Eunos Roadster, runs for 1 sec and then dies but..

[MarkGolf]

Hi all,

Yesterday I bought a Eunos Roadster half consciously, half on impulse. I kind of wanted to in order to teach myself how to drift.

Anyway, I picked up this car, it didn't run and the garage couldn't get it to run. They assumed it was an ECU fault so they bought a new ECU and it didn't fix the problem.

Anyway, I threw a new battery on it and turned the key, it turns over, coughs and splutters for all of 1 second and dies. HOWEVER, I found if I pump the thorttle, I can manage to keep it running, very rough but it stays running..

After much forum searching, I found myself with many possibilities.. Most seem to suggest the camshaft sensor or air flow meter but that seems to be for a car that just dies, no one mentions being able to keep it running while pumping the throttle so I figured I'd have to ask the question myself.
If anyone has any ideas, please help! I'm a total jap car/mx5 newbie!

Thanks

[J-Tuner]

Does sound like the AFM isnt connected or something ?

[MarkGolf]

Well, I did unplug it and found there was no difference..

[skilly1]

Fuel pump?

[MX-5 Lazza]

Plugs, leads, coils, CAS, AFM, O2....

Have you tested to see if you have a spark at all plugs?

[MarkGolf]

Thanks for the replies chaps!

It just had a full service prior to the issue, new coils, leads, plugs. I popped a plug out last night and it's sparking, didn't check the rest..

I would probably be happier investigating this if I couldn't keep the engine running by stabbing the throttle but as I can, it kinda tells me that the spark and fuel are getting to the engine ok..

I have a friend with a similar car and he's up for letting me pick a couple parts off of his to try on mine so I'll start with AFM and CAS..

I just want to driveeeee it!!

[moebiusuk]

AFM will sort it. Someone else had the same issue a few days ago actually, I can't remember where I read about it. He was in the same position as you, stabbing at the throttle to keep it alive.

I'll try to find it.


EDIT: I found it but sorry, the result wasn't conclusive. The last post was OP asking if sorting AFM would fix it.

http://www.mx5oc.co.uk/forum/default.aspx?g=posts&...

Edited by moebiusuk on Friday 27th September 17:05

[snotrag]

There's a feed comes from the afm that turns the fuel pump on - so that might explain why pumping the throttle might keep the afm flapping back and forth, and keep your engine running.

[T5SOR]

Sounds like a bad connection on the inductance chamber (AFM to throttle body). I had this very problem when I changed one and the pipes were not connected properly.

[MarkGolf]

Thank you again for the help..

I did find that thread and it sounds like the exact problem I am having, I have registered an account but am yet to be verified.. (sigh!) just so I can compare notes with the guy.

Strangely, I could believe something not being connected correctly could be the issue. Just before I purchased the car, it had a full service + cambelt change and as an end result or shortly after this, the car didn't run so perhaps something was broken or simply not connected although upon quick inspection, everything is connected...

I will be borrowing a friends AFM tonight/tomorrow so lets see although after the chap in the thread above, I'm not so positive that this will be the fix..

Thanks again!

[dblack1]

what year?

if it was just after the cambelt, check to make sure the CAS is aligned properly, this has caused a lot of people trouble. Another thought how soon after the cam belt change did this occur? is it possible your off alignment on your cam belt? Another common problem is people put the plate behind the crank pulley on backwards, but I think you don't get spark and it doesn't run at all if you do that. I'd check into all of that stuff.

[MarkGolf]

Thanks!

It's a 94..

I'm not sure how long it ran for but it had an MOT a few weeks after so I'd imagine it ran long enough to know the timing is ok...
I do get a spark as the engine 100% fires for all of 1 - 2 seconds..

If the CAS wasn't aligned correctly, wouldn't the engine still run, just badly?

I tried the LED diagnostic trick and the LED just remained on, no flashes or anything!

[dblack1]

I am not to familiar with the older 1.8s, but on mine, the CAS alignment caused it to have trouble intermittently. Mine was just barely off, but I could imagine it would have been worse if it wasn't aligned at all. Your ECU is different from the one I had as well. If my CAS stopped working, there was no spark at all. My guess is that yours is working intermittently (like mine was); however, there are a lot of other things that could be wrong with your vehicle, so I wouldn't replace anything until your sure its broke (unless it's cheap). A scantool (actual scan tool, not a code reader) would work miracles here because you could see what the ECU sees.

[fatjon]

"Well, I did unplug it and found there was no difference.."

that's a clue, change it.

[scrwright]

you can short a couple of pins in the diag port to force the fuel pump to run all the time (think its 10 & GRN) Does sound like the AFM is playing up

[dblack1]

fatjon said:

"Well, I did unplug it and found there was no difference.."

that's a clue, change it.

This is why I said I wouldn't replace anything till your sure it's broke. Just because you unpluged it and there was no change doesn't mean it is the bad part. This is also why I said a scantool would go really far here. The MAF can be tested with a voltmeter (its nothing more than a heat source and a thermometer).

[mondayo]

I'm having very similar issues with my Eunos....although pumping the throttle or trying to rev it, doesn't seem to make much difference with mine.

The garage have tried the AFM and a new (to me) ECU so far. Hopefully they'll be getting to the bottom of it this week, although there has been talk of them having to strip the whole car, so we'll see what happens.

[MX-5 Lazza]

If it runs for a second or so but then dies and you can't catch it then an old failing immobiliser is a likely culprit.