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Ram Jet 350 - Plugs fouling

1719 Views 5 Replies 5 Participants Last post by  roger1
I have installed a Ram Jet 350 in my 1957 Chevy. It was running great (never left the garage) and all of the sudden it started running lousy. I pulled a couple of plugs and found them to be loaded with black soot. I took them all out and cleaned them, put them back in and the engine started right back up.

I thought that they fouled because I was only running in the garage. So I didn't run it much until I was ready to take it on the road. I finally took it around the block 2 times. It ran great. While backing it back into the garage, it started running loosely again. I pulled a couple more plugs and found them to be loaded with black soot again.

Has anyone had experience with this?
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Could be a problem with the cold start kicking in. Or, it may be a problem w/ the O2 sensor.
A bad ground will make it a nitemare to identify.. BE SURE all grounds are 100%.
Fuel pressure is?
Do you have a way to scan it?

Adding: Exhaust leaks????
It sounds like it's not getting into closed loop. The ECM has to sense the ECT (engine coolent temperature) is high enough to go into closed loop. Make sure the temp sensor is plugged in good. The resistance between the pins with the wire unplugged, when at operatering temperature, is about 240 ohms. If the resistance is more than that, the sensor may be bad.
You could also have air in the cooling system. causeing innacurate readings. Does the temp gauge fluctuate?
A problem I had with mine, the plug wires would not seat on the distributor posts, because the boots were too long. Caused rough running and fouling the plugs.
Not the first time I've seen a problem post on these boards with the coolant temp sensor or wiring on a Ram Jet. It's the first place I'd check. If the ecm thinks the water temp is cold, it's going to put fuel in it just like a carb with the choke always on. Just seems like the most logical problem it could be.
This is probably not it but a possibility.

Could your gas be old? Did it sit in the tank only partially full? If it's E10, it could be separating on you.
Keep us updated CW.

I have a RamJet but I have never fired it up yet. I'm still a few months away from being ready to do that.
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