Engine wont start

Tiny
00IMPALAKID
  • 2000 CHEVROLET IMPALA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 174,000 MILES

I have had huge problems with car not starting. All I hear is a relay click somewhere under the dash. Had the car in Napa certified shop for a month, replaced BCM, worked for about a month, then started doing it again. Fuel pump cycles, the car just does not attempt to crank over. Its random, sometimes it works, sometimes it doesn't. In the winter or cold weather it is much worse. Check engine light is on. Codes: "mil off, Monitors, 5 inc, catalyst, evap, 02 sensor, 02 htr, egr, 3 ready, misfire, fuel, comp" I have put over a thousand dollars into trying to fix this problem. Please help me!

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Friday, December 31st, 2010 AT 10:31 PM

121 Replies

Tiny
JACOBANDNICKOLAS
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The codes have nothing to do with a no crank situation. Has the starter relay been checked? Has the ignition switch been checked?

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Monday, March 14th, 2011 AT 12:24 PM
Tiny
00IMPALAKID
  • MEMBER

Yes the starter relay has been checked, and the ignition switch has been completely replaced, tumbler, passlock, switch, etc. I can turn the key to the "on" position, and take out the crank relay under the hood, and if I jump the crank relay terminals with a wire it will start, but the guages don't work. You think it could be a bad ECU?

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Tuesday, March 15th, 2011 AT 9:01 PM
Tiny
JACOBANDNICKOLAS
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If you can jump the starter relay, then there is no power getting to where it needs to be. Recheck the wiring to the ignition switch. Even though the switch is new, there has to be a problem between the two.

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Tuesday, March 15th, 2011 AT 11:55 PM
Tiny
00IMPALAKID
  • MEMBER

Okay I will do that. Do you think that the main computer could be causing this too? Because their are lots and lots of small problems, headlights flashing, gauges not working sometimes, windshield wipers going by themselves, etc. That seem to be part of a bigger issue. And now the tranny is just not shifting right and the rev limiter or something is all weird. Thats why I am wondering about the ECU, but not sure.

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Wednesday, March 16th, 2011 AT 3:30 AM
Tiny
JACOBANDNICKOLAS
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It could be. Since you are having that many electrical problems, it makes me wonder if you have a ground issue or body control module (BCM) issue. Just for the heck of it, make sure the battery terminals are clean and tight, the cables are in good condition, and the ground to the engine block is clean and tight.

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Wednesday, March 16th, 2011 AT 3:39 AM
Tiny
00IMPALAKID
  • MEMBER

Yes all that stuff is clean and has been checked. I had it at a mechanics shop for 6 months, and he completely looked the car over (so he says) and replaced the bcm. 1,000 dollars worth of work. I have also checked all the basics, replaced the started, checked all the obvious grounds, everything I can possibly think of. I have had multiple mechanics look at it, they all seem to say its a computer or a ground issue, but they have all been checked, the ECU seems to be the last reasonable option. I also went to a junkyard and bought an ECU and plugged it in, now I have the same problems with some other new things, so I was thinking getting the ecu scanned into my actual vehicle might work. But im not a mechanic, so who knows. The problem was completely random, started about 18 months ago out of no where, so I dont know what the deal is with it

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Wednesday, March 16th, 2011 AT 3:50 AM
Tiny
JACOBANDNICKOLAS
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First, make sure the ECU you got has the same part number. If it is different, it won't work properly. Since everything has been checked, I still feel the problem is in the wiring between the ignition switch and the relay. You could have an internal break in the wiring that can't be seen. As a result, continunity needs to be checked through the power supply wires.

I have attached a schematic of the starting system for you to look at. There are a few things I need you to check. First, from the + remote (under the hood) Power is supplied to the ignition switch via a red wire. Check at the switch to make sure it is hot. From there, it follows a yellow wire to the PCM crank fuse (10 amp). Make sure it isn't blown and make sure you have power in that wire with the key in the start position. After the fuse, the wire in question is purple and runs to the PCM crank request / crank relay control in the air box (check for power). If there is still power, the wire to follow is yellow with a black tracer which runs to the underhood junction block (pin C10). (Check for power) From there, power comes out from a purple wire (pin B10) and goes to the starter solenoid. Check for power. Keep in mind, the purple wire actuates the solenoid and energizes the starter. However, the true power to the starter (to turn it) is always hot. It is the big wire directly from the battery. Also, all of the places I said to check for power needs to be done with the key in the start position, and there should be 12 volts present. If you have power throughout the map I sent you, the starter system has been checked. Which leads me to the next question. Are all the wires in the junction block (under the hood) clean, tight, and not corroded.

Sorry this is so long, but it takes awhile to explaine it all. Also, I want you to let me know if the vehicle has a factory remote start system. Finally, when you are checking for power, make sure to move the wires around to make sure power continues to flow and not stop.

Let me know what you find.

Joe

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Wednesday, March 16th, 2011 AT 4:17 AM
Tiny
00IMPALAKID
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Alright AWESOME! I will check that stuff tomorrow. And no their was no factory remote start, BUT I did install a remote start, around the time it actually started getting bad, now that you mention it. One mechanic told me to take it out, so I did, but still didnt solve the problem. Think that could be something that is related?

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Wednesday, March 16th, 2011 AT 4:34 AM
Tiny
JACOBANDNICKOLAS
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It could have caused the problem. However, if you replaced everything back the way it was, it should be fine.

Let me know how you make out with the problem.

Joe

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Wednesday, March 16th, 2011 AT 4:37 AM
Tiny
00IMPALAKID
  • MEMBER

I was checking the numbers on the original computer, and the new computer (from a junkyard) and I noticed the numbers are a little different, and I was wondering which numbers I wanted to be the same. The Original ECU and New ECU have the same "serv no.", "HDW No.", But the 4 letter number at the end of each is different. The old one says "DAXH", but the new one says "CURC". They both look the same and are the same brand and everything. The only difference is that 4 letter code. I am not sure exactly what the computer came from. I bought it from a yard and told them I needed one for a 3.4 2000 impala, but they could have gotten me the wrong one. Any idea's?

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Thursday, March 17th, 2011 AT 12:05 AM
Tiny
JACOBANDNICKOLAS
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That is a concern. The computers are different based on the transmissions, options.

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Thursday, March 17th, 2011 AT 2:06 AM
Tiny
00IMPALAKID
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Okay, so I probably shouldnt use that computer? I noticed with this computer it shifts really weird and the rev limiter seems different. Would that be fixed once it was scanned in at the dealer? Or still not right? I was also taking a test light to the wires that go into my ignition switch. When the ignition is off, one wire (red) is hot, all the rest arent. When I turn the key to on, all of the wires become hot except one (orange). But sometimes, none of the wires become hot. Is this normal? Or could this be part of my problem? And also the headlights are flashing (I can hear 2 relays clicking inside the car) even when the comp is unhooked, and the headlight switch is unhooked it still does it. I have looked through for damaged wires, but can only see so deep. Im not sure if these problems are related but i'd like to think I fix one, the other will become fixed as well. I am not so sure its the computer. With the computer hooked, or unhooked, it still does the same things when I go to start it, but with the old (stock computer) the gauges seem to work, just doesnt attempt to start. I don't know where to go. I tried to understand your directions written a few posts above, but couldnt find the pcm fuse or the +remote wire you were talking about. Its a 3.4L 2000 impala with the ignition on the dash. Im sorry im a pain in the rear. But I have put so much time into this car, and thousands and thousands of dollars into cosmetic changes but now I am stuck with a nicely done car that wont start and im in college so it just really sucks. I want to take it to a mechanic again, but the last two both screwed me over and couldnt fix it.

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Thursday, March 17th, 2011 AT 2:16 AM
Tiny
JACOBANDNICKOLAS
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The "remote +" is where the positive battery cable connects under the hood. As far as the red wire, it should be hot all the time.

Based on what you said about the ignition switch wiring being hot sometimes and not others, I think you have another bad ignition switch or something is out of alignment. Were you able to read the schematic?

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Thursday, March 17th, 2011 AT 2:27 AM
Tiny
JACOBANDNICKOLAS
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PS: Put the original PCM back in too.

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Thursday, March 17th, 2011 AT 2:28 AM
Tiny
00IMPALAKID
  • MEMBER

Damn. So should I just buy a whole new ignition switch and try that? And what could be out of allignment? I cant read the schematic the writing is too small. Any chance you could find a larger one? I blew it up but still couldnt read it. And alright, im in the garage doin it now. Putting everything back to stock

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Thursday, March 17th, 2011 AT 2:33 AM
Tiny
JACOBANDNICKOLAS
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That is the largest schematic I have and can't get it bigger. It sounds like a bad swith to me based on how you said it was working.

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Thursday, March 17th, 2011 AT 2:29 PM
Tiny
00IMPALAKID
  • MEMBER

Okay ill try and blow that up and read it. Ill try replacing the ignition too. Also, I unplugged the BCM and it stopped the headlight flashing. You think that could be bad once again? And as far as replacing the ignition, its the wires that dont have juice to them. Not sure if that is switch flaw or something to do with one of the computers or something. I want to take it to a mechanic, but don't want to get screwed out of another grand. Soo frustrating

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Friday, March 18th, 2011 AT 3:35 AM
Tiny
JACOBANDNICKOLAS
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There should be at least one wire that is always hot to the ignition. If you don't have that, the switch may be fine.

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Friday, March 18th, 2011 AT 12:58 PM
Tiny
JUNKNAF
  • 2000 CHEVROLET IMPALA

Engine Performance problem
2000 Chevy Impala V8 Two Wheel Drive Automatic 160000 miles

try to start car everything comes on in the inside but the car wont start and the check engine light comes on

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Monday, April 3rd, 2017 AT 11:59 AM (Merged)
Tiny
RASMATAZ
  • MEMBER

Check what's missing if its fuel or spark do below

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine atleast 3/16 away from ground-have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs, coil's resistances, distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it

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Monday, April 3rd, 2017 AT 11:59 AM (Merged)

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