Hi I am chasing some help and thoughts on a current motor issue.

Currently running a mopar engine. When motor is above 3000rpm the motor start popping and stumbles for power.

Battery voltage is 12.8 volts
Currently we have tried the following with no resolution

Changed the battery
Changed the ignition leads
We identified some issues with the wiring harness so we replaced this also.

We are considering changing the crank triggers which is not an issue but would appreciate if others may provide feedback if you have experienced similar issue. Issue sound electrical but we are not so sure now and weighing thoughts around a fuel issue.

Appreciate any thoughts you wish to share.

Regards
Phil

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Had a similar issue last year and it ended up being a intermittently failing fuel pressure regulator.

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You might swap the coil out as well if you have a spare one around. Do you have a fuel pressure gauge so you can verify it stays consistent.

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You might also try checking your barrel valve and making sure it's set properly,I had the linkage arm slip one time thus throwing the settings off and making the motor pop and stumble when giving it throttle.

Is this a MoPAR Midget Motor? If so, is it a Sesco Style with MSD or does it have a Standard Block?

More information on your motor.what are you running for injection

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Motor is a midget motor
MSD ignition
Standard mopar block.

Thanks for your feed back so far. Really appreciated.

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Clear out any spikes in the box. Also, ditch the spark plugs and throw in a new set.

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Phil if you have had a battery fall below 10.8 volts while the engine is running you will almost certainly see that the ignition curve has gone haywire. It will now look like a heart rate monitor.

You can check you sensors with an ohm meter. Disconnect one and put a ohm meter lead on each pin. You should have between 100-130 ohms. While you are checking them wriggle the wires around as well to see If that effects it. Then do the same for the other sensor.

Also check the sensor tip has not been damage by a rock or anything. Gap between the sensor and the wheel should be .060"-.080".

If you have any questions or are unsure of anything let me know I will give you my number and go through it with you.

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Not sure if we have solved the issue yet. Started going through the fuel system today and found the S valve jammed up and not opening properly. Engine start tomorrow.

Thanks for help so far. Has been a huge help.

Thanks

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