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tlp

New Member
Joined
Mar 30, 2003
Messages
15
Just got another GN. It has been modified quite a bit, Champion heads, lutuna(sp) cam 7th injector etc. I will mod my profile as soon as I can. Could anyone give me some history on the 7th injector. I seems like I read that it was old tech. before chip burning had progressed to where it is now. There is a control box under the hood for it. Should I keep it or go another route?
 
One theory behind the 7th injector was that it was able to add fuel on demand, and only on demand. That is, it allowed you to run 6 smaller injectors for good low demand manners, then have that 7th available to handle WOT blasts.

Sounds good, right?

In practice, some folks used the 7th injector as a band-aid for their 6 smaller injectors being too small - in order to avoid the expense of purchasing 6 new, larger injectors, and the hassle of having to install them.

Bottom line - today's better chips are very capable of running very big injectors for good low demand manners, with plenty of fuel for WOT blasts.

Perhaps in some cases the 7th injector was also a band-aid for a weak OEM fuel pump, a clogged fuel filter, kinked fuel hoses or lines, insufficient voltage to the pump, dirty injectors, and the like. Given the knowledge and equipment we have, none of these "should" happen nowadays.

I know some folks who run 7 or more injectors quite successfully. However, to me, they always seem like a legacy from the past. Expensive, and with their own set of problems.

Good luck!!!

:D
 
Thanks for your response Strikeagle! Thats about what I remember reading. I would think that they may have been used to help prevent kr also since the old school from what I've seen was to drownthem with fuel' (Kenne Belle?)This is probably what you were saying. Ithink I am going to leave it on and try 2 make it work. I just came in from the garage where I was looking at the car trying to absorb what all it had added to it over the years. I need input on something else. I noticed that the connector that reads outside air temp was unpluged and connected to a 2 wire aftermarket harness that goes over to the tos switch where it has a plug that pluges into yhe tps. The original tps plug then is pluged into a connector on the aftermarket harness and then runs to gizmo mounted on the fender next to the thingy that has a vac line for the original dash boost gage. In fact they look almost the same vac line and all, in fact the vac line are teed together. Sorry I couldn't recall what the part is called. When you start the car cold it doesn't want to idle until it warms up. I want to install my scanmaster and wonder if this change in wiring would hurt it.
:confused:
 
Actually I believe the 7th injector was designed to alleviate or help cure the problem in our engines of the back 2 cylinders running lean...the 7th provides a little shot of fuel into the air stream to richen up the back cylinders...problem at least in my case was that it made the car run too rich because the added fuel also got to the other cylinders which wasn't needed...IMO it's old technology...all you need today is the correct size injectors and a power plate...I removed my 7th some time ago...it's in a box somewhere collecting dust...
 
noticed that the connector that reads outside air temp was unpluged and connected to a 2 wire aftermarket harness that goes over to the tos switch where it has a plug that pluges into yhe tps. The original tps plug then is pluged into a connector on the aftermarket harness and then runs to gizmo mounted on the fender next to the thingy that has a vac line for the original dash boost gage. In fact they look almost the same vac line and all, in fact the vac line are teed together

Sounds like thats boost sensing hardware for Turbo-link

JFH
 
Thanks JFH. I took it off and hooked it up the normal way. Installed the SM and started it up, Everything looked ok but I wasn't sure about the airflow it showed 4 shouldn't it read6 or 7? He just put on a new one ( MAF)from napa before I picked up the car. We all know how the rebuilt ones are don't we? I didn't drive it to see how it does on the road because I started changing the pass side ttop gasket, little did I know that I have to take both off or at least partically to change the one, at least thats how it looks to me.I only had the one side. Can you still get these from GM? I'm finding all kinds of little things that need fixing allsimple so far. I'll let you all know my progress. PS- Turbo link was used to tune the car so it may have been for boost sensing like you said.
 
If you have a extender chip the MAF reading is half of what it is

JFH
 
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