We started our truck and were about to leave and it just shut off. We tried to restart and it would turn over but no engine start. Any suggestions? Thanks.

Rip it out restore the wiring to original and leave well alone these things always give trouble and no end of questions on here ,put car in the garage to keep it warm ,once started drive off straight away ,leaving the engine running to warm the car up will shorten the engine life ,do what the swedes do and fit a small electric heater into the cylinder block ,park car in the garage and dump the junk in their,then fit a block heater and using a timer to turn it on to wamr the engine a hour before you leave for work .

I would check the crankshaft sensor first... but you forgot to mention the engine size. makes it hard to help any further

i would check spark plugs

Make sure the doors and trunk,and hood are shut,open them,and shut them .activate the anti theft,wait about 1 minute,and disarm it,see if it will start,if not,the key fob may need to be relearned,try turning the key on,leave it ten minutes,then turn it off,and right back on,then wait ten minutes,and turn it off,and right back on,do this a total of three times,,30 minutes,then try and start.

Do you have the 4.3L engine with spider fuel system? That system is noted for problems. Key on engine off, fuel pressure, 60--66 psi, use a fuel pressure gage. It needs that pressure to start, after it starts, it will run with less pressure.
There could be other issues? Engine cranking, you have spark at the plugs and fuel injector pulse?

What is the fuel presure? on a vortech engine the presure needs to maintain 60-66 pounds. It is possible that the fuel filter is restricting the flow of gas or could also be a weak pump... just a another thing to check... hope it helps.

you need to have car scanned for codes and it sounds like it is due for a major service

Sounds like your crank sensor is faulty.These engines are known for crank sensor and ingition control module problems

Have you tried to jump the car using booster cables? If you haven't, I suggest you try this first. If the car starts, the battery may be the problem, but not the root cause of the problem. Problem might be originating from a bad alternator, which is responsible for charging the battery. Then againk, it could just be that the battery is going bad. Even though you may be able to run accessories, the battery may not be holding enough charge or cold cranking amps, required to start the engine. If you can boost it and get it started, I would advise you leave the engine running for a couple hours (provided you can lock your car and it's parked in a safe area). Then, shut off the engine and try to restart it. If it doesn't start up, I would say it's worth trying to get a new battery. However, you may also try getting your battery tested. Most service stations and even many automotive parts stores can do this for you for a small fee.

Good luck!

I Can Fix It

First, try a new accelerator pump. They're less than $10 and easy to install. On the side of the carburator, near the linkage. It's simple a small rubber diaphragm.