Tuning for 25lb injectors
Printed From: West Coast Fieros
Category: Technical Topics Forum
Forum Name: Technical Questions and Discussions
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URL: http://www.westcoastfieros.com/forum/forum_posts.asp?TID=1840
Printed Date: 24 April 2025 at 11:34am
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Topic: Tuning for 25lb injectors
Posted By: CFoss
Subject: Tuning for 25lb injectors
Date Posted: 06 May 2010 at 3:08pm
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Hi all. I've started to prepare a bin file for my engine with the new manifold and 25lb injectors. Initially, I'm modifying a bin for an 86 4speed, 15inch wheels, federal. I'm going to tune with the stock ecm for now, then move to a 1227170 with $58 later when I add the turbo. I deleted the egr, so the first change was to disable the diagnostics switch, and then in the constants, move the egr enable coolant temp to maximum, or about 151deg C, which means it will never enable. Second, with the 25lb injector upgrade from the original 14.6, I changed the BPC to 159 (This is based on 224*14.6/25*3.4/2.8) This changes the base pulse width for the new injectors and also takes into account the increase in displacement from 2.8 to 3.4L.
I adjusted the fuel cuttoff to 6500rpm, and the regain to 5500rpm for a little extra high end room.
I changed the shift light enable to 5600rpm for all tps settings so it acts like a red line warning light.
I'll have to fine tune these settings and the ve table and the pe tables, but it's a start. Any advice is welcome! Chay ------------- 86 SE 3.4 |
Replies:
Posted By: CFoss
Date Posted: 06 May 2010 at 3:09pm
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I think I'm going to move to a 1227730...the faster better one anyway...
Chay ------------- 86 SE 3.4 |
Posted By: Dr.Fiero
Date Posted: 06 May 2010 at 3:58pm
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If you're going to change the ECM later - why waste time on this one? You just get to do all your work over. And... it's going to be a LOT of work. I've been in your shoes. But if you insist... Remember to disable closed loop operation (set the enable temp to 300F or whatever) when you're out driving around data logging. Disable PE (if you enabled it!) or you'll never know if you're rich from that or something else. You DO have a data logable wideband on this right? If not - get one. You'll just be chasing your tail for years otherwise. Oh yeah... shoot for about 12.5:1 everywhere off idle that you want to make power. 14.7 is only for idle really (well, around it). You might find you miss fire at stoich anyhow. |
Posted By: CFoss
Date Posted: 06 May 2010 at 8:09pm
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Why waste time on this one? I've been thinking the same thing. My rational is this: I'm changing so much stuff that the more I can keep constant the better. I was toying with running the original injectors and tuning them, but I'm making the bold move to run the bigger ones now. Yeah, it will be a lot of work. That's ok, this is a project car. I feel like I need to do do some tuning to get it out of my system. I have a wideband/logger wired for map, rpm, tps and o2(of course). Good tip on the pe. I guess set up the pe thresh to 100% tps and it will be out of the way. Why disable closed loop though? I guess you could go open loop and tune bpc first, then enable closed loop and use the blms to tune the ve? The use the wideband again for pe? Chay Good tips. ------------- 86 SE 3.4 |
Posted By: Dr.Fiero
Date Posted: 06 May 2010 at 9:10pm
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Disable closed loop, so you can see what the ECM is "really" spitting out for fueling, without it trying to correct itself. I don't really tune by BLM's initially anyhow. I just go off the wideband, watching the graphs - then I'll tweek the tables. When the graph smooths out and isn't going crazy, then go look at the BLM's. I still wouldn't count on them really though. They're being fed by the narrow band (of course!) which is only accurate from about 14.5 to 14.9:1. Since your 'real' power is in the 12.5:1 area, the BLM's are kind of useless. |
Posted By: CFoss
Date Posted: 07 May 2010 at 8:49am
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Good point. BLMs for cruise if you want, but anything power, use the wideband. Makes sense.
May as well just use the wideband for everything eh? I guess that's what it's for anyway!
C ------------- 86 SE 3.4 |
Posted By: Dr.Fiero
Date Posted: 07 May 2010 at 9:00am
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That's what I was doing. I didn't even have a narrow band installed - just used the simulated NB output of the WB (purely to keep the ECM content). |
Posted By: CFoss
Date Posted: 07 May 2010 at 9:47pm
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After reading ALL the info, I have to give $59 a shot. I have a LOT of reading to do. Some of the info crosses over, some does not. It will sure be a learning process. Chay ------------- 86 SE 3.4 |
Posted By: CFoss
Date Posted: 08 May 2010 at 12:45pm
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Ok, another other approach. I'm changing back to the original ecm idea, but using the original injectors. This way I can prove out my manifold somewhat before I move to the big injectors. I think this is a prudent step in case there is difficulty with the intake manifold. Chay ------------- 86 SE 3.4 |
Posted By: Dr.Fiero
Date Posted: 08 May 2010 at 1:10pm
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Do you have a ROMulator? Makes all the tuning about 1000X easier. I modded a couple of my spare ECM's by ripping out the factory PROM socket, and replacing it with a ZIF. Now I can just easily slip in/on my ROMulator. Plug it into the laptop, and I can realtime make changes (some require stopping, and power cycling the ECM - big whoop). When I got a chunk of code I was happy with, I'd save the BIN file that I was running, and burn it to a chip (few times I just left the emulator installed for months at a time and said screw the burn). http://secure.transtronics.com/osc/product_info.php/cPath/56/products_id/329 - Link to the device: |
Posted By: CFoss
Date Posted: 11 May 2010 at 7:29pm
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Will it emulate the 2732/2732A. I guess I should look at the link eh? I bought 3-4 flash chips for the 7730, but I'm having a hard time finding 2732/2732As for the 7170. Anyone got a 286??? Apparently they were common in there. I tried digikey, jdm and newark with no luck. Chay ------------- 86 SE 3.4 |
Posted By: CFoss
Date Posted: 11 May 2010 at 7:31pm
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Looks really good, but $250 is a bit steep for me right now. It's a good price for the tool, just a bit outside what I want to spend right now. I gotta find some cheap 2732s. Chay ------------- 86 SE 3.4 |
Posted By: Dr.Fiero
Date Posted: 11 May 2010 at 7:49pm
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Uhhh, yeah... good luck on the 2732's! About 8 years ago when I lucked out and found my last NEW batch (from a guy in England!), they were just starting to turn into unobtanium. Can't imagine now! You can use larger ones that are easier to find, like the 27256's. I think you just snip off 4 pins, and then start the write sequence from a different offset. |
Posted By: Dawg
Date Posted: 11 May 2010 at 11:42pm
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Would there be one in a duke computer? DG
------------- You dream it up....I'll make it |
Dr.Fiero wrote:Posted By: Dr.Fiero
Date Posted: 12 May 2010 at 6:42am
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There would probably be a 2732 in a duke ECM. Problem is, a LOT of them are PROM's, not EPROMS's. So - you can't erase them to reflash them. If they have a small square sticker on them, they're the erasable flavour. That's not to say that you'd ever get a solid erase out of them to make them writable. Some just refuse to cooperate. |
Posted By: CFoss
Date Posted: 12 May 2010 at 8:49am
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I do have professional tools for eprom, eeprom and flashprom, so I can give it a try anyway. ------------- 86 SE 3.4 |
Posted By: Dawg
Date Posted: 12 May 2010 at 10:19am
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The computer in the strip down car is of no use to Rob because he's got an 87. Lets pop it open on the day and if it's got the needed chip we'll just take it. Stubborn chip you say? That's when you get out the 500W UV light and the egg timer....hehehe DG
------------- You dream it up....I'll make it |
Posted By: CFoss
Date Posted: 12 May 2010 at 10:30am
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I'd sure apreciate that.
There is a 99% chance the right chip is in there. It should be the large one under the removable piece on the ecm if it's like mine. It may be in a plastic 'carrier'.
16032500 or something similar.
Ok, the chip should have a label on it (On the window) which may have a 4 letter designation for the tune it has...can't remember the designation for fiero, but some other are AUJP etc.
Thanks again,
Chay ------------- 86 SE 3.4 |
Posted By: Dr.Fiero
Date Posted: 12 May 2010 at 11:24am
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And for those of you 'playing along' that may be unclear on some of the concepts.. This is a non-reusable PROM:  This is a carrier:  As is this:  (but that's a different kind!)  An inverted carrier with PROM in it:  Aaaaaand a portion of the piles of non co-operative EPROM's, or ones I've not got around to checking:  (you can see the little window in the one on the bottom left corner - those are the EPROMS) |