Now that I've corrected the duff TPS, I made the stupid mistake of being smug and believing my car would now run peachy forever.

 

WRONG!!!

 

Driving home last night when I developed a misfire as I was coming up my road. Turned out that the whole of the driver's side bank of the V6 was dead. You could pull the coil inputs on every cylinder and it made no difference.

 

Checked the sparks by pulling the coils out and holding them near an earth. Checked out OK. Listened to the injectors with a metal bar. All 6 sounded the same.

 

Wiggled every wire in sight with no effect.

 

The fuel rails are mutually dependent so I ruled out fuel starvation. The throttle was opening OK. ECU reported no errors. No air leaks.

 

I then started to fear some sort of mechanical failure but the head gasket seemed OK (no steam in the exhaust and hard to imagine failing between 3 cylinders simultaneously). Cams run off the same belt as the other side of the V so couldn't see this being a problem.

 

So, the injectors are giving it fuel, the ignition system's giving it a spark, mechanically it's hard to imagine a problem, the only thing I could think was that the spark/fuel was being triggered at the wrong time. However, as far as I know, that data comes from the CAS which would also affect the other side of the V.

 

The only thing I could think of that was left would be some sort of major constriction in the induction side. Could a seized turbo or intercooler problem cause a total blockage?

 

So I booked it into Middlehurst this morning and, to give them their due, they managed to fit me in straight away AND get me a courtesy car. So I misfire down to Middlehurst, pull up on the car park, and the thing jumps back to life! It now runs fine again. I've tried wiggling everything I can see to see if I can reproduce the problem but no result.

 

Any thoughts anyone coz it's got me stumped? The car's running fine now but I don't fancy a repeat performance.

 

[This message has been edited by Mike Duffy (edited 17-07-2001).]

Hi again Mike,

 

That is so weird, I was thinking PTU but if you're defo getting sparkies at the plugies then can't be!

 

This is what I had on mine, but on only one cyl. number 5 I think. Pull the coil plug off and no drop in RPM at all...but never investigated further. Will be interesting to see if mine is OK after a new wiring loom and engine rebuild!

 

Maybe it was the thought of having to go back to Middlehurst and maybe spend an overnighter parked up next to some Micra's that sorted it! LOL! If it happens again, just threaten the car "do you want to go back to Middlehurst then? Coz that's what will happen if you don't stop being a naughty Z!!!"

 

Sorry can't be more constructive but this does sound well iffy jiffy!

 

Could it be heat soak? I've seen some documentaries about the no.1 killer in America...Ford Explorer...most of the problems have been put down to the electrics behaving intermittently due to heat soak in the engine bay! This can never be ruled out, especially on a Z! What is the loom like? Condition of the coil plug connectors etc.

 

Don't know what else to suggest...

 

 

 

Tim

:->

 

On mine it was heat soaked wiring they replaced the part up to the coil and its run fine since

Nick

On mine it was heat soaked wiring they replaced the part up to the coil and its run fine since

Nick

On mine it was heat soaked wiring they replaced the part up to the coil and its run fine since

Nick

On mine it was heat soaked wiring they replaced the part up to the coil and its run fine since

Nick

The loom was a bit knackered but Middlehurst replaced parts of it last time it was in. Improved it a lot.

 

Tim, you mention the PTU. I know nothing about the construction of this. Is there any part of it that is dedicated to one bank of the V, thus causing all of that bank to fail. I was definately getting a spark but I was thinking that maybe the spark was too weak to do the job. However, at idle, that seems unlikely.

 

If it was just one cylinder then I would put it down to a dodgy connector somewhere. But what would affect all of one side of the engine?

 

Cheers all.

Hi Mike,

 

Your PTU is basically a digital equivalent of a distributor on any other car. If you stand in front of your motor with the bonnet up and look at the left hand side of the engine front you will see it. Small box with fins on, six leads coming off(I think! Or is it one that splits to six) and usually has either Hitachi or Mitsibushi on it!

 

Errrrr, in terms of it failing on bank of 3? Possible I suppose, most pack up with different symptoms which do tend to baffle most until someone says "PTU, that happened with me!"

 

I changed mine anyway, whether it was failing or adding to the problems that I was experiencing. Cost about £200 quid or thereabouts, if you plan on keeping the car for any period of time it is likely, or the most predictable part to pack up...IMHO! So changing it would eliminate it from the vast number of electrical components under the bonnet of the Z. Upto you though, but if you do experience this problem again, try and swap it out with someone else's know good one.

 

What are the plugs like? That article on TT.net which we've both read mentioned that the plugs can make all the difference. Personally when I get mine back I'm going to run it with Iridium plugs, I think HKS do them. Hiteq, in Wigan, can supply them...check out the plugs though...this sort of problem is a matter of elimination like that guy said in the article.

 

Check voltages with an AVO if you've got one. I've got a Techtom at home, don't know if this could help you but when you experience the problem it could show you more about what's going on around the engine.

 

Later

 

 

 

Tim

;-)