Hey everyone, new to the forum, I look forward to learning from everyone's experiences!
My question concerns my son's 2002 530i. This past summer, it popped the code for the Secondary Air Insufficient Flow. I troubleshot it to a seized secondary air pump and thought that I had it fixed. After I changed the pump, the pump ran, but I still would get the code. I followed the online suggestions and wound up changing the air pump valve. Upon further investigation, I found that I wasn't getting any vacuum to the valve, which explained why it didn't open. I found the vacuum hoses dry, brittle and completely shot, so I replaced them. I verified that there was vacuum going to the vacuum solenoid valve on the back of the engine. Still no vacuum to the air valve. So, I figured that the solenoid valve must be faulty, replaced it, still no vacuum to the valve. Also, the pump stopped running. And before you ask, yes, I am working on a stone cold engine.
I have verified that fuses F2, F31 and F107 are all good. I replaced the secondary air pump relay as a precaution, still no vacuum or running pump.
I am starting to wonder if the DME control unit is faulty, but I would think that I would have some other indications if that were the problem. The car runs great, with no drivability issues.
Is it possible that the car thinks that it's already warmed up? Where does the DME get it's signal from to shut off the pump and solenoid valve?
Any and all help is appreciated. I live in NY and I need to be able to pass emissions to be able to have the car inspected/registered.
Thanks in advance!
Welcome to the forum.
When the primary O2 sensors get hot enough they start outputting a signal. The DME then knows the engine is hot enough and tells the pump and solenoid to turn off.
Doubt the DME is bad, they are very reliable.
Not sure if the 530 has a check valve in the vac line like the V8 does, it has to be plumbed in the correct direction, same for the vac connections to the electric solenoid.
Last edited by JimLev; 12-10-2018 at 03:30 PM.
You have power at the solenoid? Vacuum at the solenoid connectors? Remove thw line from the solenoid coming from the engine, and see if it has vacuum
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e30 325i, the mighty 4 door granma mobile....Gone
e39 528i, 4 door sports tank
I need to check for power to the solenoid. I suspect that there is no power there (solenoid is new). I'll pull the wheel and fender liner and check for power to the pump as well, although I suspect that it is not getting any power either, as it was replaced and did run. I did verify that the check valve is installed properly in the vacuum line and that I had vacuum to the solenoid valve.
What's next? O2 sensor(s)?
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Also, what is the proper orientation for the vacuum lines on the solenoid valve? I plumbed it in the same way that it was. Vacuum from the manifold into the port on the end of the solenoid valve, vacuum out to the pump valve coming out of the side (90 deg) port.
e30 325i, the mighty 4 door granma mobile....Gone
e39 528i, 4 door sports tank
I have the link to the bav auto troubleshooting, but I didn’t see anything in there that provides direction in regards to the O2 sensors. Are these the pre cat sensors? Does the 6 cylinder car have one or two? Shouldn’t I get other codes if they’re bad? The system is acting like the car is already warmed up (no vacuum to the valve and no pump running).
Yeah pstas - with anything "diagnostic monitor" related its always very tricky to "force the test" and the conditions for when the engine runs the test/equipment are sometimes complicated and arcane. The SAP should run for some X seconds during stone cold startup only. As mentioned above, if the car has even run for a tiniest bit of time, it is enough for the SAI to not need to run, so the DME wont trigger the equipment. So if you test run the car for even 10 seconds that might be long enough that you need to wait for the cats to chill out again.
Some thoughts:
- First of all, 'insufficient flow' can be from carboning up in the passages in the head. So everything can be working fine on the outside but then still throw that code. The textbook solution is the head comes off and passage gets cleaned, but nobody wants to do that. The workaround solution is to try to put some Seafoam in the tube on the 'hot' side of the valve on cold startup, so that gets blown through the passages, and then hope that clears it up a bit. Might take a few tries. Might not work (mixed reports on that trick). That trick won't be exactly ideal for your cats either by the way... but might not be catastrophic either...
- You should be able to test most of the electrical components stand alone. Like provide voltage to the pump and solenoid to test them. That said there's no reason to think both of your new parts should have failed, I'd be surprised if that was the case.
- Check the supply vac line to the solenoid, with the engine idling do you have vacuum there if you put your finger over it?
- Do you have access to a "mity-vac"? If so you can test the valve make sure it opens and diaphragm doesn't leak, could even try holding it open w/ the mityvac at a stone cold start when the pump runs and see if that clears the code.
- If you have INPA you may be able to manually trigger the SAP pump and/or solenoid for testing. That is the ideal since it end-to-end tests the DME and wiring. If you can find that function (don't know off top of my head if INPA for MS43 supports that...) and the stuff doesn't come on there's a clear path of investigation to see if voltage is getting to the plugs or not etc. etc.
2003 M3CicM6 TiAg
2002 540iT Sport Vortech S/C 6MT LSD TiAg
2008 Audi A3 2.0T DSG (the daily beater)
2014 BMW X1 xDrive28i (wifemobile)
Former:
1985 MB Euro graymarket 300SL
1995.5 Audi S6 Avant (utility/winter billetturbobattlewagen)
Thank you for the swift reply. I have verified that there is vacuum to the solenoid valve, but as stated, neither the solenoid valve is opening or is the pump running. I am definitely working on a stone cold engine, so I am still leaning towards whatever signals the DME. My head may indeed be plugged, but since the pump doesn’t run and the valve doesn’t open, I’ll cross that bridge when I get to it. I don’t have INPA, so I’m stuck with troubleshooting the old fashioned way.
Do you have any more codes right now? The other thing is that certain codes will block the activation of systems. So if it detects a short in the solenoid wiring (just for example), it won't even try to run the pump...
2003 M3CicM6 TiAg
2002 540iT Sport Vortech S/C 6MT LSD TiAg
2008 Audi A3 2.0T DSG (the daily beater)
2014 BMW X1 xDrive28i (wifemobile)
Former:
1985 MB Euro graymarket 300SL
1995.5 Audi S6 Avant (utility/winter billetturbobattlewagen)
I do not believe in a risk free society where the thrill of living is traded for the safety of existence. Nick Ienatsch
The law does NOT determine "right" from "wrong". They are unrelated.
If you put cheap parts on your car, you will soon have a cheap parts car.
Even if the ports in the head were blocked (not generally an i6 problem) the pump, solenoid, and valve would still operate if you didn't have this electrical problem.
Pretty sure you said the valve and pump are new so that rules out those components.
The vacuum solenoid gets powered from the DME, have you looked at the DME connectors to make sure there is no corrosion?
I haven’t looked at the DME connectors yet. I don’t have any current or pending codes, so I may have to drive it for awhile and see what pops up. I’ll check and clean all of the connectors before I drive it.
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And Santaclause4, I do still believe in you, and points and carburetors. LOL
If you don't mind spending a little money (and it appears that you don't, given the "parts shotgun" approach to diagnostics), buy a MityVac. This is a hand vacuum pump with a gauge and a bunch of accessories.
You can use this to monitor the vacuum line, open the vacuum-operated valve while checking for opening pressure and leak-down, test the release of the solenoid valve (the valve side opens to atmosphere when closed, the manifold side seals), and verify the check valve.
With this you can do almost all of the diagnostics at the easily-reached valve on the front of the block. With an electrical pigtail or using INPA you can even verify that the solenoid and check valve are installed in the correct direction -- the line should hold vacuum with the solenoid activated and the engine off, then immediately release it when the solenoid power is removed.
Great minds and whatnot...
OP prefers parts shotgun tho' to usin' them gol'dang newfangled compoozers what we ain't never needed back in the day workin' on our Ferdz and Chebbies and we ain't dadgum gonna use 'em now! If jes' usin' good ol' common sense were good 'nuf fer keepin' my ol' pickitup truck on the road, well by Jeezum ts gonna be damn well goodnuff fer this dang pile o' Sauerkraut!
But who knows, maybe if we hang in there we can talk him into the late 1990's.
2003 M3CicM6 TiAg
2002 540iT Sport Vortech S/C 6MT LSD TiAg
2008 Audi A3 2.0T DSG (the daily beater)
2014 BMW X1 xDrive28i (wifemobile)
Former:
1985 MB Euro graymarket 300SL
1995.5 Audi S6 Avant (utility/winter billetturbobattlewagen)
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