Strange hesitation !

Y

youngsyp

Active Member
I've just noticed this over the last couple of days. Basically, at low rpm (2-3k rpm), in the lower gears (1st, 2nd and 3rd) at very little to no load and about 20-28% throttle, the car has a very pronounced 'pulsing' hesitation. Where as at over those figures, it pulls like a train as usual, all very smoothly. I also think that turbo lag might be more pronounced lately too ?!

I have an AVC-R set for 'gear learning' with '7' for feedback in all gears. I've just turned the 'gear learning' off in 1st and 2nd but, I couldn't feel any difference.

When I did glance at the boost figures on the AVC-R, they seemed to fluctuate at the point of hesitation, ever so slightly.

I can't put my finger on what it is as, if it was because of worn plugs (they've been in there for 2 years), surely it would be more pronounced as the revs and load rise, the same with a boost leak ?!

Any ideas ?

Cheers

Paul
 
warringtonjack

warringtonjack

Active Member
I'm starting to have this same issue as well. I reckon its a fuelling issue of somesort, as tho the injectors aren't feeding smoothly at lower revs. If i keep the pedal flat to the floor, you can hear the turbo spooling and it makes 1 bar, but hardly any acceleration at all. Then after it has slowly climbed the revs to about 3 - 3.5k it suddenly launches accompanied by a nice loud pop from the goose. :s

No idea what it is. Time for a service tho methinks.
 
campbellju

campbellju

Moderators
Staff member
if its missing, it has got to be either sparking or fueling (MAF sugnal, earths etc)

Check your plug gaps and condition of cap/rotor as a starting point maybe.
 
Y

youngsyp

Active Member
Checked all the above except plugs and there's no worries about the earths as, I've re-earthed pretty much the whole car ! However, I think I found what it was last night. Took the plugs out to check and possibly re gap them as, they're over 2 years old now (they were fine last time I checked them about 4 months ago) and the plug in cylinder no 3 looked like the centre electrode had broken off. On closer inspection, the ceramic insulator around the centre electrode had cracked all the way around and had slid all the way down the centre electrode. The only thing stopping it from coming off all together was the earthing electrode. I guess this is stopping the charge in the cylinder igniting at the points where I'm feeling the hesitation ?!

Anyway, on to the next point, what plugs should I replace the old ones with ? Should I stick with another set of Denso IK24's or, go for a set of NGK BKR8EIX ?

Ironically enough, I've recently read an article about the Denso plugs insulation fracturing so, it makes me think whether it could happen again ?! They did last for over 2 years though, with very little wear !

Any thoughts would be appreciated !

Warringtonjack: go and have a look at your plugs buddy !
 
Y

youngsyp

Active Member
Right, it turns out not to be the plugs after all. They have made a difference as, it's not as noticable and doesn't happen as much but, I've also noted that the car feels a bit flat in WOT accelerating. Don't get me wrong, it still goes like poo off a teflon coated stick but, it doesn't seem to have the same urgency. I'm now using NGK IX plugs in the 8 heat range with the pre set 0.8mm gap (this was checked by me).

Ive checked the earths and even re did the MAF earth reinforcement. The TPS is has the earth reinforced and cleaned the TPS with WD40. I've re done the fuel pump earth (up to 12.27v's now) and it's the original OE pump. I've checked the dizzy cap and rotor arm and they seemed fine although, I did clean off the negligable surface deposits from both with fine wet and dry.
The fuel filter is relatively new and when I had it off recently, fuel was clear when poured out of each end so, I guess that's fine. The fuel lines to and from the filter are new. All vacuum pipes to the fuel pressure reg are silicon and in very good condition.
This leaves me with the plug leads. These are at least 4 years old (as long as I've had the car from when I imported it). I've done 45k miles in the car since I got it. They seem clean and in good nick from the outside but, I guess it's the inside conductors that have the hard job ?!

I'm guessing these need replacing ?!

Oh, and it's fault code clear !
 
Last edited:
kev_200uk

kev_200uk

New Member
did anyone have any feed back from this post cause im having the same problem at the moment, just recently had a service at ninja tune factory on the sunday but the problem was there before the service and after the service, any answers will be much apreciated by anyone
 
Y

youngsyp

Active Member
It was the fuel filter in the abve case bud(s).

Take yours off and blow through it, in the reverse direction of flow. You'll probably notice the fuel that comes out, turns black from all the silt in the filter. You may also notice what feels like a partial obstruction.

You can get filters from most places. If you have a car with ABS, you'll need the GTiR specific one. If not, you can use the one for the 300ZX, 200SX etc... It's exacly the same as the GTiR one but, doesn't have a bent (90 degree) upper tube and is a fair bit cheaper.

Paul
 
davey red.r

davey red.r

New Member
youngsyp said:
I've just noticed this over the last couple of days. Basically, at low rpm (2-3k rpm), in the lower gears (1st, 2nd and 3rd) at very little to no load and about 20-28% throttle, the car has a very pronounced 'pulsing' hesitation. Where as at over those figures, it pulls like a train as usual, all very smoothly. I also think that turbo lag might be more pronounced lately too ?!

I have an AVC-R set for 'gear learning' with '7' for feedback in all gears. I've just turned the 'gear learning' off in 1st and 2nd but, I couldn't feel any difference.

When I did glance at the boost figures on the AVC-R, they seemed to fluctuate at the point of hesitation, ever so slightly.

I can't put my finger on what it is as, if it was because of worn plugs (they've been in there for 2 years), surely it would be more pronounced as the revs and load rise, the same with a boost leak ?!

Any ideas ?

Cheers

Paul
Click to expand...
mine was doing same two wks ago
was hesitating when engine was warm
popping&banging
and seemed to be black smoke coming from rear
i took it in to garage and my mechanic said there was nothing to worry about
it was slightly overfueling
and i believe he said that hed retard ignition very slightly?
i may of heard wrong


regards davey


davey
 
Last edited:
kev_200uk

kev_200uk

New Member
and how do u do that, its not the fuel filter cause i had it changed when i had the service and stil did it afterwards
 
Fusion Ed

Fusion Ed

Active Member
Retarding the timing does not cure over fuelling. Not only that retarding the timing will make the car less efficient and it will loose MPG as a result.
 
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