3FE Conversion Write-Up

[elripster]

I haven't updated in a while. The big news is my truck is running and I'm off to the smog ref Thursday the 15th at 1PM. Wish me luck.

Remaining items are...
- Adjust the valves... yes I should do this before the ref and will if it fails but I just don't have time and I really want to get at least a first run so I have time to fix any issues that spring up before the end of the month.
- Reset timing after valve adjustment.
- Figure out what to do about the oil pressure gauge, I had it hooked up wrong and probably fried it.
- Still need to get the AC lines hooked up, system cleaned, etc...
- Make my schematic notes in to Visio diagrams so I can PDF it and share with the community.

3FE impressions so far:

Well it's a fair bit faster than before. You can feel 20HP and 20 lb-ft of torque. It's not a huge difference but it keeps up with traffic a lot better. Usable RPM is higher up the band and so I stay in a given gear longer which also helps acceleration. I took it camping and got about 10 MPG fully loaded with gear. I suspect the load had part to do with it (loaded roof rack = lots of wind resistance and I did log a lot of miles off road) as did the 165 degree thermostat. I don't think the engine was warming up enough. After the last engine I was a little paranoid about over heating but that's not an issue with this engine. I have a new t-stat in there and the IR thermo says it's opening at 177 degrees (180 inside the t-state housing). I'm working on a new tank of fuel with fuel injector cleaner running through it and will continue to monitor fuel consumption.

I don't care for the muffler the shop chose for me. It sounds too ricey for my tastes but I'll live with it for now. She's not my daily driver so those little things don't bother so much.

Keeping the 2F flywheel stills makes for an engine that is resistant to stalling at low speeds in low range.

I can sure see why people like the 2FE so much. To combine the higher revving 3FE with the longer crank throw of the 2F would make for a very torquey engine with more usable RPM and less headaches then the 2F. That would just about the perfect engine for this old truck. Maybe some day...

I'm guessing the 80 series 3FE might have a heavier duty PS pump? I had a new pump on the 2F and the PS would fade out if you turned the wheel too quickly. That's not an issue anymore with this pump so I'm happy about that.

Now that the truck is perfectly happy to cruise at 75 I really want an H55F one of these days. No longer do I put along in the slow lane like I used to so the revving engine is more noticeable.

After I get through the ref I hope to have a few years of fun with the truck before thinking about engine tweaking again.

Frank

 

[Godwin]

- Figure out what to do about the oil pressure gauge, I had it hooked up wrong and probably fried it.

Frank

I did exactly the same thing and instead of replacing the gauge in the dash installed a mechanical Autometer gauge.

 

[elripster]

That's kinda what I'm thinking I will do.

Frank

 

[Cruiserdrew]

Great thread. I'd like to do the same. Already have the 3FE, but ideally I'd like to keep a 2F lower end and add the 3FE head and electronics. Nice going.

I agree that while 20hp may not be much it's the critical difference between a slow dog and a normal truck.

 

[elripster]

I have wondered (I'm sure the search button will answer but haven't had time to look) if I could just use the 2F crank, rods, and pistons.

The thing is that I have spent a lot of money re-accessory-ing the truck between new parts, hoses, etc... and don't want to undo all of that if I can help it.

I would say if you have the option to 2FE right off the back that's they best route to avoid all that accessory rework.

Frank

 

[Cruiserdrew]

I have wondered (I'm sure the search button will answer but haven't had time to look) if I could just use the 2F crank, rods, and pistons.


Frank

I can answer that--NO!

If you compare the 3F block to the 2F block you will see the block on the 3F is much shorter, reflecting the shorter stroke. In your case though, most the the new accessories could just stay with the motor, but the swap would be a lot of work.

I have a 3FE in my FJ62 as well and it's got plenty of power that I would not bother to put a 2FE in it, so if you are installed and running well, I'd just stick with it. THe 3FE is impressively better at all RPMs than a 2F.

 

[elripster]

Just passed at the referee!!! I am so happy. I am running rich though. 10 mpg was no anomaly so I'm off to research why 3FE's run rich. Nevertheless it is such a relief to have this behind me.

Frank

 

[elripster]

Thought I'd update this. I figured my running rich issue, it was due to a faulty fuel pressure regulator. I should have changed this in the beginning. While I had the intake/exhaust off (to change the exhaust manifold gasket...) I also did all 6 injectors with Rockauto remans (Cheap!). The truck runs unbelievably well and it is WAY faster than my 2F desmogged.

Frank

 

[60/40GUY]

Frank,

Any update on the trucks performance? What type of MPG are you seeing?

Frank

 

[elripster]

Sure. I was getting 9 before I replaced the injectors and fuel pressure regulator. Maybe 10 on the highway. It was very obviously running too rich which appears to be an issue with the engines as they age.

I'm up to 12 with new injectors and a new fuel pressure regulator. One could tell the injectors were an unbalanced mess (from the build up, I did all the intake/exhaust gaskets) and it's likely the original regulator was allowing too much fuel across the board. I just ordered a new cold start injector because I get a good puff of black smoke at start up sometimes.

I had a broken engine mount that was letting the engine move enough it was loosening up the exhaust doughnut gaskets. The resulting exhaust leaks were further causing it to run rich. fixing that helped.

I also ordered a snorkel because I can tell a stark difference between how the engine runs on hot vs. cold days. The 80 series air filter box does not align with the fender well so it's sucking hot air from the engine bay. On colder days the truck is almost fast. I row through the gears. On a hot day it just labors a lot more. Summer in SoCal is not more than it is cold.

So, the engine hasn't been a magic bullet for fuel economy yet but I suspect it will be when I basically do all of the maintenance I should have before the install.

I can tell too someone has messed with the air flow sensor so that's my last thing to check. I will say running rich lets me advance the timing so it revs very well. I suppose I'll find out in a year and a half if the cats survive.

I'm still very happy with the swap. The truck hums along at 75 effortlessly where that was the max with the 2F. H55 here we come.

If I have any parting advice it's to replace injectors, fuel rail damper, and pressure regulator unless you know they are good to go. If you have original engine mounts, replace them because the added torque will probably cause the d-side mount to fail.

Frank

 

[Yspen]

If I have any parting advice it's to replace injectors, fuel rail damper, and pressure regulator unless you know they are good to go.
Frank

How do you test them ?

 

[elripster]

You can do it yourself by having then squirt into a graduated measuring cup or just take them to a shop. Or, just replace them if they are original because they most likely need it.

Frank

 

[elripster]

I have trying to get an MPG number to post but have had fuel leaks that only leak when the truck is on. The first one was at the external pump. I ended up ditching it for an fj62 tank which scavenges fuel better when the level is low. It looked like my 11 MPG was going to go way up when it got worse. Turns out a sprouted another leak.

I ended up getting high pressure small tube clamps from MMC. They make a lot of different sizes and I ended ordering an assortment to get the right fit but the pressure line is tight now. I don't know my MPG yet (turns out I was leaking fuel for a long time an didn't know it because it evaporates so fast and doesn't leak when the truck is off) hope to soon. The gauge is moving a lot slower.

I still haven't sorted out the rich running condition yet either. The truck runs really well and I have been busy with other projects.

I really need an H55F. I can cruise 80MPH all day but the drone of the engine at that RPM gets to you after a while. There is just a lot more power than before.

Frank

 

[PabloCruise]

Thanks Frank!

Just found your thread, I look forward to reading!

 

[PabloCruise]

I still haven't sorted out the rich running condition yet either. The truck runs really well and I have been busy with other projects.

I really need an H55F. I can cruise 80MPH all day but the drone of the engine at that RPM gets to you after a while. There is just a lot more power than before.

Frank

I thought you had figured out the running rich was due to faulty fuel pressure regulator? And injectors...

 

[elripster]

Injectors and regulator sure helped it run better but MPG was still bad. I have since realized that I had some fuel leaks and since I don't know when they showed up I don't know how much they are contributing. One was quite bad.

I am, as far as I can tell all sealed up and will need to run another tank to see how the no leak MPG is.

I may not know how rich I am or am not running until I smog it again this summer.

Frank

 

[PabloCruise]

How did you find the leaks?
You said they evaporate quickly...
I am interested as I have a 3FE swap into my FJ55, 55 fuel tanks and external pump native to some vintage of F-150.
Sometimes I can smell gas back by the pump, but I cannot see any leaks.
So, curious how you found them...
Thanks!

 

[elripster]

Sorry for taking so long to get back to this thread.

As far as finding fuel leaks my trick is to get to the truck in the morning when it's hopefully cool out, key it on but don't start it, and start crawling around underneath. That will give you the best chance of finding a fuel leak before the fuel evaporates.

Now on the MPG saga. I upgraded to an FJ62 tank and pump as I think I mentioned and my MPG got worse. No joke. I attributed this to higher fuel pressure. I did check it and it's within spec but higher than it was with the old Summit inline pump. I have no codes mind you. The trucks starts and drives well even though the engine often runs too cool.

This week I started troubleshooting O2 sensors per the FSM. My readings made no sense. I was beginning to think I might have a bad ECU (no pulses when TE1-E1 jumped, odd voltage readings, no voltage on OX2 at all, some odd .05V on OX1 that never changed....) Today I started Ohm'ing out wires to make sure my O2's were hooked up right. My truck had been hacked to send 1 O2 sensor to both 1 and 2 on the ECU. I had corrected that or so I thought. Here is what I found after tearing into the main harness.

OX1 on the ECU was wiring direct to the 1st O2 sensor bypassing the check connector meaning I could not read it's voltage at the check connector. OX2 was wired to OX2 on the check connector while OX1 on the check connector was actually wire to the second O2 sensor. This clearly does not match the schematic so I fixed it. Both O2 sensors are Ohm'ing out at the ECU and at the check connector. I buttoned it all up and I'm now back to where I can start actually troubleshooting O2 sensors.

The second O2 sensor wiring came loose from its restraints and got melted/boogered up by hot exhaust so I will redo that short run of cable next week hopefully finally get to why I'm running rich.

Frank

 

[elripster]

Well the engine seems like it's trying to do something with the new O2 sensor signals.

Throttle response is better and power is overall up. The engine is more rev happy.

I have two odd driveability issues though. Cruising around 2k RPM with minimal pedal applied the vehicle starts to develop a vibration which seems to emanate from the engine. Accelerating makes this go away. Some times I will give it gas, it will pause, then the power comes on.

I suspect the mass air flow sensor might be showing its age. If that flapper door sticks in spots it will likely lean out the mixture. Nevertheless I think I'm making progress on this

Frank

 

[elripster]

I took the truck to get it smoged partly because I was just hoping it would squeeze by and also because the test results might help me troubleshoot this.

It did just barely pass again. HC's and CO are high. HC's just squeeze under the limit at 15 MPH, it did a bit better at 25 MPH but still well above the average. n NOx is higher than last time and I'm sure the cats are starting to suffer from the over fueling.

My O2 sensor voltages seem to indicate the sensors are dead. My spark was sufficiently week it took the shop about 20 minutes to latch onto a good signal for RPM. Most likely what I have is a collection of aging and failed sensors conspiring to produce poor fuel economy but not so out of whack that they are throwing a code. Well, I do get occasional loss of RPM signal (12) which seems to indicate weak spark.

I suppose I will start upgrading the coil, distributor, MAF, and replace the O2 sensors. The TPS checks out per the FSM but who knows, it could have an issue too. Per the FSM I could even have a bad ECU.

I climb a tall mounting in the summer heat with the AC cranking and never have to worry about overheating but I have to carry extra gas on long excursions until I fix this.

Frank