Why does my engine pop threw the intake when revved

Tiny
ALEXMUNOZ
  • MEMBER
  • 1988 FORD MUSTANG
  • 160,000 MILES
My 88 mustang 5.0 pops when u rev the engine. The popping comes from where the air filter goes connected, the intake. New wire, plugs.
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Friday, August 10th, 2012 AT 2:55 AM

9 Replies

Tiny
MHPAUTOS
  • MECHANIC
  • 31,938 POSTS
Your ignition leads correct position? It sounds like a flat cam or broken valve spring here is a guide that can help.

https://www.2carpros.com/articles/engine-backfires-while-running

Please run down this guide and report back

Cheers
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Friday, August 10th, 2012 AT 3:18 AM
Tiny
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I think they are. Except when I put the wire in firing order it doesn't work. I have to switch them backwards. Instead of it being 4 8 it is 1 5 why is that.
3 7. 2 6
2 6. 3 7
1 5 4 8
Front of engine
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Friday, August 10th, 2012 AT 5:08 AM
Tiny
MHPAUTOS
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Check the firing order with this pic.
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Friday, August 10th, 2012 AT 8:00 AM
Tiny
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I've tried it. It's doesn't work. On the engine I have to put the wire backwards. I have to put wire 1 to 4 and 4 to one and 2 to 3and 3 to 4 same on the other side. Never seen anything like this on a car before. My number 1 starts at the fire wall and four is in the front and 5 is by the Dr fire wall. And 8 is in the front
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Friday, August 10th, 2012 AT 10:17 PM
Tiny
CAROLINACARCONNECTION
  • MECHANIC
  • 66 POSTS
If it were me id pull the number one spark plug out and put the motor to top dead center on compression stroke, you can find out if it is compression stroke using a compression gauge. Once on top dead center number 1. Pull your distributor cap off and see if the rotor is pointing towards number one wire. If not you need to pull out the distributor and reset it correctly and then wire it like the diagram shows.
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Saturday, August 11th, 2012 AT 12:32 AM
Tiny
MHPAUTOS
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The distributor is 180Deg out, what you need to do is remove plugs and coil lead, turn engine by hand and feel for compression on #1 cylinder, check timing mark and turn engine till pointer is at around 10deg BTDC remove distributor and re position so rotor is as shown in pic, re fit leads as shown, this should be close enough to start and re time with timing light.
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Saturday, August 11th, 2012 AT 12:34 AM
Tiny
CAROLINACARCONNECTION
  • MECHANIC
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The reason I said this is because it sounds like someone along the line installed the distributor incorrectly and arranged the wires to make it work. The only other thing that it could be is intake valve train problems. Was it running ok before the tune up?
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Saturday, August 11th, 2012 AT 12:37 AM
Tiny
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I finally looked at the guide you sent and you were right the camshaft has a flat lob :( Looks like I will be going HP
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Thursday, September 13th, 2012 AT 4:36 PM
Tiny
RIVERMIKERAT
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Good to hear, please use 2CarPros anytime we are here to help.

Cheers, Ken
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Thursday, September 13th, 2012 AT 4:50 PM

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