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I just plugged in my last spare (used, but known good) AMM. AMM's may last a long time, but eventually they queef out and I do not want to be caught without a replacement on hand.
As best as I can tell, TASCA no longer has new AMM's and I've heard a few horror stories about remanned AMM's. Can anyone recommend a vendor for a reliable replacement?
Thanks, one and all,
Rich (near the Burgh)
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Lots of good info posted here about AMM.
And the OP has disappeared...
What is the actual AMM part number the OP is looking for? Rarity and cost of AMMs varies.
Also, be aware failure of a AMM on the LH3.1 system results in a non-running engine. No limp home mode. I know this from experience.
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I replaced my 92 240 MAF sensor with a remanufactor Cardone from Auto ZOne $159.99
part# 74-10017
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Thanks for the info.
Was that AMM for LH3.1?
I don't have the Volvo part number handy...
$160 is cheaper than $450+ for new from FCP.
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Hiya MrNabisco and neiha:
http://www.nuceng.ca/bill/volvo/database/ecu.htm is wrong. At least with the 3.1 K-Jet AMM.
More common LH-Jetronic 2.4, still available
Bosch PN: 0 280 212 016 (0280212016)
Volvo PN: 8251497
Tasca 235$
http://www.tascaparts.com/oe-volvo/8251497
Less Common LH-Jetronic 3.1 (Four Pin), and more $$$$
Bosch PN: 0 280 217 001 (0280217001)
Volvo PN: 3517881
Tasca NLA from Volvo
http://www.tascaparts.com/oe-volvo/3517881
Hi neiha. I used to reside in Novato. Please give my best to Dad O'Rourke's Bench at the South end of Bolinas Ridge, Alpine Lake and Dam, Bolinas CA, and, well, I dunno. Say NO to Chico State.
cheers,
Former CA-State Golden Boyeeeeeeee.
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hi sages- have been unable toget a straight answer to 2 questions on this mysterious device. numerous answers have been somewhere between balderdash and poppycock. back in the war we used to call this bullkweet. here goes nothing- to wit - what is the purpose of the amm and how does it work. did hear that the only way to check it is when your mpg drops all of a sudden , that shows the amm has gone to hell.since 11 my 92 245 has always gotten 25-28 mpg. this week it got 20mpg. runs fine; plugs, air cleaner, cap, rotor , bougicords, engine temp, tire pressure all check out ok. only change noted was se fla air temps have widely fluctuated lately. dont want to send this brick to the squasher so how about a shortcut sages? thanks tons oldduke
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There is a platinum wire inside of the AMM that is heated to a few hundred degrees when the car is running. As air is sucked through the airbox, it passes through thr air mass meter en route to the intake. The air passing over the hot wire changes its temperature. This changes the resistance of the wire. The ECU calculates how much air is coming into the engine by comparing "base line" resistance to the reading it gets from the AMM, and uses that info to determine how much fuel to inject into the engine.
Classic AMM failure symptoms are that the car will start and idle but is not driveable. Unplugging the AMM will cause the computer to default to "limp home mode" where the car is now driveable but has no power above 25-30 mph.
I have also seen them fail where the car runs extrememly rich, to the point where you can see unburned fuel at the exhaust.
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thanks river b and cd- good clear statements . so the amm measures the density of the air and uses it to determine the most efficient air fuel ratio. do remember stoichiometry and the best ratio was about 14 parts air to 1 part gas in a warmed up engine. it appears if the amm goes stinko literally and figuratively too much or too little gas will go in with the air for conditions and the car will run lousy and mpg will suffer. havent noticed a raw gas smell in the 245. any thoughts on my symptoms herein? thanks tons oldduke
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Have you sniffed the vacuum line to the fuel pressure regulator recently ?
Greg
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hi cd and river b - have none of those symptoms you list and no gas smell. engine runs fine. cel light has been on for at least a year when running . figure ox sensor has gone to hell. but no mpg effect untl this week- doubt failed ox sensor would derail gas miles. scuttlebutt says cel light indicating dead ox sensor is just a profit enhancer for dealer(200 to replace). did full tune up in 11 25k miles ago. no symptoms of poor running or misfiring. think amm may be dead? thanks tons oldduke
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Hiya Uncle OldDuke!
Your CHECK ENGINE dash light is on?!?!?!?! For a year now?
Noooooooooooooooooooooooooooooooooooooo!!! We cannot let this stand!!!!!!
Have you checked for engine control OBD codes for socket 2 (fuel) and 6 (ignition)? Repeat the procedure until no new codes show. Could you post here? Or a new thread as you like.
Would like to help you sort it out.
Replacing the oxygen sensor can be a bother if well secured from original install and rust and all the heating and cooling cycles. (Unless some thoughtful sort dabbled some of the non-lead anti-seize on the thread. You know, the high temp nickel anti-seize. Not lead or copper anti-seize.)
The oxygen sensor measures the 02 in exhaust gasses. The AMM / MAF measures the air mass (density x volume, I guess? Math ain't my thing, why we have wikipedia). So, the LH-Jetronic ECU, at essence, works to have a balance between what the fuel to air ratio the engine breathes in while measuring the oxygen in the exhaust gasses. If too far out of balance, well, fuel economy goes down. Yet if the imbalance is too great, with exhaust gasses to rich or too lean, your catalytic converter can fail.
Yet it is not meant to impeded your 1992 Volvo 240 performance, as when the AMM / MAF, 02 sensor, and what have you, are all aces, your 1992 Volvo 240 will perform much better. It will be more sprightly in throttle response while you encounter a better fuel economy.
Also, in current threads, what about the air filter box preheater flappy valve? Have you replaced the flappy valve thermostat or disconnect the preheat inlet or function to spare the AMM / MAF?
Welp, if you want, check the OBD codes and see what codes come up? You have the Bentley Volvo 240 manual or at least the Haynes? On k-jet.org are the green factory manuals. Yet also here in the FAQ, something I imagine you've read bow to stern and beam to beam (me too, though I forget and have to re-read), you have:
https://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm
Specifically for socket 2, the LH-Jet 2.4 / 3.1 codes:
https://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm#LH24FuelInjectionFault
And specifically for socket 6, the EZK116 codes:
https://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm#EZK116IgnitionFaultCodes
The 1-1-1 is the all clear as you know. So, if you get any code other than that, repeat the procedure for a socket until no new codes display. Meaning, after the spate of three number codes display, with a pause in-between, and then finish, as no more codes display, press the test button again.
Then post here. Or start new thread, as you like.
Lemme know if you have questions.
Hope that helps you.
Kittys Grey Data Center Volvo with Three Pedals ....
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hi kitty g- yeh been on for over a year. no change in car which runs fine and starts right up . always impressed how quickly this car starts since i did a complete tuneup(plugs, wires, cap, rotor, air cleaner) back in 11 25k ago.going to check mpg after this current full tank. car starts it seems after half a flywheel turn. first tank in 6 years where mpg was below 25 (20). may just be a fluke. suspected amm, but if so wouldnt car be running stinko or limping? told by local radicals that warning light means ox sensor has timed out. dealer wants 100 to code the system and 200 to change the ox sensor. think id be clipped if i went along. moe said he ran into a few like this at bastogne in 44 and wasted them. no sympathy for shysters. dont think ox device effects running but amm does. keep the faith oldduke
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When the check engine light turns off by itself, it will be because the bulb burned out. This problem is not for a DEALER! Five minutes of your time and you will know if it is an AMM or an O2 sensor problem, or one of 500 different problems.
Have the O2 sensor replaced at any good local garage. It takes less than an hour to put the car on a lift, replace it, and the car turned over to you. You could also do it, the auto parts stores will rent you an O2 puller (7/8" wrench) and you could do it at home.
If it is the AMM, heck, all you need is a screwdriver. But I would do one better by removing the thermostat at the bottom of the air box and eliminating the pre-heated air.
--
Keeping it running is better than buying new
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Hiya Uncle Old Duke!
Ooop, well, the 02 sensor is a critical piece of the engine control well runnin' action.
Though, to back up a bit, you can then perform the procedure, with the same OBD check, to clear the codes in both systems (socket 2 fuel and socket 6 ignition). The CEL may dismiss unless one or the other ECU encounters the fault cause in such a way as to set the CHECK ENGINE light (CEL).
You can check the codes your self with the little OBD checker box under the hood. Costs you nothing and you can enjoy some fine lemony sun tea in your Florida paradise!
Though I see you have no safety or emissions inspection in FL-state, so you don't need to do so when re-upping the licence plate registration sticker.
However, with a working 02 sensor, you run the risk of the catalytic converter failing such that you would need to replace it. Running rich or lean would mean exceedingly high temps in the cat, so the substrate breaks down or somehow clogs. In your state, an exhaust shop could fabricate a straight pipe in place of the cat.
Though they do run much better with all the emissions controls working. You don't need the cat, yet it will run much better, give better performance, and better fuel mileage.
Also, as it has been six years, at 25K, you may want to inspect the air filter. These do age with both time and amount filtered. Yet you also can verify that the air filter box flappy valve is not stuck to preheat hot air all the time, and that will ruin the AMM in your car.
Do you know if your 1992 Volvo 240 with three pedals has LH-Jet 2.4 or 3.1? The 3.1 AMM may be NLA, even from Bosch, though some VW models use it, apparently.
If The LH-Jet 2.4, you can still get one.
Even here in MO-state, no emissions inspect, yet I do check the OBD and test the components (not for sometime, now) so I know the three pedals I got are delivering all them horses (horsepower & torque) while delivery the best fuel economy.
I've also found these electronic speedos / ODO lose accuracy, even with new OD gears (still need to fix one). So, what mileage you may measure may not be accurate. At least in mine the speedo is not accurate with proper tire size and all. The ODO seems to clock up miles a bit faster while the speedo shows a slower speed than actual. At least in my kittys grey 1991 240 sedan (no kitty chauffeur, yet). So, claims of 30+ MPG highway in a 3600 # auto with manual transmission and the 400# 130 HP engine seem suspect.
iPd USA article: How can I tell which version of Bosch LH Fuel Injection is on my Volvo 240?
https://www.ipdusa.com/techtips/10087/how-can-i-tell-which-version-of-bosch-lh-fuel-injection-is-on-my-volvo-240
My 1992 is LH-Jet 3.1. The other two 240s are LH-Jet 2.4.
Hope that helps.
Happy Monday!
Salty Rice Boyeeeeeee
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Oldduke,
How does the car run? Normal power? Any hesitation?
I've personally experienced the following AMM failure modes:
a) Car starts and idles, but does not respond to throttle and cannot be driven. Unplugging AMM makes the car driveable, but it will not accelerate beyond 2500 rpm in any gear because the computer has defaulted to a pre-programmed fuel map (limp home mode).
b) Car runs but is low on power and hesitates/cuts out. A less severe version of a.
c) Car appears to run normally but is extremely rich. Can smell gas at the tail pipe and see droplets of gas on the ground if you open the throttle. Mileage sucks and car will not pass smog.
If your only symotom is poor mileage, I would try a full tune-up first, including the oxygen sensor.
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The purpose of the AMM is to let the fuel injection system know how much air is going through the motor so it can squirt in the right amount of fuel.
How it works is a little more complicated.
The AMM measures the velocity of the air flowing through the intake tube. The guts of it are a Hot Wire Anemometer. A HWA is an electronic device that tries to keep a small resistive wire (or film) at a constant temperature. The specific temperature is not critical but 250°C is what I recall for the operating temp form my days at TSI Inc.
When that hot resistor (sensor) is exposed to moving air it cools down a little. Resistance in a conductor is related to temperature so as it cools the resistance goes down. The electronics package typically uses a (wheatstone ?) bridge circuit to increase the current through the sensor (wire/film) to bring it back to the initial resistance value. The increase in current is related to the amount of air flowing through the system.
There is a bunch of physics and electronics mumbo jumbo that goes into the details. Here is just a little of that -
In addition to the air movement, the air temperature, moisture, cleanliness, etc. all affect the heat transfer. Look up Nusslelt and Prandtl Numbers for more details. Temp comp circuits help with most of these effects.
Since the sensor is only sampling a small fraction of the air flow they have to be calibrated to infer the mass of the air from the velocity. Which if everything works right should yield the perfect stoichiometric ratio of 14.7 : 1 and happy motoring.
I'll leave it to Art to explain how the Volvo AMM really works.
And BTW, don't crush that car. Rust free bodies are getting hard to find up here.
Greg
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1. Do most modern cars use AMMs?
2. Do they operate similarly?
3. Are their inputs and outputs similar?
4. Can they be adapted to the Volvo 240 systems?
--
1980 245 Canadian B21A with SU carb, M46 trans, 3:31 dif, in Brampton, Ont.
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I've been running a rebuilt injection labs AMM ($132.50 @ FCP) in my 93 for over a year with no issues. I've found the air box thermostat is most likely to kill AMMs.
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Known good used tested from ebay or a junk yard with a warranty is your best bet.
Dan
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Hi Rich,
You can buy the Made by Bosch OEM AMM (or MAF). Which LH-Jetronic fuel control do you have?
More common LH-Jetronic 2.4
Bosch PN: 0 280 212 016 (0280212016)
Volvo PN: 8251497
Less Common LH-Jetronic 3.1 (Four Pin), and more $$$$
Bosch PN: 0 280 212 001 (0280212001)
Volvo PN: I dunno right now. Can't find it.
The Tasca Search Feature blows.
Sure it is faulty? You either:
- replace the air filter box flap valve thermostat
- blocked off the hot air inlet
- connector? Art first mentioned how a pin in the AMM/MAF connector can get pushed in if misaligned connection.
Tasca offers re-manufactured, though you'll read those with poor luck. Perhaps Bosch rebuilds them with better quality?
Also, as other have suggested, to the salvage yard for used, and hope it tests good, so get a warranty or be able to return it.
There is ebay, and iPd and FCP Euro, as do others, sell Cardone and other off-brand replacements that can be bothersome, if they work at all. If used, ensure a full refund if defective.
Else, maybe someone here can help you if they have known good spares.
Yet other folks may ask you to test connection, verify the connector (watch out for that silicon seal inside the wire harness connector - can fall out, as can happen in other such sealed connectors!), and other test to ensure what you have is indeed a failed AMM.
Hope that helps.
Happy Friday.
MacDuff.
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Incorrect. Bosch 0 280 212 001 is for LH-Jet 2.0.
http://www.nuceng.ca/bill/volvo/database/ecu.htm is wrong.
More common LH-Jetronic 2.4, still available
Bosch PN: 0 280 212 016 (0280212016)
Volvo PN: 8251497
Tasca 235$
http://www.tascaparts.com/oe-volvo/8251497
Less Common LH-Jetronic 3.1 (Four Pin), and more $$$$
Bosch PN: 0 280 217 001 (0280217001)
Volvo PN: 3517881
Tasca NLA from Volvo
http://www.tascaparts.com/oe-volvo/3517881
No worries, RicoS has moved on with other threads.
cheerz and jeerz,
Spazzo Boyyyyyyeeeeeee
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My recommendation would be to buy a handful from a junkyard and store them in your garage. Boneyards here (California) typically sell used AMMs for 50-60 bucks with a short warranty (90 days). I buy two or three at a time. They seem to do okay sitting on the shelf until needed
I have had horrible luck with remanufactured AMMs. They all die after only 18-24 months. For what they cost ($300-$400), they are a waste of money. This is one of the few parts on the car where I think buying the cheapest used part you can find is the way to go because, for whatever reason, they do not hold up. I think it is just a bad design. The factory new Bosch AMMs crapped out after 4-5 years, too. Looking through the service records for the used 240's I have purchased, I noticed in every single case that the original owner had to replace the AMM within the first 5 years/60K miles. Totally unacceptable but it's a commom problem on all European cars from this era that have LH Jet, so I do not blame Volvo.
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