• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

No Start Electrical Gremlin

JohnShead

JohnShead

Member
Messages
64
Reaction score
40
Location
Kingsport, TN
Occasionally when trying to start my Suburban the glow plug light doesn't come on. No amount of cranking will start the motor either so I believe the fuel solenoid is still shut off. When I connect my Tech II it says it can not establish communications with the vehicle. I have tried swapping out the chip and the FSD to no avail. After waiting a while I try again and the glow plug light comes on and it starts right up and the Tech II connects just fine. Now, when ever it does this I just sit in it turning it off and back on over and over until finally the glow plug light comes on (sometimes taking as long as 45 minutes). Usually it comes on very briefly and sometimes the SES light flickers on and off rapidly but after that happens it will start with a lot of cranking and smoke. After starting it runs fine and there are no codes. It has never stopped while running from this problem. This is an extremely intermittent problem sometimes not happening for months. I have one at a time taken each wire out of the ECM connectors cleaned it with a small drill bit, pinched it down a little so it can get a better connection, but it has happened again after that.
 
I have also had that scenario lead to the ignition switch being the problem. But there can be other causes. Maybe search no wait to start or No glow plug light and see if you can find more results.

Double check all of your grounds and add the extras, first.

I would only use an AC Delco ignition switch
 
My grounds are good, I made my own with 8awg wire connected to both negative cables at the intake manifold then directly to the frame,the firewall and the right rear intake bolt where all of the grounds are connected. This fixed my jumpy speedometer a while back. I had trouble with my ignition switch before only sending 5 volts to my transmission causing many shifting problems and codes. I took the switch apart cleaned and polished all of the contacts inside and that fixed my transmission problems. Maybe I should go ahead and replace it.
 
I finally replaced the ignition switch, with the AC Delco of course, and it hasn't done it since. Before I changed it got to where it was happening at least once a week. It has only been a week since I changed it so it hasn't been much of a test but so far so good.
 
Now that you replaced the ign swicth have NO MORE problems comumicating with the TEch 2 right.......it's a sure sign wiring or ignition switch problems when other than jumper scanners can't comunicate with ECM .computer Jumber scanners - paper clip A+B terms up to 1995
 
No more Tech 2 communication problems. It's been more than a month now and the problem has not happened again. I took the old switch apart to look at the contacts and of the 8 sets 3 were significantly pitted and burnt and 2 others looked like they were starting to pit. I guess when I cleaned and polished the contacts before it was insufficient because the pits in them didn't allow enough contact area to give a reliable connection.
 
I need to revive this thread, the problem is back. The new AC Delco ign switch is barely 6 months old and the original problem happened twice in the last 2 weeks. During the first one I pulled the switch opened it up polished the contacts and put it back in and it worked. After that I checked the current flow through each set of contacts and determined that the pink hot in run and start wire is the only one that lights the WTS light so I bypassed the switch using a 30A relay activated by the pink wire. It happened again after a week in that configuration. I pulled the wires off my relay and connected the pink wire to the + battery terminal. Still no WTS light and today I noticed no Water In Fuel light. So back to my turn it off and on a million times and after about 10 minutes of that the WTS would come on for 1 or 2 seconds. I kept doing the switching hoping to get the glows hot enough to start it and it did. Once again no Tech2 communication with the vehicle. So, I am convinced it isn't the ign switch. It's the only problem I have with this truck but it's a frustrating one.
 
I think I might have found it but I won't know until forever passes and it doesn't happen again. The positive terminal on the side of the under hood fuse box that connects to the right side battery and the fusible link to the glow plug relay was very corroded. I cleaned it up and now I wait to see if it happens again.
 
You must log in or register to reply here.
Back
Top