ggzilla Posted June 28, 2014 Report Share Posted June 28, 2014 For some reason I am starting to think its an ignition problem. What do you guys think?? Yes, perhaps. What are the symptoms again? Easy troubleshooting of the dual-coil 720 is to swap the coils, and if it runs better you know one coil is bad. Quote Link to comment
Flailguy Posted June 28, 2014 Author Report Share Posted June 28, 2014 I replaced the o2 sensor last night. It looked factory. Rough idle, loss of power when I start to let out clutch in first gear. When you say swap coils do you mean just the coil to distributor wires? Quote Link to comment
datzenmike Posted June 28, 2014 Report Share Posted June 28, 2014 Normally both coils are firing at all times and together so swapping coils won't do much as either they are both firing or one side isn't still. Crank and check that both coils are firing. For now, good enough if they are. If the exhaust isn't, replace the fuse on the far left side of the box. The electronic feedback carb has a problematic electrical plug at the back. Too short wires break inside the insulation from flexing. Try wiggling the connector and see if the idle changes. The carb has these wires... For the ECC to work properly the ECU needs these inputs 12 volts vacuum switch (that senses full throttle) ignition coil negative (rpm) throttle switch (idle or above) water temp (is engine at operating temp) O2 sensor (for fuel air feedback) neutral switch clutch switch A system failure results in the ECU going into a 'limp home' mode. This is an over rich air fuel mixture to protect the engine from an accidental lean burn. Performance is poor and mileage is terrible. Quote Link to comment
Flailguy Posted June 28, 2014 Author Report Share Posted June 28, 2014 The tachometer works so does the temp gauge and the throttle switch. Need to check neutral switch and clutch switch. Where is the vacuum switch? Quote Link to comment
Flailguy Posted June 28, 2014 Author Report Share Posted June 28, 2014 Both coils are firing. Wiggling the plug doesn't seem to change anything, I will check continuity when I get off work. Quote Link to comment
Flailguy Posted June 28, 2014 Author Report Share Posted June 28, 2014 Both coils are firing. Wiggling the plug doesn't seem to change anything, I will check continuity when I get off work. Quote Link to comment
Flailguy Posted June 28, 2014 Author Report Share Posted June 28, 2014 Just for the record I'm getting 22 mpg. Quote Link to comment
datzenmike Posted June 28, 2014 Report Share Posted June 28, 2014 The tachometer works so does the temp gauge and the throttle switch. Need to check neutral switch and clutch switch. Where is the vacuum switch? There are two vacuum switches mounted to the pass side inner fender. Sorry I don't know which is witch. Both sense full throttle and low vacuum. Just to be sure timing is set to 3 degrees BTDC? Vacuum line off distributor (just in case) Quote Link to comment
Flailguy Posted June 28, 2014 Author Report Share Posted June 28, 2014 Okay. Yes set to 3* btdc is there any way to test the vac switches?? Quote Link to comment
datzenmike Posted June 29, 2014 Report Share Posted June 29, 2014 Visually inspect that the hose is good and connects to the intake. Electrically the switch should close or have zero ohms below 4.72 inches of mercury (vacuum) I believe it's the vacuum switch closest to the front of the truck. Quote Link to comment
Flailguy Posted June 29, 2014 Author Report Share Posted June 29, 2014 The clutch switch wasn't working it is now Quote Link to comment
Flailguy Posted June 29, 2014 Author Report Share Posted June 29, 2014 Is there any way to test the air fuel mixture solenoid? Quote Link to comment
bryant2482 Posted June 30, 2014 Report Share Posted June 30, 2014 does the engine lose power when you give it gas in neutral? Quote Link to comment
Flailguy Posted July 1, 2014 Author Report Share Posted July 1, 2014 No it doesn't. Quote Link to comment
Flailguy Posted July 1, 2014 Author Report Share Posted July 1, 2014 Only with a load Quote Link to comment
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