bigpaw

The FSM says IDL-E2 reading of the throttle position sensor should be 2300 ohms or less @ 0.57mm between stop and stop screw. The readings I get are 18 ohms @ 0.00mm and 35 ohms @ 0.57mm. Seems like if they were going to be this low, the FSM might have said 200 ohms or less. Would appreciate if someone could reply with their IDL-E2 value with throttle fully closed or at 0.57mm.

quiggs12

I think mine was in the 200s...

OrRunner

iTrader: (1)

mine was really low as well, remember these things are very sensitive to movement, so .001" could change the ohm value dramaticly...

scope103

IDL-E2 is just a switch, open when the throttle is "open," and closed when the throttle is at "idle." But rather than make you guess when the throttle is at idle (or not), they specify 0.57mm. And rather than make you guess how many ohms count as "closed," they say that anything less than 2.3k ohms is okay.

So your 18 and 35 are both "closed," and okay. The important part is that the resistance jumps to infinity (or anything much greater than 2.3k) when the throttle is opened past "idle."

bigpaw

Thanks people. I guess that isn't part of the rough idle with missing as the TPS checks out fine.

Checked ignition; fuel pressure and injector leakage (no leaks - 44psi holding for 20+minutes); vacuum leaks (replaced all hoses); egr system (blocked off completely with thin metal instead of gasket at manifold to test for sure); cleaned throttle body and intake; adjusted timing, rpm, tps, and rockers; coolant temp sensor; cold start fuel system; ran several in-tank injector cleaners; motor mounts; replaced all timing components; ect.

When I turn the key (engine hot or cold) it's like the engine explodes (a really violent bump), but when it's cold the IAC and cold start keeps things going smooth at around 1400 rpm. When starting hot, if I don't keep a light foot on the accel pedal, and just start it, it has the same violent shake/explosion and the idle stays low at 500 rpm and running rough and will stay low until given some pedal. Then idle just stays rough and misfires a little between 875 or 950 rpm.

Any thoughts? There is one thread where someone had the same symptoms, but that thread went dead. Booo.

May be time to pull injectors for professional cleaning?

Another theory is the alternator, but that seems like a longshot? Very little AC leakage (0.004v) and good charging voltage even at idle without accessories (14.5 cold 14.2 hot)...except when at hot idle with headlights on, the idle drops a bit and gets slightly more rough, then adding the heater blower on high, the voltage drops to 12.8 and the idle gets really rough and drops to maybe 600. I know the 60A alternator is not a powerhouse, but is this normal? Maybe one winding is out, but would that cause a rough idle even with accessories off?

Any thoughts would be great. Anyhow, Thanks.

quiggs12

Have you checked your timing???

bigpaw

Uh?

This is what I've done so far:
Checked ignition and replaced all except coil/igniter; tested fuel pressure and injector leakage (no leaks - 44psi holding for 20+minutes); propane for vacuum leaks (replaced all hoses); tested egr system (blocked off completely with thin metal instead of gasket at manifold to test for sure); cleaned throttle body and intake; adjusted timing, rpm, tps, and rockers; checked coolant temp sensor; checked cold start fuel system; ran several in-tank injector cleaners; motor mounts; replaced all timing components.

Those are not in any particular order. Even tried different oil weight 5w40 to 10w30 to 5w30 over several thousand miles.

Starts the same hot with cold start disabled, so there is no extra fuel to bog down idle.

quiggs12

Do you have a timing light? If not go buy one, they are not that expensive. You can't check the timing without one.

sb5walker

I don't see mention of codes. If you haven't checked, that may tell you something.

bigpaw

Already have a timing light. I guess this wasn't clear enough... "adjusted timing, rpm, tps, and rockers." How would someone adjust the timing without a timing light?

I've checked for codes about once a week, but there are none stored. The only code I have ever had was when I pulled codes soon after forgetting to to plug in the AFM.

One thing that seems like a possibility is the throttle stop setting. There is no information in the online 1993 FSMs about it except something like, "make sure there is no gap between screw and stop when the throttle is fully closed."

The 4Crawler's TPS Adjustment page says to adjust screw till touching the stop and then 1/4 turn to keep throttle plate from sticking. Seems to make more sense than the FSM info because then what's the point of having a throttle stop? Toyota's "No gap" doesn't do squat for preventing sticking. Although, my VW doesn't have a throttle stop and it works just fine...except for needing to be cleaned about every 30,000 miles to prevent sticking.

So I guess my question is, is there a Toyota procedure for setting the throttle stop that I'm missing or is the 4Crawler way what everyone does or are there other suggestions? Don't know much about these yet since I'm an aircooled VW guy.