Help with LT4 refusing to start
Thread Starter
4th Gear
Joined: Nov 2002
Posts: 4
Likes: 0
From: Marina del Rey CA
Help with LT4 refusing to start
I left my LT-4 in my garage for 2 months and it had stubbornly refused to start ever since. The starter is cranking strong and there are spark on the wire. The center console does not display any warning light.
I do not have any OBDII reader, but tried to short two of the pins to bring up the diagnostics code as I had read in forum. The dashboard displayed sub-system 1 and code H-71, H-72 [ Fuel too lean / Fuel too much ].
Any idea what's wrong this is car? Am I looking at a new computer management system??
I live in LA / Santa Monica area. Please let me know if you have a know of a reliable shop that knows how to fix C4-LT4.
Thanks !
Benjamin
I do not have any OBDII reader, but tried to short two of the pins to bring up the diagnostics code as I had read in forum. The dashboard displayed sub-system 1 and code H-71, H-72 [ Fuel too lean / Fuel too much ].
Any idea what's wrong this is car? Am I looking at a new computer management system??
I live in LA / Santa Monica area. Please let me know if you have a know of a reliable shop that knows how to fix C4-LT4.
Thanks !
Benjamin
Pro
Joined: Nov 2002
Posts: 513
Likes: 0
From: Maple Grove MN
Re: Help with LT4 refusing to start (96-white-LT4)
Welcome to the forum! :seeya I would suggest that you repost this in the C4 Tech/Performance area, probably will get a quicker response from one of the experts. Also, are you getting fuel? Might want to check to see if you have pressure. Good luck!
Le Mans Master
Joined: Dec 2002
Posts: 6,715
Likes: 2
From: Santa Teresa New Mexico
Re: Help with LT4 refusing to start (96-white-LT4)
Pull a plug to see if its wet (fuel).
Fuel in tank? Spray a carb cleaner into the air intake. If it starts to run you have a fuel problem. Don't drowned the air intake with crab cleaner, just a small spray will do.
If it trys to run it might be the fuel pump relay. If the fuel pump relay is out the car wont run.
Fuel in tank? Spray a carb cleaner into the air intake. If it starts to run you have a fuel problem. Don't drowned the air intake with crab cleaner, just a small spray will do.
If it trys to run it might be the fuel pump relay. If the fuel pump relay is out the car wont run.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,008
From: Texas
Re: Help with LT4 refusing to start (96-white-LT4)
I left my LT-4 in my garage for 2 months and it had stubbornly refused to start ever since. The starter is cranking strong and there are spark on the wire. The center console does not display any warning light.
I do not have any OBDII reader, but tried to short two of the pins to bring up the diagnostics code as I had read in forum. The dashboard displayed sub-system 1 and code H-71, H-72 [ Fuel too lean / Fuel too much ].
Any idea what's wrong this is car? Am I looking at a new computer management system??
I do not have any OBDII reader, but tried to short two of the pins to bring up the diagnostics code as I had read in forum. The dashboard displayed sub-system 1 and code H-71, H-72 [ Fuel too lean / Fuel too much ].
Any idea what's wrong this is car? Am I looking at a new computer management system??
Since you have spark, then that indicates a fuel problem. Verify the fuel pump and injector fuses are good. Verify fuel pressure. When you turn the key to "run", do you hear the fuel pump run? If not, you have a pump or wiring problem. Have you checked the fuel pressure regulator? Any fuel in the vacuum line? If so, the regulator is bad. Any fuel on the plugs? How did you verify spark?
As you can tell, not an easy problem to resolve.
Thread Starter
4th Gear
Joined: Nov 2002
Posts: 4
Likes: 0
From: Marina del Rey CA
Re: Help with LT4 refusing to start (96GS#007)
Thanks for the suggestions... Here is what I had done so far.
1. With Key in, but not cranking, I can hear the fuel pump in the back of the trunk. [ at least that's what I thought it was ]
2. I will check the fuel injector fuses. [ I also did a quick check on all fuses in the main fuse box. Are the fuel injector fuses located in the main fuses box?
3. Verify fuel pressue.... Lots like I have to buy or rent a measurement tools. So I will go to my local pep boys and see what they recommend..
4. I verified spark with a inductive spark indicator on the spark plug wire. So that should be reliable.
5. No I have not pulled the spark plugs cause I dont have my usual tool chest with me.
As you had pointed out.. This does sounds like a pretty complicated problem. I was hoping that it might be more common. Looks like I have to book an appointment with my local Santa Monica chev dealer....$$$
Thanks for your suggestions !
Benjamin
1. With Key in, but not cranking, I can hear the fuel pump in the back of the trunk. [ at least that's what I thought it was ]
2. I will check the fuel injector fuses. [ I also did a quick check on all fuses in the main fuse box. Are the fuel injector fuses located in the main fuses box?
3. Verify fuel pressue.... Lots like I have to buy or rent a measurement tools. So I will go to my local pep boys and see what they recommend..
4. I verified spark with a inductive spark indicator on the spark plug wire. So that should be reliable.
5. No I have not pulled the spark plugs cause I dont have my usual tool chest with me.
As you had pointed out.. This does sounds like a pretty complicated problem. I was hoping that it might be more common. Looks like I have to book an appointment with my local Santa Monica chev dealer....$$$
Thanks for your suggestions !
Benjamin
