Yes, have a new coil so full 12 volts match to electronic Bosch distributor.
Don't assume that because you have a '12 volt coil' you will be getting 12 volts to the distributor. As GEOFF289 said below "I eventually tested my assumption and found only 9 volts at the coil" - you should check that you are getting 12 volts at the coil.The 'Pink' resistor wire designed into Ford wiring looms is there to ensure that once the car has started, only 9 volts (approx.) is provided to the distributor so that the points don't burn out. A higher 12 volts is only provided during start cranking.If you have replaced the distributor with one that requires a constant 12 volts, you must take the pink wire out of sequence. Either by replacing it in the loom, or by using it to power a relay that then provides a direct 12 volt feed from the battery to the coil/distributor.
Has the cam been upgraded from stock? Is it possible that it requires a higher stall speed to stop it bogging down under load? Have you tried simply increasing your idle speed (within reason)?Evan.
What Glenn said.Original points set up had a resistor in the circuit reducing voltage to the coil to about 9 volts once the engine was running. Early Pertronix distributors were OK with this but newer ones and your Bosch need the full 12 volts.I had this issue when I put the new engine in a few years ago. The old one had a Pertronix kit in it and I assumed the resistor had been bypassed but the new engine with an MSD in it would start but died if the idle fell below about 1,200 rpm.I eventually tested my assumption and found only 9 volts at the coil. That's when I learned that early Pertronix kits were OK with the lower voltage. Bypassed the resistor and the problem was solved.
What Glenn said.Original points set up had a resistor in the circuit reducing voltage to the coil to about 9 volts once the engine was running. Early Pertronix distributors were OK with this but newer ones and your Bosch need the full 12 volts.I had this issue when I put the new engine in a few years ago. The old one had a Pertronix kit in it and I assumed the resistor had been bypassed but the new engine with an MSD in it would start but died if the idle fell below about 1,200 rpm.I eventually tested my assumption and found only 9 volts at the coil. That's when I learned that early Pertronix kits were OK with the lower voltage. Bypassed the resistor and the problem was solved. Hi mateHow do I test for 12 volts at the coil? and where is the resistor wire located? cheers Rob
If you just connected the original wiring to a new coil the resistor will still be active and the new coil won't like it.Start the engine - sounds like it will idle OK in Park - put a multimeter on it, positive lead to coil positive, negative lead to a good earth. If it reads 12 volts or more your issue isn't the resistor still being in the circuit. If it reads 9 or so, the resistor is still active.The pink resistor wire is found at the back of the starter switch. You may have to google how to remove the switch. A few centimetres downstream of the switch there is a kind of bulge in the pink wire which is the resistor. On the engine side of the firewall this pink wire changes colour.As Shane said, you can either connect a new wire direct to the starter switch, or use the pink wire - whatever colour it is under the bonnet - to trigger a relay that then connects 12 volts direct from the battery.All of that said, reading the symptoms again I'm starting to think this won't be the issue (but its easy to check and fix so worth doing). As I said, mine wouldn't idle below about 1,200 revs until I sorted this out. It sounds like your's is OK at normal idle in Park but can't handle the 100 or so rpm drop when it goes into gear. I wonder if its some sort of weird issue with the neutral safety switch? Anyway, I'm sure you'll get it sorted.
I checked the voltage it fluctuates but never goes above 9 volts....you guys may be onto something
I expect if the torque converter is locked up when you drop it in drive it will squeal the tyres If you drop it into drive without brakes with a little revs then come to a stop keeping it running with both feet you will soon workout if it is a locked converter It will be very hard to get it to stop completely On other thing what trans is in it?
OK, it does seem that the resistor is still active in the circuit.Now run a temporary wire direct from the battery to the coil - positive to positive - and see if it'll idle in gear. If this doesn't solve it you have another problem as well but this one is worth addressing permanently anyway.
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Topic: 302 C4 wont idle in reverse or drive i.e. under load - please help? (Read 1273 times)
