Help! Vacuum/ Map Sensor

[Williboy]

Hi, there's been a few threads lately of IS's not starting and the engine/TRC light coming on. Mine is getting progressively worse over the last 6 months and today the engine cut out whilst driving in peak traffic and couldn't get it started again! :( I took it to lexus and their code reader said it was the vacuum / MAP sensor showing a very low pressure?! Mine is supercharged (for years without any problems) and otherwise standard.

Is this pressure normal or is this the source of my problems? Is it easy to change/cost? Lexus Sheffield were a bit clueless but are kindly looking at it now. They want to blame it on mods/supercharger. Is this a lcommon lexus fault?

[sparkystav]

The black box has gone. Thats the chip that you install to adjust the ecu fuelling for the supercharger)

Thats inline with your Vacuum/boost sensor so would cause that fault.

You need an HKS FCD (STD version) set on setting 9 or 10 (depending on what feels better to drive) to replace it as TTE dont do replacement black boxes anymore, just silver ones and their not cheap.

The FCD should be about £70 -£80 on eBay,

Stav

[sparkystav]

Here are the connections:

Old Black box at the bottom, FCD at the top. (ignore the green wire on the FCD thats a different model)

Stav

[Williboy]

Thanks for that. Can I double check your diagnosis? With the black box problem would you expect the car to start up without doing anything after a while (ie. leaving it for a few hours), drive okay for a month then have problems starting for no apparent reason (ie. not dependent on temperature, weather, driving style etc); becuase its doing that.

[sparkystav]

Yeah it just means its tempremental not fully broken.

Wozza's was the same.

Stav

[Williboy]

It it straightforwad to change or best left to professionals? :)

[sparkystav]

can you solder? then its straight forward, unsolder the four wires of the black box and solder the fcd to the same 4.

Stav

[Williboy]

i can do that :) any other places i can buy it other than eBay?

[aztecbandit1]

there was a hks fcd in the buy and sell section on here if i remember?? might be worth a look think it was MOLE that had it for sale? :)

[SUPERCOUPE]

Also you could try http://www.sumopower.com/hkselec.htm

SPHKS20041549 HKS Fuel Cut Defencer STD £95.00

Not the cheapest, but their service it good, I've used them quiet a few times now.

[aztecbandit1]

Yeh thats where Mole got his from thats for sale :)

[Williboy]

The black box has gone. Thats the chip that you install to adjust the ecu fuelling for the supercharger)

Thats inline with your Vacuum/boost sensor so would cause that fault.

You need an HKS FCD (STD version) set on setting 9 or 10 (depending on what feels better to drive) to replace it as TTE dont do replacement black boxes anymore, just silver ones and their not cheap.

The FCD should be about £70 -£80 on ebay,

Stav

Finally heard back from lexus and as you correctly said, its the black box that's gone. I couldn't believe how much the silver box cost so I'll definitely be getting the HKS FCD. Btw, what's the difference in setting of 9 or 10?

Will

[sparkystav]

basically the airflow it lets he engine read, 10 is the safer one. But if it doesnt feel right lower it to 9 but dont go any lower than 8 as you risk underfuelling.

Stav