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My 92 240 wagon was recently revived after a year or so hiatus. New starter, fuel pump, fuel filter, fuel pump relay, distributor cap and plugs. It hasn’t been running tip top, with power lags and odd idling, but tolerable. Now, car won’t start without charging the battery and then, won’t stay running as it dies immediately without revving. Alternator? Thoughts considering all the facts? Thanks as usual.
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'92 245 74k, '84 245 80k, 79 245 162k rip (rust in peace)
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Have you checked your air cleaner?
Try running the car with the filter out - be sure to put the air cleaner box cover back on properly before you start the car to avoid a fire.
You may have some animals in there, the filter may be wet or too dirty, or, if the lid has a foam layer inside it, the foam may have failed and clogged the filter.
fuel, air, spark.
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Hi,
The part about the alternator causing an odd engine running issue is not likely, unless its, a Range Rover.
They have their tachometers use a pulse signal from an alternator diode or winding to give out the engine speed in the dash cluster!
This is done, despite, there is also a crankshaft position sensor, giving out the same information, probably more accurately, to their ECU. Two different pluses, for different folks, in two different design rooms, starts it!
This is on a 2002 Discovery! The Discovery part (:) is they have some of the worst, but not all, of the most confounded electrical problems, imaginable.
You don’t ever want to own a Range Rover!
This One used GM motors, made in Mexico, with special alterations to fit special accessories, like alternators and the list goes on!
Even Mercedes gave up owning them. So many problems throughout the whole production line and way of thinking!
I like the promise of it being the AMM, as they are prone to failure. Replacing is the only good test and having a spare is always a good idea.
If the thermostat, in the air filter box, is not removed, you must disable the air flap to make it not use heated air from the exhaust manifold.
If not you will be replacing your new one again!
The next thing is to consider the IAC valve is bad or the throttle plate and it’s corresponding throttle switch are not working properly.
When the engine starts does it rev up past normal idle and then right back down to the 750 idle point and hold it there despite changes in loads. Even turning on the A/C, the idle must stay the same!
The throttle switch tells ECU, hopefully ahead of time, that is a speed change is needed. If the ECU doesn’t know when to shift programs from idle, to running with power, there can be a problem in the transition period between the two.
There could be a crack in the accordian hose between the AMM and the throttle body plate.
A split or a hole messes up air mixtures and the ECU goes crazy trying to sort out the bad information.
The ECU is looking at the AMM, the throttle switch, the RPM from the CPS and the results from the O2 sensor to make final adjustments. Timing and the IAC are the only direct control it tweaks, besides fuel mixture. It’s constantly self tuning itself for a good burn!
A little cleaning, checking vacuum line leaks and adjusting is all it needs to get things “clicking” together!
Phil
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Phil could you elaborate about removing the thermostat? My 2 month old AMM may be failing again but looking back through threads I came across your comment about the therm. thanks!!
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'92 245 74k, ‘07 XC70, '84 245 80k, 79 245 162k (rust in peace)
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Hi,
Thanks for posting back!
I had to go back and read the thread some too.
I will see if I can help but it appears I will need more details as we go a long.
The thermostat I was talking about is the one that is mounted inside the air filter box.
There is an assembly that can be snapped out. It's held by four prongs into the housing.
Inside that assembly there is a brass cylinder with a steel pin sticking out that operates the linkage to push a flap over. It covers a large hole on the bottom of the housing to the right.
What happens is the brass cylinder is filled with a wax substance and it leaks out. The thermostat then fails to expand when heated from the air coming up from that port.
That port has an aluminum hose connected to a stove shield on the exhaust manifold.
When the cylinder doesn't expand the port stays open and overheats the AMM.
The air is consequently a lot thinner, as if it was a very hot desert day. The AMM should send a signal to enrichen the mixture but if it has failed from overheating the engine runs lean all the time causing an issue with all aspects of performance.
It's best to remove the thermostat and place a small square block of wood or anything solid into the mechanism to push the flap back over permanently to the hole. I use a 5/8" one in all my cars.
When you replaced the AMM did you inspect the accordion hose for any worn-in holes or cracks in it? It could be letting air in and upsetting the fuel mixture no matter a new AMM or not?
After you check the air flap and hose to square those away from the pictures of symptoms being presented we can work from there!
If you can expand on the condition of the car maintenance wise.
How many miles since its last tuneup would be helpful and/or was there a previous owner that may have screwed something up trying find a problem before you got it?
Lots of background information will be needed to iron out unknown wrinkles!
Phil
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Thanks for your input. The engine idles pretty evenly. As mentioned above just now, I replaced the mass air flow sensor and the car starts up and runs. There is still intermittent power lagging upon acceleration.
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'92 245 74k, '84 245 80k, 79 245 162k rust in peace
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posted by
someone claiming to be rjk2
on
Fri Feb 8 16:50 CST 2019 [ RELATED]
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Check your fuel pressure to see if it is in spec.
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posted by
someone claiming to be Charles Crawford
on
Fri Feb 8 14:28 CST 2019 [ RELATED]
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I don't think the problem is your charging circuit. How old is the air mass meter? What happens if you disconnect it (with ignition OFF) and then try to start the car?
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I did try that today and the car indeed started and stayed running. New one is on the way. I’m hoping it solves some of the other crumby running issues I’ve been having too. Thanks!
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'92 245 74k, '84 245 80k, 79 245 162k rust in peace
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Replaced mass air flow sensor and now it starts and runs. Still noticed some lagging upon acceleration, and now a whirring, siren sound at all speeds. I’ll start a new post for this problem. Close to a breaking point with this brick.
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'92 245 74k, '84 245 80k, 79 245 162k rust in peace
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posted by
someone claiming to be Build
on
Fri Feb 8 14:24 CST 2019 [ RELATED]
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Hi Seed,
I also have a 92 240 wagon. Does the alternator have 74k miles on it? Is the battery new?
Have you checked voltage before starting it and during the short time it's running? If you aren't getting a charge, it's most likely the brush block in the alternator. Sometimes they can last 100k plus, but it's better to check them at 50k since one brush seems to wear much faster than the other.
Does the car stay running with a known good battery swapped in?
Jim
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The battery is new. Alternator not sure of the age. Haven’t checked voltage. I’m hoping it’s not a two fold problem because as mentioned below, the mass air flow sensor seems to have gone bad.
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'92 245 74k, '84 245 80k, 79 245 162k rust in peace
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