I was using Hiperfato's suggestion of probing with the O2 sensor disconnected. I can't offset it at all and when I reconnect the O2 sensor, it drops down to 30-40mV. The resistance of the MAF can be read at the ECU harness, so I'm thinking that the ECU isn't liking something it's seeing in the MAF and discounting its reading. It occured to me after I went to bed that I probably need to reset the idle speed after cleaning it, though. The idle was noticably lower after I hit it with CRC's MAF spray and it didn't occur to me to check what it was idling at. That might be a weekend problem though. I'm also wondering if maybe the harness is flaking, so I'll check continuity through that as well.
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240 LH 2.2, trying to adjust idle CO mixture
- Thread starter Krampus
- Start date
nickm
New member
- Joined
- Aug 13, 2006
- Location
- sydney australia
Not sure if you are chasing your tail. does the car idle OK, run? then nearly stall when you disconnect the amm?
Pins 3 and 6? on the AMM is for the trim pot.
This is relevant to the volvo system.
1985 and later 900s and 9000s, poor cold starting: the Air Mass Meter, especially on LH 2.2 (1985-88 turbos, 86-87 S cars) equipped SAABs. Not much you can do here except adjust the screw as mentioned in the Adjusting Base Idle FAQ and check CO output or duty-cycle on the O2 sensor. Baseline setting for the LH 2.2 AMM is 380 ohms, measured between pins 3 and 6 of the connector on the meter. This is NOT a definitive setting but it can get you closer, every car's mixture requirements are different, just because the Bentley manual says 380 is the end-all, that's only partially correct. Now, if you've not had the AIC/IAC (air idle control) valve off and cleaned it in the last, oh, 10 years, it's probably time to get all the crud out. Pop it off, two lines and a 10mm bolt holding the clamp down, release the 2 or 3 pin electrical connector, and hit it with some good-quality carburettor or throttle body cleaner. On LH 2.4 cars you can work the little flap back and forth a little to work out the gunk. On LH 2.2 cars you cannot move the flap but tilt the valve upside down so that the insides are able to soak in the cleaner for a minute or so, toss it out, and clean out the insides as best you can with a LINT FREE RAG. If you've got a warm hunt this can be an instant cure. What, you ask, clean the throttle body too? Absolutely! Sometimes oil and carbon residue can collect near the throttle butterfly or on the throttle position sensor, so spray it out with the throttle plate open (same carb/TP cleaner) and use your lintfree rag again to wipe it clean. This is another warm idle hunting fix.
Pins 3 and 6? on the AMM is for the trim pot.
This is relevant to the volvo system.
1985 and later 900s and 9000s, poor cold starting: the Air Mass Meter, especially on LH 2.2 (1985-88 turbos, 86-87 S cars) equipped SAABs. Not much you can do here except adjust the screw as mentioned in the Adjusting Base Idle FAQ and check CO output or duty-cycle on the O2 sensor. Baseline setting for the LH 2.2 AMM is 380 ohms, measured between pins 3 and 6 of the connector on the meter. This is NOT a definitive setting but it can get you closer, every car's mixture requirements are different, just because the Bentley manual says 380 is the end-all, that's only partially correct. Now, if you've not had the AIC/IAC (air idle control) valve off and cleaned it in the last, oh, 10 years, it's probably time to get all the crud out. Pop it off, two lines and a 10mm bolt holding the clamp down, release the 2 or 3 pin electrical connector, and hit it with some good-quality carburettor or throttle body cleaner. On LH 2.4 cars you can work the little flap back and forth a little to work out the gunk. On LH 2.2 cars you cannot move the flap but tilt the valve upside down so that the insides are able to soak in the cleaner for a minute or so, toss it out, and clean out the insides as best you can with a LINT FREE RAG. If you've got a warm hunt this can be an instant cure. What, you ask, clean the throttle body too? Absolutely! Sometimes oil and carbon residue can collect near the throttle butterfly or on the throttle position sensor, so spray it out with the throttle plate open (same carb/TP cleaner) and use your lintfree rag again to wipe it clean. This is another warm idle hunting fix.
nickm
New member
- Joined
- Aug 13, 2006
- Location
- sydney australia
.
Reiterating from further up (man, this thread got long! 
), the car seems to idle fine, although there's an "almost stall" occasionally. My main concern was that the ECU wasn't running in closed-loop mode and was burning more fuel than it ought to as a result (and may not pass emissions).
The throttle body and IAC have been cleaned with carb cleaner; both are as crud free as possible and move smoothly. The TPS was replaced because it no longer clicked (although electrically it seemed ok). And I was able to move the flap in my IAC, unless they're referring to a different mechanism in it. It was previously stuck solid. I was able to move it freely afterwards.
), the car seems to idle fine, although there's an "almost stall" occasionally. My main concern was that the ECU wasn't running in closed-loop mode and was burning more fuel than it ought to as a result (and may not pass emissions).The throttle body and IAC have been cleaned with carb cleaner; both are as crud free as possible and move smoothly. The TPS was replaced because it no longer clicked (although electrically it seemed ok). And I was able to move the flap in my IAC, unless they're referring to a different mechanism in it. It was previously stuck solid. I was able to move it freely afterwards.
I want to sound a NLA warning for LH 2.2 MAFs, and this thread seems best suited to it.
The MAF on my 1987 740T crapped out recently, and I decided to break the bank and buy a new one instead of take my chances with a used one.
Ended up buying a brand new one from the local Volvo dealer, for about $425 exchange. I expected genuine Bosch for that nosebleed price.
None were in stock, so I got "next day service" from the depot in Portland, OR, IIRC.
Volvo dealers in Canada and the USA are now stocking or ordering old parts like this from "Genuine Classic Parts", web site here: http://global.gcp.se/
The MAF showed up looking like this, minus the ink smear and fade for the lettering to the left -- I had some oil on my left thumb which smeared it.
It was significantly lighter than the old MAF, and it did not have a potentiometer screw (although it had a moulded empty plastic cylinder where the screw would normally exist, as seen in the photo). Mounting holes were where they needed to be for the airbox. Looked like it would be fine, so I crossed my fingers and bought it.
But it was DOA. Useless, and the dealer had to take it back.
Moral of the story: Do not buy your LH 2.2 MAF from the Volvo dealer any more, unless they have old Bosch stock. If they have to order the MAF in, then it will be a GCP MAF.
I suspect this GCP MAF was probably produced at the same factory in China as all the other rubbish MAFs are being produced at these days.
Bottom line, the LH 2.2 MAF is no longer available (NLA). Volvo/Geely cannot help you now. Don't trust GCP.
lummert
Active member
- Joined
- Jan 11, 2008
- Location
- Portland IN
Ok, just tried Hiperfauto's suggestion... Without the oxygen sensor connected, I get ~.56V at the connector. Tried adjusting the MAF screw, no change at all.Plugged the O2 sensor in, and it's like down in the 40mV range (no real swing), so something is definately not working.
So the MAF, being a junkyard special, is absolutely suspect. *BUT* even if the MAF was toast, shouldn't the value the pot is set to be shifting the voltage? Remember that if I hook my multimeter across pins 2 and 6, I can see the resistance changing as I adjust the screw.. It's set to 300ish ohms right now. I wonder if the harness is damaged somewhere between the ECU and the potentiometer... That'll be fun.
I have my AMM pot screw set to 193 ohms between pins 2 and 6. Was set at 259 ohms but was running too rich. My spare AMM was set at 129 ohms but wouldn't idle, so I split the difference. Idle is much smoother and tail pipe is cleaner.
lummert
Active member
- Joined
- Jan 11, 2008
- Location
- Portland IN
On the subject of 007 AMM used for LH2.2. What if a person used a 016 AMM for LH2.4 and mounted a 0-1000 ohm pot between ground and the white wire that normally runs from pin 6 on the AMM to the ECU? Would this pot allow the adjustable resistance needed by the ECU?
cleanflametrap
Well-known member
- Joined
- Sep 3, 2009
- Location
- near baltimore
Sure would.
I bought a 91 244 once and later found someone had fitted it with an 007. It "worked" although I attributed that to the ability of the LH2.4 ECU to adapt. From looking at the guts and having done some at rest voltage comparisons, I'm pretty sure the 016 is not just a potless 007, but if those 007's are all that scarce, it seems worth a try.
If I were to do it, I'd put the pot inside the car, near the ECU, and break out the test point and oxygen sensor leads there too instead of under the hood. Personal preference...
Aussie240
New member
- Joined
- Mar 29, 2013
- Location
- Herbert Tersmerneha
What about the 008 version... Here in OZ there is quite a supply.