Petrol injectors. A Godsend or a nightmare!

[itguy]

Well I went and visited Jim today and it was a very informative and interesting session in his workshop.

Great service, and although when initially tested my injectors (orange 850T5 bosch's) were flowing not too bad, the spray pattern was a bit random across the 5.

30 mins in the cleaner and then another test - wow! totally sorted the spray pattern and after 6 full cycles of throughput on the testtubes (low speed, high flow) they all flowed an identical amount.

Got home, popped em back in, ECU reset and viola! smooth running and great throttle pickup.

It will be a little while (week or two) before the ECU has settled down enough to tell if it has cured my slightly hesitant part throttle when cold issue, but at least now I know it won't be the injectors at fault.

Thanks Jim for a great service.

Will.

[jimathan]

Hi Will, nice to meet you both by the way, glad I could be of help. As you say quite rightly, the injectors didn’t appear to be that bad. They did appear quite closely matched on the flow test, if not perfect on the pattern test. Do you think there is a genuine, noticeable improvement to the throttle response and the overall smoothness? I must admit after the cleaning they all flow tested bang on.
Regards Jim

[irf]

jim, just to let you know i'll be in touch very soon for you to do mine. i have some green injectors that i'm not 100% sure on what size they are. presumably you'll be able to tell me so that there's no doubt.

be in touch soon by PM.

cheers

[itguy]

Jim - certainly feels a bit smoother and more 'crisp'. Econonmy etc will have to wait for a week or two to tell.

[jimathan]

Cheers Will thanks for that. Im not realy surprised. On the odd set that I have done where little or no apparent improvements have taken place, people are still reporting quieter, smoother engines combined with slightly better mpg.
Jim.

[jimathan]

Hi IRF. No problem servicing them. The test fluid has a different specific gravity to that of petrol and I haven’t been able to find a conversion chart yet but I am working on it, so giving an accurate displacement at this time is not posible
Jim

[itguy]

Looks like i've got about a 200 mile round trip to do today, probably with lots of 60mph cruise in there (damn speed cameras!) so should be able to get a good idea of the closed loop performance as the ECU learns etc

[Engineer]

Originally Posted by jimathan

Hi IRF. No problem servicing them. The test fluid has a different specific gravity to that of petrol and I haven’t been able to find a conversion chart yet but I am working on it, so giving an accurate displacement at this time is not posible
Jim

You sure about this conversion chart jimathan considering the variables that exist under actual test conditions?

Cheers

[jimathan]

You’re absolutely right. Variations in atmospheric pressure, temperature, & humidity would all influence the outcome. So at best the readings would be an approximation. However they should be close enough to be able to identify a particular type of injector, rather than saying “this injector is displacing exactly the right amount” If you get my drift.
jim

[Engineer]

Originally Posted by jimathan

You’re absolutely right. Variations in atmospheric pressure, temperature, & humidity would all influence the outcome. So at best the readings would be an approximation. However they should be close enough to be able to identify a particular type of injector, rather than saying “this injector is displacing exactly the right amount” If you get my drift.
jim

Sure do Jim, and you’re offering a great service, so without trying to teach you how to suck eggs just be careful if you decide to quote flow rates on your reports.

Cheers