How To: Chipping a PR4 ECU

INFORMATION Articles / Teg Tips
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Backround: What chips are?
They control your air fuel mixture and revlimit.
What about chips on ebay?
They are copied chips from origional companies, Ex. Burned Cd’s
Whats the best chip for a LS?
I heard XS Engineering and PYR are among the best, i opted for PYR.

First off, you need to buy a ECU Chip, I got mine for 25 dollars shipped from a pretty good seller.

Next, you need a Desoldering Gun, I got one from radioshack for 10 Bucks

You are also going to need a 10mm Wrench to get to the ecu

You are also going to need a car, heh.

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To get to the ecu, dont be an idiot like me and think that the seat belt module was the ecu.


The ecu, and its buddy

Remove the ECU cover with the screws on top (straightfoward, no hidden screws or anything)

Heres a layout of the ECU, the chip is on the upper Left corner, it is highlighted by yellow.

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Heres the new chip next to old one, NOTE, every chip has a “Moon” Cut into the side of the chip, when you install it, make sure the moon cut is still facing the same direction!!! (Shown)

The process of Desoldering is putting the gun where the pins are one by one, meanwhile pressing the suction, when the solder melts, you release the suction, and it sucks it all up. Pretty dang easy! NOTE: Try not to leave it on too long, it might damage the Oem Chip

A good note while desoldering, When it looks physically removed (the solder) then it most likely is, a good way to test this is hold the whole ecu board up to the light, if the solder is removed, you’ll see light shining through the pins.

I had a hell of a time taking the stock chip out, it was all desoldered so i thought, what next? I tried pulling it out, and pushing it out the solder pins, no so safe…What i had to do was shove something beneith the chip so it can pop up, i looked all over the place and nothing would fit under the chip (too close to circuit board) BUT, i found my sisters hair clip, which looked perfect for the job, its thin and has a grove on it, so the more u stick it in, the chip poped right off!!

Pic of chip removed

Once chip is removed, its quite easy to solder, very easy actually. Solder the adapting chip onto it so u can switch programs.

Pic of finished Product

TEST DRIVE!!!
Right when i started it up, my car didnt studder at all. It fired right up and rumbled, pretty much amazed me at first. Make sure u let ur ecu set itself, cuz when i first got in i was revving it testing it out, it caused the motor to idle very oddly, bouncing up and down. This worried me but then i reset the ecu again, the right way. and it idled fine, although pretty high (1200) but i adjusted the idle control screw and it idles perfect now. On the throttle, i felt a big difference throughout the whole band, you can actually hear the difference, it sounds a lot more crisp and has a lot more punch to it. The redline for the PYR is 8900, although i will never take it that far, its just FYI. Overall i feel this was a great mod for its price, any novice i woulda say could accomplish it, all u need is a steady hand.

Any questions?
Email me at VNTEC@Hotmail.com
Hope you enjoyed the article!

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Repost, Sorry

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Cool write up. I just might try doing the install myself =0

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where did you get your chip?

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I got mine from eBay, pretty cheap!

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what seller? if you still have the name…thanks

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I got my chip from this guy http://cgi6.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewSellersOtherItems&userid=sileightyturbo

He sells pretty good products!

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although im not going with a premade chip (ghettodyne’ing my own), im glad you posted your experience cuz i saw that desolderer at the ratshack a few days ago and wondered if it would work cuz the tip looks kinda big. also ive been weary about doing my ecu as i have little experience and thought i’d need a lot more practice before going at it.

regarding the moon shaped dot on chips, i heard its not safe to assume that it designates pin1, it could be the opposite.

here is a thread discussing our ecu’s http://www.g2ic.com/forums/showthread.php?s=&threadid=8405

so you just install the chip only and dont need the resistors? i guess pr4 obd0 (90-91) doesnt, while pr4 obd1 (92-93) does.

afaik, auto and manual pr4’s have identical roms. i guess ill be the guinea pig for the auto.

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That method will only work on obd0 ECU’s. The obd1 ECU’s need the latching IC, resistor and jumper installed as well as the ROM.

Also, there are some things that you dont want to happen in the process of chipping an ECU like getting a cold solder joint or burning a copper contact on the PCB or having a sliver of solder jump two pins together.
I dont recommend anyone with little/no experience try to chip their own ECU. It may work, but at the same time it could cost you time and money to fix something that you may screw up.
I have a stack of ECU’s sitting in my room that people have tried chipping themselves and none of them work anymore because they screwed up bad. Makes a lot of extra work for me, fixing the damn things.

The auto and manual ROM’s are very different. You cant take one and put it in the other ECU without getting some weird side effects. The car may run, but it will do some weird shiz.

The “moon” as you guys are calling it faces the same way on every IC in the honda ECU’s (towards the plug). Honda engineers are perfectionists like that :slight_smile:

Decent write up though.

Later,
BR

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Yeah well the reason why the moon cuts are there is to determine the location of the #1 pin anyways, but following the mooncut itself will lead u to the right direction, thats why when u remove the chip theres a imprint of a chip with a “Cut” in it. As far as obd1’s, B R is right, the obd1’s require the resisters and bridging, as the obo0s simply change the roms itself. The obd1 has a way of switching to the stock program to the aftermarket program, using methods of the J1 bridging. dont worry though, doing a write up on my friends OBD1 P72 soon :slight_smile: ( already have mugen chip )

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Oh yea, another thing i wanted to add, installing this chip is pretty dang easy, its really straight foward if u followed the directions, all u really need is a steady hand :slight_smile:

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Nice, I might try this also. Or maybe I’ll just go to Jason’s next time I’m in seattle.

Ben

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Originally posted by B R
That method will only work on obd0 ECU’s. The obd1 ECU’s need the latching IC, resistor and jumper installed as well as the ROM.
Later,
BR

Originally posted by VNTEC
As far as obd1’s, B R is right, the obd1’s require the resisters and bridging, as the obo0s simply change the roms itself. The obd1 has a way of switching to the stock program to the aftermarket program, using methods of the J1 bridging.
Not always true guys. I’ve done some OBD-I ECU’s that don’t require the latching IC, resistor nor jumper. This is the case when there is an EPROM already installed at location 27256 on the board by Honda - as was the case with my own P61.

It’s the presence of a chip at 27256 that determines whether or not you have to install the extra latching IC, resistor and jumper, not the OBD of the ECU.

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Originally posted by Ive
[B]Not always true guys. I’ve done some OBD-I ECU’s that don’t require the latching IC, resistor nor jumper. This is the case when there is an EPROM already installed at location 27256 on the board by Honda - as was the case with my own P61.

It’s the presence of a chip at 27256 that determines whether or not you have to install the extra latching IC, resistor and jumper, not the OBD of the ECU. [/B]
Very true, Ive. Tony’s P61 was the same way when I chipped it for him. He already have everything there. Made it a lot easier on me, and he left a happy camper :smiley:

Later,
BR

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oh man i had a hard time chipping mine today. first obstacle was figuring out the best technique to suck the solder out. i cant tell you where to start so ill just tell you how mine came along.

i first started on an old sound card. it was cake. sucked it out, resoldered, perfect. now on to the chip. the pins are bent inward so you cant just set the iron on perpindicular to the pin. the only way to get at it is if you set it at a 90* angle from the base of the pin. it takes some practice and i can do it somewhat ok but at that point i just bent the pins vertically which made it a lot easier. just place the tip over the pin as if hammering it and release.

ok so the pins are dry and you pull it right out. wrong. i noticed the topside (other side of board) of the pins have some solder still there. desoldering braid didnt help much. ok lets try cutting the pins and rip the chip off first. hm. i heard a tip about modifying some nail clippers to snip each pin. didnt work well, too tight down there. eventually i found that wiggling the crap out of each pin helped release it. a little more heat helps too. oh ya, and it looks like honda used glue to hold them suckers down, either that or its just resin i dunno.

now the next few hours i spent having a heart attack cuz i got a code 1 (ecu) and i thought i killed it. i rechecked all the leads, plugged the stocker back in (albeit beaten and ripped apart so i had to resolder some legs on) and finally found out i didnt solder the socket in well. first of all solder didnt drip down to the other side at first. second, i didnt bend ALL the pins inward like honda did. well after that she fired up fine.
so i wonder how i can improve my soldering technique and what exactly made it work the 3rd time around. im still not good with determining when to clean or re-tin, and why halfway through the iron didnt seem to heat as quickly even after resanding and tinning it. in order for the solder to go through to the other side, i had to leave the iron on each pin for like 3-5seconds (way too long?). good thing its just an empty socket…

so i installed a g-force engineering chip for pr4 obd0, 7500 rev limit, courtesy member RaM. supposedly its for automatics, but wtf is the rev limit for? it shifts the same for me. noticed a gain at 3500, then at 5500. not bad. however when decelerating off the throttle i feel a tugging. probably has to do with my 450cc’s and maphack. also im advanced to 18*. i should probably set it back to stock (nahh). intake temp was 68F tonite.

once i get this burner working ill upload a bin of the chip :stuck_out_tongue:

90 pr4 obd0 automatic

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Haha,sorry about ur experience bro, i forgot to mention that… Yes they are bent inwards!! but what i did while heating the solder, is i bent it back using the desoldering tip, pretty easy, then at the same time sucked it up… It was pretty easy :frowning:

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np, this is something i had to do anyways. i guess overall for a person with little to no soldering experience i would rate this as a 7 on the difficulty scale. if you have any qualms about the whole procedure, it would probably be wise to just pay someone the 30-50bucks to do it for you. shops charge like 100 i think.

fyi many experienced people advise to have someone do it also. i already knew this before diving in, i just needed that extra push :stuck_out_tongue:

everything has been running great. readjusted the idle and maphack for my 450’s and that seemed to have eliminated the code 12 (egr) i was getting.

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any change in gas mileage when switching to one of these EBAY chips?

also, could someone get an old ECU from a Junkyard car and solder a new chip in…and then just swap out the old ECU with no problems?