89 5.0 firing on left bank only. Need ideas

Fireriders

Member
Mar 27, 2020
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2
13
Long Island, NY
Hey all. Have one last issue with the motor I'm working on. All the other issues I had were resolved with a new (rebuilt) computer except this one. Engine starts but runs only on the left bank cylinders. 5,6,7 and 8 are firing and running. 1,2,3 and 4 I get nothing. Exhaust ports are ice cold. Checked spark and it's very weak on all four of the cylinders in the right bank. Any ideas out there as to what would be causing this issue? I'm about out of ideas. Thanks for any help and ideas.
 
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90sickfox

I didn't really have an issue with the stink...
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That's weird having weak spark on one bank. These cars aren't set up like that. Firing order isn't split like that either. The only logical thing could be the injector harness...maybe the 10 pin salt and pepper connectors at the back of the intake. They have nothing to do with spark though.

Spark energy comes from the coil. That thing doesn't have a variable power output. It gets a signal and fires to the center of the cap. The cap just sends that energy to the tip of whatever wire the rotor button is pointing at.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Have you inspected the cap? Could be wet or cracked on one side.
Totally unusual for one side of the engine to have issues. Are the plug wires hung and separated with care?
 

Fireriders

Member
Mar 27, 2020
18
2
13
Long Island, NY
Have you inspected the cap? Could be wet or cracked on one side.
Totally unusual for one side of the engine to have issues. Are the plug wires hung and separated with care?
Cap is a brand new MSD but who knows with the crap they make today. I ordered a new Accell distributor and will post when it arrives and is installed.
 

Fireriders

Member
Mar 27, 2020
18
2
13
Long Island, NY
That's weird having weak spark on one bank. These cars aren't set up like that. Firing order isn't split like that either. The only logical thing could be the injector harness...maybe the 10 pin salt and pepper connectors at the back of the intake. They have nothing to do with spark though.

Spark energy comes from the coil. That thing doesn't have a variable power output. It gets a signal and fires to the center of the cap. The cap just sends that energy to the tip of whatever wire the rotor button is pointing at.
I thought about that so I sprayed starting fluid in the intake just to see if it would be a fuel issue. Not even a backfire out of the right bank. Should have gotten some kind of reaction feeding ether into it. I ordered a distributor and will post with any news after that. Just out of curiosity does the ECM I just got rebuilt have anything to do with firing the plugs?
 

Fireriders

Member
Mar 27, 2020
18
2
13
Long Island, NY
That's weird having weak spark on one bank. These cars aren't set up like that. Firing order isn't split like that either. The only logical thing could be the injector harness...maybe the 10 pin salt and pepper connectors at the back of the intake. They have nothing to do with spark though.

Spark energy comes from the coil. That thing doesn't have a variable power output. It gets a signal and fires to the center of the cap. The cap just sends that energy to the tip of whatever wire the rotor button is pointing at.
Ordered a new Accell distributor just to eliminate it from the mix. Will post with results. Thanks for the input also.
 
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90sickfox

I didn't really have an issue with the stink...
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Mar 2, 2015
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The ECM does but it would be an issue that affected all the cylinders. The computer controls timing by pulsing the coil according to what phase it wants the rotor to be in. The pickup below the rotor button tells the computer what cylinder the rotor is pointing at. It then calculates where timing should be and simultaneously fires the injector on that cylinder according to its programmed strategy. Anything dealing with spark or timing should affect all cylinders.

Just one bank is really unusual. The injector harness could affect one bank. The computer circuitry could affect one bank but even then it would affect at least one cylinder of the opposite bank.

20200529_193507.jpg
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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polk county florida
This may sound strange but give us a pic of the distributor with the wires connected and laid out so we can see what
spark plugs they are connected to.
 

Fireriders

Member
Mar 27, 2020
18
2
13
Long Island, NY
Ordered a new Accell distributor just to eliminate it from the mix. Will post with results. Thanks for the input also.
OK all. I Got the new Accell distributor and decided to run it one more time before installing the accell. Ran very badly again. Checked all the exhaust tubes and 3 were actually hot on the left and one on the right side. Installed the new distributor said a prayer and turned the key. Purrs like a kitten. All cylinders are firing. No smoke no shake just running. I took the old distributor popped off the cap and took a good look. You couldn't tell when it was in the motor but on real close inspection with a bright flashlight I found the issue. It was rusted and corroded beyond belief. When I turned it upside down all kinds of crap came out including small parts of the trigger wheel. Living on an island a stone's throw from the Atlantic Ocean on one side and the Long Island Sound on the other salt air took its toll. I would like to thank everyone for the help and ideas.
 
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mikestang63

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OK all. I Got the new Accell distributor and decided to run it one more time before installing the accell. Ran very badly again. Checked all the exhaust tubes and 3 were actually hot on the left and one on the right side. Installed the new distributor said a prayer and turned the key. Purrs like a kitten. All cylinders are firing. No smoke no shake just running. I took the old distributor popped off the cap and took a good look. You couldn't tell when it was in the motor but on real close inspection with a bright flashlight I found the issue. It was rusted and corroded beyond belief. When I turned it upside down all kinds of crap came out including small parts of the trigger wheel. Living on an island a stone's throw from the Atlantic Ocean on one side and the Long Island Sound on the other salt air took its toll. I would like to thank everyone for the help and ideas.
Glad that worked.
 
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