I have an annoying no start condition going on with my 97 wrangler.
Summary at bottom of post.
It all started after I changed my water pump. The gasket was installed incorrectly causing it to lose most of the coolant while driving( Thankfully only had to go 3 miles and I could take breaks every mile or so to let it cool off.)
I then correctly installed a new gasket and had no issues with it leaking etc.
After installing the waterpump I took it for a short drive to make sure everything was working correctly, I noticed the alternator was charging at 18 volts(verified with multimeter)
I then replaced all major power and ground wires along with grinding down to bare metal for a solid connection on grounds. This did not help the overcharging issue.
Since the regulator for the alternator is located inside the pcm on the jeep I added an external regulator that works exactly as it should. After installing the external alternator I was unable to start the jeep, it would just crank.
Getting desperate I decided to try using starter fluid to start it. The starter fluid worked and it ran perfectly until I shut it off. After shutting off it would not start without using starter fluid to do so.
I used starter fluid to get it started and then drove it 120 miles home with no issues at all, drove exactly how it normally did before the issue.
I purchased a fuel pressure gauge and have 48 psi which is right at spec.
I have spark since it will start on starter fluid.
I used a noid light when cranking and it showed no pulse. I check the positive to the injector and they are all 12v as they should be. This means that the pcm is not sending the signal to ground the injector during cranking.
What could cause the pcm to not send the signal to pulse the injectors when cranking but after its started to send the signal?
- Replaced water pump, gasket fail, reinstall correctly
- Alternator charging at 18v verified by multimeter, replaced and cleaned all grounds and main positive wires
- Put in new alternator, did nothing to help the 18v charging, learned that the pcm controls the alternator voltage
- Installed an external alterator regulator, works perfectly
- Jeep would crank but not start
- Uninstalled external regulator but had same issue, reinstalled regulator
- Managed to get started using start fluid, ran perfectly until I turned it off
- Currently runs perfectly after using starter fluid to get started(made the 120mile trip home with no issue)
- I have good spark and 48 psi fuel pressure
- Used noid light to test if injectors were firing while cranking, they were not. Found the problem, no idea what is causing it.
- Tested positive to the injectors and they all have 12v
- The pcm is not switching the ground to the injectors to make them fire while cranking. They fire perfectly after starting with starting fluid.
Any insight is appreciated.