enigo

This is just a compilation of all the information on 1.8 ECUs, these are the correct serial numbers. Didn't know where to put it, so I just dropped it in the DIY.

Important;

The Good:
39110-23940 is a 1.8 ECU Rev B

The Bad:
39110-23930 is a 2.0 ECU Rev B
39110-23910 is a 2.0 ECU Rev A
39150-23920 is a 1.8 ECU Rev A

The Questionable:
39100-23940 is a 1.8 ECU Rev ?

Person had a problem with this ECU type, it was never confirmed whether it was the ECU or something else. If someone is using the 39100-23940 and knows it works, please post! Otherwise, assume that the 39100 is bad.



Make sure your serial is read from the Green Box. The serial in the Red Box is always going to be 39100-23940 even for 39110s.

Where to get 1.8 ECUs? Ebay, car-parts.com, members on here...

One on ebay for $60 shipped: Link

Its a laborious process to get the old ECU out and swap it, here is a post by that will help:

From StrikeEagle:



First thing is to get the big plug out. It really limits movement if you have the other bolts off, and can be hard to get off later. There’s a metal bracket that locks the plug into the ECU, circled in blue. Lift on the left side of the bracket as far as you can, and then pull out the right side of the plug. It should come a ways, the left side of the plug will eventually come out if you’ve pulled it far enough on the right. The left side is hooked in there until it’s been bent far enough out, then it slides right just a hair and comes out.
I think there’s some sort of zip tie holding down some wires, possibly the main ECU plug that really gets in the way. Cut it, it’s not necessary at all.
Once the plug is out, unbolt the 2 big bolts circled in red. These hold the main brace that holds the ECU in place. I think they’re 12mm bolts, but possibly 14. The ECU and brace will be somewhat free to move, but you’re far from finished. The ECU itself is held in place with another bracket on top of it, and all bolted to the bottom brace (4 bolts, 2 are circled in yellow, the other 2 aren’t visible, over on the left side. You can’t pull the entire thing out as there’s also a stack of relays or something on top of it that you can’t access at all. You’re probably confused by this point, but it is not too complicated… Basically, 3 parts â€â€œ the top bracket (with the relays stuck on top), the ECU (bolted in to both brackets) and the bottom brace that holds it to the car.
At this point, you should have the bottom bracket loose from the car and the plug out. All you need to do now is unbolt the 4 bolts that hold both brackets and ECU together. 2 bolts are circled in yellow, take them out first. Then comes the tricky part, getting at the matching two on the other side… You need to play around with the whole setup and try to get it rotated so the hidden left side is facing downwards to the floor (the right side up towards the engine bay). It’ll take a bit of doing, but you just need to get it far enough so you can access the 2 remaining bolts. In essence, you’re trying to turn it all so the bolts circled in red are where the ones in yellow are.
Once you have all the 4 bolts out, the ECU will probably fall on your head, so watch out…
Installation is pretty much reverse, but a little more frustrating. Keep the other brackets pretty much where they were, and slide the ECU between the brackets how it’s supposed to fit. Bolt in the left side, then play with it to get it back in place, and you can bolt in the right side again. Once they’re all in, maneuver it back in place and put in the 2 big ones holding the bottom brace to the car. Last of all, plug in the big ECU plug.
And stretch.
This probably sounds terribly complicated, but once you’re in there, you’ll understand better. I did find it somewhat useful to take off the fuse box cover so I wouldn’t lose any bolts behind it. If you can’t figure out how to take that off, you shouldn’t be taking out your ECU!

Why should you do this?

Well... I'll leave the technical explanation to someone else. Simply it increases your mpg, throttle response, and is an upgrade especially for Rev As. Without a doubt, the best bang for your buck and easy to do!

Tibbychick

This is just the info I've been looking for. Definetly a big help. Thanks.

Caj Darkmoon

Missing info: where it's located smile.gif

mr_jeckel

I'm running the 39150-23920 1.8 ECU in my 2001 and have no problems. Car runs better in the upper RPM range, but feels slightly less torquey (is that a word?) downstairs, though.

Also, you left out a couple other ECU's.

39110-23956 2.0 ECU
39110-23931 2.0 ECU
39110-23934 2.0 ECU
39110-23931 2.0 ECU (Canada)

It is also worth mentioning that the 39110-23940 1.8 ECU can only be found in the Elantra's from 08/16/1997 - 08/16/1998. I could not locate the part 39100-23940 from the 97-01 Tiburon's and the 97-98 1.8 Elantra's. All my information comes from Hyundai's Parts Website.

Good job of describing the install! I thought it was challenging, considering the small work area...

gsasha1

combining it with the 1.8 intake cam?

TopSpeedFX

Good info man! Also its a great compliment if you've got the 1.8cam

REDZMAN

That picture showing the bracket on the harness, you should turn it sideways.

Also, a couple of helpful hints.

1. To get to the bolts easier on the left side, remove the plastic cover that covers the drivers side fuse box near your left foot. Then remove the bolts (2) that hold the FUSE BLOCK to the side wall. Should make it much easier.

2. When you put the thing back together with the new ECU, only put in 3 bolts. Do NOT bother waisting time for the PITA one on the top left, you just don't need it.

enigo

Heh, good add in information!

Where is it located? Doh, missed that one! To find your ECU, grab a flashlight, open you drivers side door and put your head where your brake pedal is, and look up. You'll see everything right there.

For me, things seemed slightly different. After removing 3 bolts, the ECU dropped on my head... The bracket holding the ECU wasn't secured to anything beyond the 2 bolts you remove in the first place (red outline in picture). What was holding it there was the bracket holding the relay boxes. So after I removed the bolts holding the relay bracket, it dropped out.

I then attached the 2 rear bolts, and pushed the 1.8 ECU back up into the mess until I could attach the relay bracket.

I also found that I could remove a bolt to the right of the ECU that was holding another metal box, which would move around slightly, giving me enough room to maneuver a socket or wrench to tighten/loosen the bolts.

For me the biggest PITA was bolt #3 when removing before it dropped on my head, and bolt #4 (which was the same bolt at #3)... took me probably 20-30 min on these since I couldn't get the socket in there, and had to use a wrench with something like 15-20 degrees of rotation mad.gif

As far as the 1.8 intake camshaft: I'm planning to that soon as I can pick one up from a yard...

Concerning the extra ECU numbers: Thats good! All the ones that I've looked out have been on car-part.com and ebay. The ECUs that you listed I'm quite sure are from 2.0 ECUs that are after 1999. After that, there was no difference between the 1.8 and 2.0 So you could only get the 1.8 Rev B ECU from a 1998 Elantra or Tib. And about half the Tibs produced in 1998 were Rev A, which is of no use. 1997 and before Elantras also were Rev A.

39150-23920 might be the 1.8 Rev B from the Tiburons. Which opens up some more possibilities for people.

The 39100-23940 is the most abundant at the moment (just search car-parts.com). I'm not sure where it fits in, and I would be questionable of it till someone else tries it and has no problems with it. I know for sure the 39110-23940 works, so thats the one I suggest!

zoned019

Has anyone actually confirmed that the non Rev-A ECU's will work in a Rev-A car? And show gains?

enigo

TopSpeedFX and I are both Rev A and have done this swap. Look at our Tiburon Years mate smile.gif 1997 = Rev A

We've both shown gains.

<div class='quotetop'>QUOTE (mr_jeckel @ Apr 19 2007, 01:06 PM) <{POST_SNAPBACK}></div><div class='quotemain'>I'm running the 39150-23920 1.8 ECU in my 2001 and have no problems. Car runs better in the upper RPM range, but feels slightly less torquey (is that a word?) downstairs, though.</div>

Errr.... Just noticed that you said you were running the Rev A 1.8 , while its a slight improvement from 2.0, its not as good as Rev B 1.8 I didn't look closely so I thought you were talking about an ECU from a Rev B 1.8 from the Tiburon. Not sure how the part lists would handle this since it swaps mid year or so...\

As I understand, people have tried Rev A 1.8s and found them inferior to Rev Bs, so you might want to try and pick one up!