Stumped with backfire from carburator
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Re: Stumped with backfire from carburator
Does anyone else see some detonation flecks on those plugs in the last photo? And does the strap look like maybe there's too much timing?
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Re: Stumped with backfire from carburator
When I looked at the video I could tell that you painted the engine components separately and then bolted everything together. Is it possible that you applied paint to the spark plug thread area inadvertently? Try a thread chaser and use the material below:
Post by Warp Speed » Fri Jun 18, 2010 12:21 pm. We use Coposlip high temp anti-sieze on the threads of all of our spark plugs. We have done extensive testing with Bosch on this, and this is about the only lube that provides the best grounding and temp transfer, while still providing the needed lubrication
https://www.semasan.com/breaking-news-archives?utm_campaign=DrivingForce_DF272&utm_content=SeeAllLeg
Re: Stumped with backfire from carburator
White mist from carb after shut off means that carb is boiling. Are you using mechanical or electric fuel pump? With mechanical you are lean at start as carb is boiled it's fuel off.
Re: Stumped with backfire from carburator
Mechanical fuel pump. Have a 1/2” phenolic spacer. Bowls are not hot to the touch
Re: Stumped with backfire from carburator
Bowls stay cool as long as there's fuel to evaporate. Bowl can also leak and fuel is evaporating in intake.
If you cut ignition off and start few seconds to fill up bowl and start then you see if problem is empty carb.
Re: Stumped with backfire from carburator
After you shut it off, look down into the carb and see if its leaking around the squirters.
Re: Stumped with backfire from carburator
No fuel leaking past the squirters. But I am looking into the fuel system carefully.
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Re: Stumped with backfire from carburator
In one of your videos there are momentary glimpses of the spark plug wires to the 2-4-6-8 bank being ziptied together and run parallel and in direct contact with each other for an extended distance. This could cause spark loss as the wire intended to fire is inducing a current in a parallel wire or wires. Spark loss could help explain why unburned fuel is being aspirated from the carb.huero wrote:Idles nice, engine revs nice but on start up (cold or warm) the engine backfires out of the carb. No fire just fuel. Ignition can be set anywhere from 12-18 btdc and the engine reacts the same.
Try separating the wires.
Kevin Johnson wrote: ↑Sun Apr 01, 2018 1:44 am When I looked at the video I could tell that you painted the engine components separately and then bolted everything together. Is it possible that you applied paint to the spark plug thread area inadvertently? Try a thread chaser and use the material below:
Post by Warp Speed » Fri Jun 18, 2010 12:21 pm. We use Coposlip high temp anti-sieze on the threads of all of our spark plugs. We have done extensive testing with Bosch on this, and this is about the only lube that provides the best grounding and temp transfer, while still providing the needed lubrication
https://www.semasan.com/breaking-news-archives?utm_campaign=DrivingForce_DF272&utm_content=SeeAllLeg
Re: Stumped with backfire from carburator
I will work on separating the wires. I thought insulation on modern wires was sufficient. Thank u
Re: Stumped with backfire from carburator
Non-conductive insulation doesn't suppress radio frequency interference. The magnetic field around one secondary wire can induce voltage in another if it runs parallel to the first.
Felix, qui potuit rerum cognscere causas.
Happy is he who can discover the cause of things.
Happy is he who can discover the cause of things.
Re: Stumped with backfire from carburator
Separated wires, still coughing. Talked to my carb builder. It maybe the carb. I’ll fill everyone in when I get an update.
Re: Stumped with backfire from carburator
Gentlemen, we found the problem!!!!!!!! Actually, my carb builder did.
And I am so mad I could not find such a simple error.
The car is a 56 Chevy and it was originally wired with points and ballast resistor (separate wires). I had a switched 12V wire source to the distributor but not a 12V ignition switched and ignition crank source!!!!
So there was no voltage going to the distributor when cranking the engine over!! I am so upset that I could not diagnose the problem and chased my tail for so long!
I want to thank everyone that tried to help. I feel so foolish. I am new to tri-fives and didn't realize how they were wired. Now I have to find out how to wire the distributor to the ignition switch as it appears there is no 12V run and crank wire. They are separate wires.
Does anyone know if I can join these two wires together and feed it to the distributor + terminal and not damage the distributor? Is this safe?
Thank you all again.
I am so glad this is over!!!
And I am so mad I could not find such a simple error.
The car is a 56 Chevy and it was originally wired with points and ballast resistor (separate wires). I had a switched 12V wire source to the distributor but not a 12V ignition switched and ignition crank source!!!!
So there was no voltage going to the distributor when cranking the engine over!! I am so upset that I could not diagnose the problem and chased my tail for so long!
I want to thank everyone that tried to help. I feel so foolish. I am new to tri-fives and didn't realize how they were wired. Now I have to find out how to wire the distributor to the ignition switch as it appears there is no 12V run and crank wire. They are separate wires.
Does anyone know if I can join these two wires together and feed it to the distributor + terminal and not damage the distributor? Is this safe?
Thank you all again.
I am so glad this is over!!!
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Re: Stumped with backfire from carburator
That makes perfect sense. I did a couple of Tri-5s and we often swapped out the ignition switch to get cranking power. It'd basically try to fire as you released the keyhuero wrote: ↑Tue Apr 03, 2018 6:44 pm Gentlemen, we found the problem!!!!!!!! Actually, my carb builder did.
And I am so mad I could not find such a simple error.
The car is a 56 Chevy and it was originally wired with points and ballast resistor (separate wires). I had a switched 12V wire source to the distributor but not a 12V ignition switched and ignition crank source!!!!
So there was no voltage going to the distributor when cranking the engine over!! I am so upset that I could not diagnose the problem and chased my tail for so long!
I want to thank everyone that tried to help. I feel so foolish. I am new to tri-fives and didn't realize how they were wired. Now I have to find out how to wire the distributor to the ignition switch as it appears there is no 12V run and crank wire. They are separate wires.
Does anyone know if I can join these two wires together and feed it to the distributor + terminal and not damage the distributor? Is this safe?
Thank you all again.
I am so glad this is over!!!
I cannot remember for the life of me why we didn't just pick up off the solenoid, but there must have been a reason
Bullock's Power Service, LLC
Plattsmouth, NE
70 Mustang, 489 FE, TKO-600, Massflo SEFI, 4.11s
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Plattsmouth, NE
70 Mustang, 489 FE, TKO-600, Massflo SEFI, 4.11s
71 F100 SB 4x4, 461 FE, 4 speed, port injected EFI, 3.50s
Re: Stumped with backfire from carburator
On a 55-56 Chevy ignition switch you have to run a small jumper from ign1 - ign2 if you eliminate the ballast resistor, Chevy trifive.com for an original wiring diagram for a 56, you'll see how they wired it.
Re: Stumped with backfire from carburator
Done!! I actually wired it using a relay. To not stress the original old wiring. Car fires right up every time!!! Thank you all!