robocog
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| posted on 28/12/09 at 03:00 PM |
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Not Locost - BMW e46 secondary air pump issues
2001 E46 316 (1.9 Petrol)
Noticed the secondary air pump was leaking a bit of water vapour on cold starts
Done a bit of digging into the issue, seems pretty common
Yes the rivets on my pump are failing (thankfully so I noticed there was an issue before the issue got much worse and bearings failed- bit pricey for
what it is!)
the valve on the manifold is jammed open hence the exhaust breathing into the pump (causing the water buildup)
The reason for the valve to be jammed open is the little Pierburg electronic valve has failed and is allowing vacc to lift the exhaust one way valve
permanently
Have bench tested the Peirburg valve and nothing is happening when I apply 12v
I eventually resorted to tapping it on the ground and running some WD40 through it with the compressor and I have managed to get whatever was holding
the valve open to close again, but applying 12v again is not moving the internal gubbins, so now jammed in the "off" position, which is
better for my pump I guess?
(I have left the outlet pipework off for now and would rather it try and expel any more water rather than force it to pump against a closed valve)
I know there a few BM owners on here, been through similar?
I think Seat and VW and Audi all use a similar setup
Best (cheapest and quickest) place to get a replacement valve?
Would prefer new to try and save the pump and valve from any more abuse
Not found any on eBay, other than a second hand one in the States!
Damn these modern cars!
Regards
Rob
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mgmiller
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| posted on 28/12/09 at 05:05 PM |
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Hi,
You do not need the secondary air injection as all it does is heat up the catalytic converter quicker to reduce emission from cold.
I did a Audi 1.8T conversion into a seven last year and just removed the the little valve so the main valve into the block stays closed.
Just ensure the little Pierburg electronic valve and the relay for the SAI pump are left fitted or the ECU will make the engine run very rich.
Cheers
Mark
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robocog
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| posted on 28/12/09 at 05:38 PM |
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The little electric valve is removed (inlet pipework bunged with a bolt to fix the vacc leak temporarily)
Car has not lit up any of the warning lights...yet, but I guess it will tomorrow as it will be its first cold cold start since removing it, left the
pumps outlet off now the exhaust isn't blowing into engine bay, hopefully it will help throw some of the collected water out along the way
Was worried incase I've done bad since trying to free the little valve up (had to get quite agressive to get it to shut off) so not dared plug
it into the cars loom
Didn't seem to take much current and nothing happening when plugged up to the bench PSU, valve definately does not switch ports, so its dead as
far as I can tell
Worried it would short out with vibration of driving and make something else go wonky/pop
I guess I will end up having to strip the pump and clean it up as its no doubt full of exhaust water, looks like the rivets are very prone to coming
away, so will have to bolt it back together and make it airtight again
I have heard you can get a device which fools the ECU into thinking that it has the gubbins still attached, but works out almost as expensive as
replacing it all second hand
As its only the little (and hopefully relatively inexpensive?) bit that has gone I guess I should just replace it and keep the cat happier -it only
does piddling little short journeys, usually nose to tail traffic so I guess I'm best keeping the system in place till something big n expensive
eg the pump gives up?
I guess running without is OK as long as you make longer journeys?
Would only short ones would mean a quicker death for the CAT?
Got some leads to ring round tomorrow if I cannot source a second hand one from work
Seems FAI carry Pierburg bit n bobs so hopefully they are open tomorrow
Regards
Rob
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mgmiller
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| posted on 28/12/09 at 11:57 PM |
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Rob,
I used 330Ohms 10Watt resisters in the SAI circuits to fool the ECU, You can get them very cheaply from RS, £1.00 each-ish.
But as you say replacing SAI Pierburg SOV is the best option unless the main pump goes.
If the SOV was electrically correct you would see a current anywhere between 50mA and 200mA from the bench power supply.
Cheers
Mark
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robocog
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| posted on 29/12/09 at 06:10 PM |
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Aha, Nice one Mark :-)
I guess its just looking for an open circuit then before it triggers a warning light?
Managed to get a replacement SOV (ooh check me out with my new found abbrv's!) today and just fitted/tested it (3 second job made harder by vacc
tubing deciding to just crumble into dust) so the fluffy bunnies will not be asfixiating as I chug past em...
All is working as it should now , apart from cleaning out the old blower unit and re-riveting it
It spat quite a lot of stagnant bong water out this morning on first start, so maybe its going to be a mess in there
The one in the scrappys looked in much better nick than mine and rivets seemed to be in tact so I may ask about it and have it as a spare incase the
motor cleaning session is not as straight forward as I hope it will be
Cheers for the heads up on the resistor to fool it - I may make one up in a connector and keep it handy if its really that simples, got bags of em
here
I thought they would have some complex system of montioring (maybe even via iBUS?) as I heard the 'bypass boards' were selling for around
$150
(chuffing expensive BMW only resistors then...LOL)
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