1977 cj7 won't start

coloradochuck · 09-09-2009, 05:13 PM

I have a 1977 cj7 thats fuel injected and has a electric fuel pump. I'm getting fuel to the engine but it still won't start. I checked to make sure i have spark and i do. Any other ideas would be helpful.

**octaneman** · 09-09-2009, 05:35 PM

Hi coloradochuck

Was the engine recently swapped to EFI ?

coloradochuck · 09-09-2009, 08:13 PM

its was swapped before i bought the jeep. I took the fuel line off at the back of the air intake and made sure fuel was pumping out and it was so i'm thinking maybe the fuel injector is clogged. i thought maybe i wasn't getting power to the pump so i ran a new positive wire with a toggle switch. i turns on and pumps. so it has to be somewhere inside the intake.

**octaneman** · 09-10-2009, 04:27 AM

coloradochuck

Disconnect the injector plugs and hook up a node light, then have someone crank the engine. The node light should go on and off very quickly indicating the pulse width. If injector pulse width is not there, then the fuel circuit from the computer to the ignition module has to be tested. You will need the wiring diagram from the original truck including the wiring schematic for the EFI connections.

09-09-2009, 05:13 PM	#1 (permalink)
coloradochuck Registered User Join Date: Sep 2009 Posts: 2 OS: vista	1977 cj7 won't start I have a 1977 cj7 thats fuel injected and has a electric fuel pump. I'm getting fuel to the engine but it still won't start. I checked to make sure i have spark and i do. Any other ideas would be helpful.

09-09-2009, 05:35 PM	#2 (permalink)
octaneman Mentor Home Support, Gearhead Automotive Center Join Date: May 2009 Posts: 564 OS: WINXP	Re: 1977 cj7 won't start Hi coloradochuck Was the engine recently swapped to EFI ?

09-09-2009, 08:13 PM	#3 (permalink)
coloradochuck Registered User Join Date: Sep 2009 Posts: 2 OS: vista	Re: 1977 cj7 won't start its was swapped before i bought the jeep. I took the fuel line off at the back of the air intake and made sure fuel was pumping out and it was so i'm thinking maybe the fuel injector is clogged. i thought maybe i wasn't getting power to the pump so i ran a new positive wire with a toggle switch. i turns on and pumps. so it has to be somewhere inside the intake. Last edited by coloradochuck; 09-09-2009 at 08:22 PM.

09-10-2009, 04:27 AM	#4 (permalink)
octaneman Mentor Home Support, Gearhead Automotive Center Join Date: May 2009 Posts: 564 OS: WINXP	Re: 1977 cj7 won't start coloradochuck Disconnect the injector plugs and hook up a node light, then have someone crank the engine. The node light should go on and off very quickly indicating the pulse width. If injector pulse width is not there, then the fuel circuit from the computer to the ignition module has to be tested. You will need the wiring diagram from the original truck including the wiring schematic for the EFI connections.