Oh, incidentally....did you ever run the throttle angle sweep test I'd described on you older TPS?

 

Little Rock was... the same as usual.

Anyway, I'm sure you're right, and that it is user error. Have not done the sweep test. Something to do tomorrow I guess. Thanks!

 

I can't seem to find the thread I was referring to on the phone. Sorry, Kyle. I know it's around somewhere's. I'll try again when I'm done with me chores.

 

HA! All it takes is just the right keyword! Found it!

https://www.yotatech.com/forums/f116...acement-86332/

You'll find as you read the very first post that this exactly what you're dealing with. Put it on right and I bet you're problems will disappear......even without Calgon!!

 

When I replaced my TPS on the 88, I just noted which way the throttle turned to open, then rotated the TPS the same direction about 1/8 turn and slid it on the throttle shaft. rotated it the other way until the screw holes lined up and it worked.
basically, the tangs on the throttle engage the tangs on the TPS therefore rotating the TPS the same direction the throttle moves put the TPS tangs ahead of the throttle.

 

You've explained it much better than I could, Kirk...lol. I tried telling him over the phone and I think all I managed to do was confuse him.

 

good input indeed kirk. Don't feel bad matthew, I was confused ling before I spoke with you. I appreciate your efforts and patience.

 

Okay - Update

So I figured out how to get the damn thing on. Go me!

But I'm having issues getting it running right. Setting it by the meter makes the truck load up with fuel as I gently rev it just before 2k rpm, kind of chokes, and then continues reving.

However, after speaking with Kirk about a week ago he showed me how to set it by ear. He said listen to when the "shift" occurs between the higher and lower RPM as you turn the TPS. I set it just on the "low" side of this point just where the RPM dips. Truck seems to run well at that point, although perhaps a bit rich, as when I rev it, it blows black suit everywhere on the concrete. Of course it does this when I rev it based on the meter... So which is right?

PS - When set with Kirk's method, I'm on target for the "idle" resistance, but off-target for the #2, &3 test where I use the thickness gauges. The resistance measures .0L (infinite) even with the thin tickness.

Help!

Today on the way home without any TPS installed the truck began bucking when I was near 0 throttle, as though the truck couldn't tell if I was mashing the gas or not. Seeing as how I drive at this point most of the time, it was quite annoying. Gotta get this dude fixed ASAP.

Thanks fellers.

 

When you get the TPS dialed in, make sure the idle speed is set- should be around 750-800 rpms for a stick (I set my 91 auto at 850-900 in drive), and the timing is set as well- I believe stock is 5 BTDC for your truck.
(I might add that you might be able to bump the TPS ever so slightly- (like tap it with a feather) towards the 'high' idle position and maybe get the idle-to-accelerate transition a bit smoother.)
We've got more we can do now that you're getting closer.

(where's matthew?)

 

Well, bad thing is that, as you know, I don't have any way to really set my timing... So... What do you think I should do? Perhaps set the TPS "by the book" - IE - with the multi meter settings, and then adjust the distributor to make the engine run correctly?


I did notice the idle is a bit high when I don't have the diagnostic plug jumped. Thoughts?

 

jumping the plug will drop the RPM's. so maybe lower the RPM's with the plug un-jumped until it idles rough, then raise the RPM's until it just smooths out.

feel free to call if you want.

 

I do recommend you get a timing light though. and mark the pulley where 0 is supposed to be.

 

Alright - Thanks to Kirk I was able to get the TPS set, per instructions so that it is in the right spot. I then adjusted the distributor. Took it for a drive and advanced the timing until I heard a hint of detonation and then backed it off a bit. Conditions this evening are pretty darn ideal with low humidity and temps in the 50's/60's so any detonation here means a lot when temps are in the 90's with the A/C blaring.

The truck doesn't seem to have the "spunk" it used to off the line. Used to in first gear it would jump, even at low RPM if you nailed the throttle. Now it kind of gallups instead. Feels like timing is retarded too much. I guess my only option (and I need to do this) is to remove the crank pulley and make a notch where it SHOULD be.

Also, my idle is a little high. It's around 900ish instead of the desired 750. The air inlet screw on top of the TB is all the way in. Perhaps I need to go back and re-visit the allen stud that holds the throttle plate to make sure it is the recommended 1/4 turn opening. It could be a bit more than that and therefore be my high-idle issue.

For the record, I don't recommend Damper Dudes. In fact, I'll go so far as to say I recommend NOT using them. Apparently the 'dudes' are doing too much extra-curricular activity to be bothered with getting you the right part for your application. I sent them an e-mail about a week ago letting them know of my situation and haven't heard anything back yet. I'll have to search for my receipt to see if it has a phone number, as their website doesn't list one. Hmmm..

 

Are you getting a smooth transition from idle to full throttle- say if you're idling in 1st and then step on the pedal, are you getting any bucking or misfiring, hesitation or rough performance or does it just shut up and start revving, albeit slower than you remember?
If you've got the idle screw on the TB turned all the way in, air is most likely getting around the throttle plates so maybe the Idle-Air Controller (Valve) is stuck in a semi-opened position. (I know we talked about this on the phone, but for posterities sake, people should know.)
If you can't adjust your warm idle down to spec, air is getting past the throttle somehow (most likely that IAC/IAV [whatever you want to call it]). You could take a round / flat piece of brass or stainless (which just fits in that IAC tube to the throttle body) and maybe drill a 1/8 hole in it... just a thought.... to put a hard limit on the air getting around the throttle and give idle adjustment back to the throttle body.

 

thanks for the input kirk. I didnt notice any issues with transitioning from idle to WOT, but I didn't spend much time with it. I will check it out further on my commute in the morning.

 

If the transition from idle to WOT is smooth, then it would appear all we have left is to deal with the timing and idle speeds.
I'll be around.

 

Well the drive in to work this morning was annoying to say the least with similar problems as I experienced yesterday. Seems it is not recognizing the transition from idle to throttle as you mentioned kirk, there is not a smooth transition from idle to WOT. At 60 mph in 5th gear if I let off the throttle entirely and then nail it the truck bucks before accelerating. Sounds like a tps symptom to me. What do you think?

 

Here I am! Spent all day yesterday working on my own vehicle. Long story short, I used to have a gutter mounted roof rack and ripped off 90% of the fiberglass gutter off on the pass. side a while back hauling too much salvaged lumber on top. I temporarily solved my hauling dilemma (I usually have something up there) by a getting gutterless roof rack so the feet (and therefore the weight) rest on the roof and not the gutters. The clips just hook under the gutters....or what's left of them....instead. So, finally the last 3" gave out Mon. and had to repair it. Took some bed frame rails and cut and ripped them to make "new" gutters, made backing plates, drilled holes, and mounted 'em up. Lotta work! I'll have to get some pics, if ya'lls is interested. Doesn't look "spectacular", but roof rack go nowhere, now.

Anyway.....
Bear in mind, Kyle, when you make electronic repairs/changes, the ECU develops driving pattern memory. So, after changes are made it does take a bit of time for the ECU to adapt to them and adjust fuel and timing accordingly. Not saying this is the whole of what's happening, but I'm sure it's part of it.

As far as the idle goes, it should idle high when the motor is cold. You're probably aware of that, but want to make sure it's being considered here. Kirk's right about the AAV. If you have the idle bypass screw all the way and you have a high "warm" idle, the AAV could be a culprit. And, possibly the idle set/throttle stop screw is too far in, but also you could have a vacuum leak. I know we all hate to consider it being that it's so fun to track them down, so you'll have to make sure the air induction system is set where it should be and functioning correctly. However, it's going to be difficult to get even a close to factory setting on your TB adjustments until you are able to set your timing to a definited degree.......5*btdc, like Kirk said. Advanced timing will give you a high idle.

The factory setting for the idle bypass on my 22re was 3 complete turns CCW from full seat. This could serve as a ball park for you, if you wanted.

I can take an exact measurement of the stop screw on my 4rnr today and you could set yours to that. But, really, the 1/4 turn should be sufficient. Is the throttle lever making contact with the stop screw now? If not, adjusting the screw won't change anything.

As for the bucking, is this the same symptom as the up/down revving you were experiencing. Or, has that gone away and this is new.....so to speak?

Incidentally, did the CEL ever come on with the TPS unplugged?

 

The bucking issue is much different than the issue I described I had earlier with the pseudo-rev limiter. This like a dead spot if you will at like 1-3% throttle as though the truck can't distinguish between idle and VERY light throttle.

The CE light is not illuminated during regular driving but when I jumped the diagnostic plug yesterday and noticed the light was flashing a bit. I assume it was the tps code.

Don't worry about measuring your idle set screw. I will get mine set. I do know that it is currently contacting the throttle lever unlike before when the throttle lever was resting against the dash pot.

 

Update number four hundred sixty eight...

Pulled the accessory belts, crank pulley bolt, & crank-pulley a/c pulley off and was able to see the key-hole. I made my mark where there SHOULD be one. Buttoned it back up and set the idle screw down a bit to lower the idle and also reset the TPS to have appropriate readings at all intervals.

Started the truck (with jumper installed) and noticed that the timing I had set to was more like 20 or so degrees BTDC. I rotated the distributor to bring it up to 5 degrees. The truck started shooting raw fuel out the tail pipe as it did the night before. I took it for a drive anyway. I had that "punch" in first gear back that I mentioned that I was missing yesterday when I played with things. However, I could tell that things still weren't right. It would kind of load up in the low RPMs in second gear and then kind of come alive around 2300 RPM or so and in the high RPMS blow black smoke out the tail pipe a-la diesel style. Not attractive, and surely not good for the environment or my fuel budget. I went ahead and adjusted the timing more toward 8 or so degrees BTDC. Took it for a drive and it was a little better, but not as good as it should be. Went ahead and bumped it a couple more degrees toward 10 BTDC and called it a night.

Unfortunately I am still experiencing the "dead" spot just above 0% throttle. If Chinese water torture is more painful than this I am surprised. Imagine hitting just the right spot in the throttle to get the truck to cruise at an steady pace, and then imagine something that would mimick essentially someone turning your ignition key off and on about once per second.

So I'll address this bucking issue as mentioned above - It all started 2 days ago when I had no TPS even on the truck. The previous 50 mile round trips to work without the TPS on/hooked gave me no such issues. But on the way home yesterday this horribleness began out of the blue. So when I got home, I went ahead and hooked up the new TPS in hopes that this would take care of my issues. Noteworthy that I have reset the ECU more than once to see if this would do any good. Nope.

So good news is that the timing issue is essentially solved, but at 5 degrees BTDC things are not well.

Bad news is I still have the bucking problem, which I'm almost starting to thing it's unrelated to the TPS since it started when the TPS wasn't even hooked up, and with the TPS checked out and hooked up, the issue continues.

As usual, I'm all ears to suggestions or ideas!