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LET cutting out under full power

822 views 22 replies 10 participants last post by  Tricky 
#1 ·
High boost (12psi) it spluttered when I changed to third and started to accelerate, then last night I chased something off the lights in first, then when I changed to second and floored it I nearly ended up chewing the steering wheel.

Fuel filter?
 
#2 ·
At the risk of sounding stupid :), because i don't know the spec of your car. Is your car chipped?. If not its more than likely the boost limiter. I think anything more than 11 psi and the engine cuts power if it sense's more boost than that. Other than that i wouldn't know soz.

Chun.
 
#4 ·
It's chipped, Courtenay did a stage one years ago but I've never looked inside the ECU tbh. I guess it is a Superchip though!

I've felt the boost limiter before and it just kangaroos as it blows a little boost off, then builds up, blows off and so on. This was pretty much silence followed by a 'phut' from the exhaust!

The fact that the car runs fine in low boost suggests you're probably right. Thanks chaps :beer:
 
#7 · (Edited)
Hi Rich, yes it breathes a little better at the top end since you kindly lent me the air filter off your old F*rd :) You've bought an Astra TDS then huh? What year is it?

I've just read the thread again and realised Man-Chun said if it's NOT chipped, it's the boost limiter. Mine IS chipped so it can't be that then can it? 12psi is not that high.

Is the boost limiter in the ECU?
 
#8 ·
yip i would think that it is the superchip setup that is causing the bother. the enginw is now setup for the superchip boost levels but the motronic doesnt know it so it cuts the boost back when it hits its limit.

this is why some ppl remove the amal valve and fit a bleed valve to stop the boost cut happening but i wouldnt recommend that setup incase something goes wrong and you blow the thing up.

HTH

rodgerq
 
#9 ·
I didnt think the superchips dealt with the motronic boost limit and that even when chipped the motronic would cut boost at standard levels - hence the bleed valve being essential for superchiped LET's.

There is nothing wrong with the bleed valve as long as its set up correctly and you're not one of these people that winds the boost up regardless of the risk (and hopes the engine will hold captain :rolleyes: lmao )
 
#12 ·
I've heard of both situations that Not_Too_Fast and scooby are discribing. Like Not_Too_Fast said i think the superchip setup bypasses the internal pressure sensor and use's the wastegate spring to control boost. Not too sure if i'm correct or not but i remember reading that somewhere. Ever thought of changing your setup to a EDS phase 1?, there kits use the internal pressure sensor to control boost. Once you start modifiying boost you should change your hose's to silicon one's, mine are starting to flex on standard boost. I will be changing over to silicon hose's and a steel pipe from intercooler to inlet manifold.

Cheers,

Chun.
 
#14 ·
The plugs are gapped correctly and in good condition, also this would cause a misfire not a complete shutdown! Fuelling was what I thought the problem might be, so..... I don't get anything from the diagnostic light so presume there is no error code?

I will change to EDS phase 2 when I have the money Man-Chun!

The pipe that collapses, are you talking about the intake pipe with the air-filter and AFM on the end?
 
#15 ·
yep the pipe petween the Air Filter and the turbo. The standard pipe is meant to get warm and soften so under higher loads causes the pipe to collapse - wouldnt expect phase 1 / superchip to cause this problem - thought it only occured with the higher phase chips?
 
#16 ·
Interesting, I'll keep an eye on it. It's quite a strong-looking pipe though, with reinforcement ridges all along it, are the ones that collapse the same as this?

Yesterday, I decided it's definitely NOT the Superchip. I turned the actuator down a little bit and then was driving in LOW boost when it spluttered badly and then cleared. :dog:

I've just remembered who fitted my fuel filter, too - if you've put it on backwards Ste_Sa I will be having words. I'm going to go check on that today. :rolleyes:
 
#17 ·
i remember my car was doin this just after we got it even on standard boost. a new set of plugs later and all was fine again. ngk platinum ones i got. dont know the code on them though.

rodgerq
 
#18 ·
I regapped and cleaned them only recently, and they looked fine, but I suppose you can't tell just by looking really can you? A friend of mine has a tuned Escort Cosworth and if he runs that in very high boost, the plugs only last about 5000 miles he says! Do plugs not last as long in turbo engines, do you know? I've never had a turbo before....
 
#19 ·
dunno how long the plugs last for. prob differs between makes i guess. ive done mine 3 times in a year just so it always has good ones in it. same platimum tip ones every time and they have been fine. most ive run my car is 1 bar overboost falling to around 0.8 bar and have had no bother.

rodgerq
 
#22 ·
has the new fuel tank got a swirl pot in it? it could be starvation due to the fuel runing away from the pickup goin round right hand bends!

rodgerq
 
#23 ·
Aah, I'm not sure. I'll try and find out.

Okay, I just rang the people who supplied the tank and they couldn't tell me who made it (I threw the box away that it came in). That does make sense though, although how the hell do I tell if it's got one or not? The biggest hole it's got for prodding the inside is where the sender goes, and I'd have to drain the tank. :( Great.

I'll try changing the pump for another one, and I might change the filter from a slightly-used one to a new one and see how I get on.

Thanks guys, I'll let you know :beer:
 
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