[v12-engine] Fuel Injector service- Opinions Please

V12-Engine
1

At 120,000 miles, I’m sure my fuel injectors would benefit from a cleaning.
I would like to hear some opinions about whether the level of services
described below (from RC Engineerings web page www.rceng.com) justify a
US$24 X12 cyl price tag when compared to having the injectors cleaned by
just anybody who does the service. I have seen prices ranging from US$9 per
injector, and up.

The purpose of cleaning and flow-testing is to 1) remove any contaminants
inside or outside the injector that impede fuel flow or degrade fuel spray
pattern 2) to accurately measure each injector’s fuel flow ability and 3)
acquire quantitative data on injector performance the vehicle owner can use
in matching injectors or tuning the engine’s fuel system.

Any set of fuel injectors will benefit from RC Engineering’s clean and flow
service, This is even true of new injectors because the individual-injector
and system-total fuel flows must be known for performance tuning purposes.
It is not uncommon for a set of original equipment (OE) injectors to have an
unacceptably wide range of fuel flow and it’s possible to even have new
injectors that do not function properly. RC’s standard testing process
identifies those problematic injectors.

The test process is as follows: first, your injectors are installed on RC
Engineering’s custom- designed-and-built, computer-controlled injector
flow-testing equipment. A unique, non-flammable, gasoline-like test fluid is
pumped at a precisely-controlled pressure through the injectors while they
are pulsed by injector-drivers built into the equipment. The volume of fuel
passed through the injector is accurately measured for a set amount of time
and from those figures, fuel flow is derived. During the flow- test, the
injector spray patterns are visually inspected and analyzed by
RC’s technicians using both bright room and strobe lights.

After the initial flow-test, your injectors are transferred to an ultrasonic
cleaning machine and connected to injector drivers. They are submerged in
cleaning solution and pulsed while being subjected to ultrasonic waves. The
combination of the solution and the ultrasound aggressively clean the
internal and external parts of the injectors.

Finally, the now-clean injectors are reinstalled on the flow-tester and run
again. At the conclusion of the test, a printed report is produced. This
report lists: fuel flow rates (in pounds-per-hour and cubic centimeters per
minute) before and after cleaning, and spray pattern assessments for each
injector tested. Also included is the “system balance” number
which is the flow difference, expressed in a percentage, between the
injectors having the highest and lowest flow rates amongst the lot of
injectors tested. The system’s total fuel delivery in lbs/hr. and cc/min
along with a computation of potential horsepower at three different brake
specific fuel consumption rates concludes the report.

The charge for RC Engineering’s standard clean-flow-balance service is
$24.00 per injector. If overnight shipping is used, the turnaround time is
three days.

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2

For that price you can buy a brand new set that are deposit
resistant. Nearly all gasoline fuel injectors use common mounting and
connectors all developed and licensed by Bosch years ago. All you need to
do is match the flow rating and impedence. You can buy a typical set of 8
24lb/h (not sure what your rating is) injectors for around $200US. For the
V12 you would need another 4 injectors to complete the set but still it
would be better than paying that just for cleaning the old ones. The
plastic and seals in the injectors can break down with time causing them to
leak.

As for cleaning, most local shops can clean all the injectors for you in
the car for about $25US total (no matter how many injectors there
are). They connect a machine that pumps a solvent through them while the
engine runs. This service is very effective. I performed this service
hundreds of times when I was a mechanic. If you are not having any
problems with the way the engine is running, I would recommend just running
a bottle of Chevron Techron in your next fillup. That will usually clean
up minor deposits.

At 01:19 PM 2/17/01, you wrote:

At 120,000 miles, I’m sure my fuel injectors would benefit from a cleaning.
I would like to hear some opinions about whether the level of services
described below (from RC Engineerings web page www.rceng.com) justify a
US$24 X12 cyl price tag when compared to having the injectors cleaned by
just anybody who does the service. I have seen prices ranging from US$9 per
injector, and up.

Jim Roal

Website: http://home.att.net/~jroal

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3

At 120,000 miles, I’m sure my fuel injectors would benefit from a
cleaning.
I would like to hear some opinions about whether the level of services
described below (from RC Engineerings web page www.rceng.com) justify a
US$24 X12 cyl price tag when compared to having the injectors cleaned by
just anybody who does the service. I have seen prices ranging from US$9
per
injector, and up.

Hey, that’s a no-brainer!

You told us here what it is that they do for their service.

As long as they actually DO the work, it is so far and away better than the
“Techron Tune-up” that a motor vac will do.

Flow matched injectors is a very cool thing.

With the miles that are on the ones in the car, they owe you nothing and
this is an opportunity to refresh them, actually have a higher standard of
consistency once redone, and since you’ll be taking care of some other
niceties such as fuel and vacuum lines, you should notice a difference in
the state of tune.

Cheers,

Jeb

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Jag-lovers Forums - Jag-lovers Peter_Cohen@Dell.com

4

I had my injectors (D-Jet) ultrasonically cleaned and flow-tested at a local
shop recently. It ended being US $15 per injector. Getting the injectors
cleaned turned out to be a good idea because one leaked (past the pintle) and a
couple more had sub-par flow. Most of the injectors had improved flow rates
after being cleaned and there is now less flow variance between them. The guy
who did the work let me come back and watch. Interestingly, the injector
tester/cleaner was made by Lucas (doh!). In hindsight I should have marked the
injectors’ locations as I was pulling them off the fuel rail. That way I could
have seen if the leaky and/or low flow injectors were on my problem cylinders
(low compression).

Had I not been doing repairs on the engine (still in progress), I probably
wouldn’t have done this as maintenance. But maybe it’s worth it if you are
planning to keep the car for a while and don’t anticipate pulling the
intakes/cam covers/heads, etc, any time soon.

The purpose of cleaning and flow-testing is to 1) remove any contaminants
inside or outside the injector that impede fuel flow or degrade fuel spray
pattern 2) to accurately measure each injector’s fuel flow ability and 3)
acquire quantitative data on injector performance the vehicle owner can use
in matching injectors or tuning the engine’s fuel system.

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Jag-lovers Forums - Jag-lovers a related note, I used to have an 88 Nissan Maxima with Bosch LH-Jet. At about 160k miles an injector started leaking. Nissan replaced all six injectors (plus the regulator and other stuff) free as part of a recall (whew!). The car ran the same in normal driving but was noticeably more responsive above 4500 RPM. Which says to me that the original injectors were not flowing to spec. So maybe it’s worth cleaning them now if you often run your twelve at full song. My two cents, Jeremy 76 XJ12C (headless) 89 Accord Peter_Cohen@Dell.com wrote: