NEED HELP Please : 930 turbo cutting of power on high RPM 4000+

[Falnaim]

Hello There,

I have 1987 930 turbo just rebelled the engine and have new Alternator, Fuel pumps, Alternator Fan, Faabspeed "Headers, Mufflers, Air Intake, Intercooler", Tial W/G with a 1 bar spring, A/C kit.

When i drive the car it cuts of power after around 3900 to 4100 RPM then i replaced the Distributor Cap, Ignition Wires & the Coil Wire with new set and still having the same problem but "more power with engine" as 2 of my Ignition Wires was broken.

Please can any one help me what to do ?

Thanks and Best Regards,

FAHAD

[herman maire]

Are you still using the stock CIS fuel injection.

You will probably find more help in the 930 forums 911 / 930 Turbo & Super Charging Forum - Pelican Parts Technical BBS

[gsxrken]

Proper diagnosis would include fuel pressure check with the proper CIS gauge set, and AFR readings.
Assuming your timing is in spec, I'd guess that your coil may not be upto the task of high RPMs.
But without any manuals or tools, parts guessing can add up quick.

Also, your orange o-rings can leak boost at higher pressures, but it's generally described as a lack of power rather than cutting out.

[john walker's workshop]

too much boost will cause the stock overboost safety switch to open and kill the fuel pumps. it's the switch with the single white wire on the forward left side of the upper intake, just below where the breather hose from the turbo sump attaches to the air cleaner.

[Ronnie's.930]

Not to mention that the overboost switch could be "bad" and the infamous, yellow, overboost relay could have problems as well . . .

In what way does power "cut" - is it sudden (as in engine stops -dash in the face style) - or simply lessening of power at the upper RPMs? Usually, and overboost circuit problem results in the "dash in the face" as power to the fuel pumps is cut off . . .

[Falnaim]

when I mentioned " power cutts of " dos not means (as in engine stops ) it jurcks & los the power.

[djcdmv]

Newbie chiming in, but what about the reference sensor?

Help! 3.2 looses power at 5500 rpm while accelerating,

[Ronnie's.930]

Originally Posted by djcdmv

Newbie chiming in, but what about the reference sensor?

Help! 3.2 looses power at 5500 rpm while accelerating,

His car (930 / 911 Turbo) doesn't have one as the Turbos use the old-school, K-Jetronic (CIS) system . . .

[john walker's workshop]

Originally Posted by Falnaim

when I mentioned " power cutts of " dos not means (as in engine stops ) it jurcks & los the power.

that's what the overboost switch does. for test purposes, do one quick run with the white wire grounded and see if anything changes. you will probably need to dial the boost back to .8bar to avoid detonation, broken rings, etc.

[djcdmv]

Originally Posted by Ronnie's.930

His car (930 / 911 Turbo) doesn't have one as the Turbos use the old-school, K-Jetronic (CIS) system . . .

One of these days I'll help somebody...

[MT930]

Originally Posted by john walker's workshop

too much boost will cause the stock over boost safety switch to open and kill the fuel pumps. it's the switch with the single white wire on the forward left side of the upper intake, just below where the breather hose from the turbo sump attaches to the air cleaner.

What ever JW says I listen to.

Over Boost Switch And Or Pressure Sending Unit For Turbo Boost Gauge.
Pelican has both of them
930-606-101-00-M100
993-606-103-01-M100

I had had to replace both of these at different times to solve that exact problem your having. The switch and then the sender 2 years later.

You want to make very sure the car is not actually over boosting, the switch or the Sender will stop a over boost condition by cutting the fuel by stopping the pump. Over boosting is expensive !

[Falnaim]

Thanks all for your help

[Falnaim]

Originally Posted by MT930

What ever JW says I listen to.

Over Boost Switch And Or Pressure Sending Unit For Turbo Boost Gauge.
Pelican has both of them
930-606-101-00-M100
993-606-103-01-M100

I had had to replace both of these at different times to solve that exact problem your having. The switch and then the sender 2 years later.

You want to make very sure the car is not actually over boosting, the switch or the Sender will stop a over boost condition by cutting the fuel by stopping the pump. Over boosting is expensive !

Many thanks,,,,,, I replaced the Over Boost Switch And Or Pressure Sending Unit For Turbo Boost Gauge.
Parts Number:-
930-606-101-00-M100
993-606-103-01-M100

My car working now perfectly .

Regards,


FAHAD