EVAP error SES light

[TriX5]

Hoping to help some others suffering EVAP errors by posting this experience.

About two years ago I replaced the EVAP purge valve (front of the engine block) as INPA reported a failed activation circuit. I still got the occasional EVAP error but infrequently. Some time back I replaced my gas cap in the hope of curing this EVAP error. For a few weeks no error and all was well. Then my fuel pump went out and a new fuel filter turned out to have a defective regulator. Frustrating, not much fun and too much time spent crawling around under the car to remove and replace stuff.

After that was all back in order I started getting EVAP codes again. For example, I reset the SES last Friday and while running some errands on Saturday morning it came back on again. My INPA and ISTA versions do not give much more than cryptic descriptions. "Initial too small and actual too small. Hmmm, what to make of that? After pondering for a while on how the DMTL works I figured that the DMTL pump was probably still functioning ok as it has a self test mode before each EVAP test. The "Too low"" should thus refer to a lack of pressure holding capacity in the fuel tank and associated items.

So, yesterday I lifted the back seat out again and removed the fuel pump. The seal on the pump looked softer and less substantial than the original item (and it also has an odd shape but same as the OE item). But nothing seemed substantially wrong with it. So, cleaned it, put some lube and re-installed the pump. However, then I noticed there seems to be some play between the pump and the ring that holds it in the tank. It was off center by about 3-4 mm or so. Easily overlooked when installing the pump in a hurry. Backed of the ring a bit and corrected this offset, then tightened again. After that I put a bit of lube on the gas tank seal and reassembled everything.

This morning had to run some more errands and stop at a number of places. No SES as yet, crossing fingers!!

[crystalworks]

Good info. Evap codes are notoriously hard to track. Smoking the system is a pain.

[andrewwynn]

If there was any offset the seal was not doing its job. I think you found the problem.

When pulling the pump the seal will come with. It needs to be installed into the tank before putting in the new pump. Sometimes it will try to go into the tank with the pump and you have to start over.

I have on occasion reused the old seal when the new seal wants to follow the pump into the tank.

[TriX5]

Thanks, makes sense. I had started to think about building a smoke generator but this seems to have done it.

[andrewwynn]

I was getting an evap error but rarely. I had recently redone the left side fuel sender so I was suspecting the tank seal.

Before I could smoke it, deer killed my car and the replacement doesn't have evap problem.

[StephenVA]

My EVAPORATE pump error was a wiring splice under the LR INNER fender liner where the wires split off to the pump. Factory fail? No chew marks no impact hits, just split open like someone pulled on it somewhere in the life of the X5.
In my case the pump would run perfectly daily until a high humidity day for the last 10 years. One 10 min drive the issues would go away for another humid day.

[TriX5]

Interesting info. I had no idea of the level of complexity in the Evap system, until now that is.

I am inclined to build a smoke generator anyway, it might have made my life with the 35d a bit easier as it makes tracking down vacuum leaks way easier. It is relatively easy to do,

Found one on YT themed Mr. Fusion :-) On the pressure side I have seen different versions; a bicycle tire pump, an oil transfer pump and somebody used a low pressure regulator. I don't think you can put much pressure into any of the systems you are likely to smoke test so the oil transfer pump might be the way to go. If you have an old valve from a TPMS sensor a bike pump could be the way to go.

[Effduration]

What brand was the fuel filter with faulty regulator?

I recently replaced filter on my e39 wiith a brand new Hengst from FCP euro.
Turns out it was putting out fuel pressure at 60 psi ( should be 50 psi) which was causing a rich running condition.

E39 and E53 use the same filter...

[andrewwynn]

Yikes 60


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[StephenVA]