- Apr 2, 2015
Old school feeler gauge will work for the shims, I've accumulated a handful over the years. Then again, we were still using slide rules when I started college.
Thanks! What was out of tolerance on the one you replaced?TPS adjustment is difficult and tedious. I found this was the one thing that made the biggest improvement in overall performance. I ended up buying a brand new TPS from Toyota. I made a shim stack and a test lead from an old harness I had around. Follow the steps in the FSM they are exacting and detailed if something is out of range the parts need to be replaced. My old TPS was ok in all parameters except for one and I figured it would be okay.....NO WAY! Replaced it and it was like a new engine.
Yeah I found that having the throttle body on the bench was the best way to get it right the first time. You have better access to the screw you need to shim so you get it set perfect.After a close study of the FSM and watching a few videos on youtube, I now understand the critical and sensitive nature of the TPS being aligned properly, as well as the need to confirm the TPS is working properly. For me to be confident that I am testing the TPS properly and potentially needing to replace it, I plan to remove the throttle body so I can do the testing and calibration on my workbench. I'm waiting for the new throttle body gasket delivery from RockAuto early next week before I disassemble.
I'll update as I go.
fully agree. I have my multi-meter ready and waiting! I plan to go to one of the local auto parts stores to buy the feeler shims. If they are on a spinout loop, I also plan to disasembe the loop so the shims are not attached to anything. I picked up this tip from youtuber. His logic is that the weight of multiple shims pressed or bolted together was throwing off the sensitivity to the three gages of shims that need to be used. any thoughts on this point?It's tedious, but not difficult - take your time and you'll get it right.
As I posted in your other thread, my 62 felt like it was very "draggy" off the line as well, and it was a total dog on hills. I pulled the valve cover and found that the valve clearance was all over the map, and most of them were out of spec. After adjustment, it was like a totally new truck. Can't say this is your problem, but if you don't know when the valves were last adjusted, it needs to be on your list of things to do anyway.
(also, and maybe you mentioned this above, but how's your air cleaner looking?)
Cleaning the throttle body makes a HUGE difference, to be sure, as well as properly adjusting the TPS. I also did mine on the bench, along with a thorough cleaning of every tiny minuscule passageway in the throttle body. I also gave the idle speed control a good cleaning around the plunger so that it would function properly, along with cleaning out the adjustment screw's passageway, the screw itself, and replacing its O ring. Result when reinstalling was a MUCH higher idle than before cleaning, which I got dialed down to 700 RPM when hot (though sometimes it randomly idles at 900RPM under normal conditions while driving. Then I'll be stopped at another light shortly after and it'll be idling at 700 RPM. I'm suspecting the ISC might be having issues but haven't seriously troubleshot it yet), and far better overall performance. Fuel economy IIRC stayed about the same on average.This is a quick update on my efforts to find and destroy the gremlins in my 3FE.
Thanks to all the good advice, I taught myself how to properly calibrate the TPS. I was super hopful that the TPS was the cause of my lack of throttle response. As a point of redundancy, I hunted down a new TPS for an 88 3FE, so I had a replacement in hand if the unit in the rig was faulty. I ended up taking the throttle body off so I could test the TPS on my workbench. I also bought a set of feeler gages, my first set!
After taking the throttle body off, my attention immediately shifted to how much gunk there was on the inside of the throttle body and the intake manifold. WOW!!!!! I was expecting some issues in this regard, and had my throttle body cleaner and rubbing alcohol on the ready. What I found though, was shocking!! I spent about two hours deep cleaning the inside of the throttle body, and scrapped off some of the intake manifold, as much as I could without removing it. I then tested the TPS that was installed, though I should have done that first. The readouts on the TPS all fell within the tolerances.........which was frustrating. I elected to swap in the new TPS and calibrate it using the feeler gages. I got it dialed in.......dead on. After scraping off and replacing the gasket, and reinstalling the throttle body, I was still hopeful the combination of cleaning the TB and replacing/caliberating the TPS would solve my issues. These are the results...
1) At a dead stop, the throttle response is WILDLY better.
2) I can maintain speed on steep hills. On moderately steep hills, I can even accelerate.......which is a massive imporment.
3) The wild RPM spikes seem to be meaningfully reduced, which also seems to allow the transmission to function better.......limiting unnecessary gear shifting. I have to assume this will result in the MPG's being much improved. I will test this over the next few tanks.\
4) No longer throwing a 51 code. No codes at all.
Overall, the rig is performing on the streets, in steep hill country, MUCH MUCH better. I dont know if this is a result of the TPS being "tuned" or the throttle body being completely cleaned. It's likely that the improvement in performance is a result of both.
HOWEVER, I am still having issues. Even after the improved throttle response from a dead stop, I'm still feeling a meaningful amount of dead pedal.......meaning, after the rig is in forward motion on a flat street, if I hit the throttle in a meaningful way, RPM's drop and there is a hesitation in acceleration. This seems to be isolated to first gear. Knowing the intake manifold needs to be degunked, I plan to do this next. Also, when I'm coasting downhill, with the windows down, I can hear what sounds like a missfire coming from the muffler.... a compression release sound. Something I haven't heard before. I have had all 6 cylinders tested in the BIG engine rework that was done a few weeks back.....$4K worth, and all 6 tested as they should. New plugs, wires, and cap were installed at that time. I'm reading that my cat's might be the problem if one of them is blocked. So, a cat delete is also part of the plan when I go to replace the exhaust in a comprehensive manner.
Also, I plan to test the fuel pump, and injectors.
Any thoughts??? Thanks
Madness is a perfect description!!! I have been considering an LS swap. At this point, I'm on a mission to get this 3FE running like it should so I can get a feel for the rig, what it can and can't do. If I can get the dang thing to run correctly, I'm sure it will meet my expectations....which are apt for an '88 inline 6. I'm not expecting to own the road or the trail in this one, that's what my 06 LC 100 is for )) Ultimately, I think the inline 6 pack is cool and would like to play with it for a while.Stop the madness and swap it! I did and will never look back LQ9 6.0....doubled the gas mileage, dropped 500 lbs in weight and tripled the horsepower with v8 bone stock. I'm now 10 years plus later and rebuilding it frame off.....will just rebuild 6.0 and add a small cam. Love it! it will be my daily! Follow Besty Build . I would have loved to go back with a Toyota but just not worth the extra money. rebuild a 2001-2004 Tundra 4.7 maybe. Go this far gotta make it a FJ142 and swap frame with an 80 or use a Tor kit. Just MHO
Can't argue against either of you lol. There comes a point when it becomes personal.Madness is a perfect description!!! I have been considering an LS swap. At this point, I'm on a mission to get this 3FE running like it should so I can get a feel for the rig, what it can and can't do. If I can get the dang thing to run correctly, I'm sure it will meet my expectations....which are apt for an '88 inline 6. I'm not expecting to own the road or the trail in this one, that's what my 06 LC 100 is for )) Ultimately, I think the inline 6 pack is cool and would like to play with it for a while.