My 88 7.3 is hard to start at freezing point . Any colder than that, and it will not start at all with out the block heater. if it is pluged in, it starts on the first or second crank all the time.

I have check all the GPs with a test light and repalced the one bad one. When I turn the key, the wait to start light comes on for 5-8 seconds. I can then hear the controller cycle in about 1 secon intervals. Its a fast Click click click.


The controler was replaced about 8 months ago.
I am not sure what else to look for.

Thanks,

Adam

 

when i am not pluged in and the temp is below freezeing i will cycle the plugs twice and give it about half throttle and crank and it will start right up runs a little rough and pumps out a lot of smoke but it clears up after a bit

 

I put in a bypass switch on my 86 6.3 this winter after having hard starts in the colder weather. I did this after replacing all the GP, and now have no problems on cold starts.

 

Make that a 6.9 not a 6.3, sorry about that.

 

79 I think you still have some bad GPs in the flock.

Sailors 6.9 and 7.3 are two different systems. The bypass is recomended on 6.9 but if the 7.3 solid staste system is working it can't be beat.

If you have 2 or more bad GPs, the controller may not cycle at all.

Two problems that occur with the solid state ( 1987 to 1994 IDI engines ) GP systems. If a GP burns out ( circuit resistance goes up ), the controller cycles the GPs at a faster rate which doesn't let them get to max operating temp. If 2 or more GPs fail, the controller may not cycle the GPs at all ( very rapid or no clicking heard ). When you check the GPs, use an ohmmeter. A high resistance ( not necessarily burned out ) GP can cause circuit resistance to go up and the controller will then cycle the GPs too fast. You probably will not find this problem with a test light. Resistance spec for GPs = .5 to 1 ohm cold. Second problem. A poor controller ground ( black wire attached to valve cover stud ) will cause the controller to leave the GPs on longer, often damaging or failing them. If you are having mulitple GP failures, I would check closely the controller ground. Now the confusing part. Bad ground --> longer GP on time ( slower cycling ). Burned out GPs --> faster cycling If you have both situations, it may appear that the controller is cycling the GPs at the proper rate. Bad ground slows it up while the burned GPs speed it up ---> normal cycling. The system acts/sounds like it's working normally, but you have a hard starting concern.
DieselDon

Glow plug torque is 12 ft lbs, I always use antisieze on the threads.

 

I had just one gp go out but replaced the whole set. Boy did that make a big difference in starting. cycled correctly etc.