Bloody Car! Car turns off randomly, replaced fuel pump.

RG.net · Postby **RG.net** » Thu Nov 27, 2008 6:35 pm

hi guys,

mxhevn is a daily again and i was caught in traffic today on the cumberland (car was on, in bumper to bumper for about 20mins) and he switched off on me again :roll:

it was quite frustrating, abusing motorists dont help either, whats wrong with people these days?, anywhos giro-pilot swung past and stuck around for a bit which was nice.

got the car started and as parinoid as i was, i drove through all the backstreets i could to get home (also lost my front p plate, and i saw an undercover parked in a street so i parked quickly phew!)

anywhos i was doing some reading on m.net and there is someone with similar symptions like myself, he ended up changing his main fuse and his problem went away for 6 months (i changed it, had the original lying in the car, switched them over, nothing happened) so that cancels the fuse. Now i am thinking cam angle sensor (which i heard arent cheap) because the way it turned off today was instant, and behaved like a loose CAS. i got home, parked him in the garage and took the CAS out, bloody hell it was hot! so hopefully a new (or used) CAS will solve my problem.

before anyone asks, i have a 3/4 tank petrol and fuel pump was replaced 40,000kms ago.

has anyone else had similar symptions like this before?

RG.net · Postby **RG.net** » Thu Nov 27, 2008 7:23 pm

i just found this, sounds interesting and could be it

http://forum.miata.net/vb/showthread.php?t=148548

edit, cant be it as it wouldnt turn the car off in the first place.

RG.net · Postby **RG.net** » Mon Dec 01, 2008 4:56 pm

Argh! it did it again to me today, i noticed it was sitting at 600rpms for a few seconds then turned off, same deal.

judging by the lack of replies i am guessing no one has any idea what it could be

Benny · Postby **Benny** » Mon Dec 01, 2008 5:25 pm

Sounds like a fuel pump problem to me.
I know yours has only done 40,000K's, but the symptoms seem just like a problem I had with my first MX-5.

Even though the car was less than 20,000K's old, it would just stop for no apparent reason every now and again.
At first, you could re-start it after a few minutes, but the intervals became longer and longer, and the stalling happened more and more often.
The symptoms sounded the same as yours.
Just driving along, and for no apparent reason, the engine would cut off and wouldn't want to start.
It could go for days or even weeks without any problems, then it might happen every time I drove it then settle down again.

I eventually sold the car and bought another 5.

RG.net · Postby **RG.net** » Tue Dec 02, 2008 6:00 pm

and it happened again today but today he coughed and spat about, as soon as i touched the throttle he turned off. sat around for about 20minutes and gave it a hit, started beautifully!

i hope whatever it is it is an easy fix, i will be investigating a replacement fuel pump ASAP, hopefully on thursday.

are there any other symptions that a stuffed fuel pump show?

MX5CHIC · Postby **MX5CHIC** » Tue Dec 02, 2008 8:05 pm

I had the same problem 2 years ago - it was at first an intermittent problem with the fuel pump .... after 3 weeks it died totally. Finding the problem was a nightmare because when I tested the pump with a multimeter it showed a perfect circuit ..... when it was getting worse I used to slap my hand on the rear parcel shelf and it started!

RG.net · Postby **RG.net** » Tue Dec 02, 2008 8:29 pm

okie dokie, i will be looking for one asap!

Cent · Postby **Cent** » Tue Dec 02, 2008 9:07 pm

Pull out the pump assembly and check the wiring from the pump to the plugs at the top, i have replaced them on a mates mx5 he had the same problem.

RG.net · Postby **RG.net** » Thu Dec 04, 2008 12:35 pm

plugs looked fine cent.

i replaced the pump today, so now i'll go take it for a long drive and see if the problem persists, if so it might be the plugs, or something else, stay tuned!

RG.net · Postby **RG.net** » Fri Dec 05, 2008 5:40 pm

my heart sunk whilst i was sitting at the lights, the car turned off on me again, i guess it wasn't a fuel pump, i will be taking it to a mechanic tomorrow and see what they can solve, i really need it fixed by this weekend as i am traveling on the far end of pennant hills road next week for work, and we all know that is a busy road

any suggestions/thoughts please post them, i need anything i can get!

blue_na · Postby **blue_na** » Fri Dec 05, 2008 6:49 pm

These might sound simple and stupid, but here goes :roll:

Have you changed the fuel filter when you did the pump?

Is it only stalling at idle? maybe the idle is set too low?

How rough does it get before stalling or does it just cut straight out?

Could it be a coil pack issue?

Edit: Have also heard of similar thing happening with dirty fuel... where do you fill up? Please dont say Shell! :roll:

RG.net · Postby **RG.net** » Fri Dec 05, 2008 7:08 pm

blue_na wrote:These might sound simple and stupid, but here goes

Have you changed the fuel filter when you did the pump?

Is it only stalling at idle? maybe the idle is set too low?

How rough does it get before stalling or does it just cut straight out?

Could it be a coil pack issue?

Edit: Have also heard of similar thing happening with dirty fuel... where do you fill up? Please dont say Shell!

no i didnt change the filter, i changed it roughly 5000kms ago so i figured it would still do, as i had this problem a while ago and had the old filter in at the time.

mainly at idle, if idle was set too low, wouldnt it have been doing it a long time ago and more often? today it cutted straight out, on wensday it was being a bitch and revving stupid, but once i tapped the accelerator it was ok, i was holding idle at 1500rpm, as soon as it went below 1k it started again and died. on tuesday same thing, but as soon as i touched the accelerator it died on me!

i was thinking a coil pack issue originally, but i dont know what issues the mx-5 coilpacks have, are they prone to fail when they are overheated?

to me i am thinking it is something overheating but i cant confirm it, it didnt happen yesterday, it wasnt that hot yesterday and it never happens in the morning, around 6-7am.

RG.net · Postby **RG.net** » Fri Dec 05, 2008 7:15 pm

i am currently using Mobil 8000 as my fuel, i noticed with shell i used to get alot of exhaust soot, my car likes BP ultimate too, but i doubt its dirty fuel.

blue_na · Postby **blue_na** » Fri Dec 05, 2008 7:24 pm

If its only happening when warm, sounds like it could maybe be an Air-Fuel Ratio problem? are you running the standard ecu? If its an aftermarket one it could be the calibration but probably unlikely.

If you have eliminated fuel issues then it would probably be a spark issue, so I would be looking at coil pack next. If you could swap coil packs with someone and see if the problem remains or moves to their car would be the best way to check.

Mobil 8000 is great fuel, BP Ultimate is... Ultimate! so no issues there. :mrgreen:

I used to have overheating problems in my Torana when i used Shell... couldn't figure it out, changed to BP Ultimate and overheating issues went away! :shock:

RG.net · Postby **RG.net** » Fri Dec 05, 2008 7:51 pm

blue_na wrote:If its only happening when warm, sounds like it could maybe be an Air-Fuel Ratio problem? are you running the standard ecu? If its an aftermarket one it could be the calibration but probably unlikely.

If you have eliminated fuel issues then it would probably be a spark issue, so I would be looking at coil pack next. If you could swap coil packs with someone and see if the problem remains or moves to their car would be the best way to check.

Mobil 8000 is great fuel, BP Ultimate is... Ultimate! so no issues there.
I used to have overheating problems in my Torana when i used Shell... couldn't figure it out, changed to BP Ultimate and overheating issues went away!

engine is basically standard, the AFR was similar to other 5's at the mania dyno day too.
i might try borrow my mates coil pack out of his 5, could be a long shot though.