Help with tuning for 38# Lucas injectors

[dgreene]

Here's the deal. I started burning(or should I say, trying to burn) my own chips for my own vehicles. One is the GN's that I own, the other is the 87' TPI 350 Firebird that I drive daily. Messing around with one for the stock setup seemed real easy, so I purchased up a set of 38# Lucas injectors....not so easy. I can't seem to get a smooth idle no matter what I do. Idled great with the stock injectors. I have tested and re-tested everything that I can think of, including the coil pack, module and the MAF(switched with a known good one).

I have the BLM's pretty close, but can't seem to get the idle smoothed out, or the WOT stuff down pat. I don't have any hesitation or dieing out, but it does seems to want to over boost for a second and then come back down and level out. It didn't do that before the injectors and (attempted custom) chip, and I have tried everything I could think of to bring it back down including replacing the lines, boost solenoid, actuator, lowering the boost setting in the chip, and so forth....

If anyone would care to share any tips that they may have on these injectors, or known issues, please direct them to my personnal email. I wouldn't want anybody to blurt out any trade secrets or anything.

TIA.

dgreene@shelby.net

 

[Eric Stage I]

What is your blm at idle and maf reading at idle? What inj. constant did you use? Is the rough idle when cold or hot or both?

Eric

 

[dgreene]

My BLM at idle is 122 currently. It seems to run rougher once warmed up, but I think that is because it idles down once warm. I currently have the idle set for 750 RPM in P/N from 68 Celsius on up. I've tried upping the idle just a little but then even at idle I was in cell 1 instead of 0, so I lowered it back down. The MAF count, once it warms up and the idle comes down is 6 to 7. Oh, incase I didn't mention it in that book I wrote above, I'm using a DirectScan for my data gathering. I've even swapped out the ECM for one that has not been opened up to make sure that it wasn't the DS that was causing my troubles, but that didn't change a thing either.

 

[Eric Stage I]

Those numbers look ok. At least the ecm thinks it has the commanded a/f if the blm is in range. Maybe the o2 sensor is off.
You might double check the injector wiring or see if the injectors have been flowed. I've played with lucas #38's and the idle was not rough (it was typically lucas rich).
It doesn't "sound" like a chip issue. I have 38's in my car right now with my own chip. If you want, we could swap .bins and I'll see if my car develops the rough idle.

Eric

 

[dgreene]

That sounds cool. I'm gonna check that wiring one more time though. I also have a new AC O2 sensor hanging on the wall. For ****s and giggles, I'll change it again and see if helps any. Just send me an email to dgreene@shelby.net and I will send you the bin file that I'm currently useing. I'll tell ya, it's pretty tame. No wild timing or anything. Thanks!!

 

[TurboJim]

Originally posted by dgreene
Here's the deal. I started burning(or should I say, trying to burn) my own chips for my own vehicles. One is the GN's that I own, the other is the 87' TPI 350 Firebird that I drive daily. Messing around with one for the stock setup seemed real easy, so I purchased up a set of 38# Lucas injectors....not so easy. I can't seem to get a smooth idle no matter what I do. Idled great with the stock injectors. I have tested and re-tested everything that I can think of, including the coil pack, module and the MAF(switched with a known good one).

What are the BLM's at idle? What is the ECM doing? Below you say you got your BLM's close, but what is close?

I have the BLM's pretty close, but can't seem to get the idle smoothed out, or the WOT stuff down pat. I don't have any hesitation or dieing out, but it does seems to want to over boost for a second and then come back down and level out. It didn't do that before the injectors and (attempted custom) chip, and I have tried everything I could think of to bring it back down including replacing the lines, boost solenoid, actuator, lowering the boost setting in the chip, and so forth....

What I have done is ramp down the WG DC right where I see the spike. IE: at umm....$3780 or $3781 ?(I forget where the table starts without looking) go like FF FF CC EC EC EC. The CC there makes the turbo slow down a little. I had problems in some cars where I felt the turbo would still speed up a little before slowing down. Especially on larger units with heavy wheels. This would be a boost spike on a gauge. So what I did is kinda anticipate where the spike occurred and then try to slow the turbo down a lOT before finally setting at where I wanted it ultimately. Doing this solved a lot of spike problems. Not all, but a lot.

 

[dgreene]

What are the BLM's at idle? What is the ECM doing? Below you say you got your BLM's close, but what is close?

Jim, I have Cell 0 at 122 and Cell 1 at 123. Cell 15 is a 133 and the rest are between 134 and 115.

I'll try your suggestion on the WG DC. I'll base it off the last run that I made on the DS and the mental note of where the spike occurred(since DS doesn't have boost sensing).

Oh yeah, I wound up using a injector constant of 45.1. Seemed kind of high to me but it's where the BLM's started coming close to 128.

 

[bruce]

Originally posted by dgreene

Oh yeah, I wound up using a injector constant of 45.1. Seemed kind of high to me but it's where the BLM's started coming close to 128.

Your using 45 for 38s?.
Your not even close, grab a stock bin, put the right injector size in and start with that.

Base line the car with just that mod and see what your idle cruis and WOT are like. And take notes.

Then sit down, and see what and where you need to change things.

Then look at the excel spreadsheet and see what you need to do and look thru to figure out what seems like a logical path to get your desired result.

With your inj constant right, I suggest trying some fuel presure changes to get you BLs closer, and then use the PE stuff to get your WOT right.

Always have several spare chips, ie have a base chip that will always get you home, and then a few to play with.

 

[dgreene]

Bruce,
That's what I'm up to right now. The bin that Eric sent me gave me some ideas about what I was doing wrong and where I should be going with it. So did Jim. I was getting the BLM's close, but it's was way out of whack everywhere else. That's what I get for jumping blindly into this affair. After lunch today I should have some time to do a little driving on this Donnie/Eric/Jim chip that I have and see where that takes me. I'll post this evening where I have gotten too.

I have the FP set at 42 line off right now. I'll try it there and see where it goes and then move it up or down a little if it needs any slight change.


I would like to thank everyone who it helping me out. It's nice to know that there are some good people out there who are willing to help out a stranger on their quest for performance!!

 

[Eric Stage I]

Donnie, you may have to use the bin I sent you "as is". You may not be able to use the table info out of it. I wrote some code into it that tells the program "this is not a linear injector". Therefore, you may look at the chip and see an injector constant of 38.3, but its not 38.3 (at least not all the time ) I would try burning it exactly like I sent you first, and if you need to adjust it, I'll tell you how.

Eric

 

[dgreene]

OK, here's what I've found so far.

I went back and checked my Coil pack and module again and found out that the center tower wasn't firing so good. I replaced the module and solved that problem. I also pulled the plugs and changed them, gapped to a real tight .035. Man did that help the idle!! Duh. I should have know that it wouldn't be the injectors.

I've got about 2 hours on that bin from you Eric. It works great. I would like to change the timing a little though, but when I do it gives me a faulty eprom code. We still have 93 and 94 octane gas around here so I would like to give that chip a little more here and there. I have found the antitamper code in a few chips that I have but yours has some more patches, and I haven't been able to find it yet. Drop me a line and let me know.

As for my own chip project... I've started putting together a bin from scratch as well. It won't be untill next week before I will be able to put much drive time into it so as to see how well I'm doing on that one. Hopefully it will be better than what I had going on before.

 

[bruce]

Originally posted by Eric Stage I
Donnie, you may have to use the bin I sent you "as is". You may not be able to use the table info out of it. I wrote some code into it that tells the program "this is not a linear injector". Therefore, you may look at the chip and see an injector constant of 38.3, but its not 38.3 (at least not all the time ) I would try burning it exactly like I sent you first, and if you need to adjust it, I'll tell you how.
Eric

It does what?.
Why would you need to do something like that?.

 

[Eric Stage I]

Donnie,
The bin I sent you has no antitamper code in it. However, it has the fast update code in it. One of the things included in the fast update code is location $3002 is changed from 00 to FF. The Tuner 6 software calculates the checksum incorrectly because it leaves the first 4 bytes out instead of the first 2 bytes when it calculates. What this boils down to is you're going to have to calc the checksum manually with some hex editing software, or you can set location 7A2 to AA so it doesn't run the checksum at all.

Hi Bruce,
Basically, I changed the code so the injector constant is variable. Why? (My opinion only) The factory program allows you to tell it what the flow rate of the injector is at max pulse (or static). I simply feel this is not enough info about the injector. It was enough for the factory injectors because they were pretty linear. By linear, I mean if the duty cycle 10%, it flows 10% of static. Many injectors are not linear (you already know that), especially some Lucas injectors like the 42's. At 10% duty cycle, it might flow 25% of static (I just made up that number).
One way to fix this might be to adjust the MAF tables in the lower flow areas to lie about how much air is being ingested so that it leans out. This method works very well, but I thought that if I could tell the program "hey, this 38# injector flows like a 44# at low pulsewidths and flows like a 41# at mid pulsewidths" that it would be easier to tune.
So just for grins, I tried it and it seems to work all right, but its still experimental as I think the coding could be improved. Let me know what you think (be nice) . I value your opinion.

Eric

 

[dgreene]

Thanks for the help Eric. My cars BLM's are at 131 in Cell 0 and 125 in Cell 1, and 121 in cell 15. Looks good so far. I hope to be done with my own version within a day or so. I'll send you a copy when I get done with it. I think alot of my troubles were coming from that eratic ignition module that I just changed yesterday evening. Maybe now I can make a little better headway. I've not ever messed with the fast update code since I'm using DS, but I do have it printed out and laying around here somewhere. Guess I should have looked a little harder, huh? I'm still new at chips, so you will have to forgive me.

 

[TurboJim]

This is why I preach, to people that buy a chip from me, or anything, that the chip is not a cure for a malfunctioning component. IN most cases, a stock cal with only a constasnt change should run OK. If it doesnt, you need to makesure the CAR is right. THEN go playing in the calibration.

In your case, you might have spend a lot of time trying to fix somethjing in the chip, that was wrong with the car, and gotten no where.

 

[dgreene]

I agree. I had checked that thing before I started trying to make my own chip, but somewhere along the way it started acting up and I thought it was something I had done to the chip. Live and learn(the hard way).

 

[dgreene]

I just wanted to say thanks to Eric, Bruce and Jim for the help that you guys were on this subject. It's good to know that there's people out there who will lend a hand when things get frustrating.

The chip that I started(from scratch-again) is coming along. The only thing that I'm not sure on is the when and whys of changing the MAF counts. I working with it though, so maybe I will get it figured out. Now if I could only get all of that turbo "spike" out......