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Discussion Starter #1
Good Morning everyone. I haven't been on in a while. Update, I have my 1983 Rampage up & running, with a new/rebuilt 2.2L engine & new/rebuilt carburetor. Issues I am having now is at a warmed up idle the engine can't stay at an even idle up & down 200-300 rpm, I have looked all over for vaccum leaks (none). Do I need to adjust the idle mixture on the carb? also I think I need a new/rebuilt cruise control servo (old mechanical style). Thank you for all the hints, suggestions, and help.
 

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Is this a PCM or Electronic ignition with mechanical distributor advance equipped vehicle? If it has a PCM, the brass throttle stop at the end of the solenoid stem is a ground contact and must be resting on the throttle tab at warm idle. There is an idle stop screw on the carburetor body that must be backed off if it is preventing ground at the solenoid. This stop screw is not an idle adjustment screw.
Some carb idle solenoids also have a vacuum control. When the A/C clutch engages, it will bump the idle up to compensate for the added load. Is the A/C compressor cycling and causing this hunting idle?
The warm idle mixture should be slightly lean. If you remove a small vacuum hose to introduce an intake manifold vacuum leak, the idle shouldn't change much or get slightly rougher. If the engine speeds up with the introduced vacuum leak, then the idle mixture is too rich and needs to be leaned out.
 

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Discussion Starter #3
The distributor is electronic (a three wire plug) The A/C compressor is not running. The solenoid does have a vacuum connection & is hooked up. I will check on the idle stop screw. Thank you very much.

I was able to get the cruise control to work perfectly.
 

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All the distributors are the 3-pin Hall effect electronic type.
What I meant was, that the PCM takes care of the spark advance on most of them, but some distributors on vehicles that didn't have to meet the more-rigorous emissions (the Rampage and Scamp were considered light-duty trucks) were fitted with a distributor vacuum advance and an electronic ignition box.
Does yours have these?:
http://contentinfo.autozone.com/znetcs/product-info/en/US/msd/8463/image/3/
http://www.bmcuda.com/prodimages/large/3438850-1.jpg
or this:
http://i1223.photobucket.com/albums/dd501/92Turbo2/esas.gif
10 mpg sounds like a retarded cam and/or spark timing and/or a rich fuel mixture.
Looking down into the venturi at a warm idle with the choke wide open, do you see fuel dripping onto the throttle plate?
 

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Discussion Starter #6
I don't have any vacuum advance on the distributor. I do have a PCM. I will check the distributor timing & look down the venturi.
 

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The cam sprocket cover peep plug can be removed at TDC and you should see the hole in the sprocket centered in the hole of the cover in order to check valve timing.
It isn't a true vertical, but on the centerline of the engine which is canted slightly rearward.
http://www.allpar.com/fix/timing-belt-22_clip_image004.jpg
Follow the instructions in the service manual when setting distributor timing. You may need to remove and plug the vacuum hose to the PCM in order to get the correct setting.
Some asked for disconnecting the coolant sensor connector when setting timing (the one at the thermostat for the PCM, not the one at the #1 spark plug which is for the dash gauge).
 

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Discussion Starter #9
I unplugged the temperature sensor wire & pulled the vacuum off the PCM & plugged it, my idle got more steady it is still hunting but it has gone from a 500 RPM swing to a 200 RPM swing. It also idles absolutely beautifully at first cold (fully choked) start up.
 

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Discussion Starter #10
Twice now the car has died on me for no apparent reason, I am wondering if the PCM is not good or has weak solder connections on the circuit board.
 

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Twice now the car has died on me for no apparent reason, I am wondering if the PCM is not good or has weak solder connections on the circuit board.
I would suspect the Hall effect sensor in the distrubtor before that.
 

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Discussion Starter #12
The distributor, cap, rotor (everything) is new. I am at a point now everything is new except the PCM and I've sunk too much money to walk away & I've found a NOS PCM on ebay for $87, so I am buying it and getting it installed. I am sinking all prayers & hope that this will 'fix all my problems' LOL
 

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Unlikely. More diagnostics are needed.
 

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I'd bet on a bad (new) Hall effect before I'd suspect the computer. But that's just me.
 

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Not really. A Hall effect sensor is a magnetic device. It produces a voltage pulse synchronized with the passage of one of the distributor wheel "shutters" through the sensor's gap. The ECU uses these pulses to figure out where the engine is in its rotation cycle and how fast it's rotating. The general "test" for the Hall is to go buy another sensor (they're about 30 bucks) and replace the one in the engine. If this solves the problem, the Hall was bad. If nothing changes, you can just return the new sensor.

Make sure the distributor shutter wheel is firmly attached to the shaft. If the shutter wheel moves, it can generate erroneous data that can "trick" the ECU.
 

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You could pass a steel flatblade screwdriver tip through the HE slot that the shutters pass through with the key on. You should get a nice spark off the coil wire. Use a noid light for safety.
Manipulate the connector and harness while doing this to look for a possible intermittent contact.
 

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In my experience, the Hall effect failures seem to be mostly a connector which has oxidized/compromised contacts, or harness pinched at the edge of the dist cap, with intermittent performance from broken wire strands inside the insulation.
 

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I have replaced numerous hall Effect switches for the same dying problem with a hot engine. Also did the R&R on GM ecms and Ford TFI modules. It seemed that back in the 80-90s, all American manufacturers were having the heat/cold problems on thier electronics. PCM's were pretty good, only replaced them once in while. The Lean Burn PCM were different as they were mounted on the air cleaner so the engine heat would bake them. Alo, please, don't remove the air intake tube fom the PCM to the air filter as this helps direct/draw cooling air through the PCM. I have seen this problem surface back then also.
 
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