At around 4k revs in third gear the car seems to stutter. Not sure hat it is though, perhaps the fuel cutting out??? I was on boost at the time but nothing major. (wasn't exactly flooring it).

 

Anyone had this or have an idea what it could be?

fuel temp sensor? air flow meter? doubtful its the fuel pump. are all your connections wiring wise ok?

has it just started?? when did you last change your plugs??

Plugs probably have less than 2000 miles on them, seems like it has only just started happening

It's doing it in 2nd, 3rd and 4th gears

2nd at around 4700 revs

3rd and 4th at around 4000 revs

 

I think I have a vacuum leak, could this be the problem?

does it idle ok?

It revs high on a morning til it warms up butthen calms down to around 1 to 1.5k.

Been idling around 1k today though.

 

It's not irratic in then sence of it's siting there changing every second so to speak

for the fault first described i wouldn't put that down to vacuum leak. always worth a check round all the clips and pipes though. i personally would change fuel filter ,replace or clean air filter .then give it a run . if there's no change then i'd start thinking about maf,fuel temp sensor .but only after double checking all supply electical leads and connectors. i'm no expert though so don't take this as gospel mate. good luck on the task in hand anyway.

Does it appear to be running rich?.....may be worth checking the coolant temp sensor connection.

make sure the MAF is dry? i get this occasionally when its rained hard

Could be a tonne of things but mine was losing power big time after 3500 or so at full load, that was a failing PTU.

I know what that is !

 

It's exactly what mine is doing !

 

Jeff has changed fuel filter, plugs, coil packs, Fuel ECU, Vacuum pipes and is currently sourcing a fuel pressure gauge to use and check the pressure

 

It does vary by temperature as to how it does it......

Thanks all. Seemed to be ok when cold but I didn't really have my foot down at all. Was very cautious lol.

 

Tony - So what is it then? Cos your post suggests it could be any of that stuff lol

Does it appear to be running rich?.....may be worth checking the coolant temp sensor connection.

I think its always running rich to be honest, always hearing pops from the exhaust

 

 

make sure the MAF is dry? i get this occasionally when its rained hard

 

It has been raining a lot but It was dry all of yesterday when it was happening.

 

for the fault first described i wouldn't put that down to vacuum leak. always worth a check round all the clips and pipes though. i personally would change fuel filter ,replace or clean air filter .then give it a run . if there's no change then i'd start thinking about maf,fuel temp sensor .but only after double checking all supply electical leads and connectors. i'm no expert though so don't take this as gospel mate. good luck on the task in hand anyway.

 

Would datascan pull any of these faults do you think?

Dunno yet....still waiting a call from Jeff to say he's got a fuel pressure gauge to try

 

The way I described the problem to Jeff was it's like an F! car going down the pitlane. The tubs are spinning, it's driving but there's a sudden loss of power and it won't rev any further. Mind you, I get round the problem by short shifting and it's phenominal because I must be shifting gear at max torque because it seems quicker and I spun the wheels in FOURTH ! Never done that when I've been changing at higher revs .....

 

We shall see and let's keep in touch and feed each other informed

I got a similar problem once and out turned out to be the air filter getting wet , water was dripping inbetween the nose panel and bumper and straight onto the air filter which was a cone filter , i put a little cover over the top to deflect any drops and problem solved , i hope it,s something as simple as that bud . :thumbup1:

Could be mate, I do have a cone filter. I also tried it again last night and it didn't do it. I guess it could be temperature related though

I had that problem with the MAF getting wet from a cone filter but caused a massive misfire... not just a refusal to rev any higher

 

that wa fixed by removing the cone for clean standard filters and a new MAF

Tony was yours ever fixed and the problem narrowed down?

My guess: one one the coils. Check them. If one seems bad. Don't need to be broken. But if you have a bad coil you'll noticed it around 4000-5000rpm to begin with. change it and take the car for a spin.

I just changed them all from standard to splitfires and first drive all was great, next day it was like this again,

Don't know if it's worth mentioning but it only happens when driving under boost. If my foots on the clutch or the car is in neutral it revs perfectly fine

Hi,

 

I wouldn't out a vac / boost leak.... do the test!!!

 

your idle is too high and could be masking some other issue.

 

get it on conzult or ecutalk that will confirm O2's working, TPS voltage, IAA is working at the right percentage.

 

what checks have you done?

what plugs are you running?

what series ptu do you have?

do you have lager injectors and has the ecu been mapped for them?

Edited June 17, 201213 yr by Medallion Man

I did a boost leak check and couldn't here anything coming out. Would be much better if I had the smoke ones but seemed ok.

The idle is a little up and down to be honest mate, goes from around 1k to 1.5k somewhere. But I'm worried if I turn it down that I might stall.

 

The injectors are 740cc nismos. I did have it mapped but boost etc was turned right down because it was Mis-firing. But the car has ran fine for ages since then.

 

Ptu is a series 2

 

The plugs are decent ones, heat rating 8.

 

I'm a little unsure about the O2 sensors to be honest as one is sitting at 100 but they do move when car is revving. I've changed the tps to .44.

 

I haven't a clue how to check the IAA :/

 

Here is the datascan thing.

 

 

Have you had the plugs out to check them…(if you have them, iridium’s aren’t recommended, go back to platinum), in the very least give them a clean…. and test to make sure all are working / sparking on the car.

 

This is my understanding….

 

Your temp isn’t up to 80 so not sure if this is affecting some of the readings…

 

From your readings your TPS looks OK

AAC is OK but should be 15%.

Air flow is good.

Injector pulse 2.2 for standard, yours looks low but I don’t know how 730’s will affect that .

Injector duty also looks a bit quick but this could be because of the idle.

A/F is OK but a bit high... 111.

only works if you have fully functional O2-sensors and ideally you want this value to be close to 100%.

any value over or under 100% means the ECU has to compensate with less or extra fuel to get the mixture right.

Extreme compensations (> +/- 15%) usually mean something is wrong with either air (airleaks) or fuel (injectors/fuel pressure)

 

 

Now the O2 (LH) is not right… should pulse up and down not be right up there all the time.. try unplugging it. And see what happens.

 

Have you done the timing with a timing light (no good reading it from the diags, as the ecu compensates and makes it read at 15).

 

You need to get the idle speed back down, it’s hiding the problem.

Hi mate, thanks for the above info. I'll get the car up to temp and take another reading. I have a feeling the plugs are iridium but john dixon told me the ones to get so would have thought they were good.

 

The strange thing is it was completely fine untilthe other week then it started being a pain in the butt lol.

O/T where did you get your Splitfires from?

 

everywhere I've tried are out of stock, or there's a long wait from Japan

Have a read here on how to adjust the IAA; http://s95014253.onlinehome.us/63104/157335.html?*session*id*key*=*session*id*val*

 

tbh though, I found easier to take the whole thing off the back of the engine, strip it down, clean it and then rebuild and put back on.