wootri04

Hey Toyotaholics.

There has been a recent addition to my yota family. She's a 1985 Toyota Rogue motor home. She's powered by a 22re with 129k. Cab is in near-mint condition. Back was gutted and redone with hardwood floors and new appliances. Runs great but burns a little oil. I'm thinking valve stems since it goes away once everything is warmed up, and after idling for a bit it smokes when revved. When I remove the oil cap there's a lot of pressure and oil sprays out. (blowby?) Way more than my other truck... It also leaks a bit of oil around the exhaust manifold which burns off, so it may be exhaust valves. Someone did the head gasket 10k ago (have receipt), but my guess is they just put the head back on without doing the valves.

But anyway that's not why I'm here. My question for you all is regarding the idle. When I start the engine, it doesn't have a high idle like my other truck, it just drops straight to 750rpm.

Things I have checked:
Timing - 5 degrees jumped - check
Idle air control valve - slightly open @ 68F - check
Coolant temp sensor resistance was also within spec - check
PCV valve rattles - check
I am going to do the TPS just to be sure, but it runs so well I don't think that's it. There is nothing in the manual troubleshooting section that addresses this. It idles smooth, sounds great, revs well and overall runs like a top. But no high idle worries me. The engine has to warm up before idling to be happy, and I'm just about stumped.

Any ideas?

Pictures are on my phone so I will post some in a bit.

Co_94_PU

iTrader: (-1)

Yeah don't expect much of a warm up cycle at ~70°F

You've probably got a 1.0 ECU (designated as EFI, compared to the 1.1 designated as TCCS.. It's not really relevant but for real your modern TV remote has more calculating power, IO channels etc...)

#1 timing, what is it without the jumper?
#2 idle air control valve/bypass, slightly open is open to interpretation. Measure it cold, measure it warm, measure it with hot water flowed through it. (Freezer, counter, teapot) Does it change ?
#3 Rattles is not a valid test of anything more than its not froze/stuck and shaking it could have applied enough force to unstick it anyway.. Is it a Toyota part (metal), or parts store (plastic)?
#4 TPS, do? What does this mean exactly?

Ok so the idle up when cold is entirely controlled by the air passages. The idle screw, the throttle plate, and the by-pass. There are various alternative air pathways, aka every vacuum line behind the throttle plate that could throw this out of design specs. What have you done to ensure these lines are all soft/supple and sealed? (If it slips off easily it's not sealed. If the rubber is hard it's not sealed.)

If your vacuum lines are soft, tight, sealed, your throttle plate is closed, throttle plate closes reliably regardless of if you close it fast or slow, your IACV responds to coolant temperature, and your idle screw isn't out of spec (way to far out, dry hard oring).. We can talk about the warm up enrichment program in the ECU and how THW (coolant temp sensor) and IAT sensor interact.


TL;DR odds are you're getting significant air bypass of the throttlebody from somewhere other then the IACV!
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wootri04

Thanks for the reply Co_94_PU.

1. Without the jumper timing is 12 degrees btdc
2. I only tested the IACV cold because the problem occurs when cold. The FSM says it should be "slightly open when cold" and it was, so I put it back on. I can remove and see how it responds to different temperatures just to be sure.
3. PCV valve is plastic, and has the right angle built in. My other 22re is a 1990 and has the straight metal PCV valve. I assumed this one was the older type but it's definitely not metal. I can order an OEM replacement to rule that out but it sounded like it was working.
4. do the TPS = test the Throttle Position Sensor. I have the feeler gauges and all that but it's complex and I just didn't feel like doing it until I ruled out everything else. Again I figure if it was out of whack the engine would not run as well as it does. It revs quick, drives fine, sounds fine. Has plenty of power. The only issue I can tell (apart from a bit of blue smoke) is the low idle on startup.

Dash pot appears to be working, throttle plate feels good, but I have not removed the throttle body to do a visual check yet. The idle adjustment screw works great (I set the idle with a tachometer before I checked the timing)

I assume more air=higher idle which has informed my troubleshooting so far. So maybe this is way off but wouldn't a vacuum leak mean higher idle? And my problem is low idle. The vacuum hoses are the factory type and look original, but I could not find a leak via a visual/ pinch test. They are not brittle and all connections are solid. I have a vacuum gauge so I can pull and test them one by one. There was a bit of a hissing sound coming from the manifold area, but upon close inspection I decided it was the pressure regulator on the fuel rail. I suppose I should dive deeper into the vacuum lines to rule them out...

I appreciate the input. I will keep checking things and post my results.