Cranks won't start

Is the security light staying on? It sounds like the BCM is going out which is common here is a guide to reset the security system and the BCM replacement instructions in the diagrams below.

https://www.2carpros.com/articles/how-to-reset-a-security-system

Check out the diagrams (Below). Please let us know what you find. We are interested to see what it is.

Check for injector pulse, engine cranking, use noid lite. Remove egr valve, see if dirty and pintle moves ok. Some makes and models have heard of clogged exhaust causing egr codes?

The security light comes on some times and stays on until I shut the engine off.When the light comes on is when the starting problem happens.The security light was coming on 2 days,every time I drove it,prior to the no start.Are they related?

The truck started today.After, I used the key fob and turn the alarm system on and left it alone for about 5 minutes.Is the security system shutting off the fuel injectors?What could make this happen?

I hate to say it, but the problem lies in the anti-theft system. If it ever strands you, turn the key to the run possition and let it there for about 10 minutes until the light goes off. It should start then.

As far as the problem, it needs to go to a dealer to be diagnosed. They are the only ones that have the proper test equipment to check the system. Otherwise, most shops will just start replacing parts. You could try a different key when this happens to see if that helps, but chances are it is internal.

Let me know if you have other questions.

Joe

Thank you for this post I had this problem and had to get a BCM cost me $340.00 all fixed.

My 01' GMC Sierra will not start occassionlly and i have not been able to pin point exactly when or what causes this to happen. Sometimes in the morning it won't start right away and when i drive somewhere and shut it off then try to start it again later it won't start. Sometimes I have to crank it over 5 or 6 times befor it will start. Then it run like a top, smooth good as new, It's not all the time its totally at random. I've changed the fuel filter, had the injectors cleaned, fuel pressure is good,(new fuel pump, and fuel pressure reg.) . This seemed to begin with the cold weather, Any help or suggestions??

I have the same problem on my 2000 gmc z71 i replaced the throttle positioning sensor or tps andit seemed to help a little but not completely. if you find the problem please let me know. thanks

My 8.1L Gas engine sometimes will not turn over. To make it start, one time I moved shifter, one time I opened and closed driver door, one time I pushed truck 10 ft in driveway. Time between occurances one month. When trying to start, turning key does nothing. New battery, found no loose wires in system, head lights work, radio plays, interior lights work, dash lights work.

Could it be a loose connection wire, defective key switch, or a starter block in fuse box?

Thanks,

Tom

Not sure if 1500--2500--3500, may not matter, when the problem occurs, I'd check the circuits at the starter relay in the power distribution center, under the hood. Voltage to the coil side of relay, goes hot with the key in the crank position. Voltage to load switch side of relay, is hot all the time. Terminal 85, hot, with key in crank position. Terminal 30 is hot all the time. When relay is energized, the arrow swings to terminal 87, continuity between 30 and 87. 87 carries voltage to starter solenoid.

This guide should help https://www.2carpros.com/articles/car-cranks-but-wont-start and https://www.2carpros.com/articles/starter-not-working-repair Please run down these guides and report back.

took it to a professional mechanic, an he said it was the ignition coil. they replaced it. an told my husband to replace the spark plugs,wiring, an distributor cap. so he did that an it runs worse now. like its misting an wants to die on us while going on road or sitting idle. now they say its out of timimg, an my husband is trying to fix it himself cause we cant afford $1000. to get it fixed professionaly. could you plz help us?

If it runs worse since he replaced the parts, then that would mean he messed something up in the process. Sometimes paying a professional; is cheaper in the long run. Everything he did will have to be done over and inspected. he may have cracked a spark plug or crossed some wires.

truck starts sometimes then go somewhere and trk wont even make a click. battery is fully charged, and no other reasons it not starting sometimes starts just fine last time this happended was about 3-4 months ago.the last time i disconnected battery for awhile and reconnected and it started right up. now i disconected the bettery all night and still nothing please help.

do your lights come on and everything on dash light up? although the battery is connected can you move the positive cable? there is a lead spacer between the 2 positive cables, if your model has 2 positive cables. the lead spacer melts causing terminals to be tight but the cables are still loose. hope this helps. feedback and votes are much appreciated.

yes all lights are working, and rechecked battery cable it does have 2 wires going to it. they are tight and connected.is there a seperate module or sylinoid to check?

i would be leaning to a bad starter motor. you can tap on it while someone tries to crank it, this usually jars the starter and it should start. to tell for sure, check the small purple wire at the starter for power when cranking. if there is power there then you definately have a bad starter motor. feedback and votes are greatly appreciated.

I've had the truck for about two years now since 155k miles. It's been great except for having the transmission rebuilt, front bearing issue and new tires. I do continue to have a problem I need resolved. The truck does not start at times. It's not the battery charge or alternator as these have been tested. When it happens, it's just like you are trying to start the engine while in drive. All dash lights and chimes work but nothing happens when turning the key. I have taken it several times to a reputable Goodyear mechanic who could not duplicate the issue. I have been told by them and friends that it could be the built-in security system or possibly still the starter. Have you heard of this issue and what should I do? Thank you.

It could be those things. First, if it is the security system, the light will stay on and flash. Next, if the starter is bad, you can check it. Have a helper turn the key to the start position while you check for power to the smaller wire on the starter. You should have 12+ volts. If you do, replace the starter. If not, then check the relay.

Let me know what you find.
Joe

2001 GMC Sierra 4x4 mileage: 111,000. I was traveling on a bumpy dirt road, when my truck stalled. I tried to jump it but it wouldn't start. In troubleshooting, I have determined it is not getting fuel. It will start if I put a little gas in the carburetor. I suspect the auto fuel shutoff switch but can't locate it either in the manual or through tracing the fuel line. The reason I suspect this is that I have had trouble with the cutoff switch before on other vehicles.

Your vehicle is not equipped with a fuel shut off switch. If you do some checking, you will probably find the fuel pump has failed.

Have an issue 1 - 2 times a month. Truck will not start, will turn over but doesn't seem to catch. Can try and try no luck. Let it sit for 10 minutes and it will start and run great for several weeks and then the problem will occur again. Can happen day or night, hot or cold, just seems to be random. Not sure where to start. Possible fuel pump issue? Thanks.

Has there been any work done that required the fuel pump to be unplugged at all?
This also sounds like a passlock problem. Check the voltage of your battery with a volt meter and not the one on the dash.

Never had a problem starting.
It's zero degrees outside
I have a block heater.
Truck won't start, seems not to be getting fuel. it has been sitting for a couple weeks. When I first tried it it did start to run for a few (15) seconds. I wore out the battery trying to start it. I have a 50 amp charger on it now.
I tried to start it with some ether but I'm by myself and it's hard to do that.
any suggestions?

So have you checked the actual fuel pressure? Also with the key in the run position is the security light on solid or flashing?

Driving down the road at 45 mph and the engine stalls. Still rolling, I throw the truck in neutral and restart. The truck drives 1/4 to 1/2 a mile and stalls again. This time however, it does not restart. I figured it may be the fuel pump. What do the experts think?

Hello,

Good possibility...

When you turn the key to the on position can you hear the pump turn on for 3 - 4 seconds? If not check Fuel Pump Relay.

Where can I find the fuel pump relay?

It is in the under hood power box. It should be labeled on the under part of the cover. If not there is a row of 8 fuses just below them will be 2 sqaure relays with fuses inbetween, the next relay under those will be the fuel pump relay and it will be rectangular.


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Thanks obxautomedic