testing & cleaning dirty fuel injectors

grumpyvette

Administrator
Staff member
Before you do any trouble shooting Id suggest verifying the fuel filters clean (IF OVER A YEAR OLD REPLACE IT) and get a fuel pressure gauge connected to the fuel rail, once you hit the ignition the starter, spinning the engine should boost oil pressure above 5 psi allowing the fuel pump to run,and the fuel pump should bring the fuel pressure up to about 40-43 psi, that pressure should only slowly drop off ,after the engines turned off, if it drops noticeably in under 5 minutes an injector is leaking or the fuel pressure regulator leaks.
now get out the VOM meter and measure the resistance across the two contacts on each injector, ONE AT A TIME after you've unplugged the harness it should fall in the 12ohm-15 ohm range , now plug a noid light into each connector on the harness ONE AT A TIME after you've unplugged the harness, from each injector, start the engine with the remaining 7 injectors connected and watch for the light to flash on the noid test light plugged into the one harness injector connector your testing.
once your sure that all the electrical harness connections work and the injectors read the correct resistance, you can try adding two totally different brands of injector cleaner and 8 oz of marvel mystery oil to a full tank of fresh high test gas, as just doing that, and going for a 30 minute drive , occasionally will sometimes lube and free up a partly clogged injector, as the solvents in the oil and injector cleaners tend to break loose crud.
you might be amazed at your options , the tests you can do,and the info those test results provide, yes you can in many cases take out injectors and clean them, if you do a bit of research on whats required,or you can send them out to be professionally cleaned out and match flowed
BTW To remove the connector from the injector, push carefully in the middle of the locking clip, with your thumb, This will make the sides, and tips move OUT WARD in their connector slots allowing the tips that hold the injector into the connector to slide out of the way from the injector body, and you can then pull the sides away. WATCH the locking clip - IT can and WILL come off and get lost, if your not careful

Spray-pattern.jpg

partly clogged injectors, or injectors running at over 80% duty cycle tend to reduce power and increase emissions
read these, yeah I know you hate links, force yourself youll be amazed at the info, they cover


viewtopic.php?f=55&t=606

viewtopic.php?f=32&t=596&p=783#p783

viewtopic.php?f=32&t=67&p=37351&hilit=cleaning+injectors#p37351

viewtopic.php?f=55&t=6203&p=19416&hilit=cleaning+injectors#p19416

viewtopic.php?f=55&t=1906&p=6456&hilit=cleaning+injectors#p6456

http://garage.grumpysperformance.co...-system-and-injector-cleaners.1846/#post-4825

viewtopic.php?f=55&t=1241

viewtopic.php?f=55&t=606&p=7969#p7969

viewtopic.php?f=55&t=1378

viewtopic.php?f=55&t=2055&p=5481#p5481

viewtopic.php?f=55&t=606

viewtopic.php?f=55&t=1846

http://www.aa1car.com/library/2003/ic30336.htm

viewtopic.php?f=55&t=613&p=817#p817

http://qualitytoolsforless.com/Product. ... uctID=7448

viewtopic.php?f=55&t=635

http://www.tooltopia.com/index.asp?Page ... =nextag_r1

http://www.tooltopia.com/index.asp?Page ... =nextag_r1

MX0406Auto001-lg.jpg


most of the injector cleaners work reasonably well, I tend to use these

WYNNS
TECHRON
STP
REDLINE

use any TWO in succession

http://www.chevron.com/products/prodser ... s/tcp.aspx

http://www.gumout.com/default.asp

Ive had good results adding a can of either one of these, on particularly dirty or suspect injectors Ive added a can of both but one on one fill-up and the other product on the next full tank of fuel.

 
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Injector3.gif

http://www.witchhunter.com/injectorcalc1.php4

http://www.scottsautorepair.net/viewtopic.php?f=10&t=33

http://garage.grumpysperformance.com/index.php?threads/what-kills-o2-sensors.3049/#post-8053

http://www.injector.com/injectorselection.php

http://www.fuelinjectorconnection.com/s ... rcalc.html

http://www.witchhunter.com/injectorcalc1.php4

http://www.rceng.com/technical.aspx

http://www.slowgt.com/Calc1.htm#FPHP

http://www.iroczone.com/calcs/injectorsize.htm

http://www.injectorsplus.com/

http://www.csgnetwork.com/fiflowcalc.html

http://www.bgsoflex.com/pwcomp.html

http://golenengineservice.com/calc/calcpchg.htm

http://www.ecs.fullerton.edu/~sowell/ja ... estRig.pdf

http://www.witchhunter.com/injectorcalc1.php4

http://users.erols.com/srweiss/calcpchg.htm

http://www.z31.com/software/injector.pl

http://www.solutions29.com/injcalc.htm

http://www.injectorrx.com/sizing.html

viewtopic.php?f=55&t=2055
efisystem.jpg

Holley Injector Tech Said:

HIGH IMPEDANCE INJECTORS — Most injectors can be divided into two major categories: high impedance 12 to 16 Ohms and low impedance 1.2 to 4.0 Ohms. The high impedance injectors are used with ECUs that are designed with saturation drivers. The advantage of using saturation drivers is that the currents running through the ECU circuits and the injectors are relatively low thus generating less heat. The disadvantage of saturation drivers is that the driver has a slower response time, which could affect the full utilization of such a system at very high engine RPM.

LOW IMPEDANCE INJECTORS
— The low impedance injectors are designed to be run with an ECU that employs peak and hold drivers (also called current sensing or current limiting drivers). The current ratio (peak to hold) is generally 4:1 and the most common drivers available are 4 amp peak/1 amp hold or 2 amp peak/ 0.5 amp hold. The peak current is generated to overcome the inertia of the closed valve and once the valve is open the driver cuts down to 1/4 of the peak current to hold the injector open until the end of the metering event. Low impedance injector designs are mostly used in high flow applications.

http://www.racetronix.biz/itemdesc.asp? ... 6x&eq=&Tp=

http://www.racetronix.biz/itemdesc.asp? ... 91&eq=&Tp=

http://www.racetronix.biz/items.asp?Cc= ... =1&Tp=&Bc=
STOCK TPI,LTI,LSI ENGINES USE HIGH IMPEDANCE INJECTORS —

yes your fuel filter design matters a good deal, Im always amazed at the guys that either don,t read the filter specs and can,t tell a 10 micron filter from a 60 micron filter and the guys that think a stock fuel filter designed to support 350 hp will still function if asked to supply a 550 hp engine without restricting the fuel flow rates, you need to understand your applications minimal flow rates and pressure requirements BEFORE selecting a MATCHING FUEL FILTER DESIGN

some filters are for EFI, some for CARBURETOR APPLICATIONS ,and they generally are not interchangeable as the carburetor, filter designs usually operate below 15 psi and efi filters are designed to run up in the 40-70 psi range and both the flow rates and the filtration in microns does matter, carbs can generally tolerate more particulates than injectors, and its rare to exceed 17psi in a carb fuel system or be under 35 psi with injection


look at these five fuel filters, you would need to be rather optimistic to think they all provide the same flow rates, pressure ratings and degree of filtration

http://www.summitracing.com/parts/SUM-230105/
sum-230105_w.jpg

Deliver maximum fuel filtration to your engine.

Designed for carbureted systems, our filters flow 130 gph and have a reusable 40-micron element. Each 4.00 in. long filter is machined from aircraft-quality billet aluminum. They're available in red, blue, or black anodized or polished finishes with -6 AN or -8 AN fittings.

OR
http://www.summitracing.com/parts/FRM-HPG1/
frm-hpg1.jpg


These Fram high-performance fuel filters can trap particles as small as 10 microns. They have a maximum flow rate of 90 gph, and a housing that can handle pressures up to 200 psi.


http://www.summitracing.com/parts/SUM-G1512/
sum-g1512.jpg

Designed for carburetor systems, our precision-welded fuel filters are rated to handle pressures up to 100 psi and trap particles as small as five microns. They are made from high-quality stainless steel and polished to a show-quality finish.

http://www.summitracing.com/parts/SPE-2228/
spe-2228.jpg


http://www.summitracing.com/parts/PRM-8 ... mage=large
prm-81794.jpg


read this
viewtopic.php?f=55&t=1939
 
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