Car Judder when slightly pressing on accelerator

[CMF_PhillT]

Hi,

I'm having issues with my 1995 micra juddering when I slightly put my foot down on the accelerator or take my foot off.

If I heavily press the accelerator then the issue does not occur, its only when i press it slightly.

I've tried the soldering on the MAF. No luck. I think it must be the throttle body as it would seem that the incorrect fuel air mixture is occuring, but want to see if anyone has had a similar issue before buying one.

Also for info, I had starter issues recently and got a new distributor (also the mechanic sprayed WD40 down the throttle body - I've since decided to start reading about cars as its too expensive getting them fixed by someone else) this was done to fix the starter issues, but has now caused the issue described above.

Thanks in advance and for all the free info that is on here.

Phill

 

[CMF_frank2]

hi phill
i dont think WD will do the hotwire any good, nor the cat, was the dizzy and cap new or secondhand ?

frank

 

[CMF_PhillT]

Hi Frank,

Thanks for the quick response.

Yes I was thinking the hotwire might be knackered after that.

Dizzy is from the scrappers and cap is the original that was already on before problem occured. I was thinking of re-checking the cap and seeing if that looks alright (not sure what to look for, may just check general connnection).

Its a really odd issue and I haven't seen a similar issue posted on here.

Phill

 

[CMF_frank2]

the 4 contacts inside the dizzy cap are usually quite pitted phill, you could check that they look equal or look for any cracks or tracking, does it feel like a random total missfire, or running on 3 or 2 cylinders ?

frank

 

[CMF_PhillT]

Feels like a missfire, or not the correct air/fuel mix as the whole car goes back and forth. But it only happens when the I slightly depress the accelerator initially. It runs fine otherwise, nice and smooth, even when accelerating hard.

If i don't have my foot on the accelerator and its at normal postion idleing on the engine, then it occurs if I press it slightly. And if I try to bring the accelerator back to rest with no pressure on it, the juddering happens. Not so much in high gears, mainly 1, 2 and 3rd gear. I've checked the accelerator cable and looks to be moving fine to the throttle body.

With the specific circumstance above, could it be the dizzy, spark plugs etc? As it all seems to run fine when pressing accelerator constantly its just on initial press.

I've heard of tracking before on the dizzy cap, but what does it actually mean? Sorry I'm new to all these technicalities.

 

[CMF_frank2]

i think tracking is just a residue left from a leaking spark phill, ideally you need to borrow a spare throttlebody and dizzy so-as to eliminate one or the other eh.
unless you can induce the missfire long enough to be able to try removing plug or injector leads, or check exhaust port temps or plug colours ?

frank

 

[CMF_PhillT]

Yes ideally I do need to borrow one or the other to see which part is at fault but I don't know of anyone with a spare micra.

I'm tempted to just buy a new throttle body and see what that does. Seen one brand new for £95.

I remember when the mechanic fitted the new throttle body he said that it was exactly the same as the existing one apart from one number on it. Is this ok or does anyone have the part number of their dizzy so I can check (around the Nissan logo on it).

Thanks
Phill

 

[CMF_PhillT]

Forgot to mention. Before this happened the car was showing all the classic signs of throttle body wear:

Iratic Idling
Failed MOT emissions

and now the juddering.

If it was the distributor at fault wouldn't the juddering always happen ie its electronics so I would have thought it would be pretty consistant therefore if there was a fault you would always see it, rather than what is happening now.

 

[CMF_PhillT]

I've checked my distributor number in my car. It has:

42537N

However the haynes book reads (from the pictures)

42537K

Can anyone confirm the letter difference above and if it has any meaning?

Thanks,
Phill