No start No spark

Tiny
BOWHUNTER247
  • MEMBER
  • 1988 CHEVROLET S-10
  • 2.8L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 120,000 MILES
Great truck never had a problem with it. Its my daily driver. I pulled into the store yesterday and came back out and it would not start. Towed it home got up the next morning took battery cables off and put them back on and she fired right up like nothing happened. Let it run for about 30 min cut it off came back out 1 hour later to go to the store and it just cranked so I took 1 spark plug out and tested it and it was not getting any fire so I replaced ignition module and still no start then I replaced ignition coil and still no start the check engine light has been coming on and going off for 3 days now also it idles a little higher and louder when It was running. Also when I turn the switch on the fuel injectors are not spraying gas out of them. I have no idea why its not fireing up it has to be something simple. Fuel pump is kicking on this has never happened any advice would be great thanks.
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Saturday, February 20th, 2016 AT 12:45 PM

9 Replies

Tiny
CARADIODOC
  • EXPERT
Everything you described is typical of a failing crankshaft position sensor or camshaft position sensor. The Check Engine light tells you the Engine Computer detected a problem and set a diagnostic fault code. You can go here to read the codes yourself to get a starting point.

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Only Chrysler makes reading fault codes yourself easier.

When you referred to no fuel spraying from the injectors with the switch on, are you expecting to see fuel spraying by just turning on the ignition switch? Or are you referring to a helper is cranking the engine? If you're missing both spark and fuel during cranking, neither system is going to have the problem. You have to look at what both systems have in common, and that's the two sensors I listed.
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Saturday, February 20th, 2016 AT 1:54 PM
Tiny
BOWHUNTER247
  • MEMBER
I am not shure a 88 s10 has a crankshaft position sensor. Any other advice? I am leaning more to the distrubuitor cap and rotor.
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Sunday, February 21st, 2016 AT 8:00 PM
Tiny
CARADIODOC
  • EXPERT
Now hold on. The engine failed to start, you're guessing because of two parts that failed at the same time, then somehow they fixed themselves by removing a battery cable? Did you even try starting the engine before removing the cable?

No-start conditions are not "reset" by disconnecting the battery cable. If that's all it took, every car owner would know how to do that.

If you want to look at something that really COULD magically fix itself simply from cooling down for an hour, that's the crankshaft position sensor. You're right that your engine doesn't use a part with that name, but it does use a part with that function. It lives inside the distributor where breaker points were many years ago. On your engine it's called the "pickup coil" or "pickup assembly". It's not uncommon for the tiny wires to break due to constant expanding and contracting from temperature changes. That occurs more commonly when a hot engine is stopped. While driving, cool air flows through the engine compartment and keeps the distributor cool. When you stop somewhere, "hot soak" allows engine heat to migrate up into the distributor where the pickup coil expands just enough to break a connection. It will cool down and work again after about an hour. This is by far the most common way these sensors fail. They'll be intermittent for days or weeks before they finally fail completely.

The clue to this is the pickup coil's signal is used by the Engine Computer to time spark and injector pulses. If there's no signal, the computer assumes the engine isn't rotating, (cranking), so why would it fire injectors or the ignition coil?

The first thing to do is read and record the diagnostic fault code(s). This page will tell you how to do that yourself:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

It takes just the right set of conditions to set a code related to a crankshaft position sensor, and often they will not set unless the computer sees the loss of signal while the engine is coasting to a stop. Regardless, disconnecting the battery erased any codes so that valuable information was lost. Whether there was a code or not before, and regardless if there is no code now, don't take that to mean the sensor is okay.
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Monday, February 22nd, 2016 AT 9:33 AM
Tiny
BOWHUNTER247
  • MEMBER
I checked the pickup coil everything seems to be working right. The good news is I am getting fuel out of the injectors now. Tried to jump my battery off and it cranks real slow so I am assuming my battery is pretty much shot. I changed my dist-cap and rotor and noticed my rotor was a little burnt checked my fire order and it is right. The truck still did not fire up. I am going to replace my battery today to see if it that is my problem. I am getting frustrated with buying all these parts and its not fixing my problem.
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Tuesday, February 23rd, 2016 AT 10:53 AM
Tiny
CARADIODOC
  • EXPERT
Have you checked the diagnostic fault codes?
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Wednesday, February 24th, 2016 AT 10:47 AM
Tiny
BOWHUNTER247
  • MEMBER
I used a paperclip to check the codes and the only code I got was code 12. Witch means system normal accoeding to the chart.
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Wednesday, February 24th, 2016 AT 8:36 PM
Tiny
CARADIODOC
  • EXPERT
Rats. If there was a code, it got erased. The next thing is to connect a scanner to view live data. There should be an "inputs / outputs" screen that shows the crank sensor, and an indication of whether that signal is being received by the Engine Computer. If that isn't shown, it should show if the fuel pump is being commanded to turn on. It's much more common to have a no-spark condition that includes no fuel pump due to something they have in common than it is to have a simple ignition system problem.
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Friday, February 26th, 2016 AT 8:48 AM
Tiny
BOWHUNTER247
  • MEMBER
FIXED-Should have replied sooner. I found the problem it was my distributior replaced it and it fired right up thanks for all the help.
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Tuesday, April 19th, 2016 AT 1:59 PM
Tiny
CARADIODOC
  • EXPERT
Dandy. Happy to hear it's solved.
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+1
Tuesday, April 19th, 2016 AT 3:09 PM

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