NEED HELP no start but cranks

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,642
Tampa Bay Area
Welcome to GMT Nation…

First… Courtesy @MAY03LT… Visit this link and Download his “Cranks… But NO Start” Video:


Then…Likewise View and Download his “No Crank… No Star” Video..with START CIRCUIT WIRE DIAGRAM:


..and to Check the Fuel Pump Circuit...


First Chance you get… Visit THIS Link and Follow @Mooseman’s Instructions for Downloading the Gift of a FREE Complete GM OEM Service Manual for your particular SUV… it will become “The GM Bible” to refer to for ALL of your Service Needs and Repairs:

https://gmtnation.com/forums/threads/need-service-manuals-get-them-here.361/
 
Last edited:
  • Like
Reactions: Maverick6587

Maverick6587

Member
Dec 16, 2018
730
Sterling Heights, Michigan
Crank and no start is my absolute favorite to diagnose/follow!

This issue is the one time where you HAVE to be VERY detailed in your diagnostic procedures!

Let's start with the basics....
1. Do you have spark at atleast 3 of your spark plugs and ignition coils
2. Do you have good fuel pressure at the fuel pressure port, near the engine
3. Are you getting air into your intake and does your intake flap work/move with pedal operation
4. Has anything else happened recently to point us in a good direction to help you
5. How long have you had the P0403 error code

Possible items that could be broken/bad:
1. Bad fuel pump
2. Bad ground
3. Bad relay/fuse
4. Clogged fuel filter (depending on the year of your vehicle)
5. Bad Fuel injectors (probably not the issue though)



I assume the grounds are the same for the 5.3 as the 4.2. I would check the two grounds on the outside of the frame near the driver's door and passenger's door. There is also one on the outside of the frame, in the driver's side front of the vehicles (this one is very prone to corrosion).

I would then check the plug going to the EGR itself. Make sure it's clean and not corroded. I would spray the plug and plug socket with an electrical cleaner as well. If the code doesn't clear, I would try to clean the EGR valve or just replace it. Realize that replacing the EGR valve may not fix the problem and you're looking at possibly having to replace the fuel pump. Which could cost $200-$400, depending on where you purchase it from.


Going on MRRSM's instructions:
Have your GF/Wife/Buddy stand at the rear of the driver's side of the vehicle and listen near the ground as you turn the key on (do not attempt to start it, just turn the key on position) and they should hear the fuel pump prime for about 2-3 seconds. If nothing is heard after a few attempts, then try and hit the bottom of the fuel tank with a rubber hammer a few times and attempt to start it again. If it starts then you probably have a bad fuel pump.

If it doesn't start then you could still have a bad fuel pump but, I would check for power at each pin of the relay, using MRRSM's link he provided from MAY03LT.
 

Forum Statistics

Threads
23,273
Posts
637,499
Members
18,472
Latest member
MissCrutcher

Members Online