Eunos 30x common issues

Dave262 · Post by **Dave262** » April 16th, 2007, 9:09 am

Hi everyone,

I was just browsing the net for some info on a Eunos 30x, and came across this great site. Seems to be one of very few that is active with good information =D

Anyways... A good friend of mine has just gone overseas for a few weeks, and left me her car to look after for the time she is there. After driving it home I realised just how many problems it seems to have, mainly most likely due to having done over 260,000km...

A little while ago we replaced the front left driveshaft as it had nearly ceased due to a cracked boot, and all the spark plugs were replaced from being completely carbon coated (the car was completely unable to start). At that same time air filter was replaced also (which I take it was the cause of the dirty plugs). Timing belt and pulleys were also done about 230,000km.

I am going to fix the car a little while she's gone and try to bring back the economy (which currently is making about 250-300km to a tank, much worse than even my old 1990 magna!) I have a feeling the oxygen sensors may be dead, and the leads look stock, so I think they may be faulty too.

My question is - are there any common problems that I should watch out for on these cars, and if so, are they easy to fix? Also, the gear changes seem to be rather harsh as even under light acceleration it tends to rev up to about 3500rpm - 4000rpm before changing gears. It also idles rather rough in a sort of "pulsating" type vibration.

Thanks in advance!
Dave

MX3ak · Post by **MX3ak** » April 16th, 2007, 5:01 pm

Nice to meet you Dave

Me too have one of those Mx-3 from the far past.
I'm from Portugal in Europe, since you talk about Eunos 30x I assume you are from Australia, right?
Excuse my poor english. I will try to give you some issues about our old Mx-3's.

Like you said and well, O2 sensors will certanly need to be changed. Although the car still's running, it is running rich. ECU will replace the bad readings by some safe values.

Now that summer is approaching, you better change thermostat too, so the cooling system flows normaly.

Oil level should be checked regulary and if you plan to keep the engine running for some years to come, change it as soon as it gets dark.

These are the ones I remember right now. You can do the repairs one at a time and let us know the results.

Best luck!

Dave262 · Post by **Dave262** » April 16th, 2007, 6:18 pm

Thanks for the reply

Yes I am from Australia, and so far I am finding these cars are incredibly hard to find parts for... there are many places that have no idea what the car is! No matter though, as I am nearby to shops that can source any parts usually hehe. Plus I did see some at the wreckers the other day, so might be able to get some stuff from there too.

Any idea how much an oxygen sensor would cost for these? I think I read somewhere that there were about 3 of them or something like that... and if that is the case, I'm betting that all 3 are dead...

Oil I will probably change this weekend too. What type of oil works best usually? I know that I tend to try and use genuine oil for cars, as I find it runs better and in the case of Mitsubishi at least (whether it's the same for Mazda or not), the oil is actually cheaper than what I can get from the shops too!

I have a funny feeling the thermostat actually needs replacing too, as I noticed when the car was idling every minute or so the cooling fans would come on...

Dave

PATDIESEL · Post by **PATDIESEL** » April 16th, 2007, 9:11 pm

Is the car an auto or manual shift?
The car has alot of miles and sounds like it could use some much needed maintenance. I would start with the replacing the wires, dity cap and rotor. Then take a look at how long is has been since it had an oil change. Look at the coolant as it may need a flush and fill. Thermo as stated above is always a good idea to replace if you don't know much about the car's history. Replacing the fuel filter is a good idea for the same reason. Then run some high octane gas and some fuel system cleaner to help old clogged injectors. Checking the fluid of the trans is a good idea. If an auto I would suggest a drain and fill (make sure it is not a pressurized "flush") Older transmisions will have a good deal of metal flakes in them and after a period of time that metal will acutally wedge itself in places that are now dependant on the metal holding things in place. You should change the trans filter too if an auto. If a manual I would drain and fill the trans fluid. There is no filter or power flush on a manual trans. DO NOT use an fluid that contains sulfur on a manual trans MX-3. The sulfur will eat away at the synchro mesh in the trans and destrot it.
Not sure about Aussy model MX-3s, but we only have 2 O2 sensors on the North American MX3s. One for each bank, front and rear. They cost about 250 each here in the US from Mazda. The reason they are so expensive is that Mazda used some choice parts on the MX-3 making it such a sporty car. The O2s are 4 wire heated O2s, the best functioning, but most expensive. You can buy generic 4 wire O2 sensors that are much cheaper, but you have to find out how to wire them into the stock harness. There should be several posts on here, if you search, that will tell you what the four wires on the MX harness are for. Then you can use that and the wiring diagram for your new O2 to wire them up.
You can also check out TeamEunos.com for more local help. They are a Mazda forum with some good memebers that all live in and around Australia.

Nd4SpdSe · Post by **Nd4SpdSe** » April 16th, 2007, 10:26 pm

PATDIESEL wrote:Not sure about Aussy model MX-3s, but we only have 2 O2 sensors on the North American MX3s. One for each bank, front and rear.

4 I believe if it's OBDII

Dave262 · Post by **Dave262** » April 17th, 2007, 1:44 am

Thanks for the replies

PATDIESEL wrote:Is the car an auto or manual shift?

It is an auto transmission, and seems to change at really strange points. I'm not sure if it's an ODBII type yet... will have to check that maybe tonight if I have time.

It recently had some general maintenance done on it by mechanics (maybe about 4 months ago), where the oil was changed and coolant as far as I know. I doubt the transmission fluid was changed, and I know they didn't test any of the sensors to see if they are working properly or not. I really hope I can find some cheap-ish sensors around, coz US$250 is like AU$300 or something... that x4 is $1200 on sensors alone! 0_0

What oils would you recommend to refill with? Are there certain brands that perform better in these cars than others? I can most likely get transmission filter from bursons or something fairly easily, as they always seem to stock things like that. I will go over the car on the weekend and work out what things need fixing on it. Considering it's an old car, it's in pretty good condition, and does seem to run ok, albeit is guzzling fuel and unnecessarily changes gears at really high rpm.

Dave262 · Post by **Dave262** » April 17th, 2007, 1:46 am

Nd4SpdSe wrote:4 I believe if it's OBDII

How can I check if it's ODBII? Is it just the connector for the ECU diagnostics that gives it away, or is there another way?

MX3ak · Post by **MX3ak** » April 17th, 2007, 6:09 am

Relax, your car is not obdII. Anyway you still have a plug from were you can "pull" some codes. Look at the V6 Faq for a thread about Cell Codes...

As for the O2's, I got the 2 universal 4 wires from an ebay seller. The seller sold them as "universal 4 wires mazda". It was almost plug and play, since the wire colors were the same.

Remebered now, what about timming belt, huh?

Nd4SpdSe · Post by **Nd4SpdSe** » April 17th, 2007, 6:26 am

How do you know his car is not OBDII? I looked and I see no reference of the year of his car...In Canada (cause I believe GS's in the US we're discontinued after 93) OBDII Mx-3's started trickling out in 94, farily common in 95 and pretty much standard in 96. You guys overseas had the Mx-3 until 98, right? For who've I've talked to about ZE swaps in OBDII Mx-3's, they said they had four O2 sensors...

Dave262 · Post by **Dave262** » April 17th, 2007, 9:09 am

Sorry... I forgot about the year of the car... the one thing I always forget to say in my posts lol

Anyways, it's a 1997 Eunos 30x 1.8L V6, which has done 260,000km. I'm in Australia, and I have no idea if it's OBDII or not.

What I know has been done on the car:

New timing belt done at 230,000km
Coolant flush (not sure about thermostat change)
Oil change
New battery
Left hand drive shaft replaced, right hand will be replaced in a few weeks

This is not actually my car, it is a friends car so I don't know every little detail about it (although I do know most of the history from when she's had it). I am just trying to fix it up to improve the fuel economy and make it a bit more reliable for her.

All your replies are really helpful - thanks in advance!

zydawn · Post by **zydawn** » April 17th, 2007, 11:32 am

1997
definatly OBDII
don't do the transision fluid untill your freind gets back and she definatly says ok or you might be up for a new atx.

just do the filters ,plugs,wires and then if you would like to do more get the injectors cleaned and the O2 sensors replaced.

If you need some local help have a look at teameunos

there a great bunch of guys and can often provide good info and were to source parts from.

luck

Dave262 · Post by **Dave262** » April 18th, 2007, 7:10 am

Thanks for the good info

After driving the car today I'm starting to think it shouldn't take all that much to get it running properly again. It is running quite nicely - especially at higher RPM (despite it changing gears at really wrong times!)Definitely the O2 sensors need replacing no doubt about it... and I have a feeling the TPS may need some major, major readjustment (assuming it is working properly at all!). I'll have a search for info on readjusting that, but I know it is changing gears at really wrong times. The oil was done not that long ago, but I think I might get some oil flush, drain the oil, refill with cheap crap oil, run it for like 15 mins or so to clean out the old sludge, then flush it again and refill with good oil. Obviously will also need to use a couple of new filters for that process.
Transmission oil I will leave alone for now, which from your suggestions sounds like a wise move. But I will check the fluid colour and level to make sure it is ok from that aspect. Thermostat I think is stuffed too, as it stays cold for quite a long time and temp guauge seems to stay quite low during normal operation (about 1/4 way). Will probably put some good coolant in it too. I just filled it up with a full tank of premium fuel too, and will run some injector cleaner through. Air filter is clean, so it should be fine too.

Gonna be a long weekend!

MX3ak · Post by **MX3ak** » April 18th, 2007, 7:22 pm

How do you know his car is not OBDII? I looked and I see no reference of the year of his car...In Canada (cause I believe GS's in the US we're discontinued after 93) OBDII Mx-3's started trickling out in 94, farily common in 95 and pretty much standard in 96. You guys overseas had the Mx-3 until 98, right? For who've I've talked to about ZE swaps in OBDII Mx-3's, they said they had four O2 sensors...

Sorry, somehow I thought the car was from before 96. Maybe by the number of kilometers. 260,000km thats amazing for a 97' MX3