Hello everyone,

I have just joined the forum to get help with a real problem on my 300zx. firstly ill describe the car:

1990 300 zx twin turbo

100,000 miles

Twin decats

twin cone air filters

Horsham developments remap

That about sums up the car, now for the issue. I recently got the car remapped at Horsham developments, car was fine but I was told that a small misfire was detected. the car drove fine back home, all was well until 2 days later. I put my foot down to make it through an amber light and when the car boosted around 5k rpm, the boost cut and the rpm went all over the place with the engine cutting soon afterwards. the engine wouldnbt start for about 40-60 mins. when it would start, it died and misfired when bought up to high rpm. I managed to get it home while driving slowly. the next day I started the engine and noticed it was only firing on 5 cylinders by pulling each coilpack power cable in turn. I assumed that the ptu may have gone so I replaced the series1 with a series 2 ptu with no change. after some research I cleaned the connectors to the fuel injector/ coilpack on afected cylinder. the next day when I started the car it was only firing on 3 cylinders. ive since replaced the CAS as I was told that it could be faulty. next day the car is only firing on 1 or 2 cylinders. the problem persists with MAF connected or disconnected, so I assume that is not at fault. ive also changed the spark plugs, tried different coil packs.

 

Im now pretty clueless as to what it could be, Im in London and as far as I know there aren't many zed speciallists around these parts to take it to. Does anyone have any idea what could be causing this problem? Any help greatly appreciated guys

forgot to mention the ecu reports a 55 code. thanks

Another miss firing zed and you have covered all the usual suspects but hopefully someone will come along with some more ideas. Welcome to the club Luther.

Thanks gary.:thumbup1: just to add a bit more info guys, the car starts with difficulty and then runs at about 500rpm and sounds like a hedge trimmer. strange thing is the degradation over a week or so from 5 good cylinders to 1 good cylinder?!:confused1:

Whereabouts in London are you?

Welcome to the club Luther - and as Andrew says, where in London are you?

 

It might be that someone nearby could pop over with a Conzult and test it for you.... Otherwise we can suggest places within reasonable distance that you could take your car to.

 

Good luck in getting it fixed, mate.

 

Richard:)

how much mechanical skill do you have?

 

have a look at this guide and see if you can follow some of it..

 

http://twinturbo.net/net/viewmsg.aspx?forum=technical&msg_id=922678

So you have a permanent miss on several cylinders? Or is it intermittent?

When you accelerated hard did you get any black smoke?

I would guess either you have a fuel fouled plug caused by a rich map or a vac leak. Hence the poor starting and loss of cylinders.

Just gotta start at the bottom and work out what's missing.

There used to be a member in London that worked on zeds, I think he still does by the name of silver bullet. He may be your best bet, or powerzed is in avon mouth, near Bristol straight down the m4 which isn't too bad.

@ AndrewG, @RichardSmith: hello gents, I am based in east London near canary wharf

@Medallion man: thanks for that link, im probably average in terms of mechanics. at the moment ill try anything within my means

@z32bolt: yes, its a permanent miss on all cylinders bar 1 now. since the problem has started I haven't been able to boost but I haven't noticed any smoke but some crazy back firing and misfiring. At the moment its running so bad on that one cylinder I dare not open the throttle much

hi ,give me a call if you want zed sorted out

xxxxxxxxxxxxxxxxxxx

Edited November 23, 201312 yr by Gaz 300
Trader offering services

Have you spoken to Jez at Horsham since it developed the issue?

I'm sure he would seek to rectify the issue if it's believed the remap could have caused the problem.

Let me know if you want me to speak to him for you as he is a trader on a forum that I moderate.

@bad300z thank you very much ill call you in a minute:)

@lexx thanks for your message, I haven't spoke to him as I didn't believe it was because of the remap. he did mention that there was a misfire whilst he was doing power runs so it was probably pre existing but not too noticeable. I would be very grateful if you could ask him for his input on the matter however

so thanks guys for all you help, I now have a few more things to check. im going to pull the plugs to see if they are fouled, check ecu is seated properly, and double check the gapping on my plugs just in case. thanks again for the replies and help guys, has given me a bit more hope of resolving this

@lexx thanks for your message, I haven't spoke to him as I didn't believe it was because of the remap. he did mention that there was a misfire whilst he was doing power runs so it was probably pre existing but not too noticeable. I would be very grateful if you could ask him for his input on the matter however

 

Done.

Just waiting on Jez getting back to me. Hopefully I'll have some news in a short while.

hi ,give me a call if you want zed sorted out

xxxxxxxxxxxxxxxxxxx

 

Hi BAD300z we have had several complaint's that you are a trader offering services to our members so your number has been removed as you are breaking the rules on trading.

Cheers lexx

Jez says to give him a ring anytime and he'll discuss your issues.

 

For those reading, Luthers car was mapped with NisTune, it had a small misfire on a power run, so the boost was dialed back a touch and it cleared.

hello gents I have just seen that in the fuse box, the fuse for the EGI is missing. could have anything to do with my issue perhaps?

hello again guys just a small update. yesterday I removed my spark plugs and saw they were black, fouled up. cleaned them and replaced with other spark plugs. car is now firing on 4 cylinders. I noticed whilst moving the ptu that the engine pitch changed whilst I was moving it, telling me that the wiring to the ptu is perhaps causing my misfiring. the connector to the ptu is in a sorry state so im going to cut the wires, strip of some of the sheathe, and replace the connector with a brand new one to see if this helps.

 

also, the very kind 300zx forum member Markderby has agreed to bring his trailer down to London to pick up the car to work on it so it looks like this prob shall get resolved one way or another

Sorry guys, thread closed pending committee discussions.....

 

....Traders have their trading arrangements set out and agreed with Graham - and we will look into any traders stepping outside their permitted remit.

 

Richard