K-Jet info and testing.

[86gti]

Engine does not start/starts hard when warm

Symptom: Engine does not start/starts hard when warm


Leaks in air intake system (false air) Check air system for leaks
Sensor plate and/or plunger not moving freely Check for free movement
Air flow sensor plate stop incorrectly set Check and reset
Electric fuel pump not operating Check pump fuse, pump relay and pump
"Warm" control pressure too high Test pressure
Fuel system leakage Inspect fuel system for leaks
Injector leaking, opening pressure low Check injectors on tester
Injected fuel quantities unequal Check for equal fuel quantities
Basic idle setting incorrect Check and adjust CO level
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[86gti]

Irregular idle during warm-up

Irregular idle during warm-up

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Leaks in air intake system (false air) Check air system for leaks
Auxiliary air valve does not open Check valve for correct function
Cold start valve leaking Check cold start valve
"Cold" control pressure outside tolerance Test pressure
Injector leaking, opening pressure low Check injectors on tester
Injected fuel quantities unequal Check for equal fuel quantities
Basic idle setting incorrect Check and adjust CO level
Lambda control system not functioning correctly Check Lambda control system

[86gti]

Irregular idle with warm engine

Irregular idle with warm engine

Leaks in air intake system (false air) Check air system for leaks
Sensor plate and/or plunger not moving freely Check for free movement
Cold start valve leaking Check cold start valve
"Warm" control pressure too high Test pressure
"Warm" control pressure too low Test pressure
Injector leaking, opening pressure low Check injectors on tester
Injected fuel quantities unequal Check for equal fuel quantities
Basic idle setting incorrect Check and adjust CO level


*Lambda control system not functioning correctly Check Lambda control system (KE ONLY)

[86gti]

Engine will not accelerate, backfires

Engine will not accelerate, backfires

Leaks in air intake system (false air) Check air system for leaks
Sensor plate and/or plunger not moving freely Check for free movement
"Warm" control pressure too high Test pressure
"Warm" control pressure too low Test pressure
Basic idle setting incorrect Check and adjust CO level

*Lambda control system not functioning correctly Check Lambda control system (KE only)

[86gti]

Backfires under load

Backfires under load

Sensor plate and/or plunger not moving freely Check for free movement
Electric fuel pump not operating Check pump fuse, pump relay and pump
"Warm" control pressure too high Test pressure
Primary system pressure out of tolerance Test pressure and adjust with shim
Injector leaking, opening pressure low Check injectors on tester

[86gti]

Poor Performance

Symptom: Poor Performance

You mistakenly purchased a 1.3 litre golf or a honda civic.
Leaks in air intake system (false air)- Check air system for leaks
Sensor plate and/or plunger not moving freely -Check for free movement
"Warm" control pressure too high -Test pressure
"Warm" control pressure too low -Test pressure
Primary system pressure out of tolerance- Test pressure and adjust with shim
Injected fuel quantities unequal- Check for equal fuel quantities
Throttle butterfly does not open completely- Check butterfly and stops in throttle venturi
banana in the exhaust

*Lambda control system not functioning correctly Check Lambda control system (KE only)

[86gti]

Engine runs on

Sensor plate and/or plunger not moving freely Check for free movement
Air flow sensor plate stop incorrectly set Check and reset
Cold start valve leaking Check cold start valve
Injector leaking, opening pressure low Check injectors on tester
Basic idle setting incorrect Check and adjust CO level

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Fuel consumption too high

Cold start valve leaking Check cold start valve
"Warm" control pressure too low Test pressure
Basic idle setting incorrect Check and adjust CO level

**Lambda control system not functioning correctly Check Lambda control system (KE again)

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Driving performance unsatisfactory

Sensor plate and/or plunger not moving freely Check for free movement
Excessive fuel delivery to control circuit Check fuel delivery
"Warm" control pressure too high Test pressure
"Warm" control pressure too low Test pressure
Primary system pressure out of tolerance Test pressure and adjust with shim
Basic idle setting incorrect Check and adjust CO level
vehicle has Holden badges fitted

=================================================

[86gti]

CO concentration at idle too high

CO concentration at idle too high

Sensor plate and/or plunger not moving freely Check for free movement
Cold start valve leaking Check cold start valve
"Warm" control pressure too high Test pressure
Basic idle setting incorrect Check and adjust CO level

===================================

[86gti]

Idle speed cannot be adjusted

Idle speed cannot be adjusted

Auxiliary air valve does not close Check valve for correction function



and a quite common problem.

Engine starts but dies staright away.

Electric fuel pump not operating Check pump fuse, pump relay and pump
Excessive fuel delivery to control circuit Check fuel delivery
"Warm" control pressure too high Test pressure
"Warm" control pressure too low Test pressure
Primary system pressure out of tolerance Test pressure and adjust with shim

[86gti]

That pretty much covers the whole system from tank to injectors.
But there is still quite allot of info if you are interested in the system. I got very interested in it after messing around trying to fix problems.
It is actually a good system if you look after it and maintain it correctly as it's getting fairly old now.
I will make another section soon on modifications.

Thankyou for all the replys!!!
If any one wants to add to this please feel free!!

Cheers.

[86gti]

ANother update,
An old video on youtube outlining the system.
Bosch K-Jetronic (CIS) explained - YouTube

[Depone]

Handy info and easy enough to read if you have no mechanical back ground like me...

Cheers

[RedMk2Gti]

A liitle supplement to this

Although not for VW, it contains valuable information about k-jetronic system

K-Jet.org | Mechanical Fuel Injection Power!