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89 5.0 firing on left bank only. Need ideas

  • Thread starter Thread starter Fireriders
  • Start date Start date May 28, 2020
F

Fireriders

Member
Mar 27, 2020
18
2
13
Long Island, NY
May 28, 2020
#1
  • May 28, 2020
  • #1
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.
 

mikestang63

SN Certified Technician
Aug 27, 2012
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In the garage
May 28, 2020
#2
  • May 28, 2020
  • #2
What distributor are you running and do you have a spare to swap in.
 

90sickfox

Wasn't a pretty sight...and I've got big hands
SN Certified Technician
Mar 2, 2015
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May 28, 2020
#3
  • May 28, 2020
  • #3
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
20+ Year Stangneter
Aug 25, 2016
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May 28, 2020
#4
  • May 28, 2020
  • #4
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?
 
E

Espo720

Member
May 4, 2016
55
2
8
May 28, 2020
#5
  • May 28, 2020
  • #5
I’m goin with 90sickfox on this one. Maybe ya got a fueling issue
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,949
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polk county florida
May 28, 2020
#6
  • May 28, 2020
  • #6
I agree it's worth checking out.
 
F

Fireriders

Member
Mar 27, 2020
18
2
13
Long Island, NY
May 29, 2020
#7
  • May 29, 2020
  • #7
mikestang63 said:
What distributor are you running and do you have a spare to swap in.
Click to expand...
Running stock but just ordered a new Accell distributor. Will find out when it gets here. Will post results.
 
F

Fireriders

Member
Mar 27, 2020
18
2
13
Long Island, NY
May 29, 2020
#8
  • May 29, 2020
  • #8
General karthief said:
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?
Click to expand...
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.
 
F

Fireriders

Member
Mar 27, 2020
18
2
13
Long Island, NY
May 29, 2020
#9
  • May 29, 2020
  • #9
90sickfox said:
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.
Click to expand...
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?
 
F

Fireriders

Member
Mar 27, 2020
18
2
13
Long Island, NY
May 29, 2020
#10
  • May 29, 2020
  • #10
90sickfox said:
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.
Click to expand...
Ordered a new Accell distributor just to eliminate it from the mix. Will post with results. Thanks for the input also.
 
Reactions: 90sickfox

90sickfox

Wasn't a pretty sight...and I've got big hands
SN Certified Technician
Mar 2, 2015
6,945
5,816
213
May 29, 2020
#11
  • May 29, 2020
  • #11
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.

 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,949
10,587
203
polk county florida
May 29, 2020
#12
  • May 29, 2020
  • #12
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.
 
F

Fireriders

Member
Mar 27, 2020
18
2
13
Long Island, NY
Jun 4, 2020
#13
  • Jun 4, 2020
  • #13
Fireriders said:
Ordered a new Accell distributor just to eliminate it from the mix. Will post with results. Thanks for the input also.
Click to expand...
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.
 
Reactions: 90sickfox

mikestang63

SN Certified Technician
Aug 27, 2012
11,606
8,859
214
In the garage
Jun 4, 2020
#14
  • Jun 4, 2020
  • #14
Fireriders said:
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.
Click to expand...

Glad that worked.
 
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