This may be way out there but are you using Bosch relays with no capacitor wired inside the relay? If no capacitor that could be source of rf. They make both kinds of relay with & w/o.
car misses when ac and blower is on
- Thread starter camoman22
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Bb70charger500
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Did you check the blower motor could have a dead short or sorts and sucks the power without a fuse pop
Shorthorse
Well-Known Member
You mentioned "under a full load", so are you saying turning just the headlights off or turning off any device that decreases the load will allow the car to run correctly?
I'm not familiar with HEI distributors at all. Did this issue start at the same time you replaced the ignition? Looking online I noticed that some require an ignition box and some do not. What distributor, brand/model do you have? Do you utilize have an ignition box?
camoman22
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Shorthorse
Well-Known Member
Well I'm totally confused. From full load to turning off just the headlights works, it doesn't sound like RF to me anymore. Your test of running the coil directly off the battery and the car running fine is telling us something. So it likes the voltage/connection from the battery but not from the blue field wire even though you said you had 13.5V at that point. I believe you said you bypassed the ballast resistor. I'd say to try to find another switched 12V source but you have to find one that is not shut down by the momentary start position of the ignition switch. I'm sure someone will know where to find such a source. Also, if that ignition module is mounted on the distributor it will need to have a good ground as shown.
camoman22
Well-Known Member
I ran a wire from acc terminal at fuse box to coil and got the same results of missing . was wondering about the bulk head connector?
ign module is mounted on firewall with ground wire running to engine. Also remember it only misses when car reaches temperature. with all things turned on during
warm up it rev's smooth. My Gut says ground... not familiar with rfi that much.
Really appreciate you guys responding. My Dad was a electrician by trade so I understand most of the 12v system.
What get me is steady 13.5 vdc at coil wire 3000 rpm engine snaps and cracks.
Shorthorse
Well-Known Member
I always believe that the first thing you do with an electrical problem is check all grounds. The goofier the problem, the more likely it is a ground. I have to admit, you have reached the end point of my very limited knowledge. There are members here that are smart and have excellent input. Good luck, don't get frustrated and please keep us informed.
Glenwood
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Have you pulled the bulkhead connector to inspect? If the terminals are showing signs of overheating, corrosion, black/pitting, etc, you will have voltage drop across those connections. I'm not familiar with HEI coils or the ign module you are using, but it or the dist pick-up may be sensitive to voltage fluctuations. Voltage fluctuations are very difficult to read with a voltmeter because they can be happening so fast.
I was thinking about the AC clutch. The AC compressor clutch usually turns on and off as it cycles, depending on temperature, etc., and is applying additional load to the engine. This cycling causes fluctuations as the voltage will dip momentarily when the clutch comes on and spikes when it releases. With all devices on, this fluctuation could disturb the charging system and perhaps the alternator cannot react fast enough. If the voltage regulator is a constant voltage type, maybe it is not suited for this combination? Do HEI type ignition have additional filtering or capacitors to help regulate voltage? Just food for thought.
I was thinking about the AC clutch. The AC compressor clutch usually turns on and off as it cycles, depending on temperature, etc., and is applying additional load to the engine. This cycling causes fluctuations as the voltage will dip momentarily when the clutch comes on and spikes when it releases. With all devices on, this fluctuation could disturb the charging system and perhaps the alternator cannot react fast enough. If the voltage regulator is a constant voltage type, maybe it is not suited for this combination? Do HEI type ignition have additional filtering or capacitors to help regulate voltage? Just food for thought.
Shorthorse
Well-Known Member
In post #20 you said "So I ran wire from battery to coil. started car turned all things on and it ran fine.". That's a big clue.
camoman22
Well-Known Member
I will look into bulkhead as soon as I can . I will report back.
camoman22
Well-Known Member
Ok I just want to let everyone know I found the problem. It was the battery. I think someone
mention it in the beginning. The car would start fine so I assumed..... yea I Know. Many thanks
for all the reply's and help. You guys are the best! Have a nice Christmas Maybe Santa will put a HEMI under the tree for ya!
Camoman
mention it in the beginning. The car would start fine so I assumed..... yea I Know. Many thanks
for all the reply's and help. You guys are the best! Have a nice Christmas Maybe Santa will put a HEMI under the tree for ya!
Camoman
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