Re: Bucking, lurching leads to no camping and bummed out kid
Posted: Thu Jul 26, 2012 9:31 am
My personal strategy is to eliminate ignition gremlins first, then move on to vacuum and fuel-related gremlins. With that in mind:
1) Replace cap, rotor and wires (just plug and play?)
Pretty much. It's easy to get the wires mixed up going into the top of the cap, but if you transfer them one at a time from the old cap to the new cap and put them in the same order you should be fine. Make a note of where the indexing tab is under the rim of the cap (it mates with the notch in the rim of the distributor) and hold the new cap in the same orientation as you transfer the wires one-by one.
When you replace the rotor, put a drop or two of engine oil on the little felt disc you will find in the shaft under the rotor. This keeps the advance mechanism happy. Make sure the new rotor is fully seated.
Don't replace the wires and cap all at once, unless you're certain you can replicate the firing order from scratch. Do the cap first, as described above, then replace the wires one at a time, matching the lengths and the plug ends of old wires to new.
2) Check plugs
If you've never had the plugs out, then plan to replace the plugs as well as check them. Use Bosch copper plugs. Avoid the fancy platinum ones. Keep track of which plugs came out of which cylinders (I mark mine with a Sharpie). Analyze the plug conditions using information available on-line. Keep the old plugs around for when Colin comes to visit.
3) Test vacuum with a vacuum gauge (once I get one, where/how to I hook it up?)
In retrospect, I'll recommend getting a MityVac hand pump instead of just a gauge. It comes with a vacuum gauge attached to it, so it can be used just as a gauge, but it also enables you to test vacuum pots (like the ignition advance pot and decel valve) by applying vacuum to them. It will cost just a little more than a standalone gauge, but gives you so much extra flexibility.
You would hook up a vacuum gauge to the tiny spigot off of the central plenum that feeds the decel valve and fuel pressure regulator. Use a tee fitting so that these two important parts are still getting their vacuum signal as you are doing your tests.
4) Remove S boot and inspect for cracks (what else do I have to remove to get this out? I do not want to damage this NLA part, could not find Bentley procedure for removal)
I find it easiest to keep the S-boot attached to the AFM and remove them together, unclipping the top half of the air cleaner and just loosening the band clamp at the throttle body.. The breather hoses should come off easily. Vanagons and Bay Windows may differ in the level of difficulty for this task, however.
5) Distributor vacuum can/diaphragm?
Use your MityVac for this. Or use the old-school method: with the distributor cap off, and with a good view of the distributor internals, apply mouth suction to the hose coming from the distributor vacuum can. You should see the actuator rod from the vacuum can retract and the point plate rotate with it. Hold your tongue on the hose end for a few seconds and make sure the vacuum holds. That's it. The MityVac gives you the ability to measure how much vacuum is needed to move the actuator, but the mouth suction method is perfectly valid for a functional test.
6) brake booster/hose
The MityVac again, although it may take a lot of pumps.
7) Check valve cover gaskets for leaks
Plan to do a valve adjustment instead and do the gasket check or replacement then. Have replacement gaskets on hand, because you don't know the condition of your existing ones. If replacing, clean the valve covers scrupulously and use a thin layer of Hylomar or Curil on the valve cover gasket mating surface. It helps to keep them in place.
Switch back to points and condenser (not sure how to do this, yet)
Probably best done with Colin on hand. Adjusting points can be fussy and frustrating on Bosch distributors.
1) Replace cap, rotor and wires (just plug and play?)
Pretty much. It's easy to get the wires mixed up going into the top of the cap, but if you transfer them one at a time from the old cap to the new cap and put them in the same order you should be fine. Make a note of where the indexing tab is under the rim of the cap (it mates with the notch in the rim of the distributor) and hold the new cap in the same orientation as you transfer the wires one-by one.
When you replace the rotor, put a drop or two of engine oil on the little felt disc you will find in the shaft under the rotor. This keeps the advance mechanism happy. Make sure the new rotor is fully seated.
Don't replace the wires and cap all at once, unless you're certain you can replicate the firing order from scratch. Do the cap first, as described above, then replace the wires one at a time, matching the lengths and the plug ends of old wires to new.
2) Check plugs
If you've never had the plugs out, then plan to replace the plugs as well as check them. Use Bosch copper plugs. Avoid the fancy platinum ones. Keep track of which plugs came out of which cylinders (I mark mine with a Sharpie). Analyze the plug conditions using information available on-line. Keep the old plugs around for when Colin comes to visit.
3) Test vacuum with a vacuum gauge (once I get one, where/how to I hook it up?)
In retrospect, I'll recommend getting a MityVac hand pump instead of just a gauge. It comes with a vacuum gauge attached to it, so it can be used just as a gauge, but it also enables you to test vacuum pots (like the ignition advance pot and decel valve) by applying vacuum to them. It will cost just a little more than a standalone gauge, but gives you so much extra flexibility.
You would hook up a vacuum gauge to the tiny spigot off of the central plenum that feeds the decel valve and fuel pressure regulator. Use a tee fitting so that these two important parts are still getting their vacuum signal as you are doing your tests.
4) Remove S boot and inspect for cracks (what else do I have to remove to get this out? I do not want to damage this NLA part, could not find Bentley procedure for removal)
I find it easiest to keep the S-boot attached to the AFM and remove them together, unclipping the top half of the air cleaner and just loosening the band clamp at the throttle body.. The breather hoses should come off easily. Vanagons and Bay Windows may differ in the level of difficulty for this task, however.
5) Distributor vacuum can/diaphragm?
Use your MityVac for this. Or use the old-school method: with the distributor cap off, and with a good view of the distributor internals, apply mouth suction to the hose coming from the distributor vacuum can. You should see the actuator rod from the vacuum can retract and the point plate rotate with it. Hold your tongue on the hose end for a few seconds and make sure the vacuum holds. That's it. The MityVac gives you the ability to measure how much vacuum is needed to move the actuator, but the mouth suction method is perfectly valid for a functional test.
6) brake booster/hose
The MityVac again, although it may take a lot of pumps.
7) Check valve cover gaskets for leaks
Plan to do a valve adjustment instead and do the gasket check or replacement then. Have replacement gaskets on hand, because you don't know the condition of your existing ones. If replacing, clean the valve covers scrupulously and use a thin layer of Hylomar or Curil on the valve cover gasket mating surface. It helps to keep them in place.
Switch back to points and condenser (not sure how to do this, yet)
Probably best done with Colin on hand. Adjusting points can be fussy and frustrating on Bosch distributors.