Coil Pack Question

ja9 · Postby **ja9** » Tue Dec 29, 2015 7:55 pm

Hi guys,
How do you test if your coil pack is working or not. Car has no spark and doesn't start.
Fuel pump can be heard working, battery fully charged, car has fuel. Trying to eliminate the obvious.
Cheers - John

pezchops · Postby **pezchops** » Tue Dec 29, 2015 8:40 pm

you could check your engine fuse under the dash for a start.
i just had your problem and it was a blown 25 amp engine fuse.
the root cause was a short in the O2 sensor wiring.
no power was getting to the coil packs.
i thought my cam belt was broken because that would give similar symptoms .

zossy1 · Postby **zossy1** » Tue Dec 29, 2015 9:38 pm

Engine fuse, and cam/crank angle sensors - they should be your first check. The NB8A coil pack is notorious for failing but they only usually lose 2 cylinders at a time IIRC.

93_Clubman · Postby **93_Clubman** » Wed Dec 30, 2015 10:29 am

ja9 wrote:How do you test if your coil pack is working or not.

zossy1 wrote:NB8A coil pack is notorious for failing but they only usually lose 2 cylinders at a time IIRC.

Yep, usually one of the two coils become unserviceable, so will start but only runs on two cylinders.
Would add the EGI relay (usually green in the NB8) in the engine bay fuse box to above suggestions of engine fuse, cam angle sensor, & crank angle sensor.

ja9 · Postby **ja9** » Wed Dec 30, 2015 7:03 pm

Thanks to all that replied.
93_clubman you're the man. Thank you so much for taking the time to post. I'm a visual learner, helps a lot.
Btw, fuses are fine.
Zossy1 where abouts is the crank angle sensor?
The thing that's got me baffled is there is no spark and I don't believe there is any fuel going to the injectors despite you can hear the fuel pump working. I can't even find the fuel hose to see if any petrol is being pumped through.

Thanks again.

zossy1 · Postby **zossy1** » Wed Dec 30, 2015 10:05 pm

You have two sensors John - the crank angle sensor lives behind the crank pulley, on the passenger's side. The cam angle sensor is on the front of the valve cover on the driver's side (running off the intake cam).

If the ECU doesn't see a trigger pulse from the CAS, it won't trigger the injectors to inject fuel. You may have fuel pressure but if the injectors don't trigger, you won't have any fuel. Sounds suspiciously like CAS to me (probably cam).

ja9 · Postby **ja9** » Thu Dec 31, 2015 8:35 am

Thanks gents. From the information supplied above it looks like it's not the coil pack.
Chris, I'm going to explore the CAS. My feeling is you may be right.
Cheers.

ja9 · Postby **ja9** » Tue Feb 02, 2016 8:01 pm

I thought it may help others so after a month of buying parts for my car I finally got it started.

Coil pack, cam and crank angle sensors, plugs, EGI relay and more the culprit was simply the car had lost its tune. David from Mx5 Mania set me the tune from a year a go. I downloaded the file and she fired up.

What would cause this to happen? I don't think the car battery went dead at any point. Voltage spike? I'm really clutching at straws here. Does anyone think the ECU is on its way out?

Regards - John