Fj80 - No Start (1 Viewer)

Joined
Oct 12, 2005
Messages
692
Location
Flatwater, NC
Replaced the alternator on 92 fj80. Been having an intermittent no start issue. Will crank fine w no start. The a/t temp, brake, check engine and charge warning light is staying on prior to start. Isn't some of those lights supposed to go away after a few seconds prior to starting? When it feels like starting (usually a cold start) first thing in am, the lights do go away and do not stay on when running.

I replaced w a new ac delco instead of a reman denso unit. Could not rebuild the other cause had a bad rectifier plate. I think it does not like this new unit. Any ideas...truck is getting fuel already check that by jumping the diag terminals.
 
Joined
Mar 25, 2005
Messages
2,120
Location
Edmond, Oklahoma
Have you gone through Jon Held's diagram? http://www.sdsysdesign.com/tlc/images/Strife/3FE EFI Diag.pdf

The CEL and other lights are supposed to be on until it starts, so your no-start issue is normal with the lights on.

"Truck is getting fuel" by jumping the terminals. Did you check the pressure? The reason I ask is we had a similar no start issue that happened only on Fridays and only in the afternoon when the engine was warm. Turned out the fuel pressure was being relieved back to the tank and would not pressure up until the vapor lock issue cooled down. Fuel pump was running but no fuel pressure. Easy to check, get a fuel pressure kit from Autozone's free rental program. Remove the line going to the CSI and tap in right at the fuel rail where you remove the CSI line.

What did we do? Changed the fuel filter, pump, sock, fusible links, pressure regulator, afm, oxygen sensors (just because I didn't remember changing them in the last 175K miles) and I'm sure countless other items that didn't solve the issue. Turns out the fuel damper (the one with the "magic screw") was not holding the pressure on the fuel rail. Occasionally when warm, it would dump the fuel back to the tank causing a 0 pressure at startup. Changed the damper and all has been good.

Another tip: Do not tighten the screw on the damper. It acts as a pressure relief/regulating valve as well and in order for it to work properly, the screw should not be over tightened.
 
Joined
Oct 12, 2005
Messages
692
Location
Flatwater, NC
Need some more suggestions here. Truck cranks and starts fine when cold. When you try after it has idled for a few minutes, or have driven for 30 minutes, will crank, no start.
 

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