1998 Boxster Secondary Air Pump - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Manny986 · 02-13-2015, 08:59 PM

The secondary air pump on my 1998 Boxster does work but not when it should. Everywhere I read that normally it start when the engine is cold to help emissions control. Mine starts when engine is hot after a long highway run. It start and run for about 1 minute. If I stop the engine and start again, the pump also start but if I leave the Engine to cool down then it won't start. The CEL is on most of the time but when the pump start 3 or more consecutive times it goes off.

What could make it to behave like this?

KRAM36 · 02-13-2015, 09:20 PM

Possible bad engine temp sensor? #17 in this diagram.

Intake Distributor

Luv2Box · 02-14-2015, 05:05 AM

Are you certain it is the secondary air pump or is it the engine cooling fan? The engine cooling fan will come on and off as you drive.

Manny986 · 02-14-2015, 02:41 PM

Quote:

Originally Posted by Luv2Box

Are you certain it is the secondary air pump or is it the engine cooling fan? The engine cooling fan will come on and off as you drive.

Yep! Very good quote. I make a test today and the one I hear IS the engine cooling fan so definitely my secondary air pump is not starting at any time. First thing I would like to know now is if I have a failed pump. Any easy way to test it?

thstone · 02-14-2015, 05:26 AM

The secondary air pump will turn on under two situations: (1) At cold start to reduce emissions, and (2) to test the pressurization integrity of the SAI and fuel system.

The pressurization test usually happens the first time that the car is at idle as the engine warms up. However, this test can be delayed substantially if the car never has an opportunity to idle. For example, the car is started and driven directly onto the highway without any stoplights, this will delay the pressurization test until there is an opportunity to idle.

What CEL code is being stored? Please read it out and post it. Your car might be failing the pressurization integrity test.

Manny986 · 02-14-2015, 02:47 PM

Quote:

Originally Posted by thstone

The secondary air pump will turn on under two situations: (1) At cold start to reduce emissions, and (2) to test the pressurization integrity of the SAI and fuel system.

The pressurization test usually happens the first time that the car is at idle as the engine warms up. However, this test can be delayed substantially if the car never has an opportunity to idle. For example, the car is started and driven directly onto the highway without any stoplights, this will delay the pressurization test until there is an opportunity to idle.

What CEL code is being stored? Please read it out and post it. Your car might be failing the pressurization integrity test.

Thank you very much thstone, the codes I get are P0410 and P1411. Now I am sure that the pump is not starting as I validated today that the noise I am hearing is the engine cooling fan, not the secondary air pump. I have to determine if I have a fault pump or if something else is creating the problem.

Luv2Box · 02-14-2015, 04:31 PM

Quote:

Originally Posted by Manny986

Thank you very much thstone, the codes I get are P0410 and P1411. Now I am sure that the pump is not starting as I validated today that the noise I am hearing is the engine cooling fan, not the secondary air pump. I have to determine if I have a fault pump or if something else is creating the problem.

Same two codes I've got with a CEL. I had it diagnosed and it is the main on/off valve that has failed. Problem is it fails in the on position so it continues to put ambient air into the manifolds so the cats heat up quickly on cold start, so it still complies with emissions but it burns out the other two diaphragms in the system because it allows hot air to blow back through the system. You're looking at about $800 for a shop to replace all three switches and the vacuum tank in the system (replace this as it is cheap and gets brittle and cracks over time). If you do it you can buy all three parts for around $200 and a few bucks more for hoses. Pelican Parts has a good diagram of the secondary air system and also has the parts at a good price. It is common in the early Boxsters for this system to fail but not common for the air pump to fail so check it thoroughly as the pump alone is around $1,200. I've been driving for almost a year with my system not working as it will not damage the car but it will not pass smog test if you have to have one. I swear, but can't prove, my Boxster runs better with the system not working as intended.

Manny986 · 02-14-2015, 07:47 PM

Quote:

Originally Posted by Luv2Box

Same two codes I've got with a CEL. I had it diagnosed and it is the main on/off valve that has failed. Problem is it fails in the on position so it continues to put ambient air into the manifolds so the cats heat up quickly on cold start, so it still complies with emissions but it burns out the other two diaphragms in the system because it allows hot air to blow back through the system. You're looking at about $800 for a shop to replace all three switches and the vacuum tank in the system (replace this as it is cheap and gets brittle and cracks over time). If you do it you can buy all three parts for around $200 and a few bucks more for hoses. Pelican Parts has a good diagram of the secondary air system and also has the parts at a good price. It is common in the early Boxsters for this system to fail but not common for the air pump to fail so check it thoroughly as the pump alone is around $1,200. I've been driving for almost a year with my system not working as it will not damage the car but it will not pass smog test if you have to have one. I swear, but can't prove, my Boxster runs better with the system not working as intended.

I am damn sure that the Sec. Pump did never work since I bought this car 13 months ago and the engine has been running strong and great. I don't like the CEL showing up all the time so I will try to solve this issue in the cheapest possible way just to have that light off.

I most say that it's been quite useful to join this forum, should had done it long ago. Will keep posting on it and definitely will write again about any action taken to solve this Sec. Air Pump issue.

I sincerely want to thank you and the other member who gave me the clue to determine that the pump was not working as I though.

Gelbster · 02-14-2015, 07:55 PM

We've tried to have a constructive discussion about the SAI before but some 'green' views were expressed objecting to removing the SAI system.That was a thread killer.
In Europe they do not use SAI - not just Porsche but Jaguar and BMW also. And they are just as Green & polluted as we are. So there is at least some doubt about the efficacy and value of SAI.
Boxster owners in similar SAI threads mention the high costs of chasing down these SAI component failures.The diagnostic,labor and parts often rise to well over $1000, sometimes in multiple installments as initial repairs prove unsuccesful . That is a pity because other OEM SAI systems are simple,inexpensive and reliable(like the AC Delco system on my old Jag XJR).
This high cost repair is going to be a bigger issue for us as the cars age and simultaneously decline in value. So we really need a cost effective solution for those of us who run theses cars on a tight budget.
DME upgrade/flash for SAI delete -NO codes no more! - Rennlist Discussion Forums
These guys may be able to help with the ECu reflash for ROW?
http://www.ecudoctors.com/porsche-boxster-ecu-performance-tuning-flash-2.html

Luv2Box · 02-15-2015, 05:53 AM

Quote:

Originally Posted by Gelbster

We've tried to have a constructive discussion about the SAI before but some 'green' views were expressed objecting to removing the SAI system.That was a thread killer.
In Europe they do not use SAI - not just Porsche but Jaguar and BMW also. And they are just as Green & polluted as we are. So there is at least some doubt about the efficacy and value of SAI.
Boxster owners in similar SAI threads mention the high costs of chasing down these SAI component failures.The diagnostic,labor and parts often rise to well over $1000, sometimes in multiple installments as initial repairs prove unsuccesful . That is a pity because other OEM SAI systems are simple,inexpensive and reliable(like the AC Delco system on my old Jag XJR).
This high cost repair is going to be a bigger issue for us as the cars age and simultaneously decline in value. So we really need a cost effective solution for those of us who run theses cars on a tight budget.
DME upgrade/flash for SAI delete -NO codes no more! - Rennlist Discussion Forums

Agreed, however, whatever the solution is it would have to pass the visual part of the inspection in California. My last smog test had to be done at a STAR station because the CMVD determined my Boxster "may be a gross polluter due to its age." STAR stations, as you know, must perform a visual inspection of the motor.

bagpiperse · 08-23-2018, 05:41 PM

Hi all,

I am brand new to this forum and a new, old Porsche owner. I have already learned alot from the forum. However, I need some help to get my 98 986 working.

The car came to me with the P0410 and P1411 codes. I tested the air injector motor and it works with power from the battery. I inspected and tested the 40a fuse and put a new relay in. I also inspected the wiring around these items and did not notice any obvious problems. I also checked the conductivity between the power wire from the relay to the pump and between the fuse and the relay. All of those connections appeared ok.

So, I am new to working on cars, but it looks like the relay is not sending power to the pump. I read somewhere that there is an engine sensor that somehow activates the relay through the ECU (??).

Can anyone guide me in how to solve the problem upstream. Of course, once the I get the pump running, there could be problems downstream, but I think that I can fix those based on my research and generous souls on the internet and youtube.

Thanks in advance.

thstone · 08-23-2018, 08:23 PM

Quote:

Originally Posted by bagpiperse

I am new to working on cars, but it looks like the relay is not sending power to the pump. I read somewhere that there is an engine sensor that somehow activates the relay through the ECU (??).

One of the posts above references the engine temperature sensor. Remember that the ECU commands the SAI pump on at cold engine start. If the engine temp sensor is failed then the ECU might not ever think that the engine temp is cold and therefore, the ECU might never command the SAI pump on.

The engine temp sensor sends its signal directly to the ECU and the ECU commands on the SAI pump via a relay.

A relay is simply a component that allows a low power signal to send high power to a device. Relays allow most of the electrical system to be low power (and thus smaller and less costly). What this means is that when the ECU commands the SAI pump on, the ECU sends a low power signal to the relay which then sends (or relays) high power to the SAI pump.

To determine if this is indeed an "upstream" cause, check the temp sensor, ECU, relay, and associated wiring to ensure that they are all working properly.

bagpiperse · 08-24-2018, 04:29 AM

Thanks for those replies.

So, I think I left out some information. The secondary air pump is not coming on at cold start-up. It does work, as verified by giving it power directly from the battery.

I have checked the fuse and put a new relay in, and checked the wiring from the relay to the pump.

Thanks for the information regarding how the system works. I don't know where the engine temp sensor is to check it. I did some searching around on the internet, but didn't find anything saying where the sensor is or how to check it.

I don't know where the ECU is either, or how to check if it is sending the signal to the relay. Thanks again.

thstone · 08-24-2018, 03:33 PM

Quote:

Originally Posted by bagpiperse

I don't know where the engine temp sensor is to check it. I did some searching around on the internet, but didn't find anything saying where the sensor is or how to check it.

Pelican Parts Tech Articles - Engine Sensor Replacement

Quote:

Originally Posted by bagpiperse

I don't know where the ECU is either, or how to check if it is sending the signal to the relay. Thanks again.

The ECU is in the rear trunk. It mounts to the bulkhead between the trunk and the engine on the drivers side. Remove the lining and you'll see it.

You'll need a wiring diagram so you can find which pin outputs the signal to the SAI relay.

bagpiperse · 08-24-2018, 05:16 PM

Thanks, Thstone

There are many temp sensors on that link, but I am assuming that the temp sensor I need to check is the air intake temp sensor (as I am assuming that if the coolant temp sensor was bad, the temp gauge on the instrument panel wouldn't be working. Just my assumption though, as I am still reading and figuring things out).

Thanks again for the information on the ECU!

Gelbster · 08-23-2018, 06:24 PM

Does the air pump run from a cold start for at least 20 seconds?

Gelbster · 08-24-2018, 07:01 AM

Be careful not to confuse the SAI pump with the Engine Bay ventilation fan

bagpiperse · 08-24-2018, 11:54 AM

Thanks Gelbster. I disconnected the output hose on the secondary pump to feel for air on startup. I watched a very informative video on youtube about how to diagnose this problem.

However, beyond the relay and fuse, the author just mentions the engine temp sensor and the ECU.

Any links/info would be greatly appreciated. I am itching to get the car on the road, but need it to pass emissions.

I have driven it 3 times. Crazy fun!