Power Loss
Thread Starter
Cruising
Joined: Aug 2007
Posts: 10
Likes: 0
Power Loss
I have a 1986 4+3 with 60,000 miles. The car was running fine with a quarter of a tank of fuel when I stopped to fill the tank. After about 15 miles on the interstate the car started a slight hesitation. The car steadily lost power for the next 20 miles until it was difficult to keep it at 40 mph. The engine barely idles and is real rough. As rpms go up the engine is very sluggish.
The following were tested:
-Coil tested ok
-Pick up coil tested ok
-All plugs are new and firing
-Spark plug wires are new and ok
-Compression on each cylinder ranged from 155 to 160
-New Fuel pump flow tested at 24 ounces in 15 seconds
-Fuel pressure at 42 with engine running
-Fuel injector ohm test showed all injectors at 16.5 - 16.6
-ECM was replaced with no change in engine performance
-Tested ECM output for injectors and both 1-3-5-7 and 2-4-6-8 tested at 12 volts with the switch on and 13.8 with the engine running.
-Air filter is new and unobstructed
-New MAF installed about 600 miles ago
-Distributor cap and rotor have about 1,000 miles on them
-Ignition module has about 1,000 miles on it
-Gas tank was drained and refueled with new fuel. Tank was clean.
-No error codes are showing
Two other things were identified. There is no fuel pressure with the switch on and it does not build up until the engine is started. Each spark plug wire was removed one at a time at 1500 rpms (and then replaced), and there was no decrease in rpms when plug wires 2,4,6 and 8 were removed. There was a decrease of about 300 rpms for plug wires 1,3,5 and 7.
Any suggestions?
The following were tested:
-Coil tested ok
-Pick up coil tested ok
-All plugs are new and firing
-Spark plug wires are new and ok
-Compression on each cylinder ranged from 155 to 160
-New Fuel pump flow tested at 24 ounces in 15 seconds
-Fuel pressure at 42 with engine running
-Fuel injector ohm test showed all injectors at 16.5 - 16.6
-ECM was replaced with no change in engine performance
-Tested ECM output for injectors and both 1-3-5-7 and 2-4-6-8 tested at 12 volts with the switch on and 13.8 with the engine running.
-Air filter is new and unobstructed
-New MAF installed about 600 miles ago
-Distributor cap and rotor have about 1,000 miles on them
-Ignition module has about 1,000 miles on it
-Gas tank was drained and refueled with new fuel. Tank was clean.
-No error codes are showing
Two other things were identified. There is no fuel pressure with the switch on and it does not build up until the engine is started. Each spark plug wire was removed one at a time at 1500 rpms (and then replaced), and there was no decrease in rpms when plug wires 2,4,6 and 8 were removed. There was a decrease of about 300 rpms for plug wires 1,3,5 and 7.
Any suggestions?
Burning Brakes
Joined: Dec 2006
Posts: 936
Likes: 2
From: Tyrone PA
I have a 1986 4+3 with 60,000 miles. The car was running fine with a quarter of a tank of fuel when I stopped to fill the tank. After about 15 miles on the interstate the car started a slight hesitation. The car steadily lost power for the next 20 miles until it was difficult to keep it at 40 mph. The engine barely idles and is real rough. As rpms go up the engine is very sluggish.
The following were tested:
-Coil tested ok
-Pick up coil tested ok
-All plugs are new and firing
-Spark plug wires are new and ok
-Compression on each cylinder ranged from 155 to 160
-New Fuel pump flow tested at 24 ounces in 15 seconds
-Fuel pressure at 42 with engine running
-Fuel injector ohm test showed all injectors at 16.5 - 16.6
-ECM was replaced with no change in engine performance
-Tested ECM output for injectors and both 1-3-5-7 and 2-4-6-8 tested at 12 volts with the switch on and 13.8 with the engine running.
-Air filter is new and unobstructed
-New MAF installed about 600 miles ago
-Distributor cap and rotor have about 1,000 miles on them
-Ignition module has about 1,000 miles on it
-Gas tank was drained and refueled with new fuel. Tank was clean.
-No error codes are showing
Two other things were identified. There is no fuel pressure with the switch on and it does not build up until the engine is started. Each spark plug wire was removed one at a time at 1500 rpms (and then replaced), and there was no decrease in rpms when plug wires 2,4,6 and 8 were removed. There was a decrease of about 300 rpms for plug wires 1,3,5 and 7.
Any suggestions?
The following were tested:
-Coil tested ok
-Pick up coil tested ok
-All plugs are new and firing
-Spark plug wires are new and ok
-Compression on each cylinder ranged from 155 to 160
-New Fuel pump flow tested at 24 ounces in 15 seconds
-Fuel pressure at 42 with engine running
-Fuel injector ohm test showed all injectors at 16.5 - 16.6
-ECM was replaced with no change in engine performance
-Tested ECM output for injectors and both 1-3-5-7 and 2-4-6-8 tested at 12 volts with the switch on and 13.8 with the engine running.
-Air filter is new and unobstructed
-New MAF installed about 600 miles ago
-Distributor cap and rotor have about 1,000 miles on them
-Ignition module has about 1,000 miles on it
-Gas tank was drained and refueled with new fuel. Tank was clean.
-No error codes are showing
Two other things were identified. There is no fuel pressure with the switch on and it does not build up until the engine is started. Each spark plug wire was removed one at a time at 1500 rpms (and then replaced), and there was no decrease in rpms when plug wires 2,4,6 and 8 were removed. There was a decrease of about 300 rpms for plug wires 1,3,5 and 7.
Any suggestions?
Pro
Joined: May 2002
Posts: 541
Likes: 2
From: Kalama WA
How about a new fuel filter???? You should hear fuel pump run when ignition is turned on. Check at fuel rail- you should see pressure. Hook up fuel pressure gauge at rail and run the car. A new fuel pump does not mean a good working fuel pump.
