What is done to modify a ECM ?

[Beamer]

I have 55 lb injectors in my T. I have assumed (don't say it...), that I have a modified ECM, as anything above 50 Lbs injectors needs to be modified for the low impediance. I have also heard that some 55 Lb'ers do not require modifying the ECM.

I will be installing a powerlogger next week, and I was curious how to tell if it has been modified for sure.

Thanks all...

Mike

[Quicksilver]

All of the guys that modify ECM's with the proper peak and hold drivers also attached labels to the aluminum case indicating the modification.
sorry, i can not help with the injector question.

John

[Jack Armstrong]

Originally Posted by Beamer

I have 55 lb injectors in my T.


I have assumed (don't say it...), that I have a modified ECM,

as anything above 50 Lbs injectors

needs to be modified for the low impediance.


I have also heard that some 55 Lb'ers do not require modifying the ECM.

Mike,

First, visit this website: racetronix - index


(("Z" = Impedance)


There you will find the listing

for the various hi-Z & low-Z injectors.


Factory GM ECMs in TRs were built for the hi-Z injectors.

Modded TR ECMs can utilize the low-Z injectors.


There are both hi-Z and lo-Z 55#s.

The overwhelming odds are that yours are the hi-Z 55#s.

Likewise, the same odds stand on you having an unmodded ECM.


Since Bob Bailey does all (or practically all) the TR

ECM injector driver mods, he'd be a good one to ask

any further info as to identifying the modded units.


Look for the "Ask Bob" forum on the fullthrottle website.


HTH

[Beamer]

Thanks Jack and John for your responses...



Mike

[ryan george]

Originally Posted by Beamer

I have 55 lb injectors in my T. I have assumed (don't say it...), that I have a modified ECM, as anything above 50 Lbs injectors needs to be modified for the low impediance. I have also heard that some 55 Lb'ers do not require modifying the ECM.

I will be installing a powerlogger next week, and I was curious how to tell if it has been modified for sure.

Thanks all...

Mike

Mike, I've got 60lb Mototrons on my GN and no ECM work. Fyi...

[Beamer]

Originally Posted by ryan george

Mike, I've got 60lb Mototrons on my GN and no ECM work. Fyi...

Thanks for the info Ryan...

I guess what I am really wondering about, is if in the future... I want to upgrade my injectors to a larger size - will I havee to get my ECM modified, or buy one that has been modified.

Enjoy all...

Mike

[NC87GN]

I took a modified ECM apart just to see what is involved. To make is short I would rather leave it to the experts to make the mods. Just my .02..

[ryan george]

Performance, Horsepower, Injector, Fuel, and Turbo Guide

Mike, try this link to gnttype. There is a note at the bottom that says low impedance injectors require modified drivers in the stock ecm. It is an old file, but may help you out some...

[SouthernCal GN]

Originally Posted by Beamer

Thanks for the info Ryan...

I guess what I am really wondering about, is if in the future... I want to upgrade my injectors to a larger size - will I havee to get my ECM modified, or buy one that has been modified.

Enjoy all...

Mike

Check the numbers on your injectors, and post them...

Back in the day, the largest hi-z injector was the 42lb 009, and the 55 lo-z was the hot ticket in upgrades. The Mototron 60s are probably the finest injector ever used on these cars, and they're just about all the injector needed- especially with alky.

If history is any indication, there will continue to be improvements to hi-z injectors, and modded ECMs won't be as necessary.

If Bob modded your ECM, there should be a date sticker on the case.

HTH!

[Jack Armstrong]

Originally Posted by Beamer

Thanks for the info Ryan...

I guess what I am really wondering about, is if in the future...

I want to upgrade my injectors to a larger size -

will I havee to get my ECM modified, or buy one that has been modified.

Enjoy all...

Mike

There are 79# hi-Z injectors available now @ racetronix - index

for use with the stock un-modded ECM.


When/If you wanted to ever run low-Z injectors, it'd be
ideal to get a new (refurbished) ECM from GM & send it
directly to Bob Bailey @ fullthrottle for his low-Z mod.

ECM part # is @: Turbo Regal Web Site

Check price of ECM @ GM Parts Direct: Your direct source for Genuine GM Parts

HTH

[Jack Armstrong]

You can reference & compare the numbers found on your current

injectors easily by using the injector list provided on racetronix - index


All the data on each injector size/type

is quickly found by merely clicking on its listing.


HTH

[85 conversion]

is there advantages or disadvantages to running low z or high z injectors....
would 72#low z perform better than 79#high z ????

[Beamer]

Originally Posted by SouthernCal GN

Check the numbers on your injectors, and post them...

Back in the day, the largest hi-z injector was the 42lb 009, and the 55 lo-z was the hot ticket in upgrades. The Mototron 60s are probably the finest injector ever used on these cars, and they're just about all the injector needed- especially with alky.

If history is any indication, there will continue to be improvements to hi-z injectors, and modded ECMs won't be as necessary.

If Bob modded your ECM, there should be a date sticker on the case.

HTH!

I looked at them last night, and they have 3102 on them. I saw some 55# injectors on the boaed a month + ago, that were identical to mine, and had the 3102 on them.

Any luck in helping me determine low or high impedance is appreciated. The main question is if my ECM is modded or not. If I decide to jump up to larger injectors, it would be nice to know...

Mike

[TurboBob]

Originally Posted by 85 conversion

is there advantages or disadvantages to running low z or high z injectors....
would 72#low z perform better than 79#high z ????

low Z injectors in this size range (when properly controlled by a peak and hold driver circuit) tend to have more stable, predictable fuel delivery at low pulsewidths. Meaning that your idle and cruise AFR should be steadier, and more consistent.

Bob

[Jay Nesbitt]

There are P&H injector driver chips (LM19194?)I don't have the number at my fingertipa and my memory aint so good.....well you should be able to build an interface box to drive any injector. If anybody is interested, I'll look up the number/circuit.

J N

[Jay Nesbitt]

There, I looked it up. National Semiconductor LM1949 (oh well, I was close)....
See the link:
LM1949 - Injector Drive Controller

JN

[Beamer]

I see that there is a different type IC module to drive the injector circuit, is this a replacement IC chip? Sometning that has to be installed by modifying the circuit board? And I understand that there are some resistors that need to be added also.

I saw that FTS was selling modified ECMs for low impedance injectors, but it looks like they do not do that any more. Who modifies them now?

Mike

[Jack Armstrong]

Originally Posted by Jay Nesbitt

There, I looked it up. National Semiconductor LM1949 (oh well, I was close)....
See the link:
LM1949 - Injector Drive Controller

JN

Jay,

That's great news!
------------------------
LM1949N MDIP 8 STD
------------------------

The last of the earlier part number
were scarfed up primarily by 1-2
people & re-sold at a 10,000%+
profit.

Nice to see monopolies end.

[Racetronix]

Originally Posted by Beamer

I looked at them last night, and they have 3102 on them. I saw some 55# injectors on the boaed a month + ago, that were identical to mine, and had the 3102 on them.

Any luck in helping me determine low or high impedance is appreciated. The main question is if my ECM is modded or not. If I decide to jump up to larger injectors, it would be nice to know...

Mike

3102:
Racetronix-Siemens_Injector_Sale-55h

If you do not want to mod your ECM you can use an impedance converter box. We have V6 versions w/injector packages as well:
RX-ICH