junkcltr

iTrader: (1)

I have been looking into the $58 code and how I might be able to get the 42 #/hr Ford saturated injectors to idle properly. I have a few options.

1) Add the second injector driver & other hardware to the 730 ECM and modify the code and ECM to do alternate bank firing for low pulsewidths (most work)

2) Add 1or 3 more FETs in parallel with the existing single 730 ECM inj FET so that the total FET output resistance is lower. That would give a faster opening & closing injector time. I am not sure how much I would gain by this. Maybe even put a new smaller Rout FET in place of the stock. Could maybe gain 0.3ms in open/close time
Has anyone measured the output resistance of the stock 730 inj. driver?
This thread has some info, but most of it seems incorrect:
Third Generation F-Bodies > Tech Boards > DFI and ECM > 749 problems with larger injectors?
BTW, the total power through the 730 inj. drvr is (8*(13.8v/12ohm)*Rout_of_injector_driver) = approx. 8.5 *Ro
This is much less than 20W or 47Watts than the post stated


3) Go to Peak and Hold injectors, this I won't do.

4) Learn how to tune better. The bigger injectors are more sensitive to VE and timing changes at idle. The current 800 rpm idle has a BPW of 1.5ms. Since the code is BBZB $58 then that would mean that the total BPW is 3.0ms at idle for the complete ignition event (720 degrees) because the $58 is batch fire (ALWAYS two squirts per 720 degress/ign. event).

What I have come to realize is that the so called "quasi-async" fueling is just single fire like in the $8D code. Sync fueling is still synced to the distr. ref. pulse and squirted every for of those pulses. Async fuel is still every 12.5msec regardless of distr. ref. pulse (DRP).
I kept trying to change the min. BPW to enter quasi to a lower value like everyone said to do. Maybe I should have increased it because I was never entering quasi mode. I thought I was but the ALDL data was incorrect. Quasi/single fire would be better.

Maybe I just need to single fire at idle and low speed cruise?
Anyone measure the output resistance of the stock 730 ECM injector driver?

Just throwing ideas out there I guess. good & bad feedback welcome.

jeeps2creep

You know you really make my brain hurt!!!

Grumpy

Some injectors just have lousy low PW characteristics. ie just not very linear, for time on vs flow.

I've run the high Z 60 PPH injectors in my little 231, with the 58 code just fine (stock 749 ecm).

rooster433

I've gotten 60's to work under a 730. We didn't seem to have any problems.. defiantely not on the hardware side anyway.


realize that those injectors throw off the VE entirely along with PE and a few cranking items.

JPrevost

5) Build or buy a ~5amp DC to DC voltage converter with an input of 9-16v and regulated output of 14v. This way you have a strong steady power for the injectors.

RBob

iTrader: (1)

But is the number in that post the power 'through' the device? Or the power dissipated by the device? Reading what was posted, it is the power 'through' the device. Note the statement ". . .and you're making it switch as much as 21 watts."

The dissipation can not be calculated unless the RDSon is known. Which is the value you are currently asking for. Also notice my post didn't get a response. So we can't be sure of what the original calculations were based on.

RBob.

RednGold86Z

iTrader: (1)

Has anyone tried that but with 24V?? Will it let the magic smoke out of the ECU or injectors, or what?

junkcltr

iTrader: (1)

I agree that they are probably very non-linear at low PWs. They are cheap injectors. I believe that this can be overcome with hardware and some code changes if need be.

I have read you run 60 PPH in your "little 231". I have also read that you have the idle RPM raised to 900 RPM to deal with them.

I have a 110 CL cam & LT1 intake on/in the 355ci right now so the idle is at 850rpm to compensate for the cam and poor injectors. I idled smoothly at 700 rpm with the 24#/hr and $8D code. I kind of miss it.
I am installing a 114 CL more boost oriented cam in it. I will be able to lower the idle to something more reasonable and more stock sounding. I *think* the inject PWs will probably be lower than the current 1.5ms. So I am kind of thinking ahead I guess.

junkcltr

iTrader: (1)

I do believe that it is possible and think that I may "get it right" will more time fooling with the idle parameters. That was option 4 I think.

What got me thinking was the sound of the injectors. Putting a sound scope on them showed that a few were louder than others sometimes. That leads me to believe that some are not opening properly sometimes. Just a guess. I haven't benched them yet.

EDIT: What is the idle set it? What were the BPWs?

junkcltr

iTrader: (1)

5 amps wouldn't be enough. It would be worse. I could build a switcher DC to DC converter but the flyback clamp would be a pain. Without it the output caps would smoke. Better of with the addition FETS. Option 2 I think.

junkcltr

iTrader: (1)

True. I was looking at it as the power 'across' the FET. Yes the power 'across' the injectors is what you were referring to. I ran a few transient simulations to see how much I would gain by adding FETs to lower the Ro/RDSon. I was using an injector inductance of 600uH per injector. I think I would only gain about .3ms or so. I did this to see if what 83 Crossfie T/A said really makes a difference (the V8 vs. V6 thing).

Lots of good info here. Thanks to all for the replies. Surprised no one mentioned anything about the quasi/sync/async thing. Can't wait to get the boosted rig on the road to test out some stuff.
I am in the middle of swapping the harness over from a 165 to 730 setup. Much longer than I thought. I noticed some of Mike Davis' GND list seemed strange. I disconnected everything and ohmed out the GNDs to see what was what. I think the only one that is correct is the O2 ground. Overall, it probably doesn't matter depending on the grounding scheme inside the ECM. I don't feel like trying to figure that out so I am running the grounds as a stock 730 harness. Not like the Mike Davis GND pin list. The MAT/IAT is more than just a GND REF using his list. Enough rambling.....

junkcltr

iTrader: (1)

I don't think the flyback ckt would like that turn off if 2X the current is flowing. You could try to run the saturated like P+H using 24volts. I never tried it. I don't know the internals of an injector. Not sure if that hard of a turn on with a saturated might destroy it.
Actually, I wonder what is so different internally between a P+H and saturated besides the winding wires (resistance)?

AC

iTrader: (3)

Rooster, I see you're running a 730 ecm and $58 code with 60# injectors (same as I am). I haven't fired up the motor yet and wanted to find out what type of cranking issues you experienced? I'd like to see if I could address the cranking issues before I pull my hair out because my engine won't fire.

junkcltr

iTrader: (1)

I did some more simulations and finally the obvious hit me. The RDSon of the FET has very little to do with the turn on/off times. The turn on time is driven by the inductance and resistance of the injector. Therefore, adding FETs is just about pointless. The V8 vs. V6 number of injectors thing and turn on time is just about pointless. The injector turn on time for saturated will always be about 2ms.

It all comes down to that all saturated injectors have a turn on time driven by themselves. The turn off time is driven both by the injector and the ECM ckt. The GM ECM ckt gives a fair turn off time. I don't think could be improved all that much.
Looks like tuning or going to single fire is the the way to go. Bank fire with ECM mods if I can't get it right with the tuning/single_fire.

To all the people running injectors bigger than 36 #/hr.........what is the injector BPW at idle? I have searched and read a lot of my "large #/hr work fine", but no one reports the BPW. Most of what I read seems like people tend to raise the idle to make up for the injector BPWs.

Z69

What about the low pw offset table?

junkcltr

iTrader: (1)

I think the low PW table will come into play with tuning. If I ever get this TT 305ci finished I plan on building some cheesy test equipment. I am thinking of taking an op amp with the output fed into an ATMEL chip A/D to see where the injectors open and compare to what the BPWs in normal operation. I want to see what the BPW really are, not just the ALDL report.
Yeah, the low PW are probably non-linear but I expect them to be. Trying to control a device at it's extreme boundaries is always difficult. Ford seems to do it just fine.....using 90's and 2k's technology. I think GMs old tech. can do it just as well with some tweaking.

JPrevost

So let me get this straight, introducing a higher and steady voltage wouldn't help control the injectors? I thought, and apparently GM did too, that if you increase the voltage the time it takes to open an injectors gets reduced. Hence the whole pulse width adder vs voltage compensation that is seemingly in every calibration.
So why wouldn't a dedicated power supply (amp) work in getting better control over the injectors? I think this is your best option and not because I thought of it.
Take an old car stereo amplifier and use it for it's guts. Injectors, HUGE woofers, both drivers .

junkcltr

iTrader: (1)

Higher voltage would mean higher current and thus faster opening times. It would make the closing times SLOWER and/or more violent.
To make it worth while you would need 20+ volts. That makes the injectors open harder and I can't find data about the max. Voltage they can handle. It is also putting more heat into them.

Yes, GM does time PW correction for varying voltage. GM does not adjust voltage to maintain constant PW.
Stereo amps are designed for A/C (sine looking) signals, not square wave like the injectors want. Wacking an injector with an A/C looking wave would be worse than the ECM.

If you can find the info for Ford Saturated injectors saying they will handle 20+ volts then I will make a DC to DC converter. That means all 8 injectors will be dissipating about (8*(20/12) = 266 Watts when full on. Yeah, 266 Watts when static.

It may be worth trying with the 19#/hr I just pulled out of the 305ci. Some are junk so I think I might give the high voltage a try. Need to keep an eye on the flyback killing the ECM diodes because of the (20/14) current increase. Thanks for the idea.

Grumpy

Oh really?, care to show me where I said that?.
Idles 750-775 in gear.

JPrevost

junkcltr, I wouldn't worry about the heat generated. Ever feel the temp of an injector after it's been running for a while (it's very cool to the touch).
I didn't say use a car stereo amp, I said use it's guts. All of the amps I've opened up and inspected have large power supplies for high current draw and the better name brands have huge caps ment for the high current peaks.
I personally have no experience with anything I'm talking about, just theory. And 8 16ohm injectors is 2ohm load, or 2-channel 4ohm . Just gotta figure out that whole signal thing , I'll leave that up to the EEs.

JPrevost

And what's even crazier is people talking about TBI engines not being able to handle idle with just 2 100# injectors! That's only 200lb of fuel for 8 cylinders and you're here idling stable with 360lb of fuel on 6 cylinders and saturated injectors no less . Don't you love rumors.

junkcltr

iTrader: (1)

I must have misunderstood this post:
Third Generation F-Bodies > Tech Boards > DIY PROM > Injectors: How big is too big?

It sounded like it idled at 750rpm in gear and at 900rpm when not in gear.

Maybe I can get it better with just tuning. The more I read the more it seems that way. Seems odd that your 231 idles at 750rpm in gear with a 2.2msec pulse width with 60 PPH and that my 350ci had reported 2msec pulse width with 24 PPH at idle. You must have a real good VE at idle. If you don't mind, what is the cam specs?

That makes me curious. I will run it through the calc. to see what VE you have at idle. *** Something just dawned on me *** Is that 2.2msec using double fire batch or SEFI on the 231? That has to be SEFI (single fire), right?

Also, my old 2.0msec is double fire batch which is also 4.0msec batch single fire. My current 1.5msec double fire batch is 3.0 msec batch single fire. That is why I want to try and get it to do the single fire at idle and light cruise.

junkcltr

iTrader: (1)

JPrevost,
The fuel does act as an excellent coolant. I did some sims with 20 volts and it gains about .2 msec on the open time. It would be better to start with a fresh design than use stereo stuff. Most of the parts in such devices have proprietary numbers so you can't figure out the specs on them unless they are fully analyzed. I'll talk to some EEs and see what they say. I could be wrong also.

RednGold86Z

iTrader: (1)

In gear tends to bring PWs up. Closed loop tends to introduce a lot of the instability at idle.

Closed loop stoich with somewhat aggressive closed loop is where I typically have problems with large injectors. It takes a lot of playing and isolating (turning one thing off to calibrate another) to get it all to come together. There's sometimes 3 loops (fuel, spark, iac) all disturbing the balance, and they all have to work smoothly at a variety of loads (depending on temperature, altitude, engine condition, accessory loads, etc...). Even with small injectors, it's still a large task, especially if the cam/engine combo are "sensitive." By that I mean A/F, spark timing, and ease of misfire all impact the RPM more easily.

A wide turbo cam probably is less sensitive than a lumpy N/A cam.

Sequential makes it easier, by a wide margin. It alone keeps all the plugs and injectors happy. Single fire at least keeps the injectors happy (but may tend to be a tad rougher idle due to one or more cylinders getting different fueling/wet fuel onto the spark plugs/less vaporised fuel (take your pick).

Oh, and when comparing batch to single PW's, just doubling the PW doesn't quite work - you'll have to subtract one turn-on/off time.

junkcltr

iTrader: (1)

Every line you wrote is so true. After a lot of searching and seeing what others have done leads me to believe that my poor tuning skills are surfacing with the large injectors.
I did have it idling at 700rpm in open loop quite well. Closed loop was the killer. I just couldn't get it right. I was fooling with just the O2 constants and VE with the timing set to 25 degrees. The 114 CL cam that is going should help and at the same time give it a little more HP and drivability.

I think you are right and that it will get better with more work of the VE, spark, and IAC. I still don't like the 1.5msec PWs though so I need to figure out how to get it to go single fire batch. I think just raising the min. PW of .793msec to something higher will get me there. It transition from single to double fire will probably take some work. Yeah, the long time between squirts seems odd. That is why I was thinking of trying the modification to alternate bank fire. It would make it more consistent.

Grumpy

2.2ish, and if you recall, I've mentioned linearity. Some of the newer injectors are designed to have *long* PWs at idle....
Long being a relative thing.

206/206 @ .050.
.496 lift.
It's the mildest roller Buick 231 cam Compcam makes, is if you need more specs..

Plano SEFI....

Grumpy

Only if you totally ignore the compressor wheel, and it effect on the intake air tract. Going from cold to warm oil can make a huge difference in how much *drag* it has.

Really?. SEFI just doubles the PW. It's all the same tables.

Building the best possible calibration, for any car is going to be a project. There just aren't any short cuts. I've done both SEFI, and batch with the 148, and batch with the 749/ 58 in my car. None of them are particullary easy. Like anything else practice make perfect. The more critical you are, the more work it takes....

junkcltr

iTrader: (1)

Thank you. It makes sense now. I was curious about the duration so that answers that. I liked the 216 duration in the 350ci so I am going to stick with that change the CL.

I hear you about the tuning aspect. I wanted to go boost to learn how turbos work and how the $58 works. So the large junk injectors will kind of get me to look at things I never did before. Tuning really is an art and as it turns out I am not a natural at it.

3.8TransAM

With a little help from Bruce(he knows how much lol) my TTA is also idling around the 2.2-2.3ms pw w/ MoTron 60#'s.

Idle is in the 700-750 in gear and roughly 850 in park.

I have a little more wild setup than he has and its a 210/210 roller, right around .500 lift

Playing with my current setup or using the stock code, they have appeared to me to be pretty linear across the board as Bruce has found.

At one point a few years ago I had some info on the 42# compared to some other injectors. Its nothing I had saved and I tried searching for it. Might want to try digging thru turbo buick boards and see what u can find.

later
Jeremy

RednGold86Z

iTrader: (1)

To clarify - What I meant was about the TOTAL PW, not just base PW. Total is the output of the injector driver, and what the injector sees. Calculating the base PW is just as you say - double the batch mode PW, but the output isn't double. It's the output that makes all the difference.

When I was using one of our aftermarket ECUs on my GTA (and could control the PW directly - the output PW), my stock injectors (which had 100k on them, and were suspecting to be causing some idle issues) would literally go from a normal A/F (sub 14.7) at 2.2 ms OUTPUT, to complete and quick stall at a forced 1.9 ms. It was like a switch on those. They'll be seeing the trash can soon enough though.

11sORbust

It doesn't matter how "good" one is at tuning. The best tuner in the world cannot create a perfect calibration. I think it's most important to make the tune something one can live with. The best thing is to do is lots of real world testing, instead of thinking about the problem(what everyone tends to do).

Big injectors never create a problem for me.The largest high impedence injectors I have work with was 60lbers..

JPrevost

I agree and don't at the same time. Many a people do "real world testing" without setting up the test procedure correctly. The results end up being all wrong but posted as fact. If people were more scientific and posted their test procedure this wouldn't be a problem... but very few that extra step.

junkcltr

iTrader: (1)

There are three ways to learn something. One is to study and set up the system using the knowledge of how it works. Two is keep playing with it until it seems to work (hacker approach). Three is a combination of the two.
In the case of ECM tuning, lots is to be gained by reading the code, understanding the hardware and changing parameters. Once you do that, then go play with it. Some people don't have the skills to think about the problem but try anyway and that is how false info is spread. In my car I could just run open loop and all would be fine.....but I wouldn't really learn anything except that taking the easy way out is fast.

Thanks to all for the ideas on how to get this thing tuned at idle.

11sORbust

I think you misunderstood me. It's imperative to learn the system, no doubt. I was talking about problems that arise when calibrating a system, in pariticular. Sorry for the misunderstanding.

junkcltr

iTrader: (1)

Yeah, I think I misunderstood. What I wrote kind of sounds one way. Sometimes messing/hacking at it is the only way to figure stuff out like some of the PWM regs of the 730/749 ECM I am looking into. True, calibrating does does some figgling with to get all of the control loops to work together. After looking at some idle data from last year, I think I need to mess with the IAC an O2 parameters.

JPrevost

The great thing about the O2 pid calibrations is their dependancy on air flow. If you setup a SD system "correctly" by setting the injector flow as close to actual and THEN VE, you shouldn't have much tuning needed for the PID. With a larger cam and closed loop idle, things get flaky and that's when you should fine tune the tables. Cams milder than the Lt4 hot cam don't need much if any PID tweaking . The IAC on the other hand... depends so much on the mask. $8D seems great, $61 seems poor, $6E and $32 are imbetween and generally picky.

anesthes

iTrader: (12)

What about your 355?

On my car (350 / .040 over), with the 42# injectors I need to run around a 1.5 mSec idle or it's too rich, but the problem is, I don't think the ford injectors are reliable that low.

I've played with evrerything from timing, to tinkering with the fuel modes in $58..

I think it's safe to say, what works on a turbocharged 3.8, isn't always what works on a v8.

I'm about to go back to smaller injectors. I'd rather go static at WOT, than have a car that runs like **** everywhere but WOT.

-- Joe

RBob

iTrader: (1)

My understanding of the 42# Ford/Bosch injectors is that they are very difficult to get to idle well. This comes from someone that does a lot of tuning on various engines.

RBob.

anesthes

iTrader: (12)

I'm gonna go back to smaller injectors. I'm not making enough power to need the 42's anyway.

Anyone wanna buy some almost new 42# ford injectors? They are 10 months, and about 3,000 miles old.

-- Joe

TRAXION

Being in the Subaru community now I get to see a lot of new stuff. My STI came stock with 50lb/hr injectors. I have a set of 70lb/hr injectors ready to drop in. Most of the time people upgrade to 80lb/hr injectors. These are NOT P+H. They are just regular old high impedance injectors. Nothing special (unless you consider the side feeding which is just weird, lol). Most of the time when people upgrade to the 80lb/hr injectors (Power Enterprises, Helix, etc) the change is NEVER as simple as an injector scalar change. You have to play with the injector latency table (scoobies have one) and often recalibrate some of the tip-in tables. This is on MAF engine management. What does all this mean? Not that much I'm just relaying that things are not always as simple as just changing a scalar value (as most of us already know). However, given that the Ford Injectors have latency issues, I am thinking that some better results can be had by working the IPW vs. Batt Voltage and the low offset vs. BPW. I don't remember reading detailed posts about how someone used these tables to work with bigger injectors ... but, I really think improvements can be made by toying with these tables. Usually, aftermarket injectors have higher lag times so I would definitely keep this in mind in the tuning.

Tim

anesthes

iTrader: (12)

I've tinkered with both quasi and async fueling in $58. The issue is pulse widths. Some folks have injectors that live very hapily at 1.3, 1.45 mSec. My fords simply do not. Yet, anything higher than a 1.5 and its rich. (like, 10:1 on the wideband).

The STI I imagine is not batch fire. Whats your injector pulsewidths at idle?

-- Joe

Grumpy

Ya, it's that flux capacitor dohickey.
N/A mode is the same in either.

If you'd asked about the 42s before buying, you wouldn't feel so frustrated now.

anesthes

iTrader: (12)

I did. You told me to go bigger.

Either way, the motor is getting overhauled. I pulled a few main journal caps tonight and the bearings are burnt up and scored. Apparently that explains the oil pressure loss.

-- Joe

anesthes

iTrader: (12)

I sold the 42# ford injectors and bought some LS1 type injectors. 36# bosch they are advertised as.

The bosch part #'s on them are:

0280155868
24508208

If anyone has used them, let me know how you liked them. Otherwise, I will post back my results when I put my motor back together. (oil pressure loss, bad bearings, rebuilding this week).

-- Joe

JPrevost

Those newer LS_ injectors are rated at 4 bar right? So 58psi as apposed to the Ford injectors which run at 43.5psi, or are those newer 42# injectors rated at something else?

anesthes

iTrader: (12)

They are 38# at 4 bar, 36# at 3 from what I read.

Ford injectors are all rated at 43.5psi, with the exception of some peoples 24# injectors. Every set that I had cruzin performance check, and every set i've heard of him doing showed that they were not rated at the 38psi or whatever people think.

-- Joe

JPrevost

I don't know how that's possible unless they have an internal regulator that I don't know of... because if they're 38@58psi then they "should" flow 33@43.5, not 36. That's just simple math, maybe they do flow 36 but I'd be suprised if they did.

anesthes

iTrader: (12)

Thanks as usual to rich at Cruzin Performance:

"Hi Joe,
The #24508208 I have serviced many of and they flow an average of 34 lb/hr @ 43.5 psi. The Bosch number for those is 0 280 155 811. They are an OEM injector for the Pontiac 3.8 Supercharged engines used in the GTP's and Bonnevilles.

I don't have a record of the #0 280 155 868 in my database. It may be the same injector with simply a number change by Bosch.

All of the 24508208's that I have serviced are high impedance. 12.2 to12.6 ohms. "


Using a fuel injector calculator it appears they are:

34# at 43.5 psi
36# at 50 psi
38# at 55 psi

Hope this helps anyone else searching TGO for these #'s, because I didnt get ANY hits.

-- Joe

kevm14

Those numbers look fine, with the exception of the 36lbs being ~36.5. Another thing though. I thought Ford injectors were rated at 39psi, not 3bar. I'm pretty sure the SVO 30 pounders are rated at 39...

anesthes

iTrader: (12)

Nope. I went over that in another post a year or two ago. Had a few sets tested, as did others.