In This Thread Rootbeer Answers Your Automotive Questions

[Rootbeer]

Why? Good question.

The project has a dramatic backstory and I'm a sucker for that stuff.

The 3 liter Toyota engine is ridiculously robust but also ridiculously underpowered. I don't know of any engine its size that gets worse fuel economy while at the same time failing to get out of its own way. My 7.5L F250 gets similar fuel economy to a 1990 4Runner.

The 3.4L engine was a huge leap forward in power and economy. But with the new engine Toyota changed the chassis and some Toyotaphiles don't like it. They want the old chassis with the new engine.

With that foundation, let me tell you about this customer. He and his son spent a lot of time offroading and hunting in this rig. It was their thing, their bonding time. One day they were in the hills and the engine died. Dude didn't go into details but I'm guessing he ran it out of oil. They get towed off the mountain and decide if they gotta drop an engine in this thing, why not drop the big motor in it and tear up trails with MOAR POWAH?

The Yoda is at a shop getting the bigger engine installed when dude's kid has an accident and gets paralyzed from the waist down. The engine upgrade goes from a "yee yee wuddnt that be cool?" to a passion project for dad and son to relive happier times tearing up hillsides and chasing wild game.

I'm a sucker for this kind of thing. I enjoy challenges and I like that this could bring some joy into this kid's life.

[StrawMan]

Sounds like a worthwhile project, Rootbeer. Glad you can help that family out.

For an engine swap like this project do you make your own wiring harnesses or do you go to a specialist like Aeromotive dot us? Would an LKQ complete harness from a boneyard 3.4 help out? How 'bout a gauge cluster or gauges from a 3.4?

I'll be interested to read how you solve this puzzle. Please keep posting updates.

You have a long list of variables to juggle on this one, but I'm taking the under.

Under 60 Days

[Roach]

Over and over. Because I expect you will insist on doing it right, no shortcuts.

[Rootbeer]

Got deeper into this thing. I'm up to 17 unplugged electrical connectors with no home. EGR, EVAP, and CRUISE are all missing components so that'll account for some of them. Looks like this harness is from an automatic transmission chassis and this thing has been converted to a manual transmission. Several of my connectors will be relevant to the speed sensors on an automatic. I think that leaves me with 6 connectors to be concerned about.

The throttle position sensor doesn't match the connector for some reason. Supposedly this harness is from a 3.4L engine but if it don't fit, it don't fit. If I get a TPS that matches the connector it won't work because that sensor is meant to articulate clockwise rather than counter-clockwise so I'm going to try swapping pins to a new connector.

Biggest concern right now: I'm not sure this PCM is going to work. Spark control is completely different. The 3.0 has a distributor but the 3.4 is coil over plug, with 3 coils on a waste spark ignition system. The 3.4L coils get their command from the igniter, the igniter gets its command from the PCM and the PCM takes reference signals from the cam and crank sensors. The 3.0 reads cam and crank position within the distributor, sends those signals to the PCM, the PCM calculates spark advance and sends a command to the ignition coil and from there the spark is directed to the desired cylinder mechanically using the distributor rotor and cap. I don't see how the 3.0 PCM is capable of sending a signal that directs the igniter to spark a certain coil. It only knows how to drive one coil, not three. I've been thinking about it all day and pouring over wiring diagrams. I just don't see it working unless there is something I don't know. Maybe the PCM is smarter than I'm giving it credit for but I'll try and cross that bridge later. I have 6 connectors to figure out first.

[scotchnh2o]

ENGLISH...do you speak it!

[mvscal]

Got deeper into this thing. I'm up to 17 unplugged electrical connectors with no home. EGR, EVAP, and CRUISE are all missing components so that'll account for some of them. Looks like this harness is from an automatic transmission chassis and this thing has been converted to a manual transmission. Several of my connectors will be relevant to the speed sensors on an automatic. I think that leaves me with 6 connectors to be concerned about.

The throttle position sensor doesn't match the connector for some reason. Supposedly this harness is from a 3.4L engine but if it don't fit, it don't fit. If I get a TPS that matches the connector it won't work because that sensor is meant to articulate clockwise rather than counter-clockwise so I'm going to try swapping pins to a new connector.

Biggest concern right now: I'm not sure this PCM is going to work. Spark control is completely different. The 3.0 has a distributor but the 3.4 is coil over plug, with 3 coils on a waste spark ignition system. The 3.4L coils get their command from the igniter, the igniter gets its command from the PCM and the PCM takes reference signals from the cam and crank sensors. The 3.0 reads cam and crank position within the distributor, sends those signals to the PCM, the PCM calculates spark advance and sends a command to the ignition coil and from there the spark is directed to the desired cylinder mechanically using the distributor rotor and cap. I don't see how the 3.0 PCM is capable of sending a signal that directs the igniter to spark a certain coil. It only knows how to drive one coil, not three. I've been thinking about it all day and pouring over wiring diagrams. I just don't see it working unless there is something I don't know. Maybe the PCM is smarter than I'm giving it credit for but I'll try and cross that bridge later. I have 6 connectors to figure out first.

You should check the bypass line to the 7th Fetzer valve. It's all ball bearings these days, you know.

[StrawMan]

Got deeper into this thing. I'm up to 17 unplugged electrical connectors with no home. EGR, EVAP, and CRUISE are all missing components so that'll account for some of them. Looks like this harness is from an automatic transmission chassis and this thing has been converted to a manual transmission. Several of my connectors will be relevant to the speed sensors on an automatic. I think that leaves me with 6 connectors to be concerned about.

The throttle position sensor doesn't match the connector for some reason. Supposedly this harness is from a 3.4L engine but if it don't fit, it don't fit. If I get a TPS that matches the connector it won't work because that sensor is meant to articulate clockwise rather than counter-clockwise so I'm going to try swapping pins to a new connector.

Biggest concern right now: I'm not sure this PCM is going to work. Spark control is completely different. The 3.0 has a distributor but the 3.4 is coil over plug, with 3 coils on a waste spark ignition system. The 3.4L coils get their command from the igniter, the igniter gets its command from the PCM and the PCM takes reference signals from the cam and crank sensors. The 3.0 reads cam and crank position within the distributor, sends those signals to the PCM, the PCM calculates spark advance and sends a command to the ignition coil and from there the spark is directed to the desired cylinder mechanically using the distributor rotor and cap. I don't see how the 3.0 PCM is capable of sending a signal that directs the igniter to spark a certain coil. It only knows how to drive one coil, not three. I've been thinking about it all day and pouring over wiring diagrams. I just don't see it working unless there is something I don't know. Maybe the PCM is smarter than I'm giving it credit for but I'll try and cross that bridge later. I have 6 connectors to figure out first.

I’ll be the first to admit I’m not an engine expert, but I did stay at a Holi… ah geez… never mind.

Seriously Rootbeer, my expertise is in the collision repair industry, NOT mechanical repairs. But I easily get fixated on diagnosing and solving problems. That’s my thing. Winston Friggin’ Wolf – I fix shit. I ran into a ton of mech stuff as part of collision and comp repairs over 40+ yrs, and I do all my own restoration & repairs on my small fleet of turds [including a ’93 Toyo 3.0L Pickup].

All that irrelevance said, are you sure some LKQ parts from an actual 3.4L vehicle doesn’t get you anywhere? I know labor is more profitable than parts are, but that doesn’t seem to be the driver on this ticket. You’ve got a generous budget, so I’d think that a complete wiring harness, gauges, and maybe a LKQ or Reman PCM from a 3.4L would take you a LONG way.

Also, I’m sure you’ve heard of LC Engineering [lceperformance dot com]. They have a ton of useful Toyota repair & engine swap parts. You mentioned your EGR system has been ‘worked on’. LCE makes an excellent EGR Delete kit. Or you can fabricate your own plates.

Again, I’m very interested to hear how you solve this puzzle. Find those 6 connectors!

Still taking under 60 days.

[Go Coogs']

[quote="The Whistle Is Screaming]Del Boca Vista[/quote]

Jerry Stiller would like a word with you.


Sent from my iPhone using Tapatalk

[Rootbeer]

UPDATE

I took the winter off from this job. Reset the over/under, please.

Current tasks include:
Build a battery tray and mount it to the driver's side where the air box sits in a 3.0.
Build a mount for the air box on the passenger side.
Relocate the washer fluid reservoir or engineer a workaround where the air box and reservoir can live in harmony.
Relocate the coolant reservoir because the battery now lives in the reservoir's home.
Had to remove the alternator to properly route electrical down the side of the block.
Gotta build new battery cables once the battery tray is installed.

My prior concern about the igniter is moot. I found out a prior shop installed a PCM from a 1997 so that should work for engine electronics. Not sure about interior electronics yet.

[Rootbeer]

IT RUNS!

Still have lots of hurdles to cross but I got this alamgamation to start and run!

l to r: Disjointed mess of Toyota parts, me

[StrawMan]

Excellent! How in the hell did you get the wiring harnesses working together and speaking to the 3.4L's ECU?

So what's left on your punch list? Did you fab all your brackets for relocating components? Gauges working?

You warned me to take the over. Haven't forgotten... nice job.