Mazda Help Please

lisa534, Sep 25, 3:22am
Hey guys. I have an immaculate "1992 Mazda MS-8 Efini" which I purchased about a month ago. its done 243,000kms but the original 2.5 litre v6 engine was pulled out as it blew a head gasket & the smaller 2.0 litre v6 version with 130,000km on it from another Ms-8 Efini was fitted, well this is what the last owner told me. also told me that the gearbox had blown itself a year before the original 2.5 engine did so 3 grand was spent on a gearbox overhaul.

Anyways i have noticed two major issues, firstly the engine intermittently misses at idle like it wants to stall but doesnt. e.g. not all the time, just every now and then. could this be because the original 2.5 Litre v6 ECU computer has been left in to manage the smaller 2.0 litre v6 engine and its not managing the smaller engine correctly!

Secondly I think the gearbox isnt changing into 4th gear, the engine revvs are fine at cruising speeds of between 50-80km/hr sitting at about 1500-2000 revvs, but when you are going 100km/hr the engine seems like it is screaming as it sits on 3000 revvs or over which I think is too high. What could be causing this issue! could it be because the gearbox was obviously suited to the original 2.5 v6 that was in it! and it wont change gears correctly with the 2.0 v6. or could it have been that it wasn't reconditioned properly or something wasn't put back right!

Sorry for the life story but just trying to figure out whats going on with her. all opinions would be appreciated! Thankyou

mm12345, Sep 25, 3:34am
Could be many things.
Idle could be dirty/stuck/defective IAC valve.
Not going into 4th gear might be the result of what's causing the idle problem putting the car into some kind of "limp home" mode, but my guess would be that it's got a thermostat stuck open.Many auto cars are like this - they won't engage top gear (o/d torque converter lockup) until the car is at normal operating temperature.But of course it could be something else.

pugmyre, Sep 25, 3:45am
There was a button on the end of the gearstick of ours.Maybe yours has one too.This allowed us to change to the O/D gear, which dropped the revs about 600 rpm at 100km.

lisa534, Sep 25, 3:57am
yes most cars that ive had have a overdrive button of some description on them. but this efini is quite strange. the gearstick is located next to the steering wheel and air conditioning controls on the dashboard instead of between the seats. theres no buttons on the stick and on the panel next to the stick. it says P, R , N , D , 2 , HOLD & L, no o/d unfortunately. will investigate further into the thermostat! thanks guys

un_known, Sep 25, 5:21am
ok a sensor fault (speed sensor for eg.) can cause the gearbox to go into safe mode in which case it wont change into 4th.to check if your getting 4th gear put the stick in D take it up to 100km/h now press the hold button if the revs increase youve just changed back to 3rd.Is the hold light flashing on the dash!

in any case your first point of call is to pull the codes im sure it will have some faults and go from there.

lisa534, Sep 26, 10:43am
ok I took it for a drive, on the dashboard gearstick assembly there are two hold functions. when the car is in "D" you can slide the stick one place down to "S" or "sport" mode, this makes it jump down a gear and if you slide the stick further to the right, the "Hold" mode is suppose to engage & hold it in the gear, the "Hold" light however does not illuminate and nothing happens and the gear changes continue as normal. There is also another seperate "Hold" press type button to the left instrument panel. this also does nothing when pressed. im guessing that this system was not connected up again after the new engine was put in or maybe when the gearbox was reco'd. very complicated i know. will see if i can get the efini scanned for fault codes. :)

kazbanz, Nov 21, 12:06pm
Lisa -please don't take this wrong but you problems started a month ago.
This was when you purchased a repowered car with a "reconditioned" gearbox. -Im not being nasty here but MS8's by now are sale proof because of basiclythe symptoms you describe.
It sounds like the gearbox may have lost top suggesting that first hasn't got long to live OR that the "extensive rebuild of the box" was in fact simply a replacement of the 1st/reverse clutch pack and now the top gear pack has gone.MS8's do have a reputation for gearbox issues.
The little miss you mention I must admit I have NEVER driven a MS8 that diddn't have that exact same missfire.
In fairness I only ever encounter MS8's that people are wanting to offload. Usually towwed here because the bi=ox has gone bang
Again I'm not having fun at your expense or passing judgement