10 amp Drivers Work with Low Z Injectors?

turbonatr

More Cubes!
Joined
Jun 11, 2003
I bought an ECM to use with my 72lb. injectors that has a sticker on it with the turbo 6 logo which reads "10 amp drivers". I always thought 2.4 amp drivers were used with low Z injectors. Does anyone know if 10 amp drivers will work properly?
 
turbonatr said:
I bought an ECM to use with my 72lb. injectors that has a sticker on it with the turbo 6 logo which reads "10 amp drivers". I always thought 2.4 amp drivers were used with low Z injectors. Does anyone know if 10 amp drivers will work properly?

Low Z injectors, are *Peak and Hold* type devices.
The are designed to get a large opening current, and then immediately have the current dropped once there open, and then be shut off.

Using a 10A driver, can mean that once they're open they're left on at full current. (You might want to contact the folks that modified your ecm to see which ones they used.) This causes the injector to run warmer then heated, and put more heat into the ecm's printed circuit board circuit *traces*. The traces can get hot enough to actually lift off the PCB, and in some cases, turn parts of the PCB to charcoal.

It's at the extremes that will cause the failures (WOT then the injectors are on, with the higher DC's).

If you want to run it, just be sure to carry a spare stocker to get you home if it fails. Short term, low load driving a stocker ecm will last a while.
 
I bought the ECM from a board member who was going to use it, but decided to run the high Z 60s instead.

Here's the problem. The car breaks up badly under WOT boost...even with the boost set at 7psi (external gate). Your thoughts?
 
turbonatr said:
I bought the ECM from a board member who was going to use it, but decided to run the high Z 60s instead.

Here's the problem. The car breaks up badly under WOT boost...even with the boost set at 7psi (external gate). Your thoughts?

Well, the only way to test an ecm is on a test bench...
And even then it's kinda hard, unless the driver is roasted, not to mention that you could accidently roast it, trying to find out if a driver was dead.

If you think it's the ecm, the quick and easy answer is stuffing a stock one in, and making a pass or two. 1-2 passes shouldn't kill it.

If the stock ecm works then try closing the plug gaps up.

From there on, you'll need a data log, and a certain amount of parts swapping.


Jumping from say 50s to 72s, and while you may run the same boost, the fuel particle size in the chamber is going to be different so items that weren't a problem before, can become ones. Not to mention fuel demand, etc..
 
Tried the stock one, does the exact same thing. Part throttle driveability is fine, WOT boost it breaks up. You couldn't tell the two ECMs apart by their driving charicteristics. They act the same.

Something else I noticed is upon start-up, the car idles poorly. It lopes as if it's flooding itself and then clears up. It sounds exactly as if a sparkplug wire was off (but they are all on). Does this with boths ECMs as well.
 
turbonatr said:
Tried the stock one, does the exact same thing. Part throttle driveability is fine, WOT boost it breaks up. You couldn't tell the two ECMs apart by their driving charicteristics. They act the same.

Then the problem is ignition, fuel or mechanical.
You're to the stage of the basics of performance diagnostics.

Fuel pressure, compression test.
Plug readings.
Then scanning and looking for something out of line.

My first, *try* would be making sure the plugs look fine, and closing up the gap to like .025", and see if that takes care of it.
 
The only other thing changed before the problem other than the ECM were the injectors. They are out of my race car and have been sitting. Other than that, I parked the car less than 2 weeks ago when it was running well. I was using a set of 40s and a street chip waiting for the modded ECM to arrive. Car ran great. I pulled the 40s and installed the 72s in preperation for the modded ECM to arrive. So, if it isn't the ECM, it has to be the injectors. They were sitting with gas in them (whatever remained in the fuel rail) for a good 2 or 3 years). My best guess is they are dirty. Thing is, if they were, would they not show signs of that while idling and part throttle driving?

What I'm going to do is pull the 72s and the modded ECM out and replace them with my stand-by 40s and stock ECM to see if the problem persists and go from there.
 
turbonatr said:
them (whatever remained in the fuel rail) for a good 2 or 3 years). My best guess is they are dirty. Thing is, if they were, would they not show signs of that while idling and part throttle driving?

A poor enough pattern can with big injectors be a problem at the higher loads.

Try some Chemtool, Quakerstate, or GM fuel injector cleaner. A double dose is fine. The other injector cleaners are no more then just alcohol from what I've seen, and can't be counted on to do much.

Might call around and see if a local shop will do a quick ultra-sonic cleaning, otherwise, Chuck Leeper should be able to help you out.
 
???

Pour a gal of Xylene in the tank. It will clean them too.
 
When you installed the 72 lb injectors did you also install a chip calibrated for the injectors? If not then that would explain why you have drivability problems. :)
 
GN owner said:
When you installed the 72 lb injectors did you also install a chip calibrated for the injectors? If not then that would explain why you have drivability problems. :)

Yes. TurboTweak 72lb. race chip. I'm not that dumb.;)

Problem either lies with the ECM or the injectors (from sitting), they are the only two things I changed before the problem started. I'm leaning towards the injectors. Didn't have the time to swap out the 72s for the 40s (got out of work too late), but I'll do it this weekend.

Bruce, Should the 10 amp driver ECM work with the 40s (them being high Z injectors)?
 
Very good. Then I can positively zero in on (or eliminate) the 72s being the problem.

I would like to thank everyone for their input. Once I get this bug ironed out, the car should run well in the 10s (this engine already went 10.70s in a heavier car with a smaller turbo with more left in it).

I'll keep you all advised.
 
turbonatr said:
Once I get this bug ironed out, the car should run well in the 10s (this engine already went 10.70s in a heavier car with a smaller turbo with more left in it).
I'll keep you all advised.

Kewl, and please do.
 
a chip for 72's is going to try to deliver a LOT of fuel at WOT. You are probably WAY TOO RICH AT WOT (ok, I'm guessing).

A "10 amp" modded ECM will be rich at idle. (Depending on what parts were used, Dan used a couple different transistors in his 10 amp units)

Check with your chip guy about the fuel programming and plan on getting a properly modded ECM.

Bob
 
UPDATE;

I ended up getting out of work later than expected on Friday and I had running around to do yesterday. Finally got a chance to do something with the T today. Woke up to several inches of snow, too. :mad:

Anyway, installed a fresh set of plugs and added 5 gallons of VP to be safe. Started the car, same problem.

Removed the 72s and TurboTweak chip, installed the 40s along with the Street Lethal 40lb. chip using the modded, 10amp ECM. Took the car for a ride. The car ran fine. In fact, at 25psi, it's flat-out suicidal on the street. WAY too much. The County did a good job of clearing the streets, so the roads were dry, otherwise I would have never attempted it. Previously, I only had this turbo to 17psi. What a freakin' difference there is at 25psi!! :eek:

So, I am now leaning towards the 72 chip just being way, way rich. I am going to either have to buy or borrow a scantool to use the adjustable WOT fuel enrichment feature Eric built into the chip. I previously ran DFI exclusively, so I never really needed a scantool. It will be a while before I can do that as winter is here in full effect now. :frown:
 
Hi Eddie,
If you're getting by with 40lb injectors, then I definitely need to take fuel out of the chip. The chip is set up to pump out about 55lb worth of fuel, or roughly enough for a high 10 second car. For some reason you're not moving the amount of air I thought you would with your combo. I don't think you'll be able to remove enough fuel with the adjustment in the chip, but you can give it a shot. It depends on how much boost you end up running. I would get a Scanmaster, or if you have a laptop, Directscan to help dial it in.
If you find you can't pull enough fuel in the chip, I'll be happy to adjust the chip if you send it back. We'll get it fixed up!

Regards,
Eric
 
Bear in mind I only stayed on it for a very short time due to the car getting WAY out of shape very quickly, so I seriously doubt I could really get by with 40s. I would NEVER attempt to run the car at the track with the 40s in place with my current combo. The thing is, I was worried about turing the boost past 17psi since it was breaking up so badly with the 72s. I didn't know if it was doing that because of a lean condition or what. I played it safe and decided not to turn it up. What I can do is stick the 72s back in and crank the boost up to 26-27psi and see what happens. What I really wanted to do was determine if the modded ECM was to blame or not. Since I now know the ECM is working, I can probably stick the 72s back in and crank the boost up to see if that clears the rich condition.
 
No problem, we'll get it. Let me know what happens. Bigger injectors can be a little more touchy getting it dialed in, but once it's there it will run good.

Regards,
Eric
 
Eric Stage I said:
No problem, we'll get it. Let me know what happens. Bigger injectors can be a little more touchy getting it dialed in, but once it's there it will run good.

Regards,
Eric

I'm sure we'll get it ironed out, Eric. This is the first time I ran this engine without DFI, so it's just a learning curve. The combo ran very well with the 72s when I had a T70 on it. Should run better with the T72 I have on it now. Just a matter of getting it dialed in. Once the weather clears, I'll get the 72s back on it and test drive it. I'll keep in touch.

Thanks!
 
Top