Help needed!

[MX5Steve]

For the first time in 3 years the car left me down. I went to start it on Sunday and she wouldn't start.

Thinking it was a flat battery I jumped it. However even with the jump leads attached she still wouldn't start till the second attempt.

This morning she started first time and I drove her into work with no problem at all.

Came out of work this evening and she wouldn't start again. Checked battery and she had 12V. Put the jump leads on anyway and no difference still wouldn't start.

She will try and start and the starter gets slower and then pop out the exhaust?

I had to abandon her and take a look in work tomorrow.

Any ideas? My plan was to change the plugs they are due anyway.

Could it be the starter?, Coil Pack, Leads?

What happens if there is no antifreeze? I haven't touched this in 3 years?

Any help or direction for tomorrow would be great.

Also, whats the worst case?

Thanks,

Stephen

[mx5ash]

I wouldn't think bad plugs or leads would stop it starting, just would run rough. Nothing loose under dash after the change over? Is it getting fuel? Check each lead for a spark. Do you have an alarm/immobiliser?

[MX5Steve]

Changed the plugs today and put on a spare set of leads. After I towed it home in the ice it sounds like she's getting fuel. She will try and start and then shell go pop as thought the fuel that's made it into the cylinders has ignited. I thought it may gave been the starter but it took several attempts around the car park in work to get her going by towing. Later when I went to drive her home she started but as soon as I turned on the lights it died. But it's not the battery as it won't start with the leads on.

All plugs under the dash are checked I don't think changing the dash is anything to do with it cos when it did get going it ran with no problems.

So I'm thinking.

Buy a set of new leads.
Coil pack?
Starter?

Anyone?


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[Steve]

See if you can beg, borrow or steal an Airflow meter (check your connector first actually) to test with.

[mx5ash]

Its a 1.8 so maf not afm.

[Steve]

ah!

Is there spark Steve?

[MX5Steve]

Charged the battery over the past 24 hours. Car wouldn't start 13.2v on the battery.

Checked all vacuum hoses.

Checked all spark plugs.
All plugs will give a little flicker when you turn the ignition to Acc. When I start only plugs 1 and 4 are igniting.
These are connected to one side of the coil pack. Drivers side. Checked all connectors. Is this normal?


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[sidewaysreilly]

plugs 1 and 4 fire together and 2 and 3 together. Possibly a coil going down. Strange it happened after the dash removal.........are all the earths connected??????

[MX5Steve]

Update:

I've worked a bit on the car today and this is where I am.

Work completed so far:
1. Spark plugs Changed
2. Old set of working HT leads installed
3. Timing Belt check and not snapped.
4. All vacuum hoses checked
5. Ground strap on engine block checked
6. Spark checked on all 4 leads. Only cylinders 1 and 4 firing.
7. Coil Pack secondary resistance checked. 9.5Kohm, should be 8.7 to 12.9kohm
8. All wiring connectors under dash checked.
9. Fuel injection fuse in main fuse block checked for “clicking”. (I did not remove it and connect up 12V supply and check for switching yet!)
10. Diagnostics tool. 2 codes observed. 03 and 26
a. Haynes manual
i. 03 = Ignition G signal, Check the distributor and PCM circuitry or components
ii. 26 = Solenoid valve (Purge control) Valve Removed over a year ago when removing the charcoal canister.
b. Rod Graingers Manual
i. 03 = A problem with the camshaft position sensor or associated circuitry.
ii. 26 = Purge solenoid valve.

11. Continuity between Ground on Coil pack plugs checked. Continuity also found to be present across the start signal from the igniton and the ground on both plugs?
12. Coils physically swapped to troubleshoot only 1 and 4 firing. Problem remained so it must be normal for it to do this.

Items eradicated:
Spark plugs,
Leads,
Coil Pack.
Fuel injection Fuse and relay.
All fuses checked!
Engine block ground strap.

Possible causes remaining:
Camshaft sensor.
Ignition Ground? (How do I check?)Where are they all?

Others:
PCV valve?
Fuel Injectors? (measure resistance 12-16ohms)
Fuel pressure regulator

[sidewaysreilly]

you say only 1&4 firing?

[MX5Steve]

yeah, seems to hold against other cases.

Looks like its the CAS checking it now..

Thanks to sspecdave for these links,

http://www.mx5oc.co.uk/forum/forums/t/204.aspx

http://forum.miata.net/vb/showthread.php?t=334238

http://www.pistonheads.com/gassing/topic.asp?h=0&f=185&t=597282&nmt=Cranks,%20fires%20but%20wont%20catch.%20Why%20wont%20this%20MX5%20start%20now

[MX5Steve]

Checked the CAS today using this method from Miata.net

"Code 3 (SGT fault) means that the ECU is not "seeing" the signal on the white wire from the CAS to the ECU, as Harry Sue wrote above. Could be a bad CAS or a bad connection in that path. Disconnect the CAS connector, and with the ignition switch in the ON position, measure the voltages on the terminals of the connector in the wiring harness. You should see +12 volts (with respect to chassis ground) on one (white/red wire?) terminal, +5 volts on the white and yellow/blue wires, and zero volts (ground return) on the black wire. (Wiggle the harness while looking at the white wire terminal to verify no intermittent.)

If all the voltages are present, the ECU is OK and the connector in the harness is OK. That would pin the fault on the CAS, which would need to be replaced.
"

Results: (Expected/Actual)
Black = 0v/0v
White/Red = +12v/+12v
White = +5v/+5v
Yellow/Blue = +5v/+5v

So ECU must be ok and Wiring harness is fine.

Next checked the CAS using this method also posted on miata.net.
"If you want to test the CAS itself, you would need to remove it from the cylinder head, plug in its connector, and with the ignition ON, rotate the CAS "dog" while watching a voltmeter on the white wire. The voltage should shift from +5 volts to a lower (about 0.5 volts) value as you turn the "dog," if the system is working. If the voltage stays at +5 volts, the CAS is definitely bad.
"

I traced the white wire back to the ECU and the 5 volts IS shifting.

While I was there I checked the yellow/blue wire and this ISN'T shifting.

Not sure if this should be the case?

Haynes Manual states this:

Two signals are sent from the CAS.

1. Cylinder is at TDC
2. Crankshaft position at 180° intervals.

Failure of the 180° interval signal will usually set a diagnostic code 2.
Failure of the TDC signal will usually set a diagnostic code 3.

Seen as I have a code 3 I reckon the yellow/blue must be this.

I'm now looking for a CAS for a 1.8.

[MX5Steve]

Big thanks to cesaj (Chris) for supplying me with a used CAS, and sspecdave for the advice. My car is now zoom zooming again, purring like a kitten. Just need to check the timing at the weekend.

Thanks to all of those who gave advice.....

[Steve]

nice one Steve!