Mk1 1.6 Running and then cutting out. RAC Report Added

[ALawson]

Hello

Our Mk1 has refused to run for more than 15-20 seconds, most of the time it runs for 2s then cuts out. We had the RAC man around this evening for 2 hours trying to fix it.

He accertained that the battery was buggered. While connected to another battery he did his tests and wrote the following on the Customer Assistance Report.

"Non start car, runs for a few seconds. Found that fuel injector trigger pulse being dropped. Supply+power feed is ok. Fault could be immobiliser (he found a pirranha alarm fitted, we have never use it of knew about it) or faulty injector driver in ECU (could be external driver/comp on o/s wing). Car did run 3 times for 15-20 seconds but injectors were cutting in and out intermittantly therefore it might not be the immobiliser."

The car is back in our garage now, has anyone any ideas what it may be? Is there an immobiliser built into the ECU/Car by mazda?

Any help would be great, I recall that Alicat had a similar problem last year?

Cheers

Alex

[OnlyMX5ives]

Impossible to diagnose with that little info.

Where are you based ?

[reaper668]

I had a similar problem. Mine turned out to be a corroded connection to the earth wire on the fuel pump relay under the dash.

If the alarm has been wired in it may have a bad join hidden with tape. I only found it after 6 months of looking.

Hope this helps

[ALawson]

OnlyMX5ives said:

Impossible to diagnose with that little info.

Where are you based ?

Fleet Hampshire

[bluetone]

My UK 1.8i Mk1 has an immobiliser built-in as standard; the key has a (transponder-type) thingy in it and this has to be in/next-to the ignition barrel for the car to start, otherwise the fuel pump will cut-out. Are you using a standard or replacement key?

Try using a spare Mazda key if you have one?

Edited by bluetone on Thursday 4th March 08:25

[Howard-]

His is a 1990 so it's not going to have any immobilisation as standard. If the alarm is wired in and working (well, "working" ) then it could well be that, or it could be the fuel pump relay as mentioned. Does it start and run for exactly the same amount of time, each time? Can you hold the revs up a bit to keep it running?

Edited by Howard- on Thursday 4th March 08:35

[ALawson]

Howard- said:

His is a 1990 so it's not going to have any immobilisation as standard. If the alarm is wired in and working (well, "working" ) then it could well be that, or it could be the fuel pump relay as mentioned. Does it start and run for exactly the same amount of time, each time? Can you hold the revs up a bit to keep it running?

Edited by Howard- on Thursday 4th March 08:35

When it cuts out it only runs for exactly the same duration i.e 1-2s.

Tried holding the revs up, it still dies.

[Oldandslow]

Will it idle for any length of time? Does it cut out if you rev it or just after set time on idle?

I once forgot to plug my AFM back in after a tinker and had similar problems. Had me scratching my head until I noticed the plug dangling. D'oh

Edited by Oldandslow on Thursday 4th March 18:17

[Gad-Westy]

ALawson said:

Howard- said:

His is a 1990 so it's not going to have any immobilisation as standard. If the alarm is wired in and working (well, "working" ) then it could well be that, or it could be the fuel pump relay as mentioned. Does it start and run for exactly the same amount of time, each time? Can you hold the revs up a bit to keep it running?

Edited by Howard- on Thursday 4th March 08:35

When it cuts out it only runs for exactly the same duration i.e 1-2s.

Tried holding the revs up, it still dies.

Hot or cold or both?

[MX-5 Lazza]

If it only runs for 1-2 seconds it won't be hot

[Howard-]

Haha ^


It could be the fuel pump on it's way out I guess

[Gad-Westy]

MX-5 Lazza said:

If it only runs for 1-2 seconds it won't be hot

Thanks pedant!

What I meant was does it start ok from cold then get hot and then cut out and is then only able to run for a few seconds at a time or does it do this from cold?

[Escort2dr]

Crankshaft or camshaft position sensors... do they have those?

[ALawson]

Problem from cold, when cold cannot get hot. Never had any problems warm.

[Gad-Westy]

ALawson said:

Problem from cold, when cold cannot get hot. Never had any problems warm.

This is worth a read.

http://forum.miata.net/vb/printthread.php?t=191939

[ALawson]

Gad-Westy said:

ALawson said:

Problem from cold, when cold cannot get hot. Never had any problems warm.

This is worth a read.

http://forum.miata.net/vb/printthread.php?t=191939

Cheers I will forward this to my spanner man!

[snotrag]

Good point made in that post - does yours run in 'diagnostic' mode?

[ALawson]

snotrag said:

Good point made in that post - does yours run in 'diagnostic' mode?

Not to up to speed on MX5's, is there a diagnostic mode? How do you utilise it?

I have a port on my ATR that you can connect a computer to or bridge with a paperclip and then count flashing lights on the dash, is it any similar on the MX5?

Cheers

Alex

[the_engineer]

Depending on the alarm, you may be able to bypass the immobiliser from the engine bay. Will help you to eliminate the possibility of it potentially being faulty.

But as others have said, it does seem to be related to fuel supply. Do check the related relays in the engine bay...

Let us know how you get on.

[bluetone]

ALawson said:

I have a port on my ATR that you can connect a computer to or bridge with a paperclip and then count flashing lights on the dash, is it any similar on the MX5?

Cheers

Alex

Have a look-see here for what is needed DIY stylee for this:

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

I believe MX5 parts sell a diagnostic widget if you cannat be ar$ed making your own.