Smoke Test/ Durametric Values/ Engine Light

[Ian Harban]

I could do with a bit of help on solving Engine Light, I know, there's loads of stuff about it, but I could do with some help to dig deeper.

 

Boxster S 2000

 

History, car needed new power steering pump, local garage changed it, shortly afterwards CEL came on.

Error codes P 1128 and P1130 Oxygen sensing adaption idle range bank 1 and 2

New MAF was fitted 12 months ago.

Checked MAF readings, about 12 to 14 at idle and 50 ish at 3000 rpm, which I think is right. (BTW should you use Hot Air film reading or the other on?)

Lanmda sensors before cat fluctuating between .1 and .9 both sides, ie I think normal.

Sensors after CAT levelish, again I think right.

 

I checked the inlet ducting and it appeared the garage had not seated the cross over ducts on the inlet side properly so I adjusted and hoped it would solve the problem. It didn't.

 

Light comes on between 150 and 500 miles after re-set.

 

Idle level fluctuates a little but doesn't go up above 1000, and generally settles at 800 (a bit high?)

 

Removal of oil cap filler results in vacuum noise, as does removal of dip stick.

 

No white smoke or other symptoms. As both sides of the engine (bank 1 and 2) appear each time the light comes on I think the problem must be on the inlet side, is that right?

 

Gas mileage has gone down (running a bit rich?)

 

The fact the light came on after the garage had changed the power steering pump might just be coincidence....

 

So ideas, I thought about buying a smoke tester off ebay, they are about £100. Has anybody used one of these and where do you attach it, what is the procedure?

 

Any help would really be appreciated,.

 

Thanks

 

 

 

[JFP in PA]

1 hour ago, Ian Harban said:

I could do with a bit of help on solving Engine Light, I know, there's loads of stuff about it, but I could do with some help to dig deeper.

 

Boxster S 2000

 

History, car needed new power steering pump, local garage changed it, shortly afterwards CEL came on.

Error codes P 1128 and P1130 Oxygen sensing adaption idle range bank 1 and 2

New MAF was fitted 12 months ago.

Checked MAF readings, about 12 to 14 at idle and 50 ish at 3000 rpm, which I think is right. (BTW should you use Hot Air film reading or the other on?)

Lanmda sensors before cat fluctuating between .1 and .9 both sides, ie I think normal.

Sensors after CAT levelish, again I think right.

 

I checked the inlet ducting and it appeared the garage had not seated the cross over ducts on the inlet side properly so I adjusted and hoped it would solve the problem. It didn't.

 

Light comes on between 150 and 500 miles after re-set.

 

Idle level fluctuates a little but doesn't go up above 1000, and generally settles at 800 (a bit high?)

 

Removal of oil cap filler results in vacuum noise, as does removal of dip stick.

 

No white smoke or other symptoms. As both sides of the engine (bank 1 and 2) appear each time the light comes on I think the problem must be on the inlet side, is that right?

 

Gas mileage has gone down (running a bit rich?)

 

The fact the light came on after the garage had changed the power steering pump might just be coincidence....

 

So ideas, I thought about buying a smoke tester off ebay, they are about £100. Has anybody used one of these and where do you attach it, what is the procedure?

 

Any help would really be appreciated,.

 

Thanks

 

 

 

 

Using a digital manometer, check the vacuum level at the oil cap; if it is more than 5 inches of water, you need a new AOS.

[crwarren11]

These codes in combination for me have nearly always pointed to a vacuum leak in the intake somewhere. Cracked hoses or ripped rubber pieces have been some of my issues. The metal hose clamps can also cause some tears in the hoses. Sometimes it was just my improperly reconnecting everything after some work, or overtightening the clamps. For me the AOS failure was accompanied by lots of white smoke out the exhaust - not only at startup but during normal driving. 

[Ian Harban]

Thanks guys

 

The vacuum level when removing the oil cap does not appear to be any different before/after problem appeared. 

 

I had a feeling the problem relates to the vacuum lines and maybe the weak point closes up at higher revs due to the decreased pressure in the system at higher revs. The light comes on again sooner if i travel more int he city and stays off longer if I complete longer motorway journeys.

 

There are some smoke testers to check for vacuum leaks on ebay. Are they easy to use? assume you charge the system with the engine off and look for smoke. Just not sure which hose you disconnect from the car to attach to the smoke pressure generator?

 

 

Ian

[crwarren11]

I’ve never used a smoke tester so I can’t provide any guidance there, sorry. I have seen some YouTube videos of guys using cigars instead 😁