I was wondering if it is possible to run 80lb/hr low impedence on a 1227749 ecm? Has anybody ever done this? any help would be greatly appreciated!

Thanks, Ryan M

 

From the stickies. http://mywebpages.comcast.net/p-928/749mods.html

 

Thanks, that is exactly what I was looking for! Will this work the same for only 4 injectors? I dont quite understand the purpose of your jumper wire. Can I use this output to run 1 or 2 extra injectors for more fuel under boost? According to my sunbird schematics I only have 2 injector outputs C10 and C11. So your saying there is one more that is not labeled and your jumper wire will give you 4 outputs?

 

None of that info is mine, I just pointed out where to find it. I haven't done any research on this topic, sorry to say I don't have the answers you are looking for. Please read the stickies at the top, lots of articles that can help.

 

The 749 has 2 injector drivers that can run 2 low imps. Injectors per driver in stock form. You need to install diff. drivers and resistors to drive more injectors. As far as I know you would need to have custom software to run the drivers individually.

 

so I can run 4 80lb/hr injectors without changing anything. How do I change my tables in Tuner CATS, the ecm constants table for injector flow rate only goes to 48lb/hr? what is the purpose of this jumper wire on the circuit board?

 

No, you can't run more than 2 low Z injectors without the ecm hardware upgrade.

Injector flow rate does nothing in $58. You adjust the table base pulse constant vs % desired egr. This is effectively the injector flow rate. You will need to calculate your base pulse constant. In stock form its like .09 I think. There is a 749 BPC utilty on Moates.net it helps compute your bpc correctly. I don't know the calculation to change regular bpc into a decimal. I have the tdf editor for $58 and changed the table to read actual number, i.e. stock bpc is .09=130 which is what my table reads. You'll need to search around for BPC VS DES EGR to find the calcs.

 

Depends upon whether they are port or TBI injectors. Port injectors are typically 2.4 ohms and the '7749 will run four of those as is. TBI injectors are typically 1.2 ohms and the '7749 will run two of those as is.

The Turbo Sunbird (among others) run 4 port PnH injectors, 2 on each driver in parallel.

RBob.

 

Yes you can run 4 80 lb/hr injectors on the 749 as long as they are multi port style low imp. injectors. The jumper wire brings the sense resistor into the circut for the peak and hold pulse.

 

Sorry about giving the wrong answer. I wasn't aware of the ability to run more than 2. I just always think in terms of eight.

 

I will probably just do the driver and resistor mod anyways. These are MSD multi-port injectors. I am shure they are 2 ohms or so. How do i know if my injectors are peak and hold? how do I know if I need to put the jumper wire in?

 

PnH are around 2 ohms
Saturated are in the 14-16ohm

 

Actually, three pins are connected to the injector drivers, two pins to one driver and one pin to the other driver. I added the jumper so that it could handle the current required to drive 4 low Z injectors from one driver for my V8 app.

If you're only driving 4 low Z injectors you don't need the mod. If you're driving 8 low Z injectors you do need the mod, and you also need the C10 jumper!

hth,