My truck seems to only want to start when it wants to start. It is the truck in my sig. It has an Accel DFI Thruster system. This is what happens:

When it starts, it's great. When it doesn't, I have fuel pressure, I have proper voltage, it cranks and sounds like it's about to start, but doesn't. I get no spark, no RPM signal, no cam signal.

I was told the ignition box was probably bad so I sent it back to Accel. They tested it, it worked perfectly, they sent me a new one. Of course as soon as I put it in the truck fired up and ran great for 2 days. Hasn't started since. That was almost 2 weeks ago.

This has been going on for a few months. Started off just not starting one day. Charged the battery and it started. A few weeks went by and it happened again. Same deal. I replaced the battery but it happened again which ruled out the battery or alternator.

When it started it happened once every few weeks maybe. Then it was about once a week, now it's about every few days. Usually it will start after several days or even a week but not always.

I just checked every fuse under the hood and inside the truck, all good. I checked the main grounds, all good. (as far as I can tell). I found one from the block on pass side to the frame, one from the alternator to the battery, one from the driver side head to firewall, battery to frame, battery to block, battery to fender.

The Accel PCM is powered and grounded directly to the battery as per their instructions. I just ordered a Crank position sensor because I'm told it MIGHT be that.

Any other thoughts?

 

Here's a theory. Yesterday I purchased a new crank sensor. I decided to unplug the ignition box while changing it out. I removed the starter, removed the sensor, opened the box the new sensor was in only to find out I was sold the wrong one. Well not wrong, different. It seems there were 2 possible sensors for my year/make/model but Advance Auto's computer only showed one. They are TOTALLY different too which blows my mind. Anyway, I went back to the store but they didn't have the correct one.

Went home, cleaned the oil off the old one, put it back in, plugged it in. When reinstalling the starter I decided to put a new 4ga power supply to it cause the one on their was looking a little ragged. I also put a new 4ga power supply to the alternator and new ground the the alternator.

Got it all buttoned back up, plugged the ignition box back in, turned the key and what do you know, it started. hmmm, that got me thinking.

A few weeks ago when I was waiting on the RGA number from Accel I removed the ignition box. After a day or so I realized, oops, I need to move the truck. Prior to removing it the truck wouldn't start but I figured I'd try. I put the box back in and it fired up first try. Hmmmmm

Sent the box out, they tested it, it's perfect but sent me a different one anyway.

Got the box back, installed it, it fired right up. hmmmm

Anyone else seeing a trend here. It APPEARS that everytime I have a problem with it starting and I unplug or remove the Accel ignition box for X time, it starts when I hook it back up.

Could this be a GM security issue? I don't THINK it's VATS because everything I've read sounds like the vehicle will start for a second then die. Mine has NO spark. In HPtuners my vats is set to serial. Should I change it?

The truck is Sale Pending and I want to make sure the guy is all set before he picks it up. Thanks in advance for any info.