To all Z5 owners, please post here!

[wheresthericego]

97' with roughly 71,000 miles..

had 1 and 2 problem..

The ac compressor went bad thats why it was idling bad so got a new clutch and put a net engine temp sensor and problem fix.

misfires...problem...sparkplug was crappy...(BOSCH SUCKS) went back to GOOD OL NGK and every thing runs like new..

i have had the same ass problem with bosch. do not ever buy ****ty no good bosch +2 +4 spark plugs and just like txmzdspd2gen says use NGK. oh and yes double check the gap it is supposed to be .44 for the Z5(1.5L P.O.S )

[Kmarajh]

96 1.5L with problem #2

I saw this after posting my problem

I actually have a combination of 1 and 2

1 has been there forever and Mazda had a TSB on the front engine mount which they say causes this but its not detrimental so I wont worry for now.
#2 started only recently.
I changed plugs, used Denso from autozone, wires, cap and rotor.
I got a misfire code in #2, before and after I changed all the parts.
I compression tested 1 and 2 and got 190 each, should I bother to do the rest?
I even changed the Distributor. Most of the times the problem would go away when cold and as the engine heated up, it got worst.
Im not sure if Im saying this because I read it but the valvetrain does sound louder than before. Should I get the NGK's?
Kevin

[Mazda96Protege]

I havent posted in here yet but yes i have low compression and cylinder 4 does not fire at idle, it runs fine when on the throttle but when i start to slow down i can feel it start to shake horribly and the RPM jumps around........

[pigeon]

As for now, i think all has been said that we could involving this topic.

As a word of advice, if you're ever doing a valve job... as edwin said, make sure you replace the valve springs.

Something to consider would also be higher rate valve springs, however i dont know of anyone who has ever done that...

the long and short is, this engine is not good for any type of motorsports if left in OEM form.

Its weak valvetrain, and weak output is not inspiring at the least.
Its a decent commuter motor with good mileage and good reliability once its not pushed hard.

Other than that, if you ever start thinking of modifying it...

remember that:
1. it has a weak valve train
2. theres little to no interchangibility between any other motors
3. the exhaust cam and intake cam cannot be properly independently adjusted... despite how its a DOHC engine

If any of you like to go against the grain and insist on modifying this engine.... start with the valvetrain.

Other than that, i'd say discussion about this engine is pretty much over... any new person that does a search for peoples experiences with the Z5 should find this thread.. it has all the key terms in it.

[bassamp4jc]

I just got my 95 in december, and I'm pretty sure I have both #1 and #2 -

- I idle really rough, and pretty low, bellow 750 usually
- I did notice that my exhaust is irregular when I'm idling - you can't notice it so much when the RPM's are high but idling I can definitely tell.

Maybe I should switch my spark plugs and wires.... it's worth a shot I suppose

[midnightblue97]

,


1. it has a weak valve train
2. theres little to no interchangibility between any other motors


If any of you like to go against the grain and insist on modifying this engine.... start with the valvetrain.

.

The 'Z' engines are a new family which is an evoltion of the 'B' engine. The head is entirely different with round ports and narrow valve angles but the shortblock is nearly the same as the B6.

http://members.aol.com/solomiata/MX5Engine.html

CAn somebody shed a little bit more light on this??
Could a head swap be an option??

[Intruder]

Motor ---------- Years -- Bore Stroke - CC --- Models
1.6 DOHC B6P | 1988-1995 | 78 | 83.6 | 1597 | 323 GTX, Miata, Mercury Capri/XR2, 94-95 MX-3
1.5 Z5 DOHC | 1995-98 | 75.3 | 83.6 | 1489 | 1999 Protege

Their stroke is the same. What does that mean?

[pigeon]

Motor ---------- Years -- Bore Stroke - CC --- Models
1.6 DOHC B6P | 1988-1995 | 78 | 83.6 | 1597 | 323 GTX, Miata, Mercury Capri/XR2, 94-95 MX-3
1.5 Z5 DOHC | 1995-98 | 75.3 | 83.6 | 1489 | 1999 Protege

Their stroke is the same. What does that mean?

stroke is the amount the piston moves up/down in the cylinder
that just means that their bottom end parts could either be the same, or extremely similar

i dont think anyone ever had any real bottom end problems with this engine, its all in the head
a head swap would absolutely solve it...

i wonder if edwin could check if the valve springs from the JDM version of this engine differ from the valve springs of the USDM??

or if the heads are different?

[Intruder]

Let's say I go to the junkyard and pull a B6 cylinder head from a Merkury Capri (I read somewhere that they are more abundant). How do I go about swapping that on my Z5 block?

[Distractedfrog]

i have a 95' DX i suffer from problem 1 but it's usually when i have my stero going and when i turn on my neons, it makes my whole car shake and act like it wants to cut off.

[pigeon]

also anyone who has this low compression problems... and they just try to ignore it and drive the car anyways...

at idle the car runs pig rich.... and its ridiculous
be ready to do an annual cleaning of your egr... and potentially replace your catalytic converter prematurely

[midnightblue97]

Let's say I go to the junkyard and pull a B6 cylinder head from a Merkury Capri (I read somewhere that they are more abundant). How do I go about swapping that on my Z5 block?

First thing I would do is get a B6 and Z5 head gasket and start comparing.
Cylinder bore, oil passages, water jackets etc...........
Then intake and exhaust manifold gaskets.

[John Blutarski]

I don't have any idle problems but mine was hesitating at part throttle acceleration pretty bad. I took off the intake pipe and noticed a couple cracks. I have replaced that and the problems are gone. I have a feeling the "accordian" portion of these pipes tend to crack and its a common problem. My local dealer actually had 4 new ones in stock and they hardly ever have anything in stock.

[Lix]

Hi guys, I'm new here. I drive 1994 Mazda Neo (2 door type) with z5 engine. Last time I also had the same problem. I just brought one can of injection spray and spray through the throttle body and especially the idle hole (located inside the TB), and using fine sand paper clean through inside the contact ie the rotor and the contact point. And wala! problem sloved
Hope this will help. Cheers

[RicardoS]

1. 1997 z5-de 1.5L DOHC AT
2. 130,000 miles
3. I have both problems
4. Misfire code po304 (number 4 cylinder), unstable idle

The Engine light blinks sometimes, sometimes the light isn't present, then sometimes won't shut off. I Bought the car last month from my girlfriend who bought a new car and I needed something more economical than my 4.0L Jeep. I'm falling in love with it. Have replaced the number 4 injector, wires, plugs, rotor cap, distributer cap, o2 sensor (after Catalytic) it had a bad crack in the Exhaust Manifold that I replaced. I have the same problem when I stop, my idle dips and evens back out to 750rpms. She's only stalled once (in reverse) but I believe that is because I stopped suddenly and threw her in reverse and put lots of strain on the power steering because I was setting up to back around a corner. It usually just dips and then maintains normal idle (but she stumbles just like bad tuning)
I know this thread is old but I need help anyone? I have also found a nice air intake from this site so I'm excited to take some pics of my new obsession (cosmoracing.com) I have found troubleshooting sites that say these are related problems of po304 code, anyone please??

Ignition coil / Spark plugs / Ignition circuit / Injector / Upstream HO2S / Compression pressure / Timing belt / Crankshaft position sensor / Air intake / Fuel pressure / Crankshaft position sensor circuit and connector / Bad tuning

HO2S Heated O2 Sensor