Car not firing up

[feel_ixx]

Tried starting my car last night and it just wouldn't fire up. The car was working fine a few hours earlier. However, I haven't dríven the car for about 3 and a half weeks before that as I have been overseas.

How can I narrow down the problem?
Do I need to check for spark?

Leads were replaced with NGK leads about 4 months ago, and at the 2nd ignition stage I am able hear the hissing of the fuel pump. The battery is fine as all the electronics still work inside the car and the car still makes the normal paced (cranking?) noise when I turn to the 3rd ignition stage. The engine just doesn't seem to want to turn on. Gave the battery a jump this morning still no luck.I have about 1/4 tank left.

I was told it could be the fuel pump, but I want to make sure before I replace it.

Any advice would be appreciated.

[bigdog]

Check the main ignition relay (green one). There is a thread on here somewhere about it (and how to remove it cause it can be tricky) - quite a common problem, and perfectly fits your symptoms. You can rig an ordinary Bosch/Hella relay to replace it, but I can't tell you the pin config. An auto electrician can do this, or you can buy a working s/h one from Mania etc, or buy a new one from Mazda. I carry a spare just in case. If you are anywhere ne\arby you're welcome to borrow it - or you could try one from another MX5 if you have friends that will lend you one.

[feel_ixx]

Hi, I found that thread I think in the general section called "Patchy's stopped dead".

As for the main relay, I am looking at the fuse box in the engine, and looking at the one labeled main. BTW that one is black. Is that one the one you are talking about?
If not, where can I find it?

All my fuses seem to be intact including the one labelled "main". Which I couldn't take out as it is held on tight by some special way.

[bigdog]

Here's the thread i was thinking of... http://www.mx5cartalk.com/phpBB-3.0.2/viewtopic.php?f=55&t=27337&hilit=relay

Not sure if they are the same in an NA - could be black. Bottom line is you need to sap it and see if the problem goes away.

[StanTheMan]

I still have the fuel pump I purchased for patchy.

You are welcome to try it & if it turns out it is tyhe problem you can purchase a new pump r whatever.

PM me if you like.

[feel_ixx]

Here is a picture of my fuse box diagram. The one labeled main 80A is the black fuse that I was talking about



I'm still at a loss of where to find the relay. That removal tutorial on your link seems to be for the main fuse, and not the main relay, so I'm a bit confused here.

PS: Thanks Stan, I may go for that option if this relay stuff doesn't work.

[bigdog]

On your car it is the fuel injection relay - on mine it is the egi main.

[Rotary]

How can I narrow down the problem?
Do I need to check for spark?

Have you checked for spark?

That way you know for 100% certainty that you have an electrical/Ignition fault.

if there is spark then its almost certainly fuelling related unless the plugs are foul or spark is not regular

[feel_ixx]

I haven't checked for spark yet, how do I do this? (excuse my inexperience once again)

With the main relay, how do I take it out, and what am I looking for to see if its stuffed?

I forgot to add, prior to my car not starting, I took my air filter out and cleaned it up a bit, and I also did a head unit install. I don't think it has anything to do with this, because when I called mania, they asked me to bridge the F/P to GND in the diagnosis box, and the car still didn't start up - leading them to theorize it may be my fuel pump.

[feel_ixx]

I also just noticed a electrical buzzing sound when I go to the second stage of ignition. It's sounds like it is coming from under the car and its quite noticeable. I'm completely baffled at what is going on =(

[StanTheMan]

electrical buzzing?


is that comming from the fuel pump?

[StanTheMan]

The relay for the pump you are talking about is under a black cover on the other side of the engine bay. Passenger side.
.
There is 2 realay....I'm not sure which one is concerned with the fuel pump.

[StanTheMan]

have you tried bypassed the pump relay?

The F/P to gnd short on the diagnostics connector, bypassed the circuit opening relay and grounds the coil for the fuel pump relay (giving the fuel pump power), but this will only happen with the ignition key in the 'on' position (reds).

[feel_ixx]

Yes I have done that, but I don't notice any difference, with or without bypassing the pump relay I can still hear my fuel pump going.

And that buzzing sound seems to come from under my car, it could be my fuel pump. Frankly I don't even know what its supposed to sound like since I've never taken notice of it.

[StanTheMan]

its a hissing noise. Did you try to start it?

sounds almost like the pump is working.


if turns out not to be the pump.you could be looking at the same issue Agro Had on hers.....but that was more an intermittent problem.

but lets just be certain its not the fuel pump before you go down that track.....