1998 V70 Stalling and running rich

wyethv70 · Post by **wyethv70** » 26 Jan 2014, 22:37

Hello all,
The problem: So I have a stalling issue when coming to stops and drops RPMs when accelerating after replacing MAF with a re-manufactured Bosch one from NAPA. Also seems to have entered into limp mode. When the car stalls, has erratic idle, or sudden drop in acceleration, code P0103 is set. The car is definitely running quite rich just by the smell of it.

Before the problem: Previous to the first P0103 code and MAF replacement the car was giving a P0102 and a running rich condition. The P0102 was the reason why the MAF was replaced. Upon replacement the P0102 went away and the car was running strongly with no odor coming from the exhaust. Approximately 178 driving miles later the car stalled when my wife stopped at a red light, and the problem has worsened. Also interestingly the "shift up" arrow indicator has light. I do not know if this is associated with anything.

What has been done: Replaced MAF (before P0103), checked resistance from ECU to MAF with good results, checked input voltage to MAF with good results, unplugged MAF with no change of cold idle speed but when reconnected car engine stalls out with repeatable results.

Previous maintenance/ upgrades done (all DIY): New audio system installed (after market), PCV system overhaul, smoke tested vacuum system, bench-flowed/ tested and cleaned fuel injectors, new timing belt and tensioner, new water pump, new radiator, o2 sensors less then 5k ago, new intake filter.

Thank you for your help and time on this one!

Post by **erikv11** » 27 Jan 2014, 07:51

wyethv70 wrote:...
What has been done: Replaced MAF (before P0103), checked resistance from ECU to MAF with good results, checked input voltage to MAF with good results, unplugged MAF with no change of cold idle speed but when reconnected car engine stalls out with repeatable results.
...

That unplugging test is unambiguous: you got a bad MAF.

If you want to save on the MAF, get a Bosch unit from the junkyard, almost guarantee it will be working. But since you already paid NAPA, take it back and tell them it is bad. Kind of tough with electrical parts but there is almost no question it is bad. Or the slimmest of chances the connector is now messed up.

Post by **cn90** » 27 Jan 2014, 08:04

1+,

One thing about MAF, use only:
1. Volvo OEM, which is Bosch.
2. New Bosch, about $145.
3. Or junkyard MAF for $25.

Never buy "remfg" MAF!!!

wyethv70 · Post by **wyethv70** » 27 Jan 2014, 17:10

okay I just got off the phone with the guy at NAPA and they said they would take the MAF back. I will either exchange it for a new non-re manufactured MAF or get one from another source.

Another note I saw on other posts (but with no replies containing answers) that the switch in the air box controlling the hot air intake could fault out and cause MAF failure due to the increased heat in the air box. Does anyone think that this is realistic? Thanks for all the replies.

Post by **erikv11** » 27 Jan 2014, 18:58

The airbox thing (which applies only to non-turbo cars, is that what you have?) ruining the MAF is realistic, but it is a long term thing. Like, if it does break and get stuck to the hot side, then over years the MAF may wear out prematurely. Should not be relevant to the replacement you recently bought. But worth checking out. For where you live (southern CA), you should just wedge open the flap to the cool air side and forget about it forever. It is only useful in cold climates, and then only marginally.

About the exchange at NAPA, only do it if they have a Bosch branded MAF. Occasionally other brands work, but you are rolling the dice.

wyethv70 · Post by **wyethv70** » 29 Jan 2014, 19:02

Thanks for the replies!!
So the car had a pretty bad stall and my wife attempted the start it a few times with no success, and consequently I think the engine flooded with gas. So, on my way to the parking lot that she and the car was located, I decided to buy another MAF from NAPA and later return the old MAF. Once again the new MAF is a remanufactured Bosch, which the the NAPA guy said was rebuilt by Bosch (which I wonder if that is true or not). Anyways, when I went to replace the MAF I also looked at the spark plugs which all five were really black. I am wondering if there is anything else I should worry about replacement or cleaning after a long period of running rich. Also so far the new MAF is working well but only 40 miles driven. Does anyone know if there is a way to see whether or not the engine is working better then before other than waiting to see if it will stall again?

wyethv70 · Post by **wyethv70** » 29 Jan 2014, 19:09

Also I think the, what I am going to call, air diverter in the air intake box is malfunctioning, so I will take your advise and just wedge open the cool air side.