2.4l to 2.7l conversion. ECU reprogram required?

Hey everyone. So obviously I'm new here, thanks for any help/advice you may have to offer. I have a 1997 2.4l 2wd 5 speed manual that recently had a catastrophic engine malfunction with the engine that came stock with my truck, apparently the previous owners were not taking very good care of her based on the internal inspections, and I decided to upgrade to the 2.7l 3rzfe for a tad bit more power. Had to replace the fuel injectors and the spark plugs, but everything else seems to be compatible. However, I've been noticing a bit of hesitation and an occasional half-fire. Does anyone know if I have to have the ECU reprogrammed for the fuel-air ratios or do I have to find a new ecu?

 

I forgot to add, the transmission has been having a bit of trouble with 1st, 2nd, and 4th gear since I got it, which is probably synchros and the shifter bushings, but I'm trying to figure out if it would be better to rebuild the current tranny or swap it out for something different.

 

As for the ECU, I'm not sure if they are the same unit between the 2.4 and 2.7 but they absolutely would have different software. The easiest thing to do would be to replace the ECU with the one from a similar truck with the same engine.

As for the transmission - not enough info.

If it worked before the engine swap and now has problems with shifting between all of the gears, that sounds more like a clutch problem than a transmission problem. It's unlikely that all of the syncros went bad at the same time.
If the transmission had that problem before the swap it could be a clutch issue OR it could be all the synchronizers.
If the vehicle was abused before you got it, the transmission was abused along with everything else.

As for repairing verses swapping transmissions - unless you really can't get another transmission, it's almost always cheaper to swap the entire unit.
There are a handful of guys and gals that know how to properly rebuild transmissions (manuals and automatics) and the odds of finding one of those people are not good. PLUS, the time it takes to pull the transmission, rebuild it and re-install it is far longer than the time it takes to just swap one out. The labor costs alone to rebuild a transmission will often exceed the cost of the transmission. If you can do the work yourself, and transmissions are not a good first time DIY project, you will still be without a truck for a considerable period of time.

SO, your options are:
New transmission (very expensive but you know what you are getting)
Rebuilt transmission (less expensive and generally comes with a guarantee)
Used transmission ( generally the least expensive route but you don't always know what you are getting)

The 4th option is to replace the transmission and keep the old one. Rebuild the old one at your convenience and keep it as a spare or sell it.

 

And BTW, Toyota manual transmissions are pretty tough. So you at least have a decent chance of finding a good used one.

 

I did a bit of research on the ecus beforehand and the programming is definitely different to accommodate for the stroke and intake differences. Just had a heck of a hard time finding one for that year, and was trying to see if the 2.4s is flashable or reprogrammable.
About the transmission, i forgot to state that it was causing trouble before the engine failed and I have the clutch replaced with the engine swap. Also had the fluid flushed at that time. My concern was mainly if the gear ratios that we're designed for the high revving 2.4l we're a good match up for the 2.7l and was worth the rebuild. Maybe a different gear set up with a rebuild?

 

I thought the transmission was the same 2RZ vs. 3RZ, W-59. As far as the sloppy shifting, you sure it isn't something simple like the shifter seat, or the socket? See https://www.marlincrawler.com/transmission/shifter-parts/heavy-duty-seats

As far as the engine issue, try cleaning the MAF. I believe there is a special spray for that.

 

Is the w59 in the 4wd model too? Ya know what, I didn't even look into that. As for the sloppy shifting, I had the shop look into it and they were the ones who suggested the rebuild

 

Yep. Not to state the obvious, but the only difference is the tail housing that supports the transfer case.

 

Thanks for posting this up, been searching for one of these for a 6speed FJ cruiser with a sloppy shifter

 

Marlin is also the man for a rebuilt transmission. Just don't be in a hurry (months!), and you will get what you pay for. But, I can guarantee when you get the transmission it will be about as brand-new as it could be. His transmissions are so pretty you might want to make a coffee table out of them.

 

The W59 is in the 4 banger 4WD's? I thought all 4WD's came with the R150F?!

 

R150F is behind the V6 engines (3VZ-E and 5VZ-FE). See Marlin's table here: https://www.marlincrawler.com/transmission/rebuilt-complete

 

I knew it was behind the V6's but thought even the 4cyl 4WD's had it. Huh.

 

Don't quote me, but I believe Gen2 Tacoma use a R-series transmission (R155F? & RA60F) behind both the 2TR and the 1GR engines. I know because the 2TR bellhousing can be used to bolt a R-series transmission to a 2RZ/3RZ.

 

It's good to hear that it's the same, at least that rules out a mandatory swap. As for waiting months for a rebuild, that's out of the question for the time being. It's my only vehicle at the moment. But that's not a bad price for a rebuild

 

Yeah the 2nd gen V6's use thr RA60 and the 3rd gens use the RA61 for sure.

Unfamiliar with the R155.

I know the R151 is about the strongest tranny Toyota ever used though. That was in the Turbo trucks of the 80's. Way over built. I believe they used them in the MKIV Supra as well.

 

:lightbulb: There's an idea for the OP. Get a boneyard transmission from a 4-cyl 2WD Gen2 Tacoma with bellhousing. You not only get a newer transmission, but you upgrade to a R-series. Since you are 2WD I'm willing to bet it's a straight bolt in .. assuming the shifters and crossmember line up. Want to be the first guinea pig?

 

The R155 is the 5-speed used in Gen2 Tacomas. The RA60 is the 6-speed. The tranny pic I showed is a R151F, currently residing in my truck, soon to be behind my 3RZ.

 

I'll have to look into whether it bolts in or not, but I'm definitely game fur an r-series set up

Only problem is finding anything local at the junkyard. All of the tacomas get bought within days of them hitting the yard

 

Look regional. Search here. http://www.car-part.com/