Hi Guys,
I am having some hesitation probs over 4500 rpm and after doing a lot of searching i have not seen anything matching my issues.

Mods:
Knightsport ecu mapped to 14psi (been running this for over 3yrs with no major issues)
Pressure regulator to 4 solenoids so they only see 10 psi
XS power stock mount I/C
twin K&N filters
Magnacor leads
Earthing kit
Racing beat exhaust system (form the down pipe, inc decat pipe)
Stock twin turbos
Sparks plugs changed 3 weeks ago (300 or so miles)

Recently I was having probs with a boost leak at 4-4500+ rpm, it would be a couple of woosh noises and then the boost would kick in, then when I changed gear it would woosh once or twice and then not do it again until I stopped the car and let it cool down. My 1st thought was a faulty solenoid so i took off the UIM, checked all the solenoids and they were fine. I also checked and replaced most pipes to the crv as i know this can vent boost before the transition takes place.

Since refitting the uim the boost leak is not so a common (i still think this may be down to the crv or actuator) but now the car will hesitate over 4500 rpm.

Taking a normal journey will go like this:
Once warm the car will behave perfectly uptil 4500 rpm, then i get the woosh, woosh noise about 4-5 time in 2-3 seconds, then about 7-8 psi, if i change gear then it will woosh once or twice and then hesitate, the exhaust will pop and bang, the car struggles to accelerate.

It will rev freely to the redline but under load it hesitates. Some times this prob does not occur but 8 out of 10 time it will. It will do it if the car is warmed up or if it's hot from sitting in traffic.

Last weekend I took the UIM off again to check all the pipes and solenoids but everything is connected as it should be, there are no split pipes (mityvac was essential here) all the solenoids are plugged in etc.

As i said this happens more often that not but sometimes it will not do it at all on a journey and others it will do it everytime. Could it be fuel cut, overboosting (i've got a boost gauge but i have not seen any boost spikes, a faulty boost sensor?

Can anyone advise me on what the check next please? This is driving me insane

Thanks

Rob

 

i have a single turbo with a street port on 15psi.. and a 255 fuel pump.. but the between the stock fuel lines and probably old fuel filter.. whenever the car is below a half a tank of gas it starts to cutt out and sputter at WOT..

Try filling up the gas tank and seeing if the condition goes away

Just my o2 cents

 

Sounds to me like a fuel restriction... You should have at least 40 psi static pressure when idling.

Then if your running 10 psi boost your regulator should compensate 1 psi boost : 1 psi fuel.
Regulators are 1:1 ratio

For Example:

40 psi static fuel pressure idling + 10 psi under load (boost) = 50 psi fuel pressure while driving under load.

Check your fuel pressure regulator setting, fuel filter then plugs.

Good Luck,

Andre

 

Fuel tank is pretty much full, filled up friday just gone.
I dont have an after market FPR fitted so can I check the stock one's settings? Fuel filter was changed 8000 miles ago and I took the plugs out over the weekend and they are fine.

 

Might be a bad injector, I had a similar problem and it turned out to be one of the injectors was bad. I replace it and now my car runs strong at wot without any hesitation