Problem with cold start

[mlc596]

I have a 1999 Tahoe 4x4, I am having a problem when I first go to start my car for the day, it turns over but acts like its not getting any fuel or fire. After about 3 or 4 tries it starts then runs fine and starts fine for the rest of the day. I just changed the plugs, wires, distributor cap and rotor button and I am still having this problem. Any ideas?

 

[LI99HOE]

Just as a curiosity, when you first turn the key to ACC position, do you hear the fuel pump run? If not, check the fuel pump relay. If the pump does run, then your only option is to run some tests.
Check you fuel pressure to be sure it's correct(I believe it should be 50-60).
If the pressure is good, then I would look to see if your getting spark to the distributor from the coil.

 

[99Yuk]

A slow overnight leak in the footvalve of the fuel line?

Try this one morning:
- Turn the key on, wait three seconds or until you can't hear the fuel pump anymore, then turn it off.
- Do that four times.
- Start your truck normally.

If it starts on the first try, it's a leaky foot valve. The fuel is going back to the tank.

If this works, then you can try to reduce the # of key cycles you need. Try three the next moring. Still starts on first try, then go down to two. Etc...

Good Luck!



EDIT: to the forum.

 

[mlc596]

Thanks for the Ideas, I'll try them out. I thought it could be the fuel pump at first but noticed no performance issues once started.

 

[BattelWagun]

Also, make sure you're not putting your foot all the way down on the gas, the ECM sometimes cuts the injectors when you do that, to avoid damage.

 

[SunlitComet]

If you have a 1999 and once it is started you drive good your relay should not be the issue. You will want to get a fuel pressure gauge and find out where your fuel pressure is going when you shut down.

 

[gpracer1]

Also, make sure you're not putting your foot all the way down on the gas, the ECM sometimes cuts the injectors when you do that, to avoid damage.

Actually he should do this.

Tomorrow morning when he starts for the first time, he should turn the key on, floor the gas pedal, while holding down then try to start.

If it acts the same, its probably low fuel pressure. If it starts after a few seconds, it could be flooded from the injectors/spider leaking down overnight.

Of course normally, you dont touch the pedal at all when starting a fuel injected vehicle.

 

[Alisha]

I know this is an old thread, but wondering if anyone found the fix for this. I as well have a 99 Tahoe 5.7 Vortec. Same issue! Except after it starts and warms up I get a slight misfire at 15-1700 rpm. Also on the highway between 70-75mph. The cold start has always been an issue, but never this bad. Fuel pump, lines, filler neck to the tank, relay is all new. Fuel pressure is 65psi. I I'm thinking it may be a crankshaft position sensor or ignition coil. No Vaccum leaks found. Any ideas? Cap/rotor wires and plugs are all fairly new as well. All AC Delco. This truck is very temperamental.

 

[SunlitComet]

you can test a crank sensor for rpm consistent see with a scanner that does live data and you can do a balance test of injectors as well.