After replacing the choke and check engine bulbs I notice the choke light comes one occasionally while stopping. The choke should one come on when the engine is cold according to the manual yet the light is never on when I crank it up and it's cold

 

Back to code 41. What exactly are distributor reference pulses? After much reading it says the information comes from the ignition coil. If the ignition coil was bad the car would turn over but not run right?

I think I will check the distributor electrical connections this weekend. It is day 2 with no stalls.

 

More reading shows the vehicle shouldn't run at all if it's not receiving distributor pulses. I can check vacuum hoses. Has anyone fixed this code with a specific repair?

 

You going to need a manual, just because someone fixed a code one time does not mean that is what is wrong with your car.

Code 41 has other meanings besides no reference pulse because code 12 is no reference pulse and it is an unstored code. If you turn your key on without starting your car your check engine lite comes on. That is code 12. As soon as it starts code 12 goes away.

The full description of the code is:
EST (Electronic Spark Timing)
circuit failure – no distributor pulses OR cylinder select error OR
Tachometer input error.

Yes, without a distributor pulse you are dead in the waters. As you can see in this description you could have other things going on and also you can have an intermittent issue, meaning the issue may only happen a few seconds every 5th day. If you clear the code how quickly does it come back?

 

The code comes back immediately as soon as it's cranked. I've been thinking about the MAP or differential pressure sensor as it is called on carburetor models. Working on day 7 with no stalls but the vehicle doesn't accelerate as it should. It goes if you baby it but if you attempt to accelerate to quickly it stalls. I don't like it stalling so I haven't been doing that.

 

Why would you think MAP? The engine would feel a little gut less as the car retards the timing because of the spark knock. A fuel injected car with a bad Map sensor will make a car stall on acceleration but a computer controlled carb should take off until it runs out of the accelerator pump fuel then lean out but not stall.

That circuit has nothing to do with your 41 code? The manual should have a trouble tree, Check this- If/then No need to guess.

You could also have a combination of issues. like a bad ignition module and a failing accelerator pump. If you are stalling the car it is most likely a carb issue or you are dropping spark. You could also disconnect the carb connector and see if the issue is still there.

This is going way back for me but I think I used to use a dewell meter and watch the O2 senors to see if the metering rods where working right and to see if the computer was telling to do the right thing.

 

I need a code 41 flow chart for an 87 camaro 5.0L v8 carbureted. I looked all in my Haynes manual and no flow charts are present and the ones if find online are 5.7L v8 engines but they say nothing about vehicle type.

I want to work through this problem systematically without wasting money if I can help it.

Tomorrow I plan to reset the trouble codes and check once again if it re-appears. The vehicle gets me back and forth to work fine. I just want to get it working with no check engine light.

Thanks for any help

 

Worked on the car more today. I found a cracked vacuum hose and was able to cut it back and re-attach. I also found a vacuum hose that wasn't connected flush with the carburetor and fixed that. Still not helping my code 41 but it drives back and forth to work fine except for the occasional hesitation. No stalling in more than a week.

There is a device at the back of the carburetor that connects via hoses to the engine manifold. There is a small piece of hose, the device, and then another hose going to the top of the manifold. It is not the PCV valve but I think it has something to do with crankcase ventilation, it must be some type of filter. I am going to keep studying.

 

Have you search for the GM manual PDF? I used to have all the 80's GM manual until my sump pump went out and my basement flooded.

GM trouble trees are the best but they do assume you have all GM required special tools. Back in the day they did use volt meters a lot more then today. Full diagnoses systems did not start showing up at the dealers until late 80's and where not required till the 90's due to costs.