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Discussion Starter #1 (Edited)
Hey folks,

I'm chasing a problem and could use some advice. When I drive my car first thing in the morning I get some major bucking. Once the car warms up it goes away. This doesn't really happen on acceleration or deceleration. It seems to happen mainly when I try to maintain a constant speed (i.e. just a bit of throttle).

My initial thought from reading here was false air. In an effort to tackle that I just did the silicone hose kit conversion and cleaned out my oil vap separator this last weekend. I also installed new spark plugs. I also fixed a small crack in the intake plastic pipe where it bolts to the valve cover and sealed up both sides internally with silicone for good measure. I'd say it runs better than ever once it's fully warm but none of this seemed to help my cold driving issues.

There were three hoses I didn't replace. The two large ones connected to the vap canister and the one running inside the fender.

I also should note that I've checked the AAV. Even after cleaning and attempted adjustment I don't believe it opens as far as it should. It does however seem to close completely. When I start it cold, it fires for a second or two and will then die unless I keep a light foot on the gas. If I give it a bit of gas for 10-15 seconds or so I can then release the pedal and it'll idle OK, but a bit low.

Any thoughts on where I should look next?
 

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Check the AAV to see if it really blocks air when it closes. I had one where the internal vane would block light when warm (if I just looked through it) but I could easily blow air through it. But if it is not opening nearly 100% (90% should be fine) then the idle speed won't increase whenit is cold.

An easy way to check for false air or vacuum leaks is to remove the oil fill cap at idle. If the idle does not deteriorate then it is likely there is an air/vacuum leak. (Removing the oil fill cap introduces a large air leak. If the idle doesn't get worse it is because there is already an air leak - two air leaks don't make it noticeably worse.)
 

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Discussion Starter #3
An update on my progress.

I definitely see a change in the idle if I remove the oil cap when the engine is running.

Not wanting to get into the evap cannister area at this time I decided, as a troubleshooting measure, to disconnect both the small and large hoses that run into that space and capped off the intake ports with vacuum caps. I wanted to see if taking it out of the loop would resolve anything. This caused my idle to drop significantly. I adjusted the IAC to bring the idle back up to normal.

Does the evap canister normally allow some air to pass between the large and small hose? i.e. to act somewhat like the idle air circuit?

Anyway... this morning when cold I still had some surging/bucking going on. I guess I need to start looking towards electrical/l-jet sensor issues? The damned thing about this issue is that I can only really see the difference first thing in the mornings. The rest of the day I don't have the problem.
 
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