AMC Eagle Den Forum
The Mighty 258 => Engine Electrical Systems. => Topic started by: dkoug on September 10, 2011, 10:05:46 PM
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My 82 Eagle Limited the last few months has been rough at idle with the brakes on.
Noticed when put into neutral the roughness mostly disappears.
Today is refuses to idle.
Would new plugs solve this and what plugs for a stock 278,000 klm (Canadian car) be used.
thanks
dkoug
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Doesn't sound like a plug problem. Sounds like vacuum/carb problem.
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Real bad vacuum leak!! Check all you hoses and check valve at the booster, or the booster may be the problem too!!
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Hi
Not being a mechanic type, can you direct me how to find the Booster???
My mechanic suggest needs carburetor cleaned???????
He has it running better but still stalls when put into gear.
Also stalls when turning a corner which would relate to the power steering putting a load on the engine.
How would I determine if the Booster is the problem.
thanks
dkoug
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First step. Check all the vacuum lines for cracks/leaks.
Include in this check the thicker line that goes from the back of the carb to the big black round disc high on the firewall on the driver's side. The master brake cylinder is bolted on the front of this.
Well that's interesting. The diagrams in the Eaglepedia show both with and without a brake booster...
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Thaks for the suggestiojn,
question, does the brake booster compensate for the additional load when turning (power steering) and putting gear into drive.
thanks
dkoug
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question, does the brake booster compensate for the additional load when turning (power steering) and putting gear into drive.
Brake booster uses vacuum to provide a greater braking force when you apply the brakes.
The engine isn't running right. The first step (and cheapest) is to eliminate/fix any vacuum problems.
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Tocheck if it is your booster you could unplug it and cap it off at the manifold. However now you have no power assist to your brakes. So its extremely hard to stop.
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I'll bet you have a PCV line leak or an advance'purge leak. I see this all the time and it's simple to fix. The booster will enhance these leaks as it has a direct manifold connection. N U T T E R the system and eliminate all the unneeded vac lines. Better solution, add an MC carb and eliminate all but 2 vacuum lines. Half of the carbs I replace are not running correctly because of vacuum lines.
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I'll bet you have a PCV line leak or an advance'purge leak. I see this all the time and it's simple to fix. The booster will enhance these leaks as it has a direct manifold connection. N U T T E R the system and eliminate all the unneeded vac lines. ... Half of the carbs I replace are not running correctly because of vacuum lines.
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Easier as it's a sure solution (eliminating sources of problems rather than trying to find & fix). Better performance too.
...Better solution, add an MC carb and eliminate all but 2 vacuum lines...
I'm considering this for mine, but not sold yet.
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If you do get interested let me know. I still have the special running for Nest Members. You save some $$ and the nest gets a $5 donation. I also have a non-feedback carter too.
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Gronk
curious about the MC Carb. cost and installation difficulties.
thanks
dkoug
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Motorcraft 2150 Carburetor Conversion for the 4.2/258 - Ready to Install
http://forums.amceaglenest.com/index.php?topic=36250.0
As part of that setup, you get the Diagnostic ECM Test (bypasses the ECM stuff for testing - search).
Also recommend TFI high voltage coil upgrade. Nothing to do with your problem, but another great improvement in fuel economy and performance. In addition to a new high voltage coil, to handle the higher voltage it uses: new distributor cap, cap adapter, wires & larger spark plug gap. Search the nest.
Note: if getting the TFI coil from a junk-yard, the TFI Ignition Module doesn't work with Eagle distributor - wrong type of sensor.
Along with the TFI upgrade, you can upgrade to the GM 4-pin HEI Ignition Module . Has four electrical connections plus it has to be bolted to ground (and the back is also the heat-sink to the inner fender). This does a better job of spark control and it handles higher voltage. With it in place along with the TFI, you can permanently bypass the Ballast Resistor (in series with coil when running, bypassed for full voltage to coil when starting while turning the starter over). Get a quality one, they'll shut down if overheated; cheap ones burn out.
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dkoug, I have a current nest special of $325 shipped for the carb conversion, electric choke, air cleaner/crank case breather and a $5 donation to the nest. Shipping is also included.
Kit comes ready to go. I do just about everything for you.
See the For Sale section for more info.
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The BBD isn't that bad of a carb - when all is set up right and no leaks. Just takes a bit of fiddling, like any other.
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The BBD isn't that bad of a carb - when all is set up right and no leaks. Just takes a bit of fiddling, like any other.
Agreed. Mine, in the winter, when it was 0 degrees out, one pump of the gas pedal, and its starts instantly, faster than any other car we own. That was with a totally stock ignition system too, and no block heater.
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Ha ha.
Mine just developed a vacuum leak somewhere. Stalls when I press the brakes, unless I slip it into neutral first.
And, I just replaced all the vacuum hoses around three weeks ago...
pain
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Check your PCV valve and vac line routing.
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Went over all the vacuum lines this afternoon. All seem fine.
Problem was noticeably less after the check... but still there, just less picky.
I didn't change anything, but something obviously changed.
What a PITA.
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Disconet and plug the vacuum line to the brake power booster, if the engines runs OK then you need to change the power booster since the diaphragm is bad. If you do need to change it try to get a double diaphragm booster if possible.
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Disconet and plug the vacuum line to the brake power booster, if the engines runs OK then you need to change the power booster since the diaphragm is bad. If you do need to change it try to get a double diaphragm booster if possible.
Unless the demand by the brake booster takes the vacuum load to the point where it leaks somewhere else. Like we usually see.
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Another thing with the brake booster. How long after the car is off do you have power assist from the booster?
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Another thing with the brake booster. How long after the car is off do you have power assist from the booster?
Don't know. But I'm suspecting a leak somewhere in the vacuum lines.
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You will usually have one or two stops with power with the engine not running, or maybe only one if it takes a while. I think you will still have brakes but it will take much leg power to make them work.
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You will usually have one or two stops with power with the engine not running, or maybe only one if it takes a while. I think you will still have brakes but it will take much leg power to make them work.
If there is a bad leak at the booster or the plumbing to it. Brakes will lose power assist realy fast. If not instantly
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My 81 Concord had a hard-to-find vacuum leak that turned out to be the 'rubber' seal right where the master cylinder bolts on to the booster. I changed out the booster and the car runs much better. I later find out that the rubber bits there are NOT part of the main diaphragm and could have been changed without doing anything else to the booster.
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You have to try several times to see how long they last.
One pump may not show the leak.
According to the 81 TSM, 90 seconds after the engine is turned off you still have enough vacuum for 2 or more applications.
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Thanks, will check.