Wierd problem here, just got my car back from phil. Some amazing work he has done. And for the first few days back all has been well. But today, had a nice drive around, no mad driving, just cruising, and now this problem has come back, had it before all the works been done.

So, the problem, bear with me.

Car isnt hitting full boost (16psi), is controlled by greddy e01 controller, and monitered by the e01 screen and a greddy aftermarket gauge.

The screen reads a steady 5psi and the aftermarket guage reads 14psi ish (is in kg/cm2).

i could tell the problems had returned because the boost at idle is -15.9psi on the greddy screen, think its normally 14 or under. And when the engine is turned off the aftermarket guage reads 0 and the screen reads -6psi.

So why are both gauges reading different and why if the e01 screen is reading such low boost, is it limiting it there. It holds nice and steady, in any gear. Just nothing like as high as it should be. And obviously performance is well down but otherwise running smoothly and idling well.

Rough spec, GT2871rs tubs with forge actuators, 555 injectors, full decat exhausts and mike smith manifolds, chipped ecu, full engine rebuild.

Long shot and wil probably be giving it back to phil, but just wanted to see if it was anything obvious i could sort.

Cheers in advance.

danny

Oh also, can hear the turbos spooling up and still get the dump valve when I let off.

check your pipe work for leaks ...

most gauges will read 1>2psi diffrents between them ... they shouldnt but there no calibration control

 

do u have both sensor/gauges plumbed in at the same place ?

Hi mate, I had a problem with boost couldn't make more then around 14psi I went through everything.

Then 1 day took my blitz dump valves off went up the rd and accidently hit around 22psi.

Realised dump valves had been leaking inside the system the whole time.

 

Probley not your problem but thought I'd post just incase,

Cheers guys, had a quick look today, not had a lot of time. Think they are getting their readings from different sensors. Think the fresh gauge gets its feed from the standard boost sensor. Could be wrong there.

But on the way home today, gave it a quick blast through 1st and 2nd and all is back to normal. So its a sensor fault somewhere?

Would rather find the cause and solve it than it just go away.

Were should I be looking for these sensors?

Cheers.

Danny.

Update, car is fine now. All gauges reading as they should and its boosting bang on. Only thing I did was have a mess around were I thought the boost sensors were. So suspect a loose wire. Not what I call a solution. But its working.

Cheers for the inputs.

Danny

And its gone again. Another long day out in the car yesturday. Had sat ticking over for about 10 minutes then 1 blast through 1st and knew straight away. The boost gauge had gone back to reading -15.9psi on tickover and it isn't boosting properly. And again, the other boost gauge is reading zero when the engines off, boost controller reading -7psi.

Car still drives fine and smooth but this is no good. Really pegs the acceleration back.

Thinking I should take it back to the garage but its a hard one to pin.

Anyone any clues?

Cheers

Danny

Do a boost leak test. Gotta be either losing air somewhere or a tubs going down.

Thought that, but then how does it sort itself out and be perfect for nearly a week. Then just go. Will do a test though as a matter of coarse. Have had a boost leak in the past and the symptoms were different than this. But suppose if its leaking in different places it'll make different problems.

Cheers for the help.

Danny

but then how does it sort itself out and be perfect for nearly a week. Then just go.

Danny

 

Hi,

 

not that I'm saying that it's the same as your problem........... but it sort of answers the question you asked... to say that it is possible.....

 

I had a strange intermittent power loss problem, would only happen every now and them, generally during or after boosting (and not particularly heavy).

The car would just lag / no power, any press of the accelerator would make it worse unless you put your foot down and the boost gauge would go right up but with little response.

I would pull over ASAP and turn the car off, I noticed that the turbos where red hot...

when I started it back up all was fine.... i couldn't find any loose pipes or see any issues.

 

The only thing I hadn't done was a boost leak test....

Once I finally did what I should have done right away it was clear that there was a massive leak.

It was located on the top of the turbo (outlet), the short hose had a strange 1p size and shape split/hole but there was still a flap of rubber over it.

The flap would act like a valve, due to the position it was being kept in place most of the time but when the car boosted it caused enough pressure to dislodge it and throw out all the readings causing the car to run like shite....

The for some strange reason when the car got turned back off it would find its way back in place....

I would say look at the wiring for both sensors/gauges (not plumbing) an electric gauge tries to self zero, when ignition comes on, so if the switched power is wired incorrectly it's going to zero itself at the wrong place, and if that's then controlling your boost will cause problems.

Thing is nothing's changed with the wiring. It just comes and goes. Seems to be more gone than not now. I unplugged the greddy boost sensor from the unit and it read -19.7psi when he engine was off, but ignition on. Had a check round the connectors I could see and a general tug on everything. Will unplug the battery tommorow and see if that resets anything. Then a boost leak test, then back to Phil's.

Thanks again guys. Know this is a wierd problem and I'm a numpty.

Danny.

still think it's a wiring issue or dodgy earth, have you tried swapping the sensors round to rule that out?

Haven't seen the greddy boost gauge sensor while I've been messing in there. Imagine it'll be the same as the greedy e01 sensor so ill try that when I find it. And chase all the wires while I'm at it. Nothings easy to get at is it.

Thanks again mate.

Want to crack this now.

Danny

Update, i think its the boost sensor for the e01. Sensors are different for that and the gauges but have had a swap around wth boost/vac pipes and all is pointing to the sensor being at fault. When i unplug it, the e01 reads -20psi ish with the engine on or off. Both gauges are taking their readings from similar places, bar a few t pieces. The problem is now permenant, which makes it easier to find.

So next few questions, is boost sensor failure common, can they be calliberated. Seen that they are over £100 to buy so want to be sure its that.

And long shot, does anyone in the north west have a known working one that i could just plum and plug in. Seconds of a job. Will put that as a seperate thread in the wanted section.

As ever, any thoughts or ideas welcome, thanks for the help so far aswel. Know i should just take it back, but dont want to give it back again, only just got it back on the road.

cheers

danny

Sorted! Was indeed the sensor for the e01. I tested all the wires, swapped positions for the vac line. Even tried blowing the old boost sensor out with an air line, that just buggered it up completely. Got a sensor from fleabay, £25 new. But had to swap a few wires round on the plug and we,re sorted. Just need some dry weather now so i can actually use the boost and new power.

Cheers for the help along the way guys, was a difficult one to fix without seeing it etc.

danny

glad thats sorted after much reading! I'm still getting to know these engines, and the only thing i could relate to for boosting issues was my RX7 and that turned out to be a simple check valve had a seem split. when it was cold, it was fine, when it was hot, it would expand and leak. ******* to find, car would become hesitant, but only a £10 fix.