Right a few weeks ago i drove my car to Wigan and on the way back i started getting a slight hesitation when on boost. Its missing slightly when boosting and also slightly when on idle.

 

Well after working none stop for the last few weeks i've got some spare time tomorrow and would like suggestions on what to check. All in very simple terms please cos i dont know so much i'm afraid.

 

If people could give me a small list of the first things to check and how to check that would be great. I will be taking my strut brace etc off to gain access so what needs checking.

 

Also when boosting it i sometimes get the cat overheat light coming on.

 

I know people have had the same prob time and time again, but ideally i'd like a little list so i can just go out to it tomorrow and crack on.

 

Any and all help will be greatly appreciated!

 

Thank You,

Isaac :cool:

Hi zx-eyes,how long ago did you have spark plugs,if running higher boost the gap needs to be smaller,maybe gap has got bigger.

Nah mate not that, they're almost spanking new. Done maybe a 1000-2000 miles on them.

 

Thanks anyway.

Nah mate not that, they're almost spanking new. Done maybe a 1000-2000 miles on them.

 

Thanks anyway.

 

I'd say look at the o2 sensors

 

i know you said you have been running rich, the little ones don't like that much!

 

Boost leak also another culprit

Edited May 7, 200916 yr by stenorth

I'd say look at the o2 sensors

 

i know you said you have been running rich, the little ones don't like that much!

 

Where are they? And how do i check them?

 

Cheers.

Where are they? And how do i check them?

 

Cheers.

 

Two ways i guess.

 

The 300zx online manual fuel and emissions page 53 (not my favorite)

 

or pages 128 - 130 ( you'll need a volt meter)

 

The connectors are shown on page 129. The sensors sit in your exhaust.

 

Sorry i can't put links, macs are stupid

Ok mate thanks for that :)

 

I think i will check some simple things first. Gonna check coil packs and easy stuff etc....

 

What else please people?

 

Thanks.

If the cat overheat light is coming on you have unburnt fuel going down the exhaust,So that rules the injector connectors out.Check your coil pack/ptu plugs are tight and making good contact,see if you can borrow a known good set of coil packs and ptu and swap them and if that fails check the plugs.It could still be an issue in the loom even after youve done all the other checks but thats worst case scenario.

I've got an almost spanking new Series 2 PTU so i can pretty much rule the unit itself out - however i will check the contact is good.

 

Well i don't have any coilpacks right now to check however i will check all the contacts and what not and see if there is anything obvious.

 

I guess after the easy stuff then i'll have to start digging deeper.

 

Thanks Jimmer - much appreciated.

 

Isaac :cool:

Hope you get it sorted.Still worth checking where your loom plugs into the new ptu as you said.The pins can get very corroded.

Hope you get it sorted.Still worth checking where your loom plugs into the new ptu as you said.The pins can get very corroded.

 

Yeah i'll do that first me thinks - very easy to do and does'nt require me taking things to pieces lol.

 

Cheers Mate :duffer:

take out the coil pack, put spark plug in the removed pack, with a piece of wire that has had the insulation removed from each end wrap one end around the threaded part of the spark plug and the other to the negative terminal of the battery. Get someone to turn the engine over checking for a full spark. Obviously this will check plug and pack.

take out the coil pack, put spark plug in the removed pack, with a piece of wire that has had the insulation removed from each end wrap one end around the threaded part of the spark plug and the other to the negative terminal of the battery. Get someone to turn the engine over checking for a full spark. Obviously this will check plug and pack.

 

Superb! Thank you for that! :bow: :bow:

something else to keep in mind, if you have unburnt fuel caused by your miss fire, this can mess with all emission sensors. Let us know how you get on.

Will do - thanks again mate.

 

Isaac :)

It is missing all the time now. When first started up - when revving - when driving etc..... Its also vibrating the whole car slightly - its a bit like a big yankee engine running or summit! :(

 

One thing i have noticed today tho - have known my exhaust was on its last legs for ages but it really is disintegrating now! Massive holes etc......! Would this have any bearing on it vibrating? Obviously its not causing the missing but it could explain the vibrating - yes, no, maybe?????

 

Have hopefully got a replacement exhaust on the way soon, so will know if that makes the slightest difference soon, but just wondering if my exhaust is causing some of my probs.

 

Cheers,

Isaac :cool:

i have no idea :( but good luck :)

Thanks Dave :)