Checking injector spray pattern

	Blazer Forum Classifieds Photo Gallery Search Contact BF Sponsors
Blazer News Member List Forum FAQ Timeslips Recalls TSBs Calendars Register Login

Checking injector spray pattern

Printable Version

Blazer Forums >> Modifications >> Performance & Brainstorming >> Engine & Internal >> Checking injector spray pattern

Page: [1]

Message

<< Older Topic Newer Topic >>

Checking injector spray pattern - 4/3/2007 2:43:36 AM

aspenpup

Posts: 29
Joined: 6/25/2005
Status: offline

How do you check the injector spray pattern in '99 4.3? How do you get the injector to fire (squirt) to test the pattern? Just crank with the coil wire removed to prevent starting?

Post #: 1

RE: Checking injector spray pattern - 4/3/2007 4:31:07 AM

Zygoat

Posts: 214
Joined: 6/24/2006
Status: offline

i believe that you can just apply voltage to the fuel injector with the pump on and it will work, not sure on how much voltage tho, ive heard 9v but not sure.

i would imagine that cranking will work as well.

_____________________________

97 blazer zr2 4x4 2dr 4.3l
e fans, audiovox ax 901 w/remote start, flowmaster 50series suv custom catback dual out, turbo in the works.
exhaust vid: http://s168.photobucket.com/albums/u166/Zygoat_D/blazer/?action=view¤t=Tazer_Exhaust_clip.flv

(in reply to aspenpup)

Post #: 2

RE: Checking injector spray pattern - 4/3/2007 7:50:31 AM

swartlkk

Posts: 14499
Joined: 5/1/2005
From: Waterloo, NY
Status: offline

First, you must remove the upper intake plenum from the motor. In that process, you will have to remove the fuel lines on top of the motor as well as disconnect the main engine harness from the engine compartment fuse box. Once the upper plenum is off, you must reconnect the fuel lines to the feed & return lines at the back of the motor as well as into the SCFI spider. From there, you can either apply voltage directly to the injector as Zygoat has suggested (if you have any reservations about this, do not attempt it) or you will need to have a Tech2 or equivalent scan tool that has the injector test option. You will have to pull each of the poppet nozzles out of their bores in the lower intake and have them positioned over a container of some kind to keep from spraying fuel all over the place.

When I checked my injectors, I used my scan tool to cycle the injectors while I watched the pressure drop on my fuel pressure gauge as well as watched the spray pattern of each injector. I found that I had a slight pressure drop while all injectors were closed and found that 3 of my injectors were weeping pressure by. And only 2 injectors had decent atomization of the fuel during the actual injector test.

_____________________________

Kyle-