it will turn on every time does any body know why it does that or whats wrong
2007-11-14 15:57:34 · 7 answers · asked by Anonymous in Cars & Transportation ➔ Car Makes ➔ GMC
Kind of vague question, but sounds fuel related to me!
2007-11-18 13:30:25 · answer #1 · answered by Rick G2 5 · 0⤊ 0⤋
I own a shop, and have seen this before. It is caused from a lack of fuel and/or pressure. This may just be a clogged up fuel filter causing all of your trouble. When you first turn the ignition switch on, the fuel pump will come on for a few seconds to bring the pressure up to par, and then it shuts off until the engine is started. If you turn the switch off, and then back on again, the pump will do the same thing again. This is why it will start the second time. It finally gets the pressure up enough for it to go through the injectors. Check your filter, and change it if you haven't done so already. Semi plugged up injectors will cause this too, so using some injector cleaner will help the problem. If an injector is stuck in the open position, it is allowed to keep putting fuel into the engine, and draining off the pressure, kind of like a leaking faucet does. This could also be a pressure regulator issue, or a pump that is going bad. It may even be a worn out injector causing this. A lot can be found when a pressure test is done on the rail to see what is going on. Combine this with a scan tool that can read the numbers on the O-2 sensor, and if its a leak down problem, it can be found pretty easily if you have the equipment to do this with. Look around the engine for any vacuum hoses being off, split where they plug on, loose & sucking air around them, or just no good. Sometimes one can fix things by just looking around for simple things like this.
Glad to help out, Good Luck!!!
2007-11-16 08:28:55 · answer #2 · answered by Anonymous · 0⤊ 1⤋
what you have is lack of fuel pressure in the fuel rail on start up.
your fuel is bleeding (leaking) back to fuel tank when the truck sits for a while.
fuel pressure should be 60-65 psi when the key is turned on,
and it should not bleed more than 5 psi .
your truck is probably leaking a lot more .
the problem is either the fuel pump(in tank) or the fuel pressure regulator (underneath the upper plenum)
have a qualified repair facility diag which part is the failed component, but in the meantime, what you can do is turn the key to the on position for two seconds turn it back to the off position , now start the truck, it should start right away.
by doing that you've pressurized the fuel system.
replacing the fuel filter is not a bad idea as some other people advised. BUT that's not the problem with your truck.
2007-11-15 13:40:45 · answer #3 · answered by jesse 5 · 0⤊ 1⤋
The question is very unclear!! Be specific especially when you have a weird question. I believe you are asking why the motor stalls after the first start and then runs fine. It sounds like you either have a weak fuel pump or a plugged fuel filter. To make sure, change the filter, check the PCM for codes, check the PCM for an upgraded program, and then check the fuel pressure when cold or the first start. You need at least 55 psi to get a good start. Other things that can contribute are dirty injectors and dirty intake Throttle body bores.
2007-11-15 14:32:13 · answer #4 · answered by Deano 7 · 0⤊ 2⤋
If it cranks, but won't fire until the second or third time, the fuel pump probably needs replacing...there's something called a "fuel pump pulser" in the pump that helps build pressure, common problem...this is for a 4.3 liter, you didn't specify much....does it crank, does it not do anything?
2007-11-15 00:14:22 · answer #5 · answered by jim j 3 · 0⤊ 1⤋
my sister had a similar problem with her car and it turned out to be the cars starter.
2007-11-15 00:11:48 · answer #6 · answered by Frizz 3 · 0⤊ 3⤋
Starter or the alternater
2007-11-15 00:35:09 · answer #7 · answered by bernhardtk1976 3 · 0⤊ 4⤋