blackskidmarks wrote:Check the idle stabilisation valve on top of engine. It should feel like its buzzing when you touch it. If it isn't check connections to it.
Hi blackskidmarks, could you tell us a bit more about this idle stabilisation valve please. Pretty sure my van hasn't got one. Some early vans do have an idle stabilisation unit, but it's a box of electronics near the coil on the body work and it doesn't buzz.
Emma&Al wrote:
2. Starting - it starts first time all the time, but again, it hints that it might not actually like to..and then suddenly its like someones injected it with some super power, and BOOM it starts up. It always turns over, but sometimes sounds like the batteries really dying and then BOOF! it starts. Like its being pushed into action with some sort of Red Bull drink! Its a new battery, a new starter motor (well, 6m old).
Well that bit is indicative of one of two things. Weak starter performance or timing too advanced.
If it's a new battery and has never been allowed to go flat (damages them) then it's unlikely to be a weak battery, but it might be worth putting your meter across the battery terminals whilst cranking, it should not drop below about 10 Volts. Let us know
Now, if any of the very heavy cables to, and from, the battery and the starter (and the engine earth strap) is less than very good, voltage can be lost under the heavy current use during cranking. Worth looking at and cleaning up the earth strap connections from the battery, the main red (+ve) lead that runs from the battery to the solenoid and then from the solenoid to the starter. That last cable is a very short (~3") length of braided wire (uncoated) that connects the solenoid to the actual starter and is a fairly common fail. Trouble is, checking the connections on the starter is very tricky lying on your back and looking / reaching up.
NOTE when going anywhere near the starter with anything metal,
disconnect the battery first !! A short to earth there is something you do NOT want to be near !! Take care !! Then we have the earth strap that runs from the very front of the gearbox to the chassis. Another fairly common fail. One can test that one by, whilst cranking, connect a jump lead from a bright bit of ally on the motor to the bright metal bit of the tail gate catch (which is by your naughty bits when you are leaning into the engine bay). If when doing that the cranking speed increases it means that earth strap is weak in some respect. One can quite easily connect another earth strap (from any motor factors) from a "nice" bit of engine to a "nice" bit of bodywork, one of the bolts on the engine cross member is good, clean to bright metal of course to get a good connection, then cover with grease or paint. Takes ~15 minutes and is a good belt and braces type of thing.
However, before doing all that, check the ignition timing. If it is too far advanced it can cause the engine to be slow to crank over and then suddenly burst into life. However (again) before simply checking the timing, the following might have occurred at some point in it's life and needs checking
first. When either a vacuum pipe from the carb to the dizzy, or the vacuum "advance / retard" diaphragm on the carb fails, folk check the timing, find it's "out" and adjust it. But if they did not notice the dodgy pipe and / or diaphragm, then, now the timing is miles out across the engines rev range.
So, before you check the timing, it's important to make sure that the other "things" that alter the timing are in good order.
To test the diaphragm, do the suck on the pipe test. When sucking on the pipe, you should not be able to keep sucking and you should see the base plate inside the dizzy (cap and dust cover off) moving. Oh and then there is the centrifugal advance retard bob weights under the base plate ***
*** hey folks, what is an easy test for the centrifugal advance retard bob weights operation? I know how I do it, but it involves stripping the dizzy down somewhat
When you are satisfied that all those advance / retard pipes etc ae working,
then check and if necessary adjust the timing.
I suspect your "hunting" issue at tickover may be a timing issue too, though it may not be
it could also be an air leak on the air inlet side of things. The brake vacuum servo hose on the top left hand side of the inlet manifold is a common culprit.
