SAI Pump diagnostics with Durametric,Bentley and Multimeter - FAILED !

[Gelbster]

Failed but eventually resolved - see below.
Boxster S 2001 6 speed.
Engine starts instantly, runs smoothly but SAI pump will not run in any key position
. Bench test of pump, fuse, relay is perfect. Pump been given the Krazy K SAI Pump refurb. Thank you K !
This is a problem because I have just completed the engine rebuild and need to get Smog Test to re-register the car. The engine died 10 days after I bought it – 2 years ago !

Following are the diagnostics I did & I hope others with this problem will find them a useful reference. You just need Bentley, Durametric and a simple Multimeter.
I also hope someone way smarter than me will help and tell me what big mistake I have made !. It was a Failed connection - see Post 26 following
More diagnostics - basically a no power problem to the SAI pump fuse even when the engine is running or any key position:
1. The wonderful Durametric cable +laptop will operate the change-over valve for the SAI system. In a very quiet environment you can hear it cycle when commanded by Durametric. BUT it fails to operate the SAI pump when commanded in any ignition key position or when the engine is running. The SAI pump never runs so it will not complete it’s “Readiness” for the Smog Test.
I used - Bentley Service Manual Wiring Diagram EWD 109 Diagram 12. to check the circuit as follows :
2. The OEM Maxi fuse 40 A in the trunk is perfect. The 4 pin 40A Bosch relay in position #10 bench tests perfect . Part # is 0 332 019 156 .
3. In any key position, there is no 12v power at the 40A fuse socket .There is continuity between one conductor of the fuse socket and pin 87 on relay socket.
Do the following test first
But there is no power at pin 30 of the relay socket with KOEO, nor KOEOff,nor KOEon. So logically the problem is upstream from here ?There should be power to the #30 socket for the SAI relay with key off ,engine off.
http://www.12voltplanet.co.uk/relay-guide.html
For the sake of completeness I also did a little more testing of downstream wiring :
4. SAI pump wiring - the brown conductor shows continuity to ground (as it should). This is the uppermost terminal on the pump when installed btw.
The red conductor to the SAI pump shows no 12v power in any key position. Neither does it show continuity to ground.
5. There is 12v power at Terminal 30 the main, big "Connecting Point" with the flip top lid in the engine bay.

So here are the upstream tests from the Maxi Fuse to find the break in continuity.

From the wiring diagram EWD 109, Diagram 12 in Bentley, the terminal A2 on the 40A SAI Pump Maxi Fuse in the trunk is supplied from the 'generator'(alternator) Terminal B1. So this is where the problem must be ??
You can not reach the back of the alternator to check this connection ! Could this be the problem? I poked my fingers in between the Intake runners and groped to find loose wires – nothing. But you can’t see in there !
This suspect connection B1 is also connected to Terminal 30 & the starter ,so I assume the connections at the back of the alternator are good also.
The alternator warning light on the instrument panel behaves normally- goes out immediately the engine runs. So surely this means all is good on the back of the alternator?
The diagram shows a mystery connection(?) between the alternator and the Maxi Fuse - “14 X59” – is this the ignition switch ? I can’t find any explanation in Bentley of 14X59 – anyone know what it is?
This is both embarrassing and disheartening – all the equipment and some diagnostics yet a total failure to locate and rectify a simple continuity problem .
So I am hoping for some helpful advice please.
Unrelated but I’ll mention what else Durametric found:
Misfire on 1,2,3.
Camshaft retard of 2 degrees also on Bank 1. The Ahsai wire pointer mod would have prevented this minor adjustment .And of course Bank 1 on a Boxster is the worst for camshaft adjustment . I am tempted to leave it – at least until I can fix the SAI wiring problem.
Grateful for any help. Thank you.

[Anker]

Sounds like the SAI and its supporting circuitry work fine.

I would chase the sensors that are used to determine whether the SAI should be run. Its only activated when then engine is cold.

I'll do a quick check of the Porsche repair manual in the morning.

[Gelbster]

Thank you for your offer of research.
Others may find this instructive:
https://www.youtube.com/watch?v=98W38PDAteE

[Lapister]

The ECU commands the SAI only after engine has cooled down to certain temp. I also had a MAF sensor go bad earlier in my ownership that prevented the SAI to startup. The engine ran smoothly but no SAI. Replaced MAF and ok. I have confirmed also that you can force SAI once it comes on to go ready without driving the car. Many have doubted this to be true and stated car needs to be driven.

Have you checked the pump itself by jumpering 12v directly to the pump? Think it's only 2 wires to a motor.

[itsnotanova]

I know the sai is an emissions device and technically needs to work to pass smog. If you bring a warm car to get smog checked, how are they going to know it's not working? Is it throwing a code?

[78F350]

...between the alternator and the Maxi Fuse - “14 X59” – is this the ignition switch ? I can’t find any explanation in Bentley of 14X59 – anyone know what it is?

That refers to pin 14 of connector X59.
X59 is one of the large connectors in the left firewall in the trunk. The white one I think.






Any chance that your DME is ROW?

[Anker]

Originally Posted by Gelbster

Thank you for your offer of research.
Others may find this instructive:
https://www.youtube.com/watch?v=98W38PDAteE

I checked the repair manuals and there's desperately little on the SAI there. Something that I did notice was a reference to a ground strap to the secondary air pump bracket. If that's missing you may have a break in the circuit that drives the pump.

[steved0x]

Originally Posted by itsnotanova

I know the sai is an emissions device and technically needs to work to pass smog. If you bring a warm car to get smog checked, how are they going to know it's not working? Is it throwing a code?

When the battery is disconnected everything clears including Emissions readiness flags. The SAI has to run at least once to set its "Ready" flag, that's how "they" block people from disconnecting the battery right before going to the emissions check.

[Gelbster]

Thanks for all the replies.I very much appreciate the help fellow Forum members.
Sooner or later it seems many of us get this SAI problem so bookmark this and the links for when it is your turn !
An ROW reflash would be my last resort.That eliminates the whole SAI system from the Readiness test.
Some people say the SAI is more trouble(=cost to repair) than it is worth in emissions benefit. For that reason, the Rest Of the World do not use SAI. The SAI runs for about 60-90 seconds immediately after a cold start. The SAI system is getting a command from the DME but there is a break in the power to the pump somewhere.
78F350 - thank you for the location. Yes ,it is the white one. The adjacent connector is black. I had checked that white connector block because I just traced the red conductor from the relay tray(40A Maxi Fuse) back there. There is no 12v + power from the appropriate pins in the 'feed' side of this connector. So basically the entire rear relay tray is 'dead'. I also checked both sides of the 40A fuse connectors for a fault to ground - no continuity to ground.
BTW anyone trying to separate this type of connector - be careful ! Pull out the big tab on the face. Wiggle the tab and pull toward you firmly until the top of the connector moves upward. Then it is free to be removed. Do not try to force it. Just keep doing push-pull on the big tab until the top of the connector jumps up a little. The tap has little ramps alongside the connector and these will lift the top of the connector when it is fully released. If it does not pop up,it is not fully released yet .I hope this helps.

[Gelbster]

Originally Posted by steved0x

When the battery is disconnected everything clears including Emissions readiness flags. The SAI has to run at least once to set its "Ready" flag, that's how "they" block people from disconnecting the battery right before going to the emissions check.

Clearing the Readiness codes with a code reader or Durametric also does not work - they remain Pending and are detected when connected to the SMog Test machine=automatic Fail !

[Gelbster]

Originally Posted by Anker

I checked the repair manuals and there's desperately little on the SAI there. Something that I did notice was a reference to a ground strap to the secondary air pump bracket. If that's missing you may have a break in the circuit that drives the pump.

Yes, this is a huge ground connector right next to the SAI pump with a 13mm nut on it.You probably have to disconnect and move this out of the way when R&R the SAI pump.

[Lapister]

Late last year for reasons unknown my Maf went bad when chasing down a vacuum leak cause I had the resonance flap and SAI side vacuum hoses reversed. Car ran fine but SAI pump never came on but had P1128/1130. After Maf replacement all was well. Don't understand the relationship. Just throwing it out there.

[Gelbster]

Originally Posted by Lapister

Late last year for reasons unknown my Maf went bad when chasing down a vacuum leak cause I had the resonance flap and SAI side vacuum hoses reversed. Car ran fine but SAI pump never came on but had P1128/1130. After Maf replacement all was well. Don't understand the relationship. Just throwing it out there.

Thanks for the anecdote. If you had been able to use a Durametric in your situation it would have been useful.
For those trying to follow all the acronyms and code & with the same problem, here is a great link to Ahsai's photo of the system components.
MkII 996 vacuum line routing and related components - Rennlist Discussion Forums

[Chuck W.]

Several months ago I changed my SAI Pump because it was whining. It worked fine, but it was obviously dying a slow death. I still have the whining one and can send it to you to see if the pump itself (even after the bench test) may be the issue.

[Gelbster]

Thank you for that kind offer Chuck. I have sent you a PM.

[Lapister]

So this is your first starting of engine after rebuild? Is SAI the only one that won't go ready? Was it functional before rebuild? Sounds like a wire or connector loose if you had to pull the engine. Is car drivable? Think O2 sensors need to go ready before SAI too. Yeah, SAI =PIA

[Gelbster]

The engine runs fine after the rebuild.
The only obvious problem is the lack of 12v + power to the rear relay+fuse try. That prevents the SAI pump from running so an SAI readiness code is flagged.
The 1,2,3 Misfire codes are puzzling but one thing at a time.
I have a known good used SAI pump coming from Chuck (Thank you !). So that will eliminate one variable.
Meanwhile I have the alternator out to check wiring for continuity between the back of the alternator and the rear relay tray +40A fuse
When/if I find the wiring fault .I'll cut that conductor out and overlay a replacement as a test.The problem is access.
The looming issue is the 15mm,hex head bolt behind the tensioner pulley that is not staked.Common problem.Thinking of a mod to use a grade 8 or better carriage bolt instead but it is left hand thread !
Really need a hex head on it also(?) ,so may modify a hex head shoulder bolt .
.

[Lapister]

Still easy to rule out a bad SAI pump would be disconnect plug and feed 12vdc directly to it momentarily. Should be 2 wire plug I see in all pics. Good luck.

[Gelbster]

Bench and insitu tests already done on the current Pump as noted above.
Problem may be too high current draw or some other obscure problem. Hence the simple substitution plan.I agree ,not logical but no harm trying.
The Power Probe Continuity test with a transmitter/receiver is next. Prime suspect is the huge fat harness & specifically the conductor between the back of the alternator and the rear relay tray+40A fuse holder. Don't want to unbundle that harness needlessly ! May be multiple issues.For example - until I get power to the relay tray , I can't test the rest of the circuit.Lots of poking and probing to do.
Thanks for your positive thoughts.

[Smallblock454]

Reminds me on something Mercedes related. I know Porsche is different, but have you checked the relay contacts and the tray contacts of the relay. There is a lot of currency running when these SAI air pumps starts. So often the contacts in the relay melt which leads to misfunction.

Concerning Mercedes the SAI relays are located in a module called RCM module. The relays are mounted on a circuit board and the solder joints brake. But this is Mercedes specific.

Regards, Markus