sx needs help

Hey guys this morning I was driving and decided to open my car up and stretch its legs but something was wrong. My turbo whistles and does its thing and the boost guage shows that its boosting. But for some reason it isn't kicking in. There is no pull at all when the turbo starts boosting. The guage shows its booostiong and the dunpvalve goes off and everything but no pull. And the engine wont go past 5500 RPM. Anyone have an idea what the problem could be?

Where is boost gauge pick up??

The boost guage reads directly from the intake manifold

If the boost is there,I am stumpt, Maybe your problem lies with the tuning. Check for air restrictions aswell.

It would still show boost even with a boost leak unless its a mahooosive one.

I would start by checking if the exhaust is blocked, then the fuel filter. If either of these were the problem you would get the boost but at high rev the car will bog down.

Me, Freddy and Derek checked the spark plugs and ran a compression test. thats all fine. the theory we have is that it might be the fuel pump or management system. i am going to take the car to smart racing this week and hopefully it will be ready for westbank. thanx for the help Freddy and Derek

Sounds like a boost leak, if it sounds like the turbo is boosting its sh!tters off and you have no power... it's most likely a leak...

I had something similar when my one of my actuators bolts fell out, and was a small 4mm hole... car had no power and there was a load whistle noise

Have you check you ECU for any codes?

In all honesty it sounds like an Injector or Spark issue, if it was a boost leak it would show on your gauge.

Are you running the Stock Pump, Has anything changes since it last ran well?

Phinx wrote:

In all honesty it sounds like an Injector or Spark issue, if it was a boost leak it would show on your gauge.
well?

Not entirely... Remember, your turbo will try and compensate for the lost air, the actuator will stay closed till the required pressure is reached, your AFM will be all wrong because its reading that the car is taking in twice as much air, but its only getting half that its taking in, and thus the car will be over fueling and that can be the reason for the no kick in the butt feeling...

But the whistle is the give away on the boost leak...

I differ from your sight of the guage Vlade, the guage reads directly from the intake manifold, thus it takes a pressure reading from the turbo or pressure coming in from the turbo into the intake, whether the wastegate is open or closed it measures the presure made by the turbo into the intake, if the turbo pushes 1 bar the guege will show one bar.

Yes and for the turbo to make boost it need combustion. That is why I said if the exhaust or fuel filter is blocked at high rev it will bogg down.

true what you say Gary, only problem is he boosted 0.8 bar before as is the same now, that means combustion is right for it to boost 0.8

Derek-son wrote:

I differ from your sight of the guage Vlade, the guage reads directly from the intake manifold, thus it takes a pressure reading from the turbo or pressure coming in from the turbo into the intake, whether the wastegate is open or closed it measures the presure made by the turbo into the intake, if the turbo pushes 1 bar the guege will show one bar.

Think of it this way...

Your turbo can lets say have an efficiency of 1.2bar, the stock wastegate is set to open up fully at 0.7bar, so the turbo is still capable of 0.5 bar more...

Now lets say you are loosing 0.2bar of the pressure from a boost leak, your turbo just works a little harder to compensate for that 0.2bar pressure loss, since its still seeing the pressure as 0.5 and it will work its arse off till it sees 0.7... and that is why you hear a whistle and also hear the turbo work a little harder...

In a case where you are loosing a huge amount of air, you will notice is on the gauge

I have experienced both cases above, I have even had a leak under low pressure then when the system comes up to 0.5 the leak closes up...

😉

I understand your theory and that you experienced it, but your guage will still show you the leak, the pressure will go up to the full boost you want and then fall down a bit as the pressure escapes and then go up again. I also speak from experience so lets agree to disagree, hope gremlin gets his probs sorted out.

😀

You’re both right...

It will over fuel because the AFM will meter the air and compensate but what I meant is there will be slow pick-up and it will drop-off rapidly also I've run my car home with a pipe off and it rev's happy till 7000Rpm just no damn power.

Don’t go WOT with piping off it dies instantly because of over fueling. My money is on a Spark or timing issue but in honesty could be a number of things

OK. I got the car back yesterday and its running strong again.I heard about a mechanic from a friend. The guy is a genius with engines. He spent the whole saturday faultfinding till he found the fault and didnt even charge me for it. The problem lied with my intake manifold. Those who have seen me car know i have a wierd manifold. It is a variable manifold. It was two sets of piping into the engine block. 4 thin ones with a tight bend and 4 thick ones with a gradual bend. With normal driving it uses the thin ones which gives lots of bottom end torque and helps spool the turbo faster. whel the turbo starts boosting it changes to the larger pipes. My problem lied with the pot that changed between the piping. It broke and got stuck with the small pipes. anyway he fixed all this and tossed out 3kg's worth of crap that my engine doesnt use and re-routed my vaccume pipes and got rid of anything that was hamperreing my power. and he also neatened up my engine bay. All this costed R503. The guy owns a normal repair shop but does do all sorts of conversions at special request. If anyone wants a decent mechanic his name is Gerhad and his number is 0123264713. I will see you guys on saturday

Fantastic George. We must meet this mech man. I think we put his detail on our cellph application for all to access?

Why did you change the intake manifold?? Where did you get it from??