5sfe Idling High

[RideMR2]

Hey Guys;

Going with a 5sfe long block for my 91 MR2, new dizzy, new igntion coil, water pump, alt., timing belt, etc. It will have my 4-1 SSAutochrome header, and Open cone air filter as the only mods.

One problem I was wondering about on my current MR2 5sfe is that it idles high. It stays at 2500 rpm when warm and hits 3000 rpm when cold.

I want the new engine to idle like my camry, somewheres around 750rpm.

I am guessing it is a sensor on the intake manifold, any ideas?

I can get the intake manifold off this weekend, and get a better looksie.
The engine and tranny will be out of the MR2 by then.

The throttle body looks nice and clean, and I put a new tps on it a while back, which didn't do a whole lot for the idling problem.

Thanks.

[sickof5sfe]

check the IAC valve (Idle air control valve) if you find a Toyota BGB manual you can find its exact location by the throttle body..you could need a new one or you could just check the wiring...thats where i would start

[Fazed Out]

If you blip the throttle, does it drop lower to where it should? If so, could be a sticking throttle cable.

Also, a little more rare, you can check the butterfly valve in the intake. One guy had some play in his and it wore a gap that let air in. But that's very uncommon.

But most likely it's the IAC valve.

[Ben]

Usually a faulty IAC valve causes stalling rather than high idling. I would go with the sticking/binding throttle cable theory first.

[RideMR2]

Appreciate the Replies.

I guess that the sensors being so oil covered was not helping much...

[RideMR2]

Hello;

I worked on the engine about 2 hours yesterday with a 12mm socket, and a 10mm socket.
Just about everything came off with those two sockets.

The intake manifold is getting cleaned(inside and out) and the plating shop where it's at is going to polish it too.

The only problem I am running into at this point is the wiring harness. Mine looks ok, it is just very oil and gunk covered(see pic above).

Any ideas on what to use to clean it off?

[RideMR2]

Update;

Things are going well.

I think I found the main problem with my car, which was not making spark.

It turns out the igniter could be bad.
I had advance auto check it, and it came up as bad. They are ordering a new one, and if it comes up as good when they check it, that's the issue.

I decided to have my engine rebuilt, vs. getting a long block, and found a local toyota Mechanic in Memphis, TN with a good rep.

I have gotten the wiring harness, and just about everything cleaned up at this point.
Toothbrush and Paint thinner has been working well.

I did have a question about the injectors.
I have gotten them cleaned up, without pulling them out of the fuel rail.
Are they a simple item to remove and reinstall with new O Rings, or should I leave them alone?

I would like to clean them.

One injector is missing an insulator.(rubber seal at bottom)

Pic Below;

[RideMR2]

Hello Again;

The new igniter failed on their tester as well, so I am just gonna roll with mine.
I got an insulator for the injector today from the dealer.

Almost to the point of having all the parts I need to get things back together.

I was curious about the part below, which has a broken plugin on the top.
I have one ordered from matching up the numbers on the side.

Is it a

1.) Thermostat Time Switch
2.) Egr Time Delay Switch

[Gairloch]

The injectors just pull out of the rail. The o-ring is the only thing really holding them in. Replacing the rings is pretty simple. Just have to be careful to not tear them.

That last pic is the coolant neck, right? That looks like it's probably a coolant temp sensor to me but I'm not 100% on that.

[91mrtoo]

I also have a high idle problem. '91 5-SFE.

My car revs to about 2000-2200 RPM on startup and then settles (oscillating sometimes) to about 1500-1600 RPM.

I have checked for intake leaks, and have replaced the idle air control valve. The old valve was pretty gummy, and I couldn't move the cylinder, so I think it needed to be replaced, but it didn't really help the problem.

Now comes the weird part. I can move the TPS wires and when I let go, about 70% of the time the idle drops briefly. It is really hard to tell if I am wiggling something else, but i have tried wiggling the MAP and IAC connectors, and they don't seem to do anything.

If I put my thumb over the IAC port, it doesn't kill the engine, it just starts to idle around 700 or so.

I have not checked my coolant temp sensors, but I am planning on it.

Any ideas?

Thanks

[Gairloch]

If you're putting your thumb over the IAC and it's bring it down to ~700 RPM the engine is getting more air than it should be. Have you checked to make sure the butterfly valve in the throttle body is as close to closed as possible? If not, there's a tiny screw on the forward side of it that you adjust the throttle stop position.

Other things to look at would include the idle speed screw on top of the throttle body and the air conditioning VSV on the trunk firewall right next to the TB.

Hope that helps.

[91mrtoo]

Well, I figured out what it was. When I re-installed the throttle body, either my sister or I put the gasket on upside down! This was letting a significant amount of air in.

I found it by spraying carb cleaner everywhere. I hadn't checked there before because there wasn't a vacuum line there.

Now I just have to deal with the fact that the throttle sticks marginally open every one in a while raising idle to 1,000 (a small thing, but annoying). You can also feel it sticking when going on throttle when this happens. It only happens occasionally now, but any ideas on how to deal with this? I tried greasing the throttle shaft to no avail.

[Gairloch]

Usually that happens because the throttle stop is set too low and the brass butterfly valve is digging into the throat of the throttle body.