steelej

Hi Guys,

Been having a number of little issues with my Escos and latest one is with boost. On the small turbo the boost pegs at the end of the solid rectangle on the boost gauge until you go full throttle and you get 1.3 bar overboost for 7 seconds. My car was getting some work done recently and today after collection when holding the accelerator about half way the boost just continues to build and goes into the overboost section, it'll actually go into the red if you keep going but i wanted to avoid that. Any ideas what could be causing it to overboot and not stop at the end of the rectangle where it should?

Thanks.

John.

steelej

Ok back to this one, today i stripped all of the boost and vacuum pipes and checked for leaks, no leaks, i tried a friends AMAL valve, i then put on a new wastegate actuator and none of it has made any difference, it still overboosts but if i unplug the AMAL valve then i just get wastegate pressure. I'm really stumped on this, is there anything on the inlet side i can check, any sensors, pipes etc? Or could i just have been unlucky and my friends amal vale is goosed too, his car is modified so he expects the kind of boost i'm getting but it was a standard valve.

John

midnight_man

Check again all pipes about turbo for leaks,,,specially "T" pieces in system... I had same problem. You can easyly check you amal valve for working, unplug one side of pipe...connect 12V to amal valve (from battery) and make some pressure to pipe. You can test it if its working. (I am guessing that amal valve will be ok)

What chip you have in car? What ECU and what config of engine? Turbo, injectors...etc. Do you have vacuum on idle (on turbo pressure gauge)? When you "fast - softly" pull the accelerator pressure gauge must jump up to 0 bar for second. (If you have leaks, it will not jump to 0 bar, ).

Finally when there is a leak in the system turbo is charging pressure for a long time... car is little bit "lazy" up to 2500 - 3000 rpm.

steelej

Thanks Midnight_man,

So car is completely standard small turbo, no modifications at all, so standard chip injectors etc. if i unplug power to the amal valve i do just get wastegate pressure with no overboosting. The amal valve seems to be opening because when plugged in pressure is being bled from it to increase boost but it's either not being told to close or not getting the signal to close or somethng else elsewhere in the system but i'm pretty stumped now as when valve unplugged no overboost but with valve plugged in overboost.

Have got vacuum on idle, needle right at bottom of guage and boost does rise to 0 when pressing accelerator and have not noticed the car feeling lazy.

Any other ideas, any other sensors i can check?

John.

midnight_man

Led diagnostic say something? Have you got a spare MAP sensor 2,5 Bar for your car to test change?

Orange light on cosworth clock is ON? (on engine idle) - it signals an internal fault in ECU.

steelej

Hi Midnight man,

Don't have a spare MAP sensor but sure i could borrow one havent noticed any lights on the clock but i'll check, can an OBDII reader read the ecu codes or is there something special required?

Thanks for all the help so far

John.

midnight_man

http://www.bigturbo.co.uk/

But you have small turbo with ford EEC IV ECU I dont know if led diagnostic will work

but you will see orange light on cosworth clock if there is any fault in ECU... Try to change MAP sensor for sure ....and will see.

steelej

Top marks to midnight man, the MAP sensor was the problem. Swapped it with a friends and car working fine. New sensor now ordered

Had bought a code reader and code 126 was logged which is MAP voltage above spec, so looks like ecu wasn't getting correct info from the MAP sensor and didn't know what to do with the boost.

Thanks for the help midnight man.

John.

midnight_man

Was orange light on cosworth clock ON?

steelej

No orange light, must be different in small turbo

John.

Modest-UA

Hi Guys,

I also have a problem with the overboost but in my case the pressure didn`t go to "overboost" section on the gauge and stopped at 0,9-1,0 bar.
The fault code is 126 - MAP voltage above spec.
I`ve replaced MAP sensor 3 times, but without any result.
Any ideas?

Thanks in advance Max

steelej

Hi Max,

Same error as I was getting, have you changed the MAP sensor for a genuine ford one, i got a new sensor from Graham Goode and my problem remained, got a ford sensor from someone in the RS owners club and it fixed it. Don't ask me why that is

John.