Cali-Yota-Brudda! lol. (Btw, seen you ALL OVER the net, Abecedarian.... with some GREAT reads, input, many times! Yeah, I know we've spoken before on here, plenty... Just saying, .... appreciate your knowledge and tips that you've shared ALL OVER the place! )

Lankan

abecedarian, your hunch/input was foresight in the right direction to what my problem was. I finally gave up, and took the vehicle in on Friday afternoon. This was not a Gold shield station, or even a smog repair station... it was a shop I had been to many years ago. The owner was the same, but the location of the shop and the mechanics had changed. He told me to come by and claimed he had the BEST mechanic/diagnostic talent in the Coachella valley, so I thought what the heck... a known shop is better than an unknown shop, and the owner always let me be around my car while any testing/work was going on.

To my surprise, the lead mechanic to the garage happened to be a buddy of mine from my high school days! The first test was a smoke test. The only place that appeared to be leaking slightly was the EGR valve, as it supposedly doesn't seal properly when the engine is turned off. This was discovered during the first ten minutes or so of testing. But my buddy (the mechanic) didn't stop there, and hooked up a "Snap On" diagnostic machine, and tried to get the reading from the O2 sensor. I told him about the "code 25" and the O2 already being replaced. To make a long story short, after about an hour and a half of checking wiring diagrams on the computer, and reading from a mechanics only website (I think), he told me that the signal from the sensor was not getting to the ECU!! To verify this, we ran a separate wire from the O2 sensor to the ECU, and to my disbelief (and relief), the graph on the computer started showing the signal/pulses being read by the computer!! All this time, i had been running without any signal coming from the O2 sensor to the ECU, as the wire in-between had somehow been damaged! Even the check engine light that was on, turned off after this was fixed!!!

What a long and tedious journey this was, and as much (or little) that I think I know about fixing stuff, someone else had mentioned it before, maybe it would have been worth it to have taken it in, in the first place, without spending almost a month and a half trying to diagnose the problem myself (and with the help of you guys of course). I got lucky ending up at a shop where I knew the guys personally, so all they charged me was a couple hours of labor. If it had been another shop, who knows what they would have said to replace, and how much they would have charged me.

To ChefYota4x4 & the others that gave their input, thanks for ALWAYS being there and supporting me when I was about to give up. I learned a whole lot more about my vehicle in the process of all this troubleshooting! I still haven't had time to check the improvement in mpg's or even gone for the smog test yet, but my buddy assured me that it should pass... so I'll keep my fingers crossed. Will let you know the outcome early this week.

Finally I can move on to other things that I've been wanting to work on. Hopefully I'll be able to help/advise others on this forum the way that they helped me with this problem I had, and hopefully this thread will help someone else figure out their problem sooner in the future. Thanks again guys!!

ChefYota4x4

iTrader: (5)

SUWWWWWWWWWWWEEEEEEEEET! lol.

Great news, Lankan... And WOW, a buddy from HS? SMALL WORLD HAPPENSTANCE DOES still occur, buddy! lol.

To be honest, I'm REALLY starting to wonder, myself, regarding my own rig. See, I've had it into one of the best dealer foremen mechanics for about a week/to Jap. Auto Center (where it was figured out once before, something else) and other places that usually, well, GAVE UP! lol. They almost always said, "Just drive it!" lol. Sorry, as you can relate to, ... I'M NOT OK WITH 10-12MPG CITY AND 20-21 HWY... if I'm lucky! lol. SOMETHING is off.. And as I was eluding to.... I have a sneaking suspicion that it's something like this or a VERY tricky to read 'glitch'(tricky without a snap-on oscilloscope, etc.! lol) Guys like that are PRICELESS to have in your corner... KEEP IN TOUCH WITH HIM! lol. Heck, maybe he'll take a look at mine? hahaha.

GREAT NEWS, VERY HAPPY FOR YA, MAN! .... and my pleasure, as many have done that for me, ya know?

Lankan

Chef, yeah, I definitely got lucky with this one. I'll be going to the shop today or tomorrow, as the test only smog station is in that area. I will mention your low city/town mpg's and the good highway mpg's (or is it supposed to be more for a 22RE?) and see what my friend says. By the way, what kind of mpg's in the city/hwy are you SUPPOSED to be getting, for the way your truck is set-up?

This guy is actually very good, so if you are interested in coming down here (Palm Springs), it's only about a two hour drive from PV, it may be worth the drive! Let me speak to him and get back to you on what he thinks.