Hello new to the forums, I have a 2001 Chevy suburban z71 that has some starting problems. The truck will start when it wants to, I've replaced the fuel pump, starter moter, crank sensor twice now, alternator, fuel filter, and the BCM (Body Contol Moduel). Now when it first started with the starting problems it would crank but not fire, it's since been fixed, now when I go to start it all I'll hear is the starter motor go but it won't crank, the belt is turning and everything and I can't figure out the problem, now who ever owned the truck before me had a Speaker system and TVs installed in the back of the headrest and did one hell of a stupid job installing it, they wired the system to get power from one of the fuses that runs to the the wire that runs to the key ignition, I've since ripped all that stuff out and it kind of seems to have solved the problem, and now all of a sudden it has been starting to act up again, don't know why but I think it might be something electrical, not sure though. Can someone please help? Thanks

 

It sounds alot like the problems I've been having and it's a security issue in my case. At the ignition lock cylinder under the plastic cover behind the steering wheel on the steering colomn there is a three wire connection that goes to the passlock sensor for the ignition key cylinder. The connectors get loose and sends an intermittent signal to the pcm. Which shuts off the fuel pump. It starts and runs for around a second or two then dies. On mine it's yellow orange and red with a white stripe. Unplug this connector then you'll need to take the connector apart. Get a stick pin and grind the point off on cement or something to take the point off or just cut it off with some side cutters. Remove the connector from where it attaches. On the side opposite the connector clip about 5/8 the way up the connector there will be 3 holes you can see metal through. Push the wire into the connector to take tension off the wire connector lock gently press your blunt needle, a small paper clip may work too, and pull the wire and connector out of the plastic housing. Then use a pair of needle nose plyers or side cutters and lightly pinch the middle of the tin connection where it has a gap you can see through Be careful not to distort the tin to much or the wire connector lock may not function or you may not be able to get to back in the housing. Don't pinch it closed completely or it won't reconnect well. Only do one at a time so you don't mix the wires up. On mine left to right is yellow orange red with white stripe connector release pointing towards you plugged in. This problem baffled me for quite some time because it was so intermittent. Hope this solves your problem. I worked as a tech for 25 years until MS and a bad back took my abilitiy to function normally away. Whenever I thought I had it figured out it would start up and not give me trouble for a while. I haven't had 1 issue since fixing this connector. The best part is that it cost me nothing but some time. Be gentle with these little buggers because I don't know of any replacements you can buy.

Best wishes
Bonehead ex racer dude