03 GT won't start

03GT4.6

Member
Jun 17, 2024
13
2
13
Wisconsin
Bear with me here. New to all of this. Changed out my fuel tank because of a leak. Put it back together and now it won't start. Have one of those code readers, but, not much help. So, changed out the fuel pump, nothing, no prime sound. I have replaced the fuel rail pressure sensor, FPDM, Inertia switch. Tested the voltage with key on. 4.7 volts at fuel pump, 6.5 at FPDM, and 12 at Inertia switch, but then I have no voltage at the Inertia switch the next time I tested it. What could have happened? It ran before the tank change. Thanks guys!
 
My best guess would be a wiring issue caused by dropping and reinstalling the tank. Maybe a wire experienced a little too much tension. Check wires and connectors for continuity, bad grounds, ect.. Other than that, maybe the CCRM?
 
My best guess would be a wiring issue caused by dropping and reinstalling the tank. Maybe a wire experienced a little too much tension. Check wires and connectors for continuity, bad grounds, ect.. Other than that, maybe the CCRM?
The tank has no wiring to it, other than the pigtail that unplugs from the back before you drop the tank. I've looked at everything back there and can't find any stressed wiring, or grounds. I ordered a CCRM today. I'll know tomorrow if that was the issue, but it's just kind of weird that this issue didn't start until I replaced the tank. I keep getting a P1233 code, which is the FPDM. I've replaced that already, but just to be sure, I returned it today and will get another new one tomorrow. Thanks for your input. I'll look at the grounds again.
 
Yep... You pinched a wire or severed a ground somewhere.
Its pretty straightforward. Unplug the pigtail, drop the tank. I don't see how I could have pinched or severed a wire. Not saying it's not possible, just not much under there. My better judgement tells me to drop the tank again and look at the connection from the fuel pump. Thing is, I put a new pump in after it wouldn't start the first time I put the new tank in. New fuel pump comes with new wiring and pigtail. Thank you for replying.
 
Its pretty straightforward. Unplug the pigtail, drop the tank. I don't see how I could have pinched or severed a wire. Not saying it's not possible, just not much under there. My better judgement tells me to drop the tank again and look at the connection from the fuel pump. Thing is, I put a new pump in after it wouldn't start the first time I put the new tank in. New fuel pump comes with new wiring and pigtail. Thank you for replying.

If you end up dropping the tank again, maybe see about hooking it all up outside of the car and keep tracing voltage backward until the culprit pops up.

Do you happen to know what brand pump you put in? It's not an autozone special by chance? I only mention it because I've gotten several that were DOA, one of the them had an internal electrical short... inside the tank... I was all warm and fuzzy about it. Wanted to return it through The Zone's front window.
 
If you end up dropping the tank again, maybe see about hooking it all up outside of the car and keep tracing voltage backward until the culprit pops up.

Do you happen to know what brand pump you put in? It's not an autozone special by chance? I only mention it because I've gotten several that were DOA, one of the them had an internal electrical short... inside the tank... I was all warm and fuzzy about it. Wanted to return it through The Zone's front window.
Before you go all crazy on me, I'll admit I bought the pump off ebay. I know, I know. I've been beaten down by several guys for doing this, but keep in mind, it didn't start after the initial tank change with the old pump still in it.
 
Before you go all crazy on me, I'll admit I bought the pump off ebay. I know, I know. I've been beaten down by several guys for doing this, but keep in mind, it didn't start after the initial tank change with the old pump still in it.

Yeah, I recall but if you're gonna drop the tank anyhow... O_o
 
So, I installed a new FPDM and a new CCRM. Still won't start. So, I figured it must be the fuel pump. I jumped the pump and it works. I'm still only getting 5 volts at the pump pigtail. 7.5 at the FPDM. One thing. I had the battery on my charger. Turned the key to the on position and the charger which had been putting out 3 amps jumped up to 8.5 just by turning the key on. Is that normal?
 
So, update. I disconnected the battery to get at a ground to clean it. It was disconnected for about an hour. I hooked the battery back up, turned the key, and heard the fuel pump prime. Car started and ran great. Turned it off and turned the key back to the on position, no prime, no start. WTF!!
 
So, update. I disconnected the battery to get at a ground to clean it. It was disconnected for about an hour. I hooked the battery back up, turned the key, and heard the fuel pump prime. Car started and ran great. Turned it off and turned the key back to the on position, no prime, no start. WTF!!
 
Pulled codes several times. Kept giving me P1233, been replaced, twice. Code for fuel rail pressure sensor, replaced that. Replaced IFS. Getting a FORscan unit tomorrow to get access to every f'ing module in the car.
 
Well, you already replaced the components that you have codes for. What's left is wiring and the drivers for each of those components. Those drivers are located inside the EEC. That, in combo with the weird readings you're getting with the voltage meter tells me that you may [not] be getting proper voltage to those components.

Also... The thing is 21 years old. Do you have any 21 year old computers laying around that still boot and run? :shrug: It might be time for a health check.

Ummm.... I always forget the site https://www.theecuexchange.com/
 
Well, this is weird, but I'll take it. Pulled the pcm out and I see it had been replaced once before, with one out of a junkyard. So, figured I would just buy a new one. For some reason, I decided to hook it back up again. Everything works as it should! It primes, starts, runs. Scanned it and my scanner told me there are no issues with my vehicle. What a relief!!!
 
  • Hell Yeah!
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