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dozybee
PostPosted: Wed Mar 21, 2018 8:50 pm 
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The 1997 1.5 323f Venetian developed an annoying hesitation when transiting from idle to light throttle town use.
No error codes were found in the ECU.
The first repair was to seal the flexi connector from the MAF (mass airflow sensor) to the throttle body.
The transition from idle to light throttle persisted.
The Coolant sensor appeared fine so I cleaned the MAF. The voltage out of the MAF moved smoothly with varying airflow so seemed ok.

This model does not have an idle switch on the throttle position sensor potentiometer. Measuring the resistance showed no bad wiper values so it was assumed to be fine. (Some assumptions can be wrong)

Changed plugs to eliminate that suspicion. Measured ht leads. Inspected distributor for faults.
One of the old sparkplugs ( 2nd from left ) looked very dry with a very clean insulator. I suspected a lethargic injector.

Before removing the injectors from the car, clean the area thoroughly as refitting them is not as easy as removing them and any dirt will ruin your efforts.

I dissected the injector assembly and cobbled up an "Injector cleaner" composed of a sump (dead sonic bath), a fairly energetic windscreen washer pump, a fuel filter, some redundant piping and breadboarded an NE555 and TIP 120 pulse generator to supply 12V signals to the injector under test. The fluid is flammable so NO SPARKS allowed and keep the extinguisher handy.

The fluid was pumped from the sump through the injector and back into the cleaning fluid bottle. True to form the #2 injector actually did produce a wimpy spray. Cycling all of the injectors with the full contents of the fluid bottle per injector soon had them enthusiastically spraying.

Reassembled the bits in the car and ran to check for any leaks and then tested at normal engine temperature. So far the throttle control in the 1000~2000 rpm range in town driving had improved (Compared to previously!). When the fuel tank was really low the injector cleaner was added to the tank. The extra fuel pressure helped to finalize cleaning of the injectors.

The battery was also disconnected for a while in case the ECU was resettable for a new start.

The final result has been very good.

This car was garaged for a considerable time ( Years ) whilst the son was at Uni. The injectors must have developed laquer deposits from lack of use. The 1997 323f 1.5 Venetian is now a useful family member again.


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pitrack_1
PostPosted: Fri Mar 23, 2018 12:59 pm 
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Location: ACT, Australia
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Good effort, well done. If the injectors were varnished then probably the whole ssytem is too so may be worthwhile running full tanks through with cleaners and changing the filter etc too.

Can't help but think the ultrasonic bath would've been more helpful working :-)

If it's been parked years are you going to do oil, coolant and brake/clutch fluid flushes too?

Patrick


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dozybee
PostPosted: Fri Mar 23, 2018 1:50 pm 
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Pitrack-1,
Now that the vehicle is behaving I will give it some treats, Oil must be 4 years old (Low Mileage!) and the age of the other other stuff???. I now have another ultrasonic bath (After the fact!!).
At least I can see the bits in the engine room, the new (commodity) cars are virtually throwaway jobs nowadays.

dozybee


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dozybee
PostPosted: Fri Apr 27, 2018 12:36 pm 
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Records indicate the last oil change was 9 years ago!. Our island is only 35 miles long so the mileage is commensurately low. The timing belt is also aged but very low mileage.
Time to get off my lethargic butt and do something about the consumables!.


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