Hello to all. Well today I let my daughter use my 2001 chevy blazer to go take her driving test.Anyways on her way home she said that the battery light came on after she stopped to get gas.She said that it was hard to start after getting gas.

After about 1 mile she says the battery light came on again but the truck was running fine so she just keept on driving.....Well about 15 miles down the road the motor died on her just off the interstate.So she pulled it to the side and tried to start it again but no start.

So I get a call at work telling me of this wonderful news.So I leave work go to where she is at and ask her if it still cranks or is the battery dead because from past experiences when the battery light comes on usually its the alternator and then the car dies because all the juice in the battery is used up.

Anyways, she says "no dad it still cranks but won't start"I am like huh?So I think fuel pump????No way I say it is brand new only 2 months on it and it is not the cheap ones it is a genuine ac delco.So I turn the key listen for the pump it turns on sounds wonderfull.

I then crank and crank,plenty of juice to crank the motor and all the lights work nice and bright but no start.I check the connections,all wires,everything looks good.I then checked for spark,plenty there.I checked all fuses related and all are good.

So my question is, if the alternator goes bad and is not producing the proper voltage will this cause the motor to stop and no start back up?It has the amps to crank normal that is why I am wondering if a alternator goes bad will it cause a car to not start?I was thinking this because of maybe the pcm needs a certain amount of voltage and certain sensors need a certain amount of voltage to operate?

On older cars it was easy,battery light goes on battery goes dead car dies! I just don't get it and she is positive the battery light came on and stayed on for at least 15 to 20 miles.I asked her boyfriend that was with if this was true and he said yes.So, if anyone knows before I go through the motions of removing the alternator and buying a new one is this the problem?

Thank you for any info!

 

i would not buy an other alternator

id test the one on the truck its self and also get the battery tested

this can be done by bringing them to any auto parts stores
they do it for free

 

Ya I planned on that but was wondering if the alternator goes is this a symptom that can happen with there being plenty of cranking amps but no start.

 

its possible but it never happened to me before

have you checked the cables after cranking it ? do they get hot?

i had a truck that did that . The neg would always get hot and never would start till it cooled off
i ended up replacing the cable and it was good as new

 

Will check. You know if I remember correctly a long time ago I had a ford thunderchicken that the battery light came on car died,it still cranked good but would not start.I replaced the alternator after taking it in to find out it was bad and started right back up after replacing. At least I think that is how it happened,lol.

 

Update, well went to the truck this morning decided to just for chance try to st start it and bam it starts right up.So i drive to the local auto zone runs great all the way there.Shut it off go inside ask them to test the alternator and battery,he checks the battery and says its perfect. Then he says start it to check the alternator and guess what....it wont start. I try and try but it just sputtered once but never will fire up.

We get to talking and he says sounds like you are not getting fuel maybe so we check to see if fuel pump is priming and it prims everytime we turn the key.Next he says sounds like the ignition control module and he can test it.So he says wait 10 min see if you can get it started i wait 15 min still no start.I had to leave it there and am planning on going there later to try again to get it home to investigate more.Also the battery light was not on when I drove it to the zone so I have no idea if it was ever on but my daughter swears it was.

Any ideas?

Oh ya and also we checked for codes only ones coming up are for the secondary air pump which has been there since I bought the truck 2 years ago.

If a ICM is bad will it still produce spark? I checked for spark at the coil and it has plenty of spark.I am going to take it off and check it just was wondering till I can get to it.

 

Bet you when you go over later it will start when cold. A bad ICM will fail when it warms up then cool down and act normal. As far as your spark question, I just don't know. Oh yes, bring a drill and some small bit's. Not sure but I think they come from the factory with a couple off rivets, and replaced with small nuts and bolts.

 

Thank you for the heads up, I sure hope that is the problem cause it is a easy fix.

 

The battery lite no longer reflects the output of the alternator, it reports the operating voltage as seen by the PCM {engine computer}.
- the exception is key on, engine not running, which the PCM then lights it as 'lite test'.

The voltmeter reports the voltage at the underhood fuse block via I/P block.

Since there were no cranking problems, the alternator actually is fine and you would have seen 13 v or more on the volt gauge.
Time for the old 'tug test'
What this means is you start at the major fuses affecting the PCM in the underhood fuse block and follow the wiring harnesses to the PCM. wiggle them all the way around while looking for change.

Also look at the wiring coming from the ignition switch and the switch itself., and all the grounds at the rear of the engine.

 

Thank you for the info I sure will check the wires going to the pcm and the ignition. It is just weird how this happened.

Also I forgot to mention that over the last few weeks the truck spits and sputters when cold or damp out when you thromp the gas pedal it responded good only did this while accelerating slow to normal and when colder out or after it rained and was damp outside.As this was occurring I was thinking bad cap and rotor but never got to it.And the sputtering would go away after good and warmed up and didnt always occur either.