Code 41, TPS, truck runs poorly.

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NYNick

NYNick

10 Year 15 Year
Joined
Jan 3, 2011
Threads
59
Messages
504
Location
Old Saybrook, CT
Ok, I've been troubleshooting this problem for a long time. The truck runs really poorly, very rough, and occasionally does this rev/no rev rev/no rev thing when I give it throttle. That symptom actually got better after the new fuel pump and filter, but it did it again yesterday. I was getting a Code 41 last week, and read somewhere to try disconnecting the TPS to see what happens....voila!, truck ran much better, just idles at 1000 rpm's instead of 650.

So I tried disconnecting the battery to reset the computer, reconnected the TPS, reconnected the battery and it went right back to running poorly and threw a Code 41 again. I hooked up my ohm meter while the truck was OFF, and checked the resistances with the throttle closed. My IDLE/E2 was off the charts, and somewhat varying...80 ohms, 70 ohms etc...way off.

I checked all the voltages at the ECU and they're all good and within range.

I see that I'm supposed to put feeler gauges into the stop screw to see what kind of readings I'd get, but I'm unsure where this is. The throttle has one the hits the dash pot, and another underneath and bottom that's hard to get to that I think is the stop screw. Is this the right one? I'm not sure I even need to, the readings are so far off.

Should I just order a new TPS for $95...this problem has been going on for months.

Thanks

Nick

Nick
 
If you do a search I believe member slcfj62 has the readings from a working TPS setup that don't require any shims to get the proper resistance. Maybe he can chime in. I used this method to get my TPS calibrated and it worked out great.

If you do use the FSM method, I believe the place to shim is the stop that engages the dash pot.

Does your TPS return spring lag on the return stroke? If you pull off the TPS and carefully engage the spring does it smoothly turn?
 
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That is an awesome post of slc's. I will try all that stuff at home today. This problem has been driving me ca-razy.
 
If your TPS is in working order those specs will get you where you need to be. Make sure you are comfortable reading and adjusting your ohm meter.

As you can see in that thread it is easy to misread one as in post #12!

Also...to make adjusting the TPS easier WITHOUT pulling the throttle body, you can just CAREFULLY remove the ISC valve in front of the TPS (normally it prevents you getting to the bottom TPS adjustment screw). When I say carefully, I mean don't tear the gasket for the ISC when you are pulling it. It should come off without doing that.
 
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OK thanks. I've got a digital meter, and it's been reading at k ohms, so I'm pretty sure I'm reading it correctly. I've taken several readings in the past, and they seem to vary considerably at IDL-E2. But I'll do a final today based upon the post, and see what I come up with..I've been using the FSM values.

It seems in that post the issue ended up being the fuel return line. I hope I'm not chasing that gremlin. Any idea what would cause the engine to lose rev, regain rev, lose rev, regain rev when holding the throttle steady around 2000 RPM's? Originally thought that was fuel pump...wrong again. PCV? wrong. Coil? wrong. Runs rich, smells rich. Going in for new cats/exhaust today, so at least I'll eliminate that possibility.

Thanks

Nick
 
TPS whacked out vs. slc's?

Re-tested using values in slc's post.

Here are mine vs his;

VTA-E2 2.8 k ohms mine vs. .538 his
IDL-E2 started at 200 and fell to 80.3 vs. 17.3 his
VC-E2 started at 12 and climbed to 13.5 k ohms

I have no idea what this all means, other than nothing matches or is even close.

His:

With the throttle closed (measured at the TPS with the connector off)
VTA-E2 is .539 K ohms (which is 539 ohms)
IDL-E2 is 17.3 ohms
VC-E2 is 6.29K ohms (this won't change no matter what the throttle position)

I guess this means my TPS is whacked.

Nick
 
Yeah, there were a few things going on in that post. Let's get your TPS dialed in first and then move on to other things.

And I assume you were rotating the TPS trying to see if you could get it into spec. I would measure with the OHM meter and then move the TPS just a very small amount and then measure again until I got it into spec. I ended up adjusting mine (new) quite a bit to the left, or passenger side to get it into the range of SLC's specs. Yours just may be dead or dying. To aid in identifying the connections quickly at a glance I made a label that has the name of each connector pin and stuck it on the face of the TPS.

As for the rich-running...have you also replaced the Fuel Pressure Damper and/or Fuel Pressure Regulator? The FPR is towards the front of the engine at the end of the fuel rail. The FPD is on the opposite end near the firewall and it tough to get to. A 22mm crows-foot wrench is really the only way to get it off. Either of those can contribute to a goofy running 3FE. Also, your fuel filter on the passenger side fender well could be adding to the mess. Replace each one, but one at a time to see which one it was.

I also did my cats recently and it improved the way it runs. Mine were toast.

Again, dial in the TPS and then tackle the other items one at a time.
 
I had a tps go bad when it was adjusted per the FSM. Eventually I just bit the bullet and replaced it. I hate gambling with new parts but in this case it worked out for me.
 
TPS can get gummy and malfunction. If you are trying to save a few dollars, try removing it completely and check the operation by rotating the disk. If it feels sticky, spray some carb cleaner into it until it frees up. I have been able to salvage one this way.
 
Not too good of an idea to spray anything into the back of the TPS as some chemicals can destroy the internal electronics and contacts. Spend the $90+ and get a new one if that is indeed your issue. Worry of that component will be eliminated.
 
Hey guys thanks!

Burnoil...those readings were standing still, not adjusting the TPS or anything. Truck off, ignition off etc. Those are my readings, period. I use alligator clips so I can't screw up the terminals or touch the nearest one. I haven't even tried adjusting it yet. So obviously, it's off. Way off.

It's at the mechanics now getting the new 2.5" exhaust and single cat and high flow muffler, and they were going to take a look at the TPS. Not real optimistic about that, but the good news is it runs well with the TPS disconnected!

When I get it back, I'll give adjusting it a try. Keep you posted. Once it's in spec, if that doesn't solve the problem I'll move on to the FPD and FPR. Actually, the FPR makes alot of sense, but since the TPS is so far off, I'll try that.

Thanks

Nick
 
NYNick said:
Hey guys thanks!

Burnoil...those readings were standing still, not adjusting the TPS or anything. Truck off, ignition off etc. Those are my readings, period. I use alligator clips so I can't screw up the terminals or touch the nearest one. I haven't even tried adjusting it yet. So obviously, it's off. Way off.

Thanks

Nick
Click to expand...

Got it. Well, the TPS must be adjusted by moving it as described if it is out of spec. That is why it has slotted holes so it can go towards the right or left to get it into the sweet spot it needs. It is very easy to do yourself....but, hopefully your mechanic can dial it in...if it is still working. :)

Also, I was thinking about your engine running rich. Don't forget the O2 sensors There is a test in the FSM for them. They are not cheap so make sure yours test out good before buying new ones. The Bosch units are a little cheaper than OEM and seem to work well.

How are your plugs? Properly gapped? Plug wires and distributor?

More reading on running rich:

https://forum.ih8mud.com/60-series-wagons/6464-3fe-fuel-supply-problem-i-fixed.html

https://forum.ih8mud.com/60-series-wagons/383269-help-fj62-3fe-thats-running-rich.html
 
Not sure about the gummy part unless there is some substance in the tps shaft that is causing it to stick some what. What typically happens to the tps is track wear. If all you do since you have owned the truck is drive mostly city traffic, this is where you will get sudden dead spots in acceleration or backfires. The tps is like the volume on your stereo. Over time, the wipper will wear away at the point where the tps spends most of its time.

If its a high millage truck, just replace it. Eventually it will go bad anyway. If I lived in your area, I would put it on my snapon solus pro and show you the graphs and dead spots on the screen for the tps.
 
Ok thanks everyone!

I got the custom exhaust installed; custom Y pipe to single high flow CAT, two new O2 sensors, new Magna Flow exhaust all with 2.5" pipe. Sounds sweet, and runs great, still with TPS disconnected. Drove it right to body shop where it's getting 2 new(used) Quarters, up to the windows and from the tailgate to the rockers, to get rid of all the rust. Should be a month or so before it's back, and I'll install or adjust the TPS then

Very exciting!:clap:

Nick
 
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