ZERO boost; fuel cut??

[MarkoFu]

Hi guys,
Sorry to start another boost thread, but i\'m having an issue with my FD!
 
It flooded the other week for the first time- no big deal; I went through the motions (some good guides on here) and purchased some new spark plugs, and with the battery fully charged and a bit of ether sprayed into the vacuum hole it fired back up again. I let it warm up and took it out for a little drive. Seemed to be driving fine off boost, but when i put my foot down it wouldn\'t even get into positive boost. As soon as it gets even close it\'s like the fuel is cutting out and the car jolts as it seems to struggle!
You can accellerate gently through the revs and it\'s fine, regardless of speed. But it\'s when you put the accelerator down and the turbo tries to boost that it cuts out; it just can\'t boost up. Once you ease off the gas again it goes back to driving fine and does it again when you next try to accelerate hard. :3Confused
 
Changed the fuel filter (what a joy that was?!) as i thought it might be restricting the flow of fuel once it tried to boost but sadly that hasn\'t seemed to alter anything.
 
Any ideas for this one would be greatly received- i\'m at a loss!
 
Thanks,
Mark

[rustyrex]

:wavemine did this it was the charge control solinoid,and broke pipes in the rats nest.
symptoms seem the same,mine poped and banged loads also if i tried to rev it.

[pearl_rex]

second that ^ my solenoids were wrecked and the car wouldnt even entertain the thought of going on boost lol replaced them and all SEEMS ok, may be worth removing the plenum and having a nosey around the rats nest

[MarkoFu]

Thank you for the replies guys.
 
That sounds exactly like what\'s going on with mine. The fuel seems to cut out and it pops and bangs a lot, as if the mixture isn\'t right or something?? :3Confused
 
I\'ll try replacing the solenoids to start with and go from there! Now... anyone know a reliable source for these solenoids? :Thumbs-up
 
Cheers,
Mark

[MarkoFu]

Hello again,
So to update-I removed my solenoids and they seemed to work fine when i tested them, but typically I managed to break them when i refitted them; the nozzle that the hose pushes onto was rather brittle and snapped. Brilliant(!). :rolleyes:
 
Anywho, i got a replacement set off of \'chris\' from on here (thanks again) so i\'m going to refit them tomorrow morning. Seeing as the solenoids were working fine (before i got hold of them) i assume it\'s pretty safe to say that they weren\'t the problem. So i\'m going to have to have a dig around in the rats nest. Now, i\'ve got a load of silicone hose knocking around- It\'s the type you\'d use for a boost gauge. Is this suitable for replacing any hoses in the rats nest of would i have to get something else? If so, what? :confused:
 
Answers to me by tomorrow morning please!!:Tongue1
 
Thanks,
Mark

[adib]

iv used silicone hose in my rats nest and its been fine, just make shore it cant kink

[MarkoFu]

Okay mate. Thanks very much for your SPEEDY reply :god
 
Kind regards,
Mark

[JiM B]

Hi MarkoFu,

My FD has just started doing the very same today, let me know how you get on with replacing the solenoids and vacuum hoses.

I\'ve replaced the hoses on a previous FD, can\'t say I’m looking forward to doing it again...!

Cheers,
James.

[adib]

my m8 car is doing this all so, so will try another charge control valvue and let you no what happens

[JiM B]

I\'ve been looking into the Charge Control Solenoid, is the attached picture the one we are talking about. I thought previously we were talking about the solenoids hidden under the plenum?

I found this description of it\'s operation:

The Charge Control Valve controls the transition from Primary to combined Primary and Secondary Turbocharger operation. When ever the pressure applied to both Chambers of the Charge Control Actuator are equal, the spring force of the Charge Control Actuator will open the Charge Control Valve.

Below 4500 RPM this actuator is ON, (actuator rod pulled in), this closes the valve between the Primary and Secondary Turbochargers. This valve seals the air passage the same way as a throttle butterfly valve.

A simple test for the Charge Control Actuator is to start the engine and let it idle, the actuator rod will be pulled in. Stop the engine and remove the hose from Chamber A and the actuator rod will be out.

Chamber B is always connected to the Primary Turbo Compressor and normally will have 0 to 12 psi of boost pressure applied. Chamber A is connected to the Charge Control Solenoid, from 0 to 4,500 RPM a vacuum, from the Vacuum Chamber is applied, above 4.500 RPM the Secondary Turbo Compressor is applied to chamber A.

From 0 to 4,500 RPM with a vacuum applied to Chamber A, the Charge Control Valve stays closed, as Primary boost is always greater than a vacuum. Note, that the vacuum supply is from the Vacuum Chamber, thus leakage of the one-way check valve for the Vacuum Chamber will result in Primary boost applied on both sides of the actuator resulting in this valve opening when it should not, dumping Primary boost through the Charge Relief , Secondary Turbo and out the Charge Relief Valve. Another symptom of a leaky Vacuum Chamber one-way check valve is a loss of boost that is restored if the throttle is let off, (re-charging the Vacuum Chamber from engine vacuum) then quickly re-applying throttle results in boost.

[adib]

think its the second solenoid in, in the rats nest there talking about but i mite be wrong

[adib]

hi all, been over today and changed the charge control solenoid in the rats nest and still no joy could not find any split pipes and every thing eles seems ok, so now im stuck could it be a leak to the turbo ie gasket from turbo to engine

[Bobbit]

You tried changing your spark plugs bud?

[adib]

yep changed plugs and leads, no matter what i do as soon as you try to give it a blast it holds back and back fires any other ideas .thanks for fast reply bobbit

[kbareham]

Marks description sounds like mine when it broke a while back. If you have the stock ECU, it might be in limp home mode. Mine behaved in a similar fashion when the OMP failed. In limp home mode it runs fine up until just before boost, when the engine just cuts out.
I think that you need to wire an LED to the diagnostic plug to read the ECU fault code.

Rgds
Keith