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964 Fuel Injectors and ultrasonic cleaning

iangray100

iangray100

PCGB Member
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I thought this might be of interest ...

I recently read an article in 911Porscheworld about injector cleaning and how this is done etc .

Well after some digging on the web I selected a company and sent my 6 spare injectors away ( I brought these years ago as spares) for a full report and to be ultrasonic cleaned and rebuilt.

Well I have just received the injectors back today and will be installing these to see if there is any difference in the engine response etc, not that there is anything wrong currently so I should notice an difference immediately ...MPG or even engine pick-up.

The plan is to install them this weekend, but its not a 5 minute task to get to them all but having taken the engine out in the past and rebuilding it, injector replacement is not an issue really, its just time ;-)

At 168,000m I can't believe my current injectors are clean and optimal even with all the fuel filter changes I have carried out of the years.

The report of the injectors, before and after is attached ...its quite interesting to see the variations.

The injectors have come back with new O-rings top and bottom, new Pintle's ( the fuel injector outlet ) and are now ultra clean to the feel .

Cost £12.50 each for the refurb...very good value

The injector description is wrong in the report, but all the recording was done via the Bosch part-number on each injector so perhaps its the same part on a Carrera 2.4 ?



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Thanks for the write-up Ian - I also found the 911&PW article interesting but was disappointed that there were no performance or driveability claims for the uprated injectors. Looking forward to reading your findings after the injectors have been fitted. Mine have done 106,000 miles and I can't believe they are still performing as they should - even though there is no evidence to the contrary...
 
Definately give us an update of any noticable improvements, or otherwise (and the effort to replace etc)....
 
I have had four lots of injectors cleaned by asnu themselves over the years on different cars. The results have varied from better mpg to a real noticeable smoothness and performance on a Peugeot 205 gti. Seeing the change in spray pattern before and after with the peugeot injectors was truly amazing. I had the 964 injectors done when the engine was rebuilt a couple of years back and did not really feel the benefit at the time due to everything else being fresh so would be interested in your thoughts Ian when you fit them.
 
Refurbished and ultrasonic cleaned Injectors installed . It doesn't take too much work to get to the injectors to be honest and I worked on each bank at a time in-case these was a stuck injector etc as this is quite common when the injectors are cleaned as the cleaning fluid evaporates and the valves can stick open or closed , once pressurised fuel is running through them the lubrication is normally restored. A slight tap on the stuck injectors case at 90Deg will free it when 12v is applied to it. Injector install on the Right Side - OSR : - Remove air filter cover - Remove the injector cable retain clips on the fuel rail . x 3 - Remove the 2x 10mm bolts holding the fuel rail - Remove the clip off each injector retaining it to the rail - Put a rag on top of the rocker cover to catch the excess fuel when the rail is lifted - Remove each injector and I marked each one for reference - Clean the injector holes for a clean O-ring seat - Wipe a little Oil on each injectors O-ring top and bottom for an easy fit - Reinstall the fuel rail - Reinstall the 2x 10mm bolts - Reinstall the clips to each injector top - Reinstall the cable retainers clips x3 - Wipe an old fuel away - Restart the engine - once running check there is no miss fire-ing and all injectors are working etc - If all ok reinstall the airfilter Injector install on the Left Side - NSR : - Remove the air circulation motor 2x 10mm bolts - Remove the 12v feed to the motor and the feed to thermo switch in the ducting - Remove the air ducking from the motor to the lower left air route from the left hand heat exchangers - Remove the injector cable retain clips on the fuel rail . x 3 - Remove the 2x 10mm bolts holding the fuel rail - Remove the clip off each injector retaining it to the rail - Put a rag on top of the rocker cover to catch the excess fuel when the rail is lifted - Remove each injector and I marked each one for reference - Clean the injector holes for a clean O-ring seat - Wipe a little Oil on each injectors O-ring top and bottom for an easy fit - Reinstall the fuel rail - Reinstall the 2x 10mm bolts - Reinstall the clips to each injector top - Reinstall the cable retainers clips x3 - Wipe an old fuel away - Keep the motor and switch cabling away form the lower fuel rails as these are 12v life when the engines runs - Restart the engine - Once running check there is no miss fire-ing and all injectors are working etc - If all ok reinstall the air circulation motor 2x 10mm bolts - Reinstall the air ducking to the motor from the lower left air route from the left hand heat exchangers - Reinstall the 12v feed to the motor and the feed to thermo switch in the ducting What I did notice after a while there was a slight engine misfire, so I had to track down the injector that was stuck and tap it on the metal injector case at 90Deg to its case, once this was located all was fine. It turned out to be the OSR No 6 (plug lead numbered) injector. Immediate the tick-over was lower and the engine was smoother when driven . The response and pick up was quite noticeable, and the 30-60MPH acceleration was very noticeable . I expect the MPG would be slight better over time as well. Even in a 30min drive the MPG reading was 1-2% better ( in have the computer display on the Tachometer ) . To be 100% actual and scientific, as I've had my spare set of injectors cleaned and installed here. What I really need to do now is have the old ones that were actually in the car cleaned and reported on, then I will know how bad and blocked they had become. I'll send them off in a couple of months time. Conclusion : For my engine as I have no inlet leaks and its a fairly recently rebuilt engine, so new injectors wouldn't bring the life back of a knackered, leaking, low compression engine!! . For my engine here, I can highly recommending injector cleaning and refurbishment (its very good value I think at £12.40 each injector) and approx 2hrs work to install them. Top-end engine performance I would say was the same, but the engines low down responses and pick-up was the major difference achieved here. A rolling road would pick this up with the torque/BHP curve ramping up faster. Below are couple of pictures I have to split this over 4 messages due to upload limits ;-( 1) Old and new injector tips comparisons 2) Left hand bank with the injector out and fuel rail raised 3) Lubricating the new injectors ready for the installation
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Very informative Ian. It will be interesting to see the figures for the injectors you have just removed and how the car performs over the coming months. By coincidence I have ordered a new set of injectors that have a higher flow capacity and 4 hole disc delivery, I am intrigued to see what difference they make once installed as I have a suspicion my original injectors are not 100% .
 
I had the new injectors installed today, they are the new 4 hole type but flow 245cc/min as opposed to 195 for the standard injector http://www.fiveomotorsport.com/bosch-porsche-911. The car is running slightly rich as expected and ideally could use a rolling road remap, but on the road the engine does run differently. Power delivery feels much smoother on part throttle and it seems to get up the rev range quicker. The top end is certainly better and tbh after being set up by Wayne Schofield it has never lacked power, but I can feel an extra surge after the resonance flap opens which was not noticeable before. These impressions are from my butt dyno, for actual numbers a rolling road tune is needed as I said earlier.
 
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