my car wont start up. it is a 96 ls. it turns over easy but wont fire..i checked spark and that is fine, and i am getting fuel. i need to check the timing next, but the strange thing is once i crank it over a couple of times and leave the key in the ON position i get this electric humming noise from either the firewall side of the engine bay or the intake mainfold. i cant tell it is hard to pinpoint. i have never heard this before, and if my timing turns out to be ok i really dont know what else it could be but this weird noise has to have somthing to do with it. anybody have any suggestions??

oh ya and i am not getting any cel's

 

bump i need some answers!!!

 

My car did the exact same thing. Did it just hum for a few seconds then stop? Ended up needing a new coil and distributor.

 

it sounds like a the kind of noise a transformer emits, and it continues until i turn the key to the OFF position. it will have to remove the distributor and check it out

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bcrosby51 &raquo;</TD></TR><TR><TD CLASS="quote">My car did the exact same thing. Did it just hum for a few seconds then stop? Ended up needing a new coil and distributor. </TD></TR></TABLE>

were u getting spark though?

 

The hum could be your fuel pump

 

How did you check for fuel ? Did you take off the injectors to see if there firing ? You only need 3 things to start a car, fuel, spark, and compression. I doubt you lost all your compression unless your timing belt broke.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RCautoworks &raquo;</TD></TR><TR><TD CLASS="quote">How did you check for fuel ? Did you take off the injectors to see if there firing ? You only need 3 things to start a car, fuel, spark, and compression. I doubt you lost all your compression unless your timing belt broke.</TD></TR></TABLE>

i didnt check every injector but i can hear the fuel pump prime and i smell gas after i crank it a few times. inspecting the injectors is a good idea though.

 

did you get your car running?

 

nope i am on vacation for a week, so i havent even had a chance to look at it since i posted this the other day.

 

update:

i found out what was making the humming noise, it was the iac valve. i disconnected the iac connector and the noise stopped. i am going to remove it and inspect it further. if this was malfunctioning would it not allow the car to start??


Modified by THE LORD OF CHAOS at 10:43 PM 9/10/2007

 

iac wouldnt keep the car from starting... check for spark, distributors are very common problem and then next main fuel relay but that would mean u wouldnt get any fuel.. check for spark and make sure ur timing belt didnt break... let us know what you come up with so we can help u out

 

the timing belt is not broken, and im getting spark. i could smell gas earlier, but didnt take off the line and check yet. i will do that and if it is good then i am planning on checking the main relay next.

 

Main relay should be farely easy to check for. Turn ur key to the on position and while under ur engine bay and see if u can hear a hissing sound coming from the fuel line, it should hiss for about 2-3 seconds then stop, that'l let ya know if ur fuel line is priming or not.

 

i know with the da's if the main relay is bad the check engine light comes on when u turn the key and usually it clicks off but if the relay is bad is will stay on...

 

i checked the distributor's ckp/tdc/cyp resistances and found something interesting. the spec for a 96 year model is 500-1k ohms. i got 370 ohms across the board. i am guessing that may be my problem. i havent checked the coil resistances yet but i plan to do that tomorrow.

 

replaced the distributor and still not working.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by THE LORD OF CHAOS &raquo;</TD></TR><TR><TD CLASS="quote">i found out what was making the humming noise, it was the iac valve. i disconnected the iac connector and the noise stopped. i am going to remove it and inspect it further. if this was malfunctioning would it not allow the car to start?? </TD></TR></TABLE>

What was wrong with the iac valve?
im asking because im getting the same sound, did you end up replacing the valve also?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by takeit &raquo;</TD></TR><TR><TD CLASS="quote">

What was wrong with the iac valve?
im asking because im getting the same sound, did you end up replacing the valve also?</TD></TR></TABLE>

i didnt find anything wrong with the iac valve. i removed it cleaned and operated the valve and it opened and closed just fine. it seems to be a symptom of something else that i havent figured out yet.

 

When, how did the no start issue start? Did you just park it one day and the next time you went to start it it wouldn't fire, or were you messing with it in between when it was working and not working?

Have you had your plug wires off & Are you positive they are in the correct firing order?
Have you pulled the plugs and inspected them after cranking to see if they are wet with gas?
Maybe a bad head gasket, check for coolant on the plugs while you have them out. Plugs with coolant don't work well.
Have you tried to check for spark at the plugs while they are out?

 

i am having hte same problem. getting, fuel, spark, and crank turns over. but I have a VERY rough idle if any idle at all. My IACV is humming. I just performed a motor swap. I was able to idle for 10 seconds so i know my timing belt is good, my wires are in the right firing order, and my engine harness is not shorted, and my ECU is working fine. I get a solid CEL with teh service connector jumped.

I am really starting to think the humming is a bad IACV coil. I hear the clicking, but it might not be working right. one was a fire recovered unit, the other i have came off another motor I own that had difficult cold starts 20% of the time.

any suggestions?

 

Im experiencing this also, when i put me ear next to the hole in the passenger side fender its louder but it may just be echoing. Where is this humming coming from?

 

did any of you ever solve your problem?

 

i forgot about this post. i performed a compression test and found out that i had adjusted the valves a bit too tight.

 

bump for an old post...but did you ever figure out what was wrong?