low spark
 

hi everyone, well my car doesn't want to start and the problem i'm getting is not enough spark. it is a 1990 300zx NA with manual transmission and performance air filter, headers, and cat back exhaust.

i tried to clean the IACV and it started up just fine than shut off, i did that 3 times before i went to autozone to get some heaterhose. when i got back it didn't start or even turn over. my battery has enough volts to turn the starter, i'm getting air and fuel. my mechanic checked everything from the wiring harness, ecu, fuel system, coils, alarm system, ect and he can't figure it out. he only works on z cars so he is very knowledgeable with the car. i have done alot of work with him so i know he isn't taking his time to get more money.

so my question to you guys is what kind of ideas do you have for having low spark.

LOL. I'd say there is a 1% chance you have a spark problem.

What do you mean it won't even turn over? The engine won't crank?

What'd you clean the IACV with?

how do you know what level of spark it's getting? it's either getting spark or it's not.

also, if it won't turn over, 1. how do you know it's not getting spark and 2. why would you be worried about the spark? test voltage at the starter

ok well the engine won't crank after i came back from autozone, i used wd-40 to clean the iacv, and i have spark but it's not strong, all i get is some light shock when i put my hand on it and try to crank it

Are you sure your battery has enough amps to turn over the car? Does it just make a clicking noise when you try to start it? It could be reading the correct voltage but that doesn't mean it has enough power...

LOL. Dude, if it won't crank, it has NOTHING to do with the spark. Check wiring to the starter, check starter relay, trying jumping it (if jumping it works, you need a new battery). Search if you need any information on the starter wiring or relay.

my battery has enough volts to turn the starter, and the starter is good. when i try to start it the engine won't turn or even hear the click from the starter. however i didn't think about the ignition wire. i will ask my mechanic about that. also does anyone have any other ideas if it is not the ignition that is the problem.

volts dont matter. its your cca's that do. same thing with mine. kept dieing on me. roommate swapped batts and proved to me that its the cca's. i told him same thing no i have enough volts...well i did..just not enough cca's.

Clicking -> dead battery. Once again, try jumping it... if that works, you need a new battery. I will not provide any more assistance until you try that.

Dragon, most of these guys know what they're talking about. Just jump the car. It's free! You can have 12 volts across the board but if the plates in the battery are broken or your acids are low you won't have the AMPERAGE to push the starter.

Don't come in a forum, ask a question, then argue with the response, then say you'll get a second opinion, then argue some more. That just gets you shunned.

A combustion engine requires 3 things to run: fuel, spark, and compression. You can't test ANY of those if the motor isn't even turning.

^2nd. If the question must be asked, it's because the answer is unknown. When an answer is provided, how can you refute the answer when you asked the question purely because you didn't know the answer...? Makes no sense.

i apologize if some of you felt that i was arguing your knowledge. i'm just pissed because my mechanic had my car for over a month with no results. i asked him everything that was pointed out in this thread. he said he tried jumping the car and didn't work, my batt has enough cca to start the car. he also charged that batt and checked the starter, starter relay, ignition coils, fuel pump, fuel lines. so far he is telling me that most likely it's the wiring harness. i had problems with my wiring before and he fixed it by cutting the burnt wires and replace them and it worked fine until now

When a mechanic says he doesn't know it's because he's a mechanic and not a technician.
It's why I do all my own work, because shops don't know the difference.

What we're asking you to do is try jump starting it yourself and tell us what it does or doesn't do. That's the only way we can help.

FYI, I've seen mechanics jump batteries wrong plenty of times.

may need a new wire harness
 

i am new to Z, but i had the similar problem after i did the tt swap, starter spined but the engine wouldn't crank, there's sparks on spark plugs and we smelled fuel thou, we had been dealing with this for over two month, was really frustrated, and finally came cross an idea of changing the engine harness, the engine starts after teh harness been replaced.
i was being told that, z engine harness goes bad after 8-10 year, i tried everything else but replacing the harness, and i hit the luck.
if you try everything else, and you engine still wouldn't crank, try to replace the engine harness(about $3-400).
good luck!

ya i was thinking it was the wiring harness because i had problems with it before but i don't have the money to spend on parts/labor for it. so i'm going to take it to an electric mechanic to see if he can get it to run since the Z "expert" mechanic cant get it to run.

thanks for all your help and input, hopefully i don't have to sell the car and can drive it more.

hey, di u get ur car run yet? my car has problem now, starter crank, but engine wouldn't start, no sparks from teh spark plug, does z well known for electical problems?

nvm, i may need to replace the spark plugs with NGK

ok guys i finally took my car from the "z" shop to an auto electrician and he got the problem down to the CAS (crank angle sensor). he said the CAS is faulty and non-repairable and that i'm not getting the correct power from the ecu to the CAS. so the electrician told me that i need a new CAS and he would fix the power from the ecu, i'm guessing he is going to jump it, i'm now sure. but that is where i stand with the car right now.

any ideas?

oh and yes i did try to jump start my car before i took it to the auto electrician shop and that didn't work

i have a cas if you need one.

pm me if you want it