Ignition Question, My diaphragm was cracked--still not Prego! Options

[Robarabian]

Collective brain trust help needed.

Car is a 1971 1.7. Finished my rebuild, now 1911 CC's. (ECU non adjustable)

Car runs a Pertronix Ignition. Distributor was disassembled, cleaned and re-lubed.

Static timed the car and started it, and ran it for about 18 minutes at 2500-3000 rpm to break in the cam and rings. Did my oil change and then it sat for a few weeks.

Started it to finally set the timing and it started running rough, and I can tell it is on 3 cyl, sometimes 4, and spits, coughs etc. I know it isn't timed right and cant time it until it is on 4 cylinders.

Fuel pressure on an inline gauge is at 30 psi.

Pulled #1 and #2 plugs, they are the right color.

Pulled #3 and #4 and they are wet, and have remnants of being the right color from the cam break in.

Checked all the connections, but don't quite know where to start. The trigger points were clean in the distributor when I disassembled it, and it ran right for cam break in.

Cap, rotor, plugs, wires are all new. MPS holds vacuum.

Thoughts on what I am missing here or where would you start digging first.

I thank you in advance.

[emerygt350]

I would suspect a lean condition at cold start. Is the aux air regulator functional and is the cold start valve doing it's thing? Sounds like the csv is working since it runs for a sec. Perhaps try to get the timing closer to where it should be? If it won't idle I suspect it is retarded,. I would plug any vacuum lines going to it for the moment. Just while you are trying to get the timing set and idle going.

Since you bumped it up to a 2.0 you may want to add the inline resister to your cht. You can just make your own, I think it's 220ohms or something like that. You can Google it. Pbanders has the numbers on his djet site. As long as you have the 2.0 injectors, and the resistor, you should be able to tune that mps to your new displacement with an afr and a kit from tangerine racing. Others that have bumped up a 1.7 will know for sure. If it is running lean I would not try to drive it.

[Robarabian]

I have a spare AAR somewhere, I will clean and test that and swap them out.

Ill take a look at Pbanders and see if I can figure that out.

Anyone have any other ideas while I am digging around?

I would suspect a lean condition at cold start. Is the aux air regulator functional and is the cold start valve doing it's thing? Sounds like the csv is working since it runs for a sec. Perhaps try to get the timing closer to where it should be? If it won't idle I suspect it is retarded,. I would plug any vacuum lines going to it for the moment. Just while you are trying to get the timing set and idle going.

Since you bumped it up to a 2.0 you may want to add the inline resister to your cht. You can just make your own, I think it's 220ohms or something like that. You can Google it. Pbanders has the numbers on his djet site. As long as you have the 2.0 injectors, and the resistor, you should be able to tune that mps to your new displacement with an afr and a kit from tangerine racing. Others that have bumped up a 1.7 will know for sure. If it is running lean I would not try to drive it.

[mgphoto]

I have a spare AAR somewhere, I will clean and test that and swap them out.

Ill take a look at Pbanders and see if I can figure that out.

Anyone have any other ideas while I am digging around?

I would suspect a lean condition at cold start. Is the aux air regulator functional and is the cold start valve doing it's thing? Sounds like the csv is working since it runs for a sec. Perhaps try to get the timing closer to where it should be? If it won't idle I suspect it is retarded,. I would plug any vacuum lines going to it for the moment. Just while you are trying to get the timing set and idle going.

Since you bumped it up to a 2.0 you may want to add the inline resister to your cht. You can just make your own, I think it's 220ohms or something like that. You can Google it. Pbanders has the numbers on his djet site. As long as you have the 2.0 injectors, and the resistor, you should be able to tune that mps to your new displacement with an afr and a kit from tangerine racing. Others that have bumped up a 1.7 will know for sure. If it is running lean I would not try to drive it.

At this point your issue I believe is a combination of timing and fuel mixture.
Your MPS is not calibrated for the increase in displacement. The Tangerine Racing kit with an AFR meter is necessary for dialing in the correct mixture.
The non adjustable ECU creates an additional problem for idle.
For the timing I would try to adjust it for a smooth idle first.
This takes 2 people to accomplish, with someone turning the key and operating the throttle and someone else turning the distributor.
As the starter is engaged rotate the distributor clockwise and then counter clockwise looking for the sweet spot where the engine fires, keeping the engine running by feathering the throttle keep making very small adjustments to the distributor looking for the smoothest idle, also using the air bypass screw on the throttle body. Because of the displacement increase this will be a lean condition.
You will need to adjust your MPS to correct the fuel mixture, as a bandaid you could try the resistor added to the head temp sensor but you will be guessing at the value.
I believe the resistance is 270 ohms 1/4 watt but this is for a ‘73 2.0 with a 1.7 ECU.
I would not run a new engine in a lean condition.
I think the MPS kit is the way to go.

Additionally don’t worry about the cold start or AAR, you are in California these are not a factor in your climate.