f7cat

I have a 1999 Tahoe 5.7L V8 w/ 140,000 miles. It has been hard to start recently, having to turn the engine over a few times before it would start. Like it wasn't getting enough gas. Yesterday the Service Engine Soon light came on while driving. Now it will not start and I cannot hear the "whine" of the fuel pump when turning the key on. Is this a fuel pump issue or possibly something else. Thanks for any help.

in2pro

If your not hearing the tell-tell sound of the pump buzzing when you first turn the key to crank but dont crank it, its probalby the fuel pump. BUT check the pump fuse and relay under the hood. There is also a bypass wire near the fuse box under the hood that you can send power directly to the pump bypassing the relay and fuse, if this dosent turn on the pump then its a bad pump.
With 140K miles you probably need to be running some injector cleaner thru the tank as well, as my hard start issue was gunked up injectors and popets.
I have replaced both fuel pump and injectors on my 97 its not hard or too complicated if you are mechanically inclined. Thou I would suggest having a helper on both if you decide to do it yourself.


EDIT
Try not to run the tank empty if you do install a new fuel pump as running it very low in hot weather will shorten its life...

joeysworld

Get the codes from your tahoe and check the relay/fuses as in what in2pro has described. Your not the first one to have the fuel pump go out on you!

f7cat

Thanks for the replies. Unfortunately this morning I tried to start it again and I heard the fuel pump buzz. So of course I tried to start it. Nothing happened for the first 10 times or so, but I could hear the buzz of the pump. Eventually I got some fire and after about 20 tries it did start. I drove to a nearby parts shop and poured in 2 cans of Techron and a 1 Seafome then took about a 20 mile cruise. The service engine soon light did go out. I'm wondering if the fuel pump is on its last leg and is eventually going to die? Or could it be something else?

in2pro

You could check the fuel pressure as a way to see how the pump is performing but honestly it woun't tell a lot as the pump could have good pressure and go out next week.

I suspect your hard starts are fuel delivery via injectors...the additives will help and if it starts starting better after you run the additives thru then its almost a sure thing its injectors.

The check engine light wont go out until you have had enough start/stop cycles without an error. You can disconnect the battery to clear them but I would have them checked and write them down first, that way any that come back are probably ligit.

Remember codes don't always point to the exact problem but are indicators to help someone knowledgable / inclined / trained to troubleshoot the root casue.

With that many miles you should be coming up on a O2 sensor going out , fuel pump and injectors...

EDIT
It could also be electrical i.e. cap, wires, plugs... but I have experinace less issues with that then I have fuel delivery, thou if you have not had the cap, rotor, wires and plugs replaced those could also help.

f7cat

Thanks. Actually the service engine soon light did go out so maybe the additives did something positive. About a 1 1/2 yr ago I did have the infamous intake manifold gasket leak. I had the top end done at that time, new plugs,wires, cap, rotor. So it sounds like it could be an injector issue.

in2pro

Oh yeah... I remember having that leak too... I ALWAYS ran Exxon gas in my 1997 Tahoe but still got the build up, I am now using Chevron in the new 07 and am also using 3M fuel additive
about about every 7k miles to see if it will reduce the buildup.

I did my own injectors and was somewhat dissipointed with the build up under the intake, I thought Exxon fuels were cleaner then that. I know there should have been some build up after 100k miles but I was still suprised, I thought the Exxon brand fuels were clearer and I was even running the premium.

Now I run Chevron regular and the additive.

Good luck and let the forum know what you find!

Zed 71

Try the check valve at the fuel pump assembly. This is a common problem.

f7cat

I got the code checked:
P0171 - System Too Lean Bank 1
[blockquote]
Fuel System 1 Closed Loop
Fuel System 2 Closed Loop
Calculated Load 15.6%
STFT Bank 1 11.7%
LTFT Bank 1 23.4%
STFT Bank 2 7.0%
LTFT Bank 2 21.8%
Intake Manifold Pressure 18.6 in.hg
Air flow sensor 4.57 lb/min[/blockquote]

David Moushey

99 tahoe hard to start, just replaced fuel pump 80000 mi. any ideas where to start? thanks