I have since March 2011 had an intermittent hesitation that is defying my attempts to localize it.

It happens in all weather (though mostly warm) and all operations (idle to 45+).

The last tank of gas it was really bad and mpg dropped from 22 mpg to 17 mpg.
So something would seem to be running rich?
A sensor reading more air than is there?
Something moving too much fuel?

The only component that I know needs work is the Fuel Relay. It is my understanding that if the car starts it is working well enough - I've done the freezer cool down a few times when there was 100 degree weather.

The only other time I have had this symptom was when I was checking the idle on the car and the IAC stopped responding.
Despite the IAC passing all tests including live voltage check of the valve.
I replaced it and the hesitation part of my problems went away.
See below for more extensive list of work done March 2011.

Today:
checked throttle valve switch - Okay
checked for obstructions to air filter - Okay

checked air control valve (IAC) -
hums ... I recall a tapping sound before ...... ? ? ?
... What sound is this unit supposed to make?
... Is the IAC supposed to be lubricated?

AMM (test 3-18-11)
terminals 2 - 3 = (2.6 ohm) [spec is 3.5-4.0] drop from 3 ohm in March 2011

... Does anyone know if a low resistance across these contacts would read as too much air?

terminals 2 - 6 = (363 ohm) [spec is 0 - 1000] same March 2011
terminals 3 - 6 = (366 ohm) [spec is 0 - 1000] same March 2011


******************************************

March 2011 I went through some major operations getting the car through emissions.
That work covered most of the things I would be checking now.

cleaned PCV Oil Trap, hoses and Flame Guard
replaced IAC (idle air control) valve w/ new part
replaced Lambdasond (O2 sensor) w/ new part
cleaned Throttle Body including idle control knob
replaced Temperature Sensor
replaced Distributor Cap
replaced Distributor Rotor

More at:
http://www.brickboard.com/RWD/volvo/1481789/220/240/260/280/recap_emissions_failure_repairs_iac_idle_rpm_mpg_pcv.html

******


1988 244 DL

I've started checking wiring and sensors from the ECU connector under the passenger side dash.

Changes from 18 months ago:
Check Ground Connections:
Ground to:
# 5 - 0.1 Ohm (spec “nearly zero”)
#11 - 0.1 to 0.2 Ohm (spec “nearly zero”)
#19 - 0.2 to 0.3 Ohm (spec “nearly zero”)
#25 - 0.1 Ohm (spec “nearly zero”)
#11 connected to 19 -0.1 to 0.2 (spec zero)

Previously these all checked at 0 Ohms.

Coincidentally I get 0.1 to 0.2 Ohm at each end of the Valve Cover to Firewall Ground.

What might be causing and increase in resistance? Would a deteriorating wire conductor do this?

I also am no longer getting battery voltage (12.24)
at the ECU power supply (#18 - ground; w/ ignition On) (12.04)
OR
at the AMM (11.8)

The IAC, Temp Sensor and AMM all checks out okay, though the Lamda sond "reheat resistor" is 1 Ohm instead of 3)

Any suggestions pass swapping out the AMM?

I was just removed the IAC to check to see if the inside was clean and noticed off to the side how chunked up one of the negative grounds from the battery was and decided to remove and clean it.

As I loosened the ground connecting bolt I saw another ground directly under the bolt pointing straight down. As I was marking the wire with blue tape I noticed how slack it was. I pulled very little and came up with an unconnected wire.

The end looks like it pulled out of a connector - end is stripped back about 1/2" and the insulation does not look torn or eroded.

I have not found what the ground might have been connected to. The loose end curls back up so it looks like a 'J'. I crawled under the car to look and am not finding anything it reaches that has the other end of a wire or connector.

Will someone please see if they have this lower wire and tell me where it goes?

Thanks
1988 244 DL

---------------
Location Again:
There are two blue wires coming from the negative battery terminal. One attaches to the body wheel well and the other to the bottom driver's side of the engine behind the power steering pump and AC compressor.

The battery wire is connected by a bolt to the bottom of the engine. The undetermined wire is on the same bolt and in my case pointing straight down.

Thanks aleekat.

I felt around the back of the AC compressor top engine side bolt and found the stub of the ring connector.

Too bad the AC hasn't worked for 20 years ... otherwise this could fix it ... not.

The description of the wire sounds like the Alternator ground wire but the location does not sound right. Potentially for owner added accessory that is no longer on the car?

Sounds to me like the ground for the AC clutch.
--
Art Benstein near Baltimore

He picked up Milli-Amp and took her for a ride on his Megacycle.

Art,

That's the closest I'm getting to a guess but I cannot find the location it pulled out of. Do you know that it goes down between the belt wheel and compressor? The wiring diagram shows two grounds, and one is shown as black (SB), coming from the clutch.

As far as the running problem goes ... if this is the AC clutch ground wire ... if the AC is off ... it would not have power sparking at the loose end of the wire disturbing my fuel regulation would it?

What else have you used that meter for?
What does that section on "can't get battery voltage" mean?
Swap the AMM.
--
Art Benstein near Baltimore

By all means marry. If you get a good wife, you'll be happy. If you get a bad one, you'll become a philosopher. Socrates

Art,

I use the meter for voltage testing (AC and DC) and ohm testing and occasionally when looking for water leaks in buildings.

The section on battery voltage means that 18 months ago when I was doing diagnostics to remedy an emissions problem I was getting the same voltage as at the battery when doing certain tests but now the voltage has dropped below battery voltage.

Just as I started getting 0+ Ohm at some locations that were previously zero.

If I had a good AMM I would swap it in.

I have put out a call on locating an AMM without response yet.

I am looking into Injection Labs for a rebuild though there is some dissatisfaction in posts with rebuilds in general.
--
Thomas - Arlington, VA

I may be able to help with a loaner AMM if your 88 swaps with my cars. Let me know
--
89 240 wagon, 94 940, 200K, 94 940, 135K

I may be able to help you with a loaner AMM if your 88 is compatible with my cars. Let me know
--
89 240 wagon, 94 940, 200K, 94 940, 135K

That would be great.
Where are you located?

in fairfax city jdotpelchatatverizondotnet
--
89 240 wagon, 94 940, 200K, 94 940, 135K

Hi Thomas,

We are probably more miles apart on understanding each others' skills at making electrical measurements than we are physically, but yet I will submit, based on your insistence on using the Bentley's AMM resistance checks in an earlier attempt to judge your AMM, you are taking this recipe thing they offer way too strictly:

1. The AMM resistance checks are garbage. Like the reports on aftermarket rebuilt AMMs, the value of these tests has been reported as useless many times here on this list and others for good, sound reasons. There is no way for you to verify you have a good AMM using a voltmeter or ohmmeter.

2. Distinguishing among tenth-ohm resistances is difficult with lab equipment using spring-tensioned silver contact probes in humidity controlled environments, and basically impractical using an electrician's tool. You won't find a corroded terminal with an ohmmeter. The recipe tests are there to find unplugged connectors or broken wires.

4. "Battery voltage" includes a tolerance permitting all those readings given voltage drop of various loads, including the loads represented by the components being measured.

The procurement of a spare AMM is another suggestion Bentley makes no note of, but is good advice repeated ad nauseum by experienced Volvo owners. It is the only way to rule it out. "Buy one before you need to, so you can get a good price and test it." Yes, I know, too late for you -- but if you can't locate one in a yard, on line, or find another owner to let you borrow one, a genuine Bosch rebuild is the price you need to pay.

When you make electrical measurements, consider tolerance. Just because the meter has a digital readout, does not bestow your measurements with that last-digit accuracy. Check it against a standard, or a couple of other meters. It isn't built for rocket surgery.

When you read Bentley, remember you are reading selected words written for the dealer techs by Volvo's tech writers, preparing them for models not even on the floor yet. Not experience.

And, what happened to 3?

:)
--
Art Benstein near Baltimore

I had no Monet to buy Degas to make the Van Gogh.

Art,

I just started using a meter to help me work on the electrical components of my 244. It sounds like you have a lot on the ball when it comes to electrical testing. My know with circuitry outside the house is more sorcery than science.

You didn't have any comment on Injection Labs so I'm guessing you have survived on pick-n-pull spares.

------------
With purchased AMMs I'm seeing:
Bosch - obsolete - no longer makes replacement part
noname - $169;
Python - $169;
"remanufactuered Bosch" - $410
After Market - noname - $135
Remade - $135
Injection Labs - $95 plus
? no numbers no source - $152
------------
If anyone is selling a rebuild wouldn't it necessarily be a Bosch unit?

It looks like the pick-n-pull is the first stop.
Are here any suggested yards?

"It looks like the pick-n-pull is the first stop.
Are here any suggested yards?"

Anyone that offers a 30-90 return policy even on electronics. Those with online inventory of cars are nice.

"Anyone that offers a 30-90 return policy even on electronics. Those with online inventory of cars are nice."

I'd have to post ROFL, but perhaps you indeed have something like that where you live...

Here it is, and I quote, "No Returns - No Exchanges - No Exceptions - All Parts Sold As Is - All Sales Final"

Or as another outfit heads their brochure, "Cash Only - No returns No refunds No exchanges All sales are final All Parts are as is"


--
Art Benstein near Baltimore

"Doc, I can't stop singing 'The Green, Green Grass of Home.'" "That sounds like Tom Jones Syndrome." "Is it common?" Well, "It's Not Unusual."

We actually do!
http://www.picknpull.com/
I bought a spare AMM that immediately tripped a code and they accepted it back for exchange or store credit one week later. Their receipt lists 30 days warranty on all parts.

To the OP, they have an '86 on the lot right now if that has the LH2.2? I would be more that happy to look Saturday if it is the right AMM and if it is still there.

It is a tough call, Thomas. Biggest reason it is tough, is there aren't that many cars from the LH2.2 era left uncrushed. Even tougher is the challenge folks driving LH2.0 cars (83-84) have finding an AMM they can trust. One solution for them is to grab one like yours and do a bit of rewiring.

The easier one to find is for the 89-93 years (LH2.4) with 016 suffix. It is pin compatible with yours, and you could probably drive with one, but it lacks the CO adjusting screw needed by your ECU, so it wouldn't be easy to get the A/F ratio right.

I have no clue about yards in NOVA. Come up to Maryland and you have five Crazy Ray's locations; the closest to you probably right up 95 in Jessup. You've been struggling with this a year and a half, I see, so a bit more patience and I think you'll find something without dropping hundreds. Check brickboard classifieds, e-bay, turbobricks, but any recommendation I can give you is only second-hand gossip when it comes to the remanufactured units. From the stuff I've read, only Bosch rebuilts are trustworthy. Best one I ever bought without pulling it in a yard, hardknocks! sold to me, but that was an 016, not much help to you.

And in the end, all you get is a way to rule out the AMM being related to your symptoms. Unfortunately, it is the only way.
--
Art Benstein near Baltimore

I went to a seafood disco last week...and pulled a mussel.

..."resistance is futile"

EDIT: Or maybe the credit is yours Art?


--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

... for Fostering a revival of electrical pun exchanges for which we have no shortage of capacity.
--
Art Benstein near Baltimore

When a clock is hungry, it goes back four seconds.

It hertz me to be negative Art, but I see you lack the potential to rectifier ways here.

--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Currently I am biased toward agreement, watt with no inducement to suppress.
--
Art Benstein near Baltimore

Two peanuts walk into a bar, and one was a salted.

These puns are a switch. I'll relay them to my friends when I get ohm.

"My sister would enjoy these. I'll contact her and relay them."
--
Art Benstein near Baltimore

You mentioned blocking the hot air intake in an earlier post because of failed airbox thermostats. If you blocked the hot air inlet from the outside, without permanently fixing the flap in the interior of the airbox in the cold air position, then that flap will - with a failed 'stat - swing over and block the cold air.

You then have a strangled airbox...hot air blocked from the outside, and cold air blocked by the flap. The car will run rich, particularly when warmed up, possibly giving the symptoms you experienced.

A good way to bypass the airbox thermostat is to remove it and substitute a cutoff nail of the correct length to hold the flap in the cold position, blocking the hot intake port. Or remove the flap assembly entirely and block the hot air port from the inside. Either way, you can then reconnect the preheat hose, so it passes a visual emissions check.

--
Bob: son's XC70, dtr's '94-940, my 81GL, 83-DL, 89-745(V8) and 98-S90. Also 77-MGB and some old motorcycles.

I blocked the incoming warm air with a small block of wood. I did this a decade ago.
If I was chocking the engine I think it might have shown up before now.

I see that you have check that AMM every way but loose. I mean loose connections in the connector by unplugging it a zillion times. You have done lots of web surfing and checking on parts your car does not have. I am talking you are full of tenacious energy!

I have had other ideas. You never mentioned the fuel pressure regulator or a possible failing in-tank fuel pump, as they can be twitchy as they go bad. They can screw with mixtures or lower your mileage too boot of which was a complaint!

Working on car troubles is like having heartburn after eating. You have to think back and try to remember what was on that dinner plate. What is causing this problem, as a part of that plate of food, had something bad on it.

What ever is causing the hesitations has happened to someone sometime or another and if you stay tenacious, you will feel as happy as we have been when we found it. Just to make you feel better I remember the T.V series "Get Smart" that was not one of my favorite comedy programs. However, in my later years, I can relate to the workings of "Chaos" and the old Cause and Effect equation, working undercover, with "randomness". Sometimes, so well blended I ponder if there is a difference!

Good luck and keep us posted as we all like a good read nowadays.

Phil

The Fuel Pressure Regulator (FPR) is okay based on two tests ... the vacuum line did not evidence any fuel leak ... at idle I pulled the vacuum line and idle increased - which is what it is supposed to do.

I had a similar (not identical though) and very maddening issue that I was certain was fuel related but turned out to be the ignition amplifier.

The Bentley manual has almost zero information about the ignition amplifier and I could not tell that the spark was weak by looking at a plug.

I ended up using Fred Su's handy manual on checking the function of the ignition amplifier... stepbystepvolvo.com

I do not see what you are directing me to.

I do not find "amplifier" or manual" on the linked page.

88 LH 2.2 does not have one.
Dan

AMM

I could understand the AMM failing and causing running problems if not a failure to start.

What I do not understand is it working and then not working.
If one of those little wires burns out or starts to burn out they don't regenerate (?).

Why would a failed AMM cause hesitation to come and go in such an extreme way?
----
Pick-n-Pull Yard

I have a very bad selection of pick-n-pull yards around me.
Any recommended sources for new and used AMM? Are these still made?
----
IAC

Remember the only other time I had this problem was a year ago and it was strongly suspected to be the IAC.
----
Preheat hose flap

As far as the air box and preheat hose, I took the route, around 2005, of blocking the inlet after two thermostats had failed. My area rarely gets supper cold.

Hi,

If you had two airbox thermostat fail in the past and you are still using the same AMM it might have become damaged.

Get a used Bosch AMM from Ebay (approx. $40-$50 probably). Find one with the option to return if it is defective.

Travis

I think your 88 has LH 2.2 fuel injection with an 007 AMM-correct?

Here are 007 AMMs on ebay:

http://www.ebay.com/itm/Volvo-240-245-OEM-Bosch-mass-air-sensor-1589-/320965999230?pt=Motors_Car_Truck_Parts_Accessories&hash=item4abb107a7e&vxp=mtr

http://www.ebay.com/itm/Mass-Air-Flow-Sensor-Meter-Housing-Fits-Bosch-Volvo-240-740-Models-NEW-MAF-007-/180983881594?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a237adf7a&vxp=mtr

Travis

Make sure the pins in the AMM connector have not pushed back into the connector and not making good contact.
Dan

You can check for a defective AMM, by disconnecting it (key out), then starting up. If the hesitation remains then it isn't the AMM.

Do you have an ignition amplifier by the battery?
--
1980 245 Canadian B21A with SU carb but electronic ignition and M46 trans in Brampton, Ont.

I had a similar hesitation that turned out to be an AMM, swapped in a known good spare and all was well.
Dan

I don't take any chances and always have a good spare AMM on board. Actually I have two in case I find someone stranded that needs one leaving me with still a reserve. Just saying. Hopefully its not a failing in-tank fuel pump. I had one give me some problems for a few days before it completely went out. But the car wouldn't even react to the pedal until the fuel flow came back. Car would almost die each time it started giving me problems. The last AMM that failed gave me some bad signs but then just wouldn't start pretty quickly after presenting any signs of issues. How is the airbox thermostat? If it has failed in the hot position then that could be a key sign that the AMM is getting too much heat and being fried.

If you already know that your AMM is outside of the specified operating parameters, I would suspect that of causing your problem. Granted, it is an expensive part to replace just to find out, but . . . what else do you have to go on? At least you would have a spare if you discovered that it was not at fault.

You say the hesitation is gone, correct?

Yes the AMM is out of spec ... but ...
I went back over my records and it has been this way (fluctuating between 2.6 to 3 - mostly 2.9) since 2008 when I started recording test results. So when there have been not running problems its operational specs have been "out of spec".
I'm shopping for a bone yard replacement anyway.

No - the hesitation is not gone ... it comes and goes. It is getting worse and more frequent.

I have noticing black smoke now from the exhaust while the engine was warm, starting from a stop.

I pulled plugs and the engine is definitely running rich based on the condition of the plugs.

You might try measuring the fuel pressure.

I saw your post about the FPR, but I don't think your test was sufficient. Your test of no fuel present indicates the diaphragm is not leaking, and your test of response to installed/removed vacuum hose indicate that it's modulating, but you don't know that it's actually maintaining the correct pressure.

My dad's '85 245 ran for a long time with him trying to track down symptoms, including occasional missing and almost stalling at traffic lights. When he actually measured the pressure, it was very high; replacing FPR fixed it for him.

Good luck!

Roger

'95 854T 258k miles
'93 945T 218k miles
'87 245 M47 299k miles <--almost rolled over!