r1c

iTrader: (9)

i think im suffering with fuel cut... can some one help out? under harsh acceleration out of a roundabout, the car 'hold back' for a few seconds it feels quite violent, iv had some hesitation issues recently but got them sorted out and this feels different. the car is a MY99 turbo, with open mouth de cat, mid de cat and back box. im just wondering with the standard map and the decat if its overboosting and getting fuel cut, is this possible? if so is it worth fitting a dawes device set to standard boost which (correct me if im wrong) some one told me it was 0.7 bar. or could it be something like a ht lead. i dont have a boost guage fitted at current, maybe its worth doing that first. can anyone advise?
i will be looking to add supporting mods and remap in the near future but as times are hard at the moment im having to wait but i dont wanna cause any damage to the car, but i still like to drive it, i could always not accelerate as hard but wheres the fun in that and whats the point in having it if you cant use it!!!

Thanks in advance

DeanF

iTrader: (1)

With a Full Decat the car will be prone to Boost Spikes, Which can go above fuel cut & give you your issues.

I would fit a boost gauge to visually see what is happening first, You can get a dawes type device & Boost gauge combined here

R-Spec BOOST CONTROLLER & PSI GAUGE KIT- ANY TURBO CAR on eBay (end time 25-Sep-09 09:09:42 BST)

It has best offer also, So try your luck.
The Rspec boost controllers are not too bad & control boost V well, Eliminating spikes altogether.

Dean

joey_turbo

iTrader: (26)

It very possible. A lot of people warn you off using a Dawes, or any type of Manual Boost Controller, but used it the way you want is the best way. I've used one for 3 years to "cap" the boost.
So I say yes get one.

Interesting you mention the roundabout though. Because if you have under a 1/4 tank of petrol, and take a hard corner, you can get fuel starvation where the pump suddenly has no fuel to suck up, as its made its way to the other side of the tank. So its always worth thinking about that when you are running low.

r1c

iTrader: (9)

Thanks dean , will try that out, do you know if the standard boost is 0.7 bar? And where fuel cut comes in? I think I read in a previous post it was about 1.1bar
thanks again

r1c

iTrader: (9)

I'll check next time it happens see where the fuel gauge is, could be fuel starvation, never really thought of that. It only ever happens on the one roundabout cos I go right round almost. Thought it could be overboosting cos it's a massive load on the engine- you could be right tho same conditions different effect!

Splitpin

As always we can only guess given both that we can't sit in your car, and that you (understandably) haven't told us enough to be totally sure of what's going on.

It shouldn't be, no. The boost target and cut values on these cars are suficiently far apart that a decat alone shouldn't push it over the edge.

No, that's the wrong way to go at this point. Manual boost controllers have their uses but the right time to fit one is when you know your car's working fine and you want a little more power. Fitting one to try and "cure a problem" is potentially asking for trouble.

No. Boost target is 0.94 bar at low to medium engine speeds - starting to taper off over 5000rpm. Fuel cut is 1.21 bar at normal atmospheric pressure.

Yes, good idea. If you suspect you're suffering overboost, the only way to prove or disprove the suspicion is via a gauge.

Joey's suggestion is a good one to rule out first. Does this happen on a full tank of fuel? If it does, try cleaning your boost control solenoid and look at getting a gauge.

Edited to add: How far up the dipstick does the oil level go if you check it when the engine is hot?

DeanF

iTrader: (1)

Splitpin is right of course

Rule out any other possibilities 1st, Split hose's , Leaks, Overfull with oil, Fuel level, Fuel Type, 95 ron, V Power, Sparkies & Coil packs Etc.. Although i believe you lookled at those prior.

Dean

r1c

iTrader: (9)

Thanks for the input splitpin, I understand it's hard to diagnose a fault without seeing it, was hoping someone here may have seen something similar before and could advise where to start,

Dean thanks too, I have checked for boost leaks, oil level spot on I serviced it about 6 weeks ago, don't use v power, can't be sure of fuel level when it happens I'll check next time, I can't rule out plug or ht issue but it doesn't feel like a misfire, I think I'll fit a boost guage in the mean time. Also did a fault code check this afternoon and it's clear !!!!

r1c

iTrader: (9)

Thanks for the input splitpin, I understand it's hard to diagnose a fault without seeing it, was hoping someone here may have seen something similar before and could advise where to start,

Dean thanks too, I have checked for boost leaks, oil level spot on I serviced it about 6 weeks ago, don't use v power, can't be sure of fuel level when it happens I'll check next time, I can't rule out plug or ht issue but it doesn't feel like a misfire, I think I'll fit a boost guage in the mean time. Also did a fault code check this afternoon and it's clear !!!!

bigsinky

wild stutter there fella

r1c

iTrader: (9)

Tell me about fff****in iPhone !

Splitpin

What do you mean exactly by "spot on"? If it goes above the top hole (I mean the hole, not the notch on the side) when the car is running it's not difficult to fill the boost solenoid, which can in turn impair boost control.

Boost cut is very recognisable, it's a sudden and violent power loss that'll make you think you're about to headbutt the windscreen. As to fault codes, you wouldn't necessarily expect to find any at this point. If it is overboost, for example, you won't get a CEL, and if it's a damaged coilpack, again, the ECU won't know as it doesn't do any closed-loop monitoring of spark quality. For the time being you're a little in the dark - boost gauge will help throw some light.

r1c

iTrader: (9)

Boost solenoid is clean I checked that when I was hunting for the hesitation, oil level is spot on, and the issue is violent, like a total power loss for 3 to 4 seconds, will keep an eye on the fuel gauge, fit a boost guage see how it goes.