Idle Pulsing and Car Won't Make Power When Cold

[nipper]

Well the mileage is right for a IACV, at the very least you can try cleaninng it.

[JL421]

I'm going to go get a new IACV gasket, and I'm going to ask in they have a scan tool I can barrow. What would I be looking for on the scan tool?

[cardoc]

Originally Posted by JL421

I'm going to go get a new IACV gasket, and I'm going to ask in they have a scan tool I can barrow. What would I be looking for on the scan tool?

If you have to ask, it won't do you any good to look at data. There are several things to look at the will tell you where the problem is. You have to know what each sensor does and how it reacts to changes. Without knowing this, its pointless for you to try to read it. Now, it you could record the data and post it, that's something different.

Have you checked for vacuum leaks? Sure sounds like a vacuum leak. Especially the "hissing". Dead give away. Any air entering the intake tube or engine after the MAF is considered a leak since it will alter the actual to reported data sent to the ECM.

And, you should concern yourself with the oil filled spark plug tubes along with trying to get a steady idle and power.

[JL421]

I took out the IACV, looks like I got luckish on the gasket, but I have one on order anyway.



Should I clean that out at all?

Second the top half, it doesn't look too teriably dirty but since it's out why not...

[JL421]

Cleaned the top half, looks much better, and there was a fair amount of gunk in it.



I'm moderately concerned with the yellow residue that started spreading from my pile of cotton....

[cardoc]

When you put it back together, check for vacuum leaks.

[JL421]

Well I got the gasket and put the IACV back together...

Idle is now buttery smooth upon initial start up, and once the engine is warm.

When cold if I make any throttle movement (gear shift, tap the throttle, etc.) the engine starts pulsing again.

Checked for vacuum leaks, none to be found, and the whistle is absent as well.

It seems like there's something wrong with the fuel management system. When it's cold and I try to add gas, it bogs down and acts like the mix is way too rich/partially flooding the engine. Once it's warm, if I try to give more than 25% throttle, it hesitates and bogs down like when it's cold, for about 2 seconds then get's up and goes. Even when it does go, it just doesn't seem like it's giving all the power it should be.

I put in a new tank of ethanol free gas, and a bit of prestone complete fuel system cleaner to see if that helps.

Any other suggestions?

[cardoc]

One, stop using the Prestone junk.

Two, put a set of plugs and wires on it. You ought to change the valve covers and grommets while you're at it. And this smoking for a minute after start, is it out the tailpipe? If so, there is a high likelihood that a lot of oil deposits are gathering on the valves due to leaking valve seals. BAD on a boxer. It will lodge valves open since the 90' position of the head allows for the oil to bake to the exhaust valves when you shut it off. After replacing the plugs, run a can of Sea Foam through an intake vacuum port to clean the intake and valves. If its been doing the smoking for 30k or so, its about the time enough is built up to lodge one or two open and it may get to where you won't be able to start it.

[JL421]

The smoking comes from directly under the engine, on the y-pipe for the exhaust.

It normally smokes lightly for about 30 seconds once the exhaust system gets hot, after that nothing until about a minute after the engine is stopped, then another 30 second light smoking, then nothing. This behavior has been going on for about 20k miles, so it seems in the ballpark for what you're describing.

Just did a new set of wires as soon as this problem started about a month ago, so those should be just fine...

New plugs were about 10k miles ago, but it doesn't hurt to do them again.

Valve seals don't seem like too large of a project for the moment, so I should be able to take care of that one as well, just need a warmer weekend than single digit temps.

Finally, someone suggested that I may be looking at worn valve guides, how much of a pain would those be to replace?

[cardoc]

If the plugs are fairly new, pull and clean, check the gap and reinstall.

If its smoking from under the car it's an engine oil leak. Out the tailpipe would be an internal leak.

Valve guides or seals mean head removal and a trip to the machine shop.

Valve cover gaskets and grommets could be your oil leak onto the Y pipe. Could also be a different gasket on the engine.