Hey- Looking for a little help with a problem ive been having.
My 2007 Tahoe (equipped with a K&N cold air intake) has been having a long crank when it starts. Sometimes its worse then others. Its especially bad when I start it first thing in the morning. When it finally catches it runs without any problems; No hesitation whatsoever once it starts. I have taken it to two different dealers, the first one told me they couldnt duplicate the problem but that I should clean the K&N air filter. I cleaned the filter and it keeps doing it. The second dealer I took it to told me that they couldnt duplicate the problem either. The mechanic at that dealer told me that there was a service bulletin that said after market air filters can cause a long crank on start up. Has anyobdy else had any problems like this? My problem started about 6 months ago and I've had the intake installed for about 2 years.

 

a check valve in the fuel pump may be bleeding off. To confirm cycle the key from off to run and leavethe key in the run position (but don't start the vehicle) for 2seconds. Repeat this 4x then start the car.

The fuel pump may be on the way out also. check fuel pressure.

bleed off the fuel pressure then cycle the key and see how fast it builds up to spec.

If you have access to a scan tool you could view fuel trim and see if its adding fuel...an indication that the fuel pressure may be low.

 

you could always remove the K&N and try the OEM one.

Also, I always do the tap to start on mine, or are you holding the key?

 

If the K&N was over-oiled, it may have "coked" the MAF sensor. Don't know if that will cause long starts tho.

 

Your problem is the fuel pump. There is a bulletin for an "Extended Crank" which mine was doing. Exactly like yours. Like someone posted earlier in your thread, the mechanic needs to connect something to the fuel line, or whatever they do, to see the pressure drop off.

I was noticing in the mornings when you first put the key in the ignition in the on position, before starting it, that the fuel pump was not priming (that 2-3 second sound you hear) It sounded off and weak. Anyways....long story short....they replaced the fuel pump and all is good now. I actually noticed a little bit better gas mileage after the new one was put in as well.

Mine is a 2007 5.3 as well if that matters any....and I have a K&N intake.

Keep us posted.....

 

Thanks for the advice guys. I'll have to take it over to the mechanic and get him to check the fuel pump out.

 

Hi, did you find out your problem? Did the fuelpump fix your problem? I have just the same thing With my Tahoe back here in Norway...

 

John_Norway Welcome to the forum, have your fuel pressure checked and this will tell you pretty quickly if its the fuel pump...

 

Tnx. The fuel pressure is as it should be both on start up and normal use, but I do not hear the 2-3sek sound when start up...
After 8-10sec with crank, it's all good.

 

if you checked for fuel pressure leakdown after shutting off the engine and it was ok...have a look a the fuel pump wiring diagram. long ago they used to run an alternate voltage supply route through the oil pressure switch. This provided a backup that allowed the fuel pump to run as long as oil pressure was present