An interesting problem this weekend

[Ozark Lee]

Question to Ozark:

Sorry to hijack your thread but I do have a legit question on the mod thing as well as something else that I think may or may not be related.

In doing that airbox mod, did you remove the flex tube and seal off the opening for the flex tube to the exhaust manifold? Or did you just do the mod w/o removing that tube?

I did the mod on my wife's 98 v70 na back in the summer but I never removed the tube. I meant to for months but never got around to it. Can't say I can rejoyce in fuel savings like many here seem to have, however in a post in August I had mentioned how I did major svc on he car while she and the kids were out of the country.

I went through the changing of plugs and dist cap and rotor w/ throttle body cleaning, maf cleaning etc... I did not change the BOUGI cords that I installed in October 2007. (Dist cap and Rotor were also aftermarket that I got from FCP)

The plugs I initially used were Bosch Platinums (WRONG)
The car did not take those very well and it coughed and choked until I replaced them with VOLVO 4 prong oem's from FCP. That was a few days later. All went back to normal until about a month or so ago. The car started to stall, and choke/buck sometimes while coming to a stop light and buck at acceleration when the light turn green.

Two weeks ago I took the car for a few days and ran the codes.... I have had P0445 for a year now (the one that indicates fuel or fuel/vacum loss?) Haven't gotten around to looking into the vacum lines as yet.
I was surprised to see P0302-303 and 304 along with I think it was P0171 (not sure if the number is right) but its the one for the MAF sensor.

Remedy:
seafoam
Maf and maf contact cleaning. (yes, I did use the correct cleaners)
cleared the codes.

So far... first few days no dramatic changes... Car did hesitate on me twice. (P0445 was the only code to return about 3 weeks ago)

Towards the end of my few days of usage, I eliminated the hose, mind you I did the mod keeping the cold air intake open since August. I sis also seal the opening for the hot air side once the hose was removed.

Lets just say that the P0445 code would normally return after about two days from being cleared, maybe three.

Today, over a week later the car does not hesitate, stall or buck... As if there were no problems ever. Neither one of those codes ever returned and the car seems to run fine.

I read some threads here on the codes and remedies I mentioned above.
I did order new OEM plugs again, as a just in case and a new BOSCH cap and rotor as well as a new set of BOUGI cords from FCP... should arrive today.

Has anyone had a similar experience?
What about the box mod? Did I do the correct thing in removing that hose?

I would say that you eventually did everything right. You code is an EVAP code, it could be as simple as a bad gas gap but it is likely a cracked line between the tank and the charcoal cannister or between the cannister and the EVAP purge valve.

As far as the flex line for the hot air goes it really shouldn't matter if it is on or off since the hot air side is blocked off anyway. In either case the air goes in pre air filter so there is no chance or drawing in extra crud past the air filter itself.

The near stalling problems and the misfire problems scream ignition to me, the EVAP won't cause those problems at all. Try your new ignition parts when they arrive and my bet is that your problems will go away.

...Lee

[Matty Moo]

I posted about the exact same thing last winter AFTER doing the airbox mod. EXACT same thing. People thought I was crazy. My throttle was stuck and I was doing 60. Had no problem slowing down though.

NA, airbox mod and -15f. Moisture burning off from the crankcase plus the cold air hits the throttle body and ices up.

[osmium]

Here in central PA the temperature doesn't get that cold, so far the lowest has been 20 F. I'm thinking there's little chance of my throttle icing up this winter.

I did the air box mod last week. Haven't noticed any big change, maybe slightly quicker.

Anyway, without the mod is the engine sucking cold or hot air when its at normal op temp?

-os

[polskamafia mjl]

Depends. If the airbox and t-stat are working normally then when the engine is at normal operating temp the flap closes the hot side and the engine will suck in cold air. The issue is that the t-stat has a nasty habit of breaking and the flap gets stuck in the hot position and never opens the cold position.

[osmium]

Depends. If the airbox and t-stat are working normally then when the engine is at normal operating temp the flap closes the hot side and the engine will suck in cold air. The issue is that the t-stat has a nasty habit of breaking and the flap gets stuck in the hot position and never opens the cold position.

OK, that's what I thought.

Then when why is there concern about the throttle body freezing when the air box is modified?

The engine is only drawing the hot air for a short time before the switch, I would guess.

-os

[polskamafia mjl]

That's a very good point. I'm guessing that even though it only takes a few minutes for the engine to reach normal operating temperature, that few minutes still matters to the throttle body since it receives really hot air for a while, albeit a short while. With the mod, the throttle body is always cold, it never warms up, and this can cause it to freeze. So I guess what I am trying to say is that the little bit of time it gets hot air is enough of a break to keep it from freezing up.

[turbotim2]

It's to warn you the roads might be icy. Interestingly enough, it doesn't even bother to come on when it was 10 outside this morning.

That light comes on when the temp is between 22 and 36 F.

[turbotim2]

That's a very good point. I'm guessing that even though it only takes a few minutes for the engine to reach normal operating temperature, that few minutes still matters to the throttle body since it receives really hot air for a while, albeit a short while. With the mod, the throttle body is always cold, it never warms up, and this can cause it to freeze. So I guess what I am trying to say is that the little bit of time it gets hot air is enough of a break to keep it from freezing up.

Just curious - are the folks who are having this problem sure its the TB and not the cable itself? I have had cables freeze up before on other cars.