3FE computer questions (1 Viewer)

[PabloCruise]

I now have a 3FE that needs work.

It was driven 2-3 hours while the fuel pump block off plate was falling off and losing oil...

So I will need to go into this engine and rebuild.

I would like to put in an aftermarket cam and put a header on it.

My question - will the computer that Toyota put in the vehicle to run the 3FE FI be upset by these changes? I was thinking of a cam from Mark W.

https://forum.ih8mud.com/showthread.php?t=79962&highlight=cam

I asked the question over there, but I think the 40/55 forum is not used to discussing FI and computers.

Can anyone pipe up here?

Also, can a MegaSquirt computer be hooked up to the 3FE, or do I need to start putting a bunch of GM components on the 3FE?

TIA,

 

[Moby]

I spent a bunch of time trying to find an off the shelf cam that would work with the 3FE. Supposedly the part numbers are the same for a 2F and 3FE cam. The trouble is the computer. Downey, Man-a-Fre and Clifford all said their "rv" 2F cams would not work in a 3FE. However I couldn't get anyone to verify if they had actually tried it and had bad results or if they just didn't want to mess with it. The conventional wisdom is that the cam will physically fit (but nobody I talked to had ever tried it)

The trouble is how the computer would adapt to changes in the cam profile (think less vacuum but but more air actually entering the engine so the profile of the AFM is no longer accurate). It might be just fine (AFM based metering adapts better than MAF or speed density) but it might take custom programming to get it running right. Or maybe it appears to run fine but it leans out at certain rpms or worse under heavy throttle. However if you're thinking of running it with a different computer you're going to have to go through this process anyway.

If you do decide to go with a 2F cam or a custom profile please let us know how it goes.

 

[PabloCruise]

Thanks for chiming in Moby (BTW - good looking puppy dog!)

I talked to my friend who is a Toyota tech today - he thought the computer would do fine w/ RV cam and headers as long as the O2 sensors and air door are hooked up...

I'll post up as I know more.

 

[Moby]

That's excellent news! Let me know how it goes. I did run headers for awhile but finally gave up on them (bad leaks at the collector flanges). Top end was better with the headers (above 2000 or so) but they gave up some down low (enough to be noticeable but not terrible).

That's my dog Hunter, he's great, lots of energy and he loves my FJ62 (won't jump in to any of my other cars).

 

[Mark W]

There's a couple/three guys out there running cams they got from me (262 duration) in 3FEs. One is pretty much stock except for the cam and some added compression per my suggestion (about a .070 cut from the head). I don't know much about the other motors, but I understand that they are pretty much the saem thing.

The one I have closer contact with is a strong runner, noticably more so than when stock. The others I have only recieved very brief reports on, but these reports agreed with the first.
The ECUs have had no problem adjusting.

I'll be doing exactly the same to one I am building right now. Eventually it will get a reworked ECU, some work to the throttle plate and maybe some bigger injectors. But for now, just a cam, compression and freer flowing exhaust.


Mark...

 

[Spook50]

Since it'll be a long time before I can afford the 4BT conversion, I plan to try and pull as much power out of my 3FE as I possibly can. Once I have a break in the maintenence needed, finish my current projects and am able to spend some "fun" money, I'm going to get an entire new exhaust (including a set of headers) and try to source a used cylinder head that I can build for high performance (and up the compression a bit as well). I wonder if the 262 duration cam could be complimented well by larger valves and a shaved cylinder head? I've been debating on a bored out throttle body from Downey as well as cleaned and balanced injectors from C&C too.

Gonna be spendy, but at least I can spready that out over time

 

[PabloCruise]

The ECUs have had no problem adjusting.

I'll be doing exactly the same to one I am building right now. Eventually it will get a reworked ECU, some work to the throttle plate and maybe some bigger injectors. But for now, just a cam, compression and freer flowing exhaust.


Mark...

Thank you for weighing in sir!

Are you going to re-work a Toyota ECU? Or switch to megasquirt (or other)?

 

[PabloCruise]

Has anyone added headers to the 3FE at the same time as a cam?

Will 2F headers work?

Any recomendations? Or any vendors to avoid?

Thanks!

 

[Aseif007]

So are you saying that if you raise the compression on the 3FE to say 9.2:1 the 262° duration cam would compliment the raise in compression? What effect, if any, would that have on the pinging caused by the higher compression? I already have the higher compression and I just took off the MAF header so I could pass my inspection ( I have not had any flange leakage problems ). I am planning on installing one heat range cooler Denso plugs to slightly lower cylinder temps. I would be interested in a cam if it would give me any increase in usable power. I was told by Man a Free that my ECU would not be able to handle it. I took their word for it since I didn't want to experiment. I guess they were wrong ( AGAIN ).

There's a couple/three guys out there running cams they got from me (262 duration) in 3FEs. One is pretty much stock except for the cam and some added compression per my suggestion (about a .070 cut from the head). I don't know much about the other motors, but I understand that they are pretty much the saem thing.

The one I have closer contact with is a strong runner, noticably more so than when stock. The others I have only recieved very brief reports on, but these reports agreed with the first.
The ECUs have had no problem adjusting.

I'll be doing exactly the same to one I am building right now. Eventually it will get a reworked ECU, some work to the throttle plate and maybe some bigger injectors. But for now, just a cam, compression and freer flowing exhaust.


Mark...

 

[PabloCruise]

How did you like the MAF header for the 3FE?

 

[Moby]

Nice to see some real world experience, thanks Mark!

Here's the thing about the 2F cam vendors - everyone that I talked to (Downey and Clifford and some others) that said that the computer wouldn't compensate hadn't actually tried it. This is just from stuff that I've read (Hot Rod, Car Craft and EFI books - sources that usually do before and after dyno runs), no first hand experience, but a common pattern seems to be that most EFI systems respond OK to mild cam changes but respond even better with custom tuning to areas of the map where the computer is close but not perfect. Also, again just from stuff I've read, AFM based systems (flapper door air meters) tend to compensate the best for changes in cam duration and lift. So it's certainly possible that our EFI system would be fine with mild cam changes.

What I would be interested in (and what would be relatively easy) is before and after EGTs and A/F ratio from a wideband O2 sensor. It would be very easy to determine how the computer is compensating with these values.

 

[Aseif007]

How did you like the MAF header for the 3FE?

Honestly I didn't notice because I did most of the mods at once. But now that it is off I will pay attention to hoe the truck performs and see if I can notice any difference when it goes back on.

 

[Mark W]

So are you saying that if you raise the compression on the 3FE to say 9.2:1 the 262° duration cam would compliment the raise in compression? What effect, if any, would that have on the pinging caused by the higher compression? I already have the higher compression and I just took off the MAF header so I could pass my inspection ( I have not had any flange leakage problems ). I am planning on installing one heat range cooler Denso plugs to slightly lower cylinder temps. I would be interested in a cam if it would give me any increase in usable power. I was told by Man a Free that my ECU would not be able to handle it. I took their word for it since I didn't want to experiment. I guess they were wrong ( AGAIN ).

Higher compression and longer duration camshafts go hand in hand. I generally will not do one without the other.

I was just yesterday talking to one of the guys who is running this cam in a 3E with .070 off the head and nothing else done. Runs great and noticably more powerful. Actual experience shows that this is well within the abilities of the stock ECU to handle.


Mark...

 

[Mark W]

Has anyone added headers to the 3FE at the same time as a cam?

Will 2F headers work?

Any recomendations? Or any vendors to avoid?

Thanks!

2F headers will not work on a 3FE.


Mark...

 

[PabloCruise]

What I would be interested in (and what would be relatively easy) is before and after EGTs and A/F ratio from a wideband O2 sensor. It would be very easy to determine how the computer is compensating with these values.

Right you are - this would be very cool data to gather.

Unfortunately, I will not be able to do this, because ny before 3FE is not running all that well... Can anyone tell me what gets damaged on a 3FE that is driven while the fuel pump block-off plate is falling off? The engine was driven while losing oil until it stumbled and missed - about 2.5 hours.

 

[PabloCruise]

2F headers will not work on a 3FE.


Mark...

The 3FE headers I have seen look crazy (and the $400 price - oye!)

Why such a different exhaust header if the 2F and 3FE are so similar? Does the intake change things that much?

 

[Mark W]

That header is designed to mate up to the stock exhaust sytem. Twin head pipes going into two separate cats. The 2F headers are not expected to mate to the stock system (which is very different anyway.

The intake is different enough that the ehaders will not fit at that point. And the 3F block is significantly shorter which also affects the fit of the headers in the engine bay.


Mark...

 

[PabloCruise]

That header is designed to mate up to the stock exhaust sytem. Twin head pipes going into two separate cats. The 2F headers are not expected to mate to the stock system (which is very different anyway.

The intake is different enough that the ehaders will not fit at that point. And the 3F block is significantly shorter which also affects the fit of the headers in the engine bay.


Mark...

Thank you sir!

Is it worth it to try and run headers on a 3FE? Mine will go into a non-catalyst vehicle, so exhaust system will be custom.

Or is the 3FE manifold pretty good?

 

[Mark W]

I'm not convinced that there is a lot of gain between the stock exhgaust manifold on the 3FE and the header that is out there.

The 3FE manifold is in a completely different class than the 2F manifold. A good exhaust system from there back will make more difference.


Mark...

 

[PabloCruise]

I'm not convinced that there is a lot of gain between the stock exhgaust manifold on the 3FE and the header that is out there.

The 3FE manifold is in a completely different class than the 2F manifold. A good exhaust system from there back will make more difference.


Mark...

If my 3FE vehicle does not require cats, what size exhaust do people recomend for a cammed 3FE? (Single exhaust)

Thanks,