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Crank but no start

Tiny
PACORA
  • MEMBER
  • 2004 CHEVROLET ASTRO
  • 4WD
  • 200,000 MILES
I drove the car, parked at home and when I tried to start, I could not. So I decided to do a little upgrades in the van (I have not done anything since I bought the van a year ago). So I replaced the spark plugs, wires. Here is more info about my situation: something when I drive it will shutdown out nowhere. I lose power and everything goes dark, so I open the hood move my battery back and forward and I get power again, I go back to my van and crank, start without any problem. This has been going for about 3 months, well now I park the van and it will not start. I tested the ECM B fuse. And the fuel pump relay and they are both good. I can hear the pump when I turn the key on I confirmed there is 12 volts power and good ground. Here is where I need help. I keep hearing about the computer needs a RPM signal. Where this signal is coming from? Also there are 4 wires at the pump, gray (power) black(ground) purple? And orange? What are the purple and orange for? I am looking for that darn rpm signal and I do not where to start. Any help, tips for this? Thank you very much.
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Sunday, March 1st, 2020 AT 3:17 PM

13 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good evening,

The signal comes from the crank sensor. When you crank the motor, does the tachometer move up a little?

I would start by cleaning the battery cables for the no power issue.

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

Roy
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Sunday, March 1st, 2020 AT 4:51 PM
Tiny
PACORA
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  • 7 POSTS
I am still looking for the cause of my van, I tested the fuse, relay, they are good, I tested the fuel pump, and I can hear it, and I tested it with an outside battery and I can hear the pump working, so far so good, I tested the wires for power to the pump and the ground and they are good, I have new spark plugs and wires rotor and cap, and I can confirm the new ignition coil is working, I can see sparks, I have no idea what else to do. The van crank but will not start.
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Monday, March 2nd, 2020 AT 11:45 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Do you see the tachometer move up a little when cranking?

Do you have voltage at the crank sensor?

Do you have a scan tool to see RPM?

Can you test the fuel pressure?

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Roy
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Monday, March 2nd, 2020 AT 11:49 AM
Tiny
PACORA
  • MEMBER
  • 7 POSTS
LOL, Roy. I was reading another posts where you are helping another person test wires and find between PCM and ECM. Anyway. I have more experience in car repairs, wiring diagrams. So here are what I have done so far: I have a fuel pressure gauge, I connected to the test port and there is not pressure. It sits at 0. I have not test for voltage at the crankshaft sensor. I do have a scanner I will try it later to see if I get any live data.
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Monday, March 2nd, 2020 AT 12:36 PM
Tiny
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You need to 0 in on the fuel pressure.

Do you have power to the pump?

Roy
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Monday, March 2nd, 2020 AT 12:54 PM
Tiny
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  • 7 POSTS
There is a 12 volts on the crankshaft sensor. I just tested it, the pressure reading on my gauge is 0, also I used my scan tool and my rpm during cranking reached only 122 rpm.
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Monday, March 2nd, 2020 AT 1:48 PM
Tiny
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Okay, crank sensor is working.

You need to test for voltage to the pump.

Roy
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Monday, March 2nd, 2020 AT 1:57 PM
Tiny
PACORA
  • MEMBER
  • 7 POSTS
Here is something weird: my car did not produce a code now that I used my tool it did. So I was getting a code p0351 ignition coil 1 control circuit, let me give you a bit of history of this van: about a two months ago I was coming home and my van just lost power while I was driving, it completed shutdown on my on the road so I pulled on the side, I cranked it so many times, but no start. So I towed it, so I found out that my ignition coil was bad, so I purchased a new, installed it and my van started up nice. And I drove like that for about a month, one thing I just found out was the connector to the ignition coil does not down until clips. Weird, this is the new coil I purchased about two months ago. I tried to put my old one back. And it fits nice and snug. So I am not sure this has to do anything with my crank no start situation.
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Monday, March 2nd, 2020 AT 2:00 PM
Tiny
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You said it had spark so it is not related.

The fuel pressure is your focus now.

Roy
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Monday, March 2nd, 2020 AT 2:02 PM
Tiny
PACORA
  • MEMBER
  • 7 POSTS
Hi. An update of my situation. After doing and searching for possible fix. I did two things, I cleaned a lot of the grounds around the van, but I also noticed something weir, my new coil, was not producing the nice thick, blue spark. So I ordered another coil ACdelco. And my van started(for the first time in 3 weeks)fine. I took it for a test drive, van ran fine, a bit rough, but fine, today I went to AutoZone to get the body trim fasteners and when I was pulling out of the parking lot, my van shook like it was missing power. I get two codes p0300 and p0420. So I drove back home and now I am troubleshooting a new problems. Thanks.
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Friday, March 6th, 2020 AT 2:11 PM
Tiny
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Okay, the 300 is a multiple misfire code. The most common issue is fuel pressure.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

The 420 is for a cat converter. It needs to be replaced.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Roy
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Friday, March 6th, 2020 AT 3:00 PM
Tiny
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  • 7 POSTS
I do not understand. New wire, new spark plugs, new distributor, new fuel pump, the van ran really good all day yesterday, without any problems. So we can rule out fuses, relays, sparks, right. I just do not why cause the van to run fine one day and the next few hours. I get a p0300. Let's forget about the p0420 since I am not longer getting this code.
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Friday, March 6th, 2020 AT 4:56 PM
Tiny
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The 420 will come back. Clearing does nothing.

Can you give me the long term trim readings while it is running?

Can you double-check the fuel pressure?

Roy
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Friday, March 6th, 2020 AT 5:01 PM

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