I have an 89 IROC-Z running on the 6E mask. It is a 383 Stroker, Alum Pro-1 Dart heads 1.60 / 2.05 valves, Holley Stealth Ram, 58mm throttle body, 24 lbs Ford SVO's, Comp Cams 306 230 - 244 dur. / .510 - .540 lift / 112 deg lobe seperation, complete roller setup with 1.5 rockers, 3200 stahl, stock fuel pump, 6 deg base timing, 50 psi fuel pressure. I have Craig's AutoPROM using TunerPro RT. I have the injectors set for 26.03 in the program in order to get driveability. I don't have a wideband, just datalogs and a local dragstrip. O2 mv's .875 = 12.5:1 AFR / .900 = 13:1 AFR. I know it is not exact but all I have to go from.

I tried a custom tune chip before I started trying to learn everything myself. At that time the car had 30 lbs Ford SVO's in it. They could not get the driveability or BLMs much more than 112 so I got my money back and bought the 24 lbs SVO's, had the stock computer chip in it, advanced the timing mechanically to 12 deg and ran a 12.69 at 107 fat as could be. No datalog just visible black smoke. I knew I had something I could work with then so that is when I got into programming myself. I have driveability with BLM's 122 in town and 132 on the interstate. That would mean time for WOT / PE tuning.

Fuel Question:

I am having troubles getting more fuel in WOT / PE with the program set as is.

My PE vs RPM Table is 2800 - 21.09, 3200 - 33.59, 3600 - 43.75, 4000 - 44.53, 4400 - 21.87, 4800 - 28.12, 5200 - 43.75, 5600 - 46.09, 6000 - 39.84, & 6400 - 39.84.

My PE vs Temp is 133 - 16.02, 176 - 11.72, 219 - 11.72, & 262 - 29.69.

If I am correct and the coolant is 176 deg and my RPM is 5600 then I would be asking for 11.72 + 46.09 = 57.81% more fuel than cruising around. That seems like a lot to ask for. I am seeing an average of 825 mv's with this set up which is way lean and the spark plugs show it, they are white. If I add much more to the table then my average goes down. The way I arrived at these numbers was by taking the O2 readings and grouping them together in an RPM range, take the average, and find what percent I was off from .875 or .900. I would take that and divide by two so I did not add too much and add it to the table for that RPM range. I have not found a good thread with someone telling how to best accomplish this. I was looking for .875 till 5200 RPM and then looking for .900 from then on up the RPM range.

Are the injectors reaching their peak duty cycle and just can not flow more fuel? If these numbers get two high does the program take fuel away? What numbers do some you guys have in your tables? Am I way off on the correct way to do this? I notice the fuel drops off a lot in third gear so how would you add more under that load and not across the board on all RPM ranges? I have complete datalogs if someone wanted to take a look.

The only way I have found to get the numbers up in the .900 plus is to call the injectors 22 lbs and leave the two tables just at they are stated above. Then I have an average of .902. Of course that will not work for driving around so I am caught in the middle.

Timing Question:

Do you look for 36 deg timing constantly across the board or is it better to take timing away in the upper RPM ranges. Obviously get the fuel correct first before worrying about timing but right now I have it constant based off the load and adders.

This is my first attempt at posting on a forum so I wanted to cover everything but it seems long winded. Take it easy on me and I appreciate all help. I am big enough to know when I am in over my head and that is where I am at. I have read for hours but sometimes you just have to ask. I feel like I need to go the 30 lbs. again and start over but I don't know if they would flow enough in WOT / PE because I would probably have to call them 34 lbs. to get driveability. How far can you "cheat" the injectors before the program might be weird on you? Or does it ever get weird on you? Enough rambling now...

 

Get a WB and tune your MAF tables. That is a key to a good tune on a MAF car. Then use the WB to tune the PE. I only use the PE vs RPM (WOT) table.

As for how much spark to use, a lot depends on your heads. Some heads don't like a lot of timing and you hear detonation real fast. Others, like timing - the more the better (until around 36-38*).

I like to try and get all my spark dialed in as quickly as possible. Sometimes that is not quite possible though. But I like to get as much in somewhere around 2800 rpm. As your rpm increase, you can sometimes add a dash more spark at the high rpm (like 4800 rpm) and co-incide it with a dash more fuel.

But to tune properly, you really need a WB.

 

I appreciate the quick response. Could you elaborate on exactly how you did your MAF tune? What kind of wideband do you use? I don't know much about them. Don't you have to have a dyno to use one or do they make mobil units?

I understand it will get you the closest tune you could ask for but I still don't understand why my setup won't go rich unless I call the injectors smaller than they really are! Spark plugs don't lie, this baby is lean...

I was glad to hear I have the timing down...Now if I could just get that fuel. What numbers do you have in your PE vs RPM? I know they won't be the same because of setups but just curious.

 

When is the last time you changed your fuel filter? I was tuning a buddy's car and we JUST COULD NOT get the AF ratio down no matter how much fuel I added via PE.

We initially thought that we might have exceeded the flow capabilities of the fuel lines. But, as a "simple check", we changed the fuel filter first. It did the trick.

We suspect that given the high price of gas, some companies my be serving up "less than the best premium". This was common during the 1970s during the Arab Oil Embargo, and it seems the same thing may be happening again.

 

I put a new one on it about a year ago or so. I initally thought the same thing, filter, pump, pressure, or injectors. I have checked and the pressure is still where I set it at, 50 psi. I would think that if the filter is limiting flow then the pressure would be down. If the pump was having problems then I would see a major drop in O2 mv's but they don't, they are really constant but constantly low. The pump also shows 13.9 volts all through the run. If I set the injectors to 22 lbs then it will go rich on me so I know the "system" is capable but just not with the chip I have programmed. As little as a new filter costs and the amount of time to put it on that would be a good "simple check". It would not hurt anything having a new one but again it is capable of going rich with smaller injectors called out.

What WideBand do you use? Is it a mobil unit or do you have access to a dyno? How did you do the MAF tuning that you brought up in the last post?

I am guessing that you thing the 24 lbs injectors are capable since you have not mentioned them but 11.72 + 46.09 = 57.81% more fuel seems a lot. Am I correct in the way I figured that? What is the highest percentage that you have used when tuning?

I appreciate your time Glenn91L98GTA!

 

FYI, my buddies fuel filter was changed on months earlier. The WB we use is the Innovative Technologies version. It REALLY is the only way you can see if the fuel you are adding is actually getting there.

The more I get into tuning and acquire those "special tools", you quickly realize the "special tools" are not a "nice to have" but a necessity. Without a WB we would never have found out that fuel was being restricted at the most critical time. We would have ASSUMED that the programming was adding the fuel (just like we had commanded it) and been happily running lean in WOT.

We knew we had a problem in the fuel delivery system because we could actually see the injector pulse width increasing from our scan tool readings yet the AF ratio wasn't changing at all.

BTW, you are confirming the Injector PW is increasing? Correct?

 

PS: In case you are not familar with the Innovative Technologies Wideband. You install a bung into your exhaust and then tune directly from the readings while someone drives and the other tunes.

The narrow band O2 is useless for tuning. It is strictly for "switching" back/forth to keep the engine at 14.7:1. And, once you get a WB, you discover the Narrow Band O2 doesn't do a great job at that either.

I have found the Narrow Band can cause the car to run anywhere from low 14:1 to high 15:1. But, that's within the range of the Narrow Band O2, so what do you expect.

Do some research on Narrow Band O2 or track down some of Bruce's (Grumpy's) post on the subject. Better yet, PM/e-mail Grumpy on the subject. I'm sure he would enjoy discussing the subject with you.

 

BTW, it's Innovate Motorsports, and the product is the LM1, and it costs $350 with the sensor.

If the MAF tables are right, and the fuel flow is good, then you only need about 18 percent PE fuel to go from 14.7 to 12.5. Of course, all of the $6E .ecu's out there have a mistake that makes one of the tables correct (I think the vs ECT), and the other table (vs RPM) only delivers half of what you thought. I've fixed it in my .ecu, and I'll try to upload it to Moates.net as soon as I finish this post. Look for an older post by me about PE fuel being correct, I posted a lot of info in there about the fix to the .ecu, and the way to calculate amount of PE needed to get the commanded A/F to a desired level.

But, your numbers look like plenty of fuel (commanded) either way (but not exactly smooth or anything), and the BLMs show nice for part throttle, so I'd definitely start digging into a fuel flow problem if you believe your plugs are saying lean. If you are just checking fuel pressure at idle, it's not even close to a good guess as to what it's doing at WOT at peak HP.

 

Thanks, I usually just call it the "WideBand".

 

[QUOTE]Originally posted by RednGold86Z
[B]BTW, it's Innovate Motorsports, and the product is the LM1, and it costs $350 with the sensor.

Just recieved mine in the mail today. Comes with everything you need except the laptop. You can also view the videos on their website,that covers, installation,operation, and calibration etc. The manual also gives tips and tricks, and troubleshooting.

 

And now you can finally begin REAL TUNING that 434 of yours. I got mine all torn apart and should have my cam & timing set this weekend. Now I just have to pry the WB from Keith's hands.

I am trying to organize a group of locals to go down to the closest drag strip (about 1 hr drive) to do some "spring cleaning" in the next few weeks.

 

Glenn91L98GTA -

I guess I should not use the word "know" as much. I was just trying to use logical thinking but evidently I don't know as much as I thought! I guess the pressure could be there but the volume may not be if a filter is junk. I will be trying a new one asap. Thanks for the info on the wideband. I will be checking into those and researching more about the narrow band. As far as PM / emailing Grumpy, that just scares me ! The mail order chip I tried was from those TPI guys and I am trying everything they told me to do when they were programming the chips and I was recording data. I have read a bunch of the forums too and found information in a Chevy High Performance magazine. I did not realize the complexity. I thought just change the injector size till BLM around 128, and in PE mode look for O2's in the .875 - .900. Recalibrating the MAF was something I thought would not have to be done. I did check all my datalogs and found that the Pulse Width is not increasing as I was adding fuel. The only time I see an increase is when I call the injectors 22 lbs. instead of 26.03 lbs. for driveability. What does that tell me? I see numbers in the 7's and 8's on 26 lbs. and numbers in the 9's and 10's on 22 lbs.

 

Bruce's bark is worst than his bite (except when he bites). Bruce is great guy and I have always found him very helpful when I'v had a question or needed to confirm something. Between him and RBob, they are probably the two most knowledgable guys on the DIY Prom Board (though there are a number of other guys who now frequent the board and are extremely knowledgeable as well).

The "method" you are describing is about five years old when a Wideband was too expensive for the average guy to consider as part of his "tool kit". But today, with some of the affordable WBs, it REALLY is the only way to tune.

The WB has even spawned a completely different way to tune. Now, you just keep the engine in open-loop and tune everything for the AF ratio you want. This is especially popular with the SD guys and I've toying with doing this with my buddy's MAF car.

Just hang in there. It's not exactly computer science (well, a little).

 

He does know his stuff! I will research more on this new method. What does it mean if the Pulse Width is not increasing as I am adding more fuel to the table? Just when I call the injectors smaller than they are? Duty cycle being reached?

 

[QUOTE]Originally posted by Glenn91L98GTA
[B]And now you can finally begin REAL TUNING that 434 of yours. I got mine all torn apart and should have my cam & timing set this weekend. Now I just have to pry the WB from Keith's hands.


Hey Glenn, after we tune my car, I would be more than happy to mail mine to you whenever you need it. BTW, what have you been doing with your car? I should have known, if you are quiet, you are up to somthing! LOL.

 

Your pe vs rpm and pe vs coolant tables both look wacky. Adjust the pe vs coolant table to start at 20-22.7 at operating temp and use the pe vs rpm table to fine-tune the curve at the rpm needed. You need to get to a dyno to do this.

You can also set the cruise blm's by adjusting the inj constant, then change the 1st maf table's first 4 entries to adjust the idle blm's. Everybody does it different.