engine stalling

[cerby54]

hi all.
my sons gilfriend has a 1999 1.8 mx5 which starts runs and ticks over fine,but when driving stoping at a junction revs drop and then cuts out then restarts fine.
anyone else had the same problem?
thanks.

[Phil @ P5]

Fairly common, my M2 Sport does the same, albeit doesn't stall. You can increase the 'bleed' of air passed the closed throttle plate using the screw on the top of the throttle body. Anti-clockwise will allow a little more air through to help with the issue. It might increase the idle speed as well if the ECU doesn't compensate.

Also, check the condition of the battery, that too can have an effect on the operation of the valve.

HTH
Phil

[cerby54]

thanks for your help,battery and plugs are brand new.will get my son to have a play with her car when he can.

[MX-5 Lazza]

Probably just that the throttle body and idle control is gummed up. My bet is that the car does a lot of short trips and doesn't get "stretched" too often. If this is the case try an "Italian Tune-up" i.e. get it up to temp then thrash it around for a bit, using all of the revs. Give it 20 minutes or so like that and see if it improves at all. If not it might need the throttle-body removing so you can clean the air-ways and the idle control valve.

[anonymous-user]

My mk1 1.6 was doing this all the time, so I reset the timing (using a timing strobe) from about 14 degrees to the normal 10 degrees, and now it doesn't stall at all - I think this invlolved resetting the base idle in some way by grounding out some terminals in the diagnostic plug, so that may be why it's better now rather than the timing advance angle.

It seemed to take a couple of days of driving to establish this new solid idle after the reset, for a while it was idling at about 1200rpm. Rock solid now though, hasn't dropped below 800rpm or stalled in over 1500 kms.

Edited by anonymous-user on Friday 9th January 11:07

[franv8]

Mine did it for ages - I though the ISC (Idle Speed Control) valve had gone south (new one silly money) - but after replacing the head and a little set up time, it was tweaking that bleed screw (it's facing you as you look at the engine, on the wing side of the throttle body. May be under a small plastic cap) that got it back into its 'controlling' range. A few goes and tweaks got it sorted and now it's a solid 800 rpm on mine.

Also check that the throttle cable is not too tight, this can hold the throttle plate open a little, it should positively close against its stop.

Lastly - do check for any vacuum leaks or split hoses, particular culprits can eb the cam cover breathers, they turn hard and split.

Hope the fix goes well,

[GravelBen]

JimSuperSix said:

My mk1 1.6 was doing this all the time, so I reset the timing (using a timing strobe) from about 14 degrees to the normal 10 degrees, and now it doesn't stall at all

Interesting - mine does it less since adjusting timing to 14°. Still does it occasionally, generally the first time you slow to a stop after starting on a cold morning.

[anonymous-user]

GravelBen said:

JimSuperSix said:

My mk1 1.6 was doing this all the time, so I reset the timing (using a timing strobe) from about 14 degrees to the normal 10 degrees, and now it doesn't stall at all

Interesting - mine does it less since adjusting timing to 14°. Still does it occasionally, generally the first time you slow to a stop after starting on a cold morning.

Yeah, I think it was actually the bridging of the 2 terminals when setting it that reset the base idle and caused it to behave rather than the actual timing setting.

[cerby54]

thanks for the help guys.
Italian Tune-up" went to pick sons girlfriend up in her car last night,on the return journey it was ok will have a better look at it over the weekend.
once again thanks for the advice.

Edited by cerby54 on Friday 9th January 14:02