No More High Idle on Cold Start (2 Viewers)
- Thread starter harrydunn
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- Thread starter
- #142
Passenger side of the firewall (US models) you have a plastic black rectangular OBD port with a hinged cap covering it.
You also need the Toyobd reader tool.
I think I may have misunderstood how that tool reads timing, I think it reads the before tdc as a negative number, is that correct?
I think I may have misunderstood how that tool reads timing, I think it reads the before tdc as a negative number, is that correct?
- Thread starter
- #144
Correct.
- Thread starter
- #146
ZF-ScanTools as discussed here: OBD1 reader app, temp If you want the previous version (same as the current version with the voltage being one of the more notable missing features) at half the price, drop me a PM.
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I have a 93 and I’m following every word here. Great effort in trying to find the bug. After warmup my idle falls to 400 rpm. So I have a dog in this fight too.
@harrydunn I have followed this thread for a while but can't recall if you ever swapped the ECU?
- Thread starter
- #150
- Thread starter
- #151
Good news about swapping in all these parts is that I’m able to turn around and sell them for same price. Ha.
- Thread starter
- #152
Quick compression test tonight to rule anything major out. First time I’ve done one since buying it in 2009. No surprises. Pretty good for 240,000 miles I feel.
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I joined this thread since I have (occasionally) the same problem as the OP but I also (more than occasionally) have a low idle after the engine is warmed up. I have recently started looking at the OBD1 output (thank you, Jean-François!)
When the engine runs fine, my IAC is at 24% (warmed up, 35%+ when first starting) or so. Every once in while, however, I would be tooling down the road at 1900-2200 RPM and the IAC will dip to 19-21% and stay there. If I then allow it to idle (either by stopping or shifting into N), the idle drops down to 400 or lower, depending on where the IAC is. If I blip the throttle, the IAC (and the RPMs) may come up. If I blip the throttle enough (or get bored and drive off), the IAC (and the RPMs) has gone back up every single time.
My "cold idle" occurs (and persists) most times after the ECU looses power. I am changing my belts soon and will disconnect the battery at that time. Will report IAC percentages after an ECU reset, if anything interesting happens.
When the engine runs fine, my IAC is at 24% (warmed up, 35%+ when first starting) or so. Every once in while, however, I would be tooling down the road at 1900-2200 RPM and the IAC will dip to 19-21% and stay there. If I then allow it to idle (either by stopping or shifting into N), the idle drops down to 400 or lower, depending on where the IAC is. If I blip the throttle, the IAC (and the RPMs) may come up. If I blip the throttle enough (or get bored and drive off), the IAC (and the RPMs) has gone back up every single time.
My "cold idle" occurs (and persists) most times after the ECU looses power. I am changing my belts soon and will disconnect the battery at that time. Will report IAC percentages after an ECU reset, if anything interesting happens.
ppc
M Go Blue
My theory (guess) only but by chance have you tested or adjusted the TPS? I would think the IAC would only change position when at idle, not when the throttle has opened. If there was a fault in the TPS signal the ECM may interpret that as throttle closed and re-enabling the IAC to change position.
- Thread starter
- #156
Dropping mine off with my shop Sunday evening so they can see a cold start Monday morning. We both think it's electrical, we're just not sure what. He's going to do some probing. Beyond that, my hand throttle came in. If nothing else, that will be great for cold starts and then I can disengage it once its warm since it idle great when warm. May come in handy when idling in Moab this year too when I want to cool things down a bit.
- Thread starter
- #157
Cold start revs.
I'm new here (and new to the 80 in general) - so take this for what it's worth:
I just replaced my coolant temp sensor, which wasn't working and was pretty toasted (gauge was inoperable). While replacing the sensor, I broke the clip on the connector. The connector is in rough shape and is very brittle so it doesn't stay connected very well. Whenever the connector pops off, the car has a real rough time starting (cranks but no start). When it does start, it tends to sputter and shut off. I'd say the car starts about 40% of the time now. The check engine light comes on when I have the key in the ignition, which I understand is a good thing...
This behavior wasn't present before the connector debacle. Mine is a 1997 LX450 (1FZ-FE), not sure if it makes a difference.
I've only had the truck for about a month but I've barely used it, as I'm trying to sort things out before relying on it for my daily 10 mile commute (round trip).
Would anyone know where I can buy a new connector for the coolant temp sensor? I've been having lots of trouble finding a direct match for one.
Thanks!
- Thread starter
- #159
Thanks for the warm welcome! I think I've learned a lesson here, don't search by 1997 LX450 on Ebay and Amazon. Once I toggled from LX450 to Land Cruiser in the link you sent me, the product went from "Not Compatible" to "Compatible" with my truck
