Car dies, starts right back up

**herculesrider1** · 10-18-2017, 07:32 PM

While driving down the road, the car is running smooth as silk, and then out of nowhere, it dies. All the lights come on on the dash. When I try to restart it, from run position, it won't do anything, until I turn the key all the way to off, and then restart it normally, immediately it restarts. Drive a few more minutes, and it does it all over again. It went for several days without doing it, and then tonight it did it again. I've seen EGR valve, fuel filter, fuel pump possibilities, but in those cases, their cars would not restart immediately. Mine restarts right away, while I am still rolling, as long as I turn the key all the way to the off position before trying to restart it. Hopefully when it happens I am going straight ahead!! It happening in the middle of a turn could be bad news. Any help would be greatly appreciated!! Thanks in advance!

**pajeff02** · 10-19-2017, 03:10 AM

Scan the PCM for codes?

**herculesrider1** · 10-19-2017, 07:07 AM

Will it throw a code even if the check engine light does not come on?

**pajeff02** · 10-20-2017, 06:58 PM

Certain codes can show up as "pending". Depends upon the issue as to whether or not the SES is tripped. Some faults trip it the first time the issue occurs, others require the issue to repeat a specified number of times before the light is set. I would scan it to start the diagnostic procedure. Post the codes, if any.

Absent any codes, the engine needs fuel, air and spark to run. An intermittent fault can sometimes be traced to a loose or damaged wire connection. Pay particular attention to grounds too. Always start the diagnostic by looking at anything that has been modified from stock. This includes any wire connections in the area that the work was performed.

**herculesrider1** · 10-22-2017, 01:48 PM

I checked with an OBDII analyzer and there were no codes thrown. It happens usually about 20 to 25 minutes after starting the engine. Runs fine during that time frame.
When it starts dying, it happens about every 30 seconds. Going to try replacing the fuel filter for starters and hope that does it. Least expensive first!! Thanks for your help!

**pajeff02** · 10-23-2017, 02:56 AM

Check fuel pressure while you are at it, please.

**herculesrider1** · 10-25-2017, 07:20 PM

I replaced the fuel filter, but it died on me about 5 times tonight, so, obviously it's not the fuel filter. I don't have a pressure gauge, so can't check the pressure here at the house. Will have to hit the mechanic shop. Just doesn't make sense, running for 25 minutes and then dying. Runs strong during that 25 minute time frame. My headlights and dashlights stay on while and after it dies. The only thing that has changed is the bright light connector got plugged back in under the dash. Before that, I did not have bright lights, but this dying never happened.
I wonder if unplugging the bright connector would stop it. Will have to try that.

**pajeff02** · 10-27-2017, 03:11 AM

Any time an issue pops up out of the blue, it is never a bad idea to go back to the last thing you did on the car and double check your work.

**herculesrider1** · 10-27-2017, 11:37 AM

I thought initially that when the dimmer switch connector got plugged back in, that it might be a stray ground. However, after subsequent research, it seems like it would take more than a ground to stop the engine from running. Three components are needed to allow the engine to run:Air, Fuel, and Spark. I am thinking that I am losing fuel and spark that is making the engine shut off completely. And it has to be something that shuts off and then immediately resets itself in order to immediately fire back up. I am narrowing it down to a sensor. Can't be a fuse,
because a fuse does not repair itself. However a sensor can be on it's way to going out, before total failure. Troubleshooting sensors is a job in itself!

**pajeff02** · 10-27-2017, 04:01 PM

Swap out the fuel pump relay with another of the same type in your electrical box and see what happens. Without any codes to point you in the right direction this could be a time consuming diagnostic. Is the pump stock?

**herculesrider1** · 10-27-2017, 05:22 PM

Ok, I'll try the relay swap. I don't know if it is the stock pump. The guy I bought if from built it for racing, and included all the receipts when he sold it to me, but a receipt for a new fuel pump was not there. I would assume it would be a high flow racing fuel pump. The typical "hatch" is not cut out over the fuel pump, but he might have dropped the fuel tank to replace it, if he did. I will contact him and find out. On another note: I have been reading that the Crankshaft Sensor controls fuel and spark. My little sister had the dying issue in her Dodge Ram pickup and they told her it was a Crankshaft Sensor. She never got it replaced, so I don't know if that was the fix. I don't have all the diagnostic scanners or software that some have, so my troubleshooting capabilities are extremely limited. And I hate to guess and replace, guess and replace....that gets expensive! Thanks for all your help! Will keep on trying!

**pajeff02** · 10-28-2017, 03:22 PM

Crank sensor is fairly easy to get to. Back side of the block on the passenger side. A faulty sensor should trip a code though.

**herculesrider1** · 10-28-2017, 05:13 PM

Yes, I was surprised that when I went to AutoZone, and put it on the scanner, it had absolutely no codes. I have read that the problem has to happen so many times before it registers a code that will stay, and then the check engine light will come on, but none of that has happened. Passenger side? I have been told that the Crankshaft Sensor is behind the starter motor on the drivers side of the block. And in order to get to it, you have to remove the starter motor. I have seen that the Camshaft Sensor is at the very back of the block, center, right up against the firewall. Let me know, because I don't want to jack up the drivers side of the car, when I need to be on the passenger side!!

**pajeff02** · 10-29-2017, 10:10 AM

Starter motor is on the passenger side.

Depending upon the DTC (Diagnostic Trouble Code), some will set the light on the first failure, while other may require two or more failures to set the light.

**herculesrider1** · 10-29-2017, 02:17 PM

Thank you sir! Should be an easy job!

**herculesrider1** · 11-02-2017, 10:20 AM

Hello Jeff, I replaced the Crankshaft Sensor, which was fairly straightforward, but still have the dying issue. I have read also that it could be a Camshaft Position Sensor.
Can you tell me where it is located? Is it on the back of the block directly behind the intake manifold? Is it accessible without taking off the intake? Thanks in advance!

**herculesrider1** · 11-02-2017, 10:30 AM

Hey Jeff, I just called the Chevy Dealership and they told me that the Camshaft Position Sensor location was on the top of the block, in the rear, near the firewall, in between the heads, directly behind the Intake Manifold, and installs vertically down into the block.

**herculesrider1** · 11-02-2017, 07:35 PM

Ok, I contacted the previous owner, the one that built the car for racing, and he said that he did not replace the fuel pump. I went to AutoZone this afternoon, and purchased a new Camshaft Position Sensor, but the more I think about it, if it was a CMP Sensor, it would be throwing a code. That is most likely why replacing the CKP Sensor had no effect,
because it did not throw a code, and most likely nothing was wrong with the old one. Once it starts happening, it happens many, many times, and it seems like it would throw a code. Scratching my head on this one.....

**Whamhammer** · 11-03-2017, 06:56 AM

Kinda reminds me of what use to happen to Fords old EEC-IV system. Car would run, the computer would get heat soaked and stop working, car shuts down. After the computer cools down for a few minutes, the car would start right up again.

**herculesrider1** · 11-03-2017, 06:31 PM

That's another thing that has me baffled. It doesn't have to cool down to restart. After it dies, while still rolling down the road, I turn the key to the off position, and then push in the clutch, and turn the key to the start position, and it immediately starts right back up! The red bird is spending the night in the mechanic's shop. They put her on a scope, and stated that they didn't know how it was that she was even running! Said the sign wave was almost flat lined, when it should have been a wave form that resembled the top of a castle wall _l-l_ , the middle dash would be at the top is the way they say it normally looks on the scope. I was also told that the new Crankshaft Sensor needed to go through a crankshaft relearn procedure on a Tech 2 tool.
Anyone heard of that before?