Interesting, thanks.

 

thanks for the post. that's good info.

 

Thanks for the post. Great info.

 

Interesting it was a ground to the coil packs. Do you think rust played a role in a bad ground?

 

Yes I believe corrosion but I don't know where. The ground wire is still attached to the block. It's possible that corrosion between the ring terminal and the block interrupted the ground but it's not likely. It was hard to get at so I didn't mess with it, but it didn't look bad. The break is somewhere between the ring terminal attached to the block and where the wire pokes out of the harness up by the alternator (which is where I spliced in a new ground). The harness and plastic sheath appear to be intact so I have no idea where the break is. I do have critters (probably squirrels or mice) that have chewed up, and actually removed, a lot of the fiberglass insulation on the firewall. I don't see where they've chewed on any wiring but who knows?

 

Definitely going to file this one away for later.

 

So we're is it you are from turbojimmy?

 

check the grounds on back of the heads, under the radiator and under the drivers door on the frame

 

Since he was reporting back 6 months ago that he had it fixed, your advice is a wee bit late.

 

This is exactly what my truck is doing right now. I thought it was a fuel issue because gauge is off from big tires. I put gas in and it would fire up and run. Not working this time. 55psi at rail so I was going to check spark in the morning. Sometimes sitting idling it will just die. Weird.

 

Yes that's what my Sierra did. It was intermittent so I was convinced it wasn't electrical. But it was. Eventually it quit running completely.

 

Update as stated above I should have checked that coil ground wire. They called and diagnosed that. They must have gave old plug wires a workout since it is now missing bad. I am waiting for it to cool and change plugs and wires. Pryor to it dying it wasn't missing like I picked it up. The guy shrugged his shoulders. That is why I usually do my own work. $200 lesson. I am also going to find where that main coil ground wire is also.

Edit: I see from above post
So there's either a break in the ground wire or it's corroded where it's attached to the block. The ground in question is directly above the front axle "pumpkin" attached to the bottom of the block (driver's side). It's not easy to get at. I inspected the wire as well as I could and didn't see any break in it. I cut open the harness, found the wire and used a line tap to run a ground to the alternator bracket. That fixed it.

 

Good job. Grounds can cause a lot of problems.

 

I have that problem now was running changed the coil, now not start cranks no spark at coil.... so put old coil back not start now no spark at coil! 1500 Sierra lt 4.3 19400.

 

sounds like you screwed up the wiring somehow.

 

One wire to the distubutor and a one plug in the coil I don't see how?

 

connector got broken when you removed it, or it's not tightened down/fully inserted, no connection to ground maybe.

 

Just has this issue with my 04 5.3, all I did is replace the ignition cables and wow, no start, I about went haywire, started with taking the heatshields off the wires thinking they could be grounding out, eventually it led me to a broken ground wire that attached to the hood, I fixed that and now all seems well, I was shocked that such a minute often overlooked item could be the fault. Just doing some more reading, discovered that if the coolant temp sensor is unplugged it will cause a no start condition, I did find this next to cylinder, very close to where I was doing the cables. so who knows, I guess I can go disconnect it and see if that is what it was.

 

My purple wire doesn't work any thoughts? Pink works.

 

You should see a doctor about that?

Alternately, you can replace the purple wire, or find the other end of it and see if what it's connected to is still working?
And perhaps update your account signature to include the year/make/model/engine/trim level.

 

It sends the trigger signal from pcm/crankshaft positioning sensor to make the coils work at TDC.

I'm gonna try a OBD scanner to see if that works I think it's the pcm not the crankshaft positioning sensor


In the Haynes it says after you've verified 12volts at pink wire check the purple wire I have nothing could that be a bad ground?

 

Look on charm.li (website) for your truck, it has a version of the full service manual for your truck, and is WAY more detailed and informative than the Haynes manual.

 

Will a scanner get my purple wire working again?

 

A scanner with the right capabilities, used by someone who can use and interpret what data it produces, can likely help with getting it to work again.

 

I wonder if I need to lock and unlock my drivers door with a key, my code reader is showing a code crankshaft position sensor I'll replace it see if that works.


Was your purple wire good or no?

Was your purple wire good or no?

My security light flashes for a couple minutes then turns off is that my problem I have a 5.3 no spark hot pink wire


Is this thread for crank no start pink plus purple wire good? Cuz I have pink good purple bad? I'm stumped I've already replaced my Ckp and tried 4 extra grounds and erased codes with a $350 code reader. I still have a code for ckp everytime I crank it over after erasing it. Anybody know flawless physics about this matter to get my truck running again

 

I have 05 silverado and ran into no spark, I ran a wire from harness connector on valve cover to ground also going to back of engine and 5.3 started. I took a short cut and just added a nut to the already ground to the rear of the motor... next day it ran for a short time and same thing. I removed those grounds and run a dremel drum grinder on both sides of the ground connectors, now showing some copper, and engine started and ran. I couldn't get continuity before I cleaned the grounds but I can now.

 

Just helping out. I have a 2005 GMC Sierra w 5.3. It just died no codes nothing the coils didn't have spark. Went threw diagnostics cam crank sensor ect.. scratched my head got a voltmeter out ok had a week ground at the coils. I Thought the coils were grounded at the back of the heads WRONG! But you should check it! After cutting the harness open,, like big time!! I followed it and. They are grounded behind the power steering pump 13mm in the block. The wire end rusted off and caused a no start situation just helping out anybody that needs it, check all the grounds around the engine.

 

Thank you for this information I have been stumped and the problem you had is exactly what I'm dealing with. I will try this tomorrow and keep fingers crossed.