A couple questions (possible MAF issue)

[Wolf]

Hey friends, instinct came with the near 70 degree weather we’re having in Nebraska this week, naturally i want to drive my Boxster

Well ive had her stored in the garage for the past month due to snow and ice, and only drove her once in the past month. Didn’t have any issues then, just connected my battery as normal (i store it in a warm place as i have for the past few year without any issues) and it started right up and i had a nice 70+ mile drive to and from my destination.

Well today, did the same, but immediately the car died. Never dealt with that before, and naturally i started searching online for remedies, which included:
-Swapping back up relay and fuel pump (no change)
-Swapping out a few other of the smaller fuses (none were broken, just the what if)
-Disconnected MAF and tried starting (didn’t start at all)
-Reconnected MAF after wiping it down (there was a residue on it, probably oil) mind it still looks brand new on the inside, the actual unit
-Waited a while because i was still looking at online solutions, went to start it up and boom shes good to go


I let it run for a good 15 or so minutes before taking a drive which all seemed normal. Brought it all up to temps and came back home and here I am.

The second question regards to a small bog when coming to a stop, I noticed it heavily when the AC is running, and on a warm day it wont go below 800 RPM, but with it off its going a little lower for my liking and a little uncomfortable knowing it could die on me possibly in the middle of the road again.

Any responses would be amazing, i apologize in advance for the long post and rambling.

[blue62]

Originally Posted by Wolf

Hey friends, instinct came with the near 70 degree weather we’re having in Nebraska this week, naturally i want to drive my Boxster

Well ive had her stored in the garage for the past month due to snow and ice, and only drove her once in the past month. Didn’t have any issues then, just connected my battery as normal (i store it in a warm place as i have for the past few year without any issues) and it started right up and i had a nice 70+ mile drive to and from my destination.

Well today, did the same, but immediately the car died. Never dealt with that before, and naturally i started searching online for remedies, which included:
-Swapping back up relay and fuel pump (no change)
-Swapping out a few other of the smaller fuses (none were broken, just the what if)
-Disconnected MAF and tried starting (didn’t start at all)
-Reconnected MAF after wiping it down (there was a residue on it, probably oil) mind it still looks brand new on the inside, the actual unit
-Waited a while because i was still looking at online solutions, went to start it up and boom shes good to go


I let it run for a good 15 or so minutes before taking a drive which all seemed normal. Brought it all up to temps and came back home and here I am.


The second question regards to a small bog when coming to a stop, I noticed it heavily when the AC is running, and on a warm day it wont go below 800 RPM, but with it off its going a little lower for my liking and a little uncomfortable knowing it could die on me possibly in the middle of the road again.

Any responses would be amazing, i apologize in advance for the long post and rambling.

What year is the car?
How many miles?
You mention a possible oil reside on the MAF.
Are you running a stock air filter or after market???

If it is a year 2000 or newer you have the e-gas throttle so if you disconnect your battery you need to recalibrate your throttle.

Second thing, never touch or wipe any part of a MAF sensor other than the base.
Clean it with a MAF sensor spray cleaner made for MAF sensors. They are very sensitive, touching them or wiping them damages them then they don't function properly.

[BYprodriver]

I recommend
you buy a new Bosch MAF & install in your car. If it runs better leave it in & toss the old one. If there is no improvement keep it because you will need it sometime & it's good to have for issues like this

[blue62]

WOLF:

Another thing I failed to point out in my first post.

If you are disconnecting your battery the DME/ECU drops certain settings.
They are more or less reset to a base line setting once you reconnect the battery.
One of those settings or conditions is fuel trim.
So since fuel trims are a "learned" condition or setting, the ECU/DME has to relearn the fuel trims once the battery is reconnected and the car has gone through several drive cycles.
So sometimes the car runs differently until the DME/ECU relearns the old settings or conditions.

[Wolf]

Originally Posted by blue62

What year is the car?
How many miles?
You mention a possible oil reside on the MAF.
Are you running a stock air filter or after market???

If it is a year 2000 or newer you have the e-gas throttle so if you disconnect your battery you need to recalibrate your throttle.

Second thing, never touch or wipe any part of a MAF sensor other than the base.
Clean it with a MAF sensor spray cleaner made for MAF sensors. They are very sensitive, touching them or wiping them damages them then they don't function properly.

Its a 1998 base with 124k miles on it. Recently changed the air filter to an brand new one, stock.
The residue was on the outer rim that goes inside its housing. Plastic part only, didn’t touch any of the rest of the piece, was extremely careful with it. Did notice some dust or whatever where the pins are, should probably spray that with some MAF cleaner.

[Wolf]

Originally Posted by blue62

WOLF:

Another thing I failed to point out in my first post.

If you are disconnecting your battery the DME/ECU drops certain settings.
They are more or less reset to a base line setting once you reconnect the battery.
One of those settings or conditions is fuel trim.
So since fuel trims are a "learned" condition or setting, the ECU/DME has to relearn the fuel trims once the battery is reconnected and the car has gone through several drive cycles.
So sometimes the car runs differently until the DME/ECU relearns the old settings or conditions.

Yes i really need the trickle charger that plugs into the lighter outlet. I have one of the battery tender things from the parts store but i do not trust keeping it plugged in 24/7.

[blue62]

So about the bog you mentioned when coming to a stop with the AC on.
That sounds pretty normal. The engine has extra load on it from the AC compressor.
I will see if I can find an RPM spec. for idle with AC on.

Couple of questions:

Is it a stick or automatic transmission.
What is the RPM at idle with AC off an at operating temp.
If you step on the brake at idle with AC off, does RPM change -vs- not stepping on the brakes.

[Wolf]

Originally Posted by blue62

So about the bog you mentioned when coming to a stop with the AC on.
That sounds pretty normal. The engine has extra load on it from the AC compressor.
I will see if I can find an RPM spec. for idle with AC on.

Couple of questions:

Is it a stick or automatic transmission.
What is the RPM at idle with AC off an at operating temp.
If you step on the brake at idle with AC off, does RPM change -vs- not stepping on the brakes.

Manual transmission, when idle there isnt much difference, about 100 or so between 800-900 both on and off. Only time i notice a change is when i am actually driving, i have to shut the AC off before coming to a stop or turn, once it died on me while making a turn(started right back up and i was only a block from home thank god). After that happened and i started turning it off for that, i havent had any bog issues until recently. Bogs down to about 400-500 then it’s fine. Maybe a leak in the compression area?

[blue62]

Originally Posted by Wolf

Manual transmission, when idle there isnt much difference, about 100 or so between 800-900 both on and off. Only time i notice a change is when i am actually driving, i have to shut the AC off before coming to a stop or turn, once it died on me while making a turn(started right back up and i was only a block from home thank god). After that happened and i started turning it off for that, i havent had any bog issues until recently. Bogs down to about 400-500 then it’s fine. Maybe a leak in the compression area?

Your idle RPM's for AC on or off are within spec.
I am at a lose as to the dying while making a turn and the bog.

[Wolf]

Originally Posted by blue62

Your idle RPM's for AC on or off are within spec.
I am at a lose as to the dying while making a turn and the bog.

What is the spec? is it in then maintenance manual?

[blue62]

Originally Posted by Wolf

What is the spec? is it in then maintenance manual?

The only thing I could find in the Bentley manual was sensor default values.
The ECU goes to a default mode if it detects an open circuit in an AC component or sensor.
That info is on page -87-3 if you have the Bentley manual

The info I used for idle specs. is from my personal notes on research I have done.
I also used my 2000s with a manual transmission as sort of a proof.
I took it for a short drive to get it to operating temp. and it falls in the same range as your car.
My 2000s is in stock tune with 52000 miles and runs excellent.
Idles AC off at 700-750 will go up about 100-150 with AC on.

[blue62]

Wolf
After going back and rereading this thread I see you car is a 1998.
I believe your car has an "idle air control valve" as part of the throttle body.
Perhaps there is an issue with it that relates so the bog problem and the issue with the AC on when stopping.

I am not familiar with the setup so I can't be of much help.
I would do a search here on the forum and a general search on the "net".

I would scan you OBDII for codes or pending codes if the CEL has not set.
Then do some research and learn what you can about idle control valve issues.

I am not saying there is an issue with it just pointing out something to look at

[Homeoboxter]

Originally Posted by blue62

Wolf
After going back and rereading this thread I see you car is a 1998.
I believe your car has an "idle air control valve" as part of the throttle body.
Perhaps there is an issue with it that relates so the bog problem and the issue with the AC on when stopping.

I am not familiar with the setup so I can't be of much help.
I would do a search here on the forum and a general search on the "net".

I would scan you OBDII for codes or pending codes if the CEL has not set.
Then do some research and learn what you can about idle control valve issues.

I am not saying there is an issue with it just pointing out something to look at

Blue is probably right. Pull the IACV and clean it, quite an easy job:
P0506 Idle Air Ctrl Sys and Failed smog test

[Wolf]

Originally Posted by blue62

Wolf
After going back and rereading this thread I see you car is a 1998.
I believe your car has an "idle air control valve" as part of the throttle body.
Perhaps there is an issue with it that relates so the bog problem and the issue with the AC on when stopping.

I am not familiar with the setup so I can't be of much help.
I would do a search here on the forum and a general search on the "net".

I would scan you OBDII for codes or pending codes if the CEL has not set.
Then do some research and learn what you can about idle control valve issues.

I am not saying there is an issue with it just pointing out something to look at

Yes the code is thrown quite a bit actually, never really care since it goes away after a couple days anyways. I have looked up the valve on pelican parts, about $40 so not terrible, maybe it can be a winter project. I’ll have to locate it first and give it a look, maybe just needs a cleaning.

[Wolf]

Originally Posted by Homeoboxter

Blue is probably right. Pull the IACV and clean it, quite an easy job:
P0506 Idle Air Ctrl Sys and Failed smog test

Nice, thank you for the link. I responded below before seeing this, said basically just clean it. I’ll see how that goes. Thanks

[blue62]

Originally Posted by Wolf

Yes the code is thrown quite a bit actually, never really care since it goes away after a couple days anyways. I have looked up the valve on pelican parts, about $40 so not terrible, maybe it can be a winter project. I’ll have to locate it first and give it a look, maybe just needs a cleaning.

If The code your throwing is related to the IACV it is going to be directly related to all your running, stalling issues.
What is the code???

[Wolf]

Originally Posted by blue62

If The code your throwing is related to the IACV it is going to be directly related to all your running, stalling issues.
What is the code???

Last time i scanned it at the beginning of the year it was P0410 & 411, that came up more often than it does now.

[blue62]

Originally Posted by Wolf

Last time i scanned it at the beginning of the year it was P0410 & 411, that came up more often than it does now.

Both of those codes are for issues with the secondary air injection system.
Sounds like you have multiple issues going on with the car.

[Wolf]

Originally Posted by blue62

Both of those codes are for issues with the secondary air injection system.
Sounds like you have multiple issues going on with the car.

Yes, the fixes for those are oxygen sensors or an air diverter valve but like i said thats from April this year( had the car a while, things tend to pop up every now and then, depending on the severity i fix them right away) I don’t see any from scanning concerning any with the IACV.