Quick - help needed.

 

My luvly zed has been driving very nicely thanks very much, up until I got in it to come home from work this evening and something has gone horribly wrong.

 

I've suddenly got a misfire!

 

Even before the engine was hot I could hear it very clearly and the power delivery was decidedly lumpy. I stopped and turned off, waited a few minutes and re-started and still the same.

 

When I got home I checked I hadn't lost an obvious hose connection under the bonnet and although I'm far from being mechanically minded, there wasn't a lose bit waggling around.

 

Can anyone suggest a possible cause? and even better a remedy that doesn't involve dropping it in at a garage!

Check to see if one of those crappy injector connectors is not fully pushed on to the injector as they sometimes rattle loose when they are old, or u might have get a bad connection use some contact spray.

Richard

Also check all connections on the coil packs are secure.

 

How old are plugs? No 'hissing' like air leak anywhere?

Plus it could of course be the PTU. Happened to me 2 months ago.Wait till the engines cold and start it up. If alls ok until warm then the PTU has gone south.

Guys, thanks for the quick response, but just imagine for a moment that I'm one of those sad gits that doesn't understand what you're talking about!

 

I'm afraid you have to spell it out to me, like 'just above the engine are a few bits of blck tube, follow the narrow one to the end and that's the heamoglobin coagulator, on the back of this is the connector you need to check!'

 

if you know whgat I mean - pretend I know NOTHING and I'll be fine!

 

otherwise, I have to print out your messages and give them to the garage with the keys and wait for the BILL!

The check for the PTU sounds easy, but I definitley had a misfire whilst it was still warming up, does this mean the PTU is probaly OK?

 

and what is a PTU???:confused:

Originally posted by james300

Also check all connections on the coil packs are secure.

 

How old are plugs? No 'hissing' like air leak anywhere?

 

The transmission on this car is so noisy it almost drowns out the extraodinarily loud exhaust (my back boxes are just 5' long - very loud indeed!) - so I'm not detecting the hissing noise you mention, but that's not to say it isn't there.

 

I'd be happy to change the plugs, but I'm totally confused after reading all the postings about plugs on this forum. I'd be happy for some advice on what to buy and where (and how much I should be paying!)

 

Thanks

Check to see which cylinder (if any) are misbehaving. Disconnect each coil pack in turn while the engine is running. When you disconnect 1 the engine revs will dip and become slightly more lumpy. If when you pull a connector this does happen, that cylinder''s ur problemo. See here ;- http://www.300zx.co.uk/forums/showthread.php?s=&threadid=17731

Shit!

 

That was supposed to say: If when you pull a connector this doesn't happen, that cylinder''s ur problemo.

OK, I read this and I'm praying my car will be as easy to fix!

 

Just one question (to demonstrate my complete ignorance!) where do I disconnect the coil packs?

 

(Just imagine some numpty pulling cables at random out of his engine bay and pannic!)

 

I can almost guarantee that the coilpack and injector connectors will be gunked up with green crap. Buy a can of electrical contact cleaner, pull all of these plugs off, give them a good spray and put them back. On the front you will see I labelled the PTU and CAS. Do these also, to do these you will need to remove the 2 top boost hoses, the PTU has 2 connectors on either end, the CAS just the 1 on the right hand side of it.

 

You will see what I mean when I say these will need cleaning ;)

 

Once you have put it all back together im pretty sure it will run fine again.

 

If it doesnt, it might be something more serious, as said above, pull each one of the coilpack connectors off in turn, when you pull one out and the engine revs do not fall, this is your problem cylinder. To be sure, give the connectors a second cleanup. If theres still no joy then try somebody's knwon good PTU in it, these are notorious for dieing. If that still doesnt help, then try the electircal connections. The injector pulse is easy to check for, pull the injector plug out and put an LED across it, the LED will flash if you have a pulse. The coilpacks are a little more complicated and will involve an afternoon with a multimeter and the wiring diagrams.

Clarkey, thanks mate, that was certainly comprehensive and I appreciate you taking the time out to help.

 

Looks like I'll be spending the evening with green gunk!

 

(but sadly I will have to limp around in the car on 5 cylinders in the meantime, hope I don't break anything!)

Let us know what you've done and how you get on......at the very least you will start to learn more about your engine. Not that that seems like much consolation at the moment I guess.

 

Good luck. Just one more bit of advice, when disconnecting the coil packs, be as gentle as possible as over time and due to under bonnet temp-they will be very brittle...well, that goes for ALL connections really! You will soon discover what I mean.

 

Are you going to get plugs? I get mine from Courtesy, have you discovered them yet? Or I know Stu (SMW1) is selling a set.

Originally posted by james300

Let us know what you've done and how you get on...... be as gentle as possible as over time and due to under bonnet temp-they will be very brittle...

 

Ha, wish I'd read that first!

I managed to locate the coil connectors and opened them up to have a look, but they were all VERY brittle and I managed to damage the clips on 3 or 4 of them!, but they went back together ok and I sorted the misfire,

 

So thanks to you all, now I just need to think about replacing the clips!!!!

 

I'll sort some new plugs at the next service I think, I have no idea what state the current ones are in, but the car runs ok, (NOW!)