Cascade Crew

[aaron_sK]

Or how to put your truck on the Atkins diet...

Or how to do in three days what it's taken you two years to do in a Camaro...



For those of you who aren't cool kids and didn't make it down to dyno let me fill you in: I have gone even more insane than I was previously and bought a mini truck the night before dyno. Unfortunately I decided it wasn't worth putting on the rollers which I regret in hindsight as it would have been cool to see the change in the torque curve with the FI.

I did find the one thing I hate more than automatic transmissions, and that is Japanese carburetors. This truck has the god-awful Nikki 2bbl feedback carb on it. The issue with these carbs is that the EGR and mix control solenoids are known to get sluggish or downright stuck and cause everything to run like crap.

The truck had no power below 3K and would outright stall if you didn't floor it when it was cold, so obviously it was running lean below a certain point. I was down to about 23mpg from all the driving with my foot on the floor, and it probably wasn't too good for the rest of the motor either.

After looking at options for a carb swap (Weber 32/36 or Holley 5200) or an EFI swap using MegaSquirt or something, I found a couple guys who had built custom intake manifolds and used the EFI system from a Mazda 626.

Now the 626 EFIis a real dumb animal. It has no spark control (uses a vacuum distributor) no IAT, and no crank or cam sensors (uses the coil). This makes it very easy to swap. The downside is finding or building an intake. Not wanting to mess with building one I found a manifold off of a newer B2200i and had it shipped up here.

I then went to the local Mazda junkyard (the one off Canyon Rd. for those who have been to my house) and bought the entire ECM, harness, injectors, ect. off an '89 626. That was my first mistake. The few people who had done the swap had used '90-'92 cars. I asked Jeff (who owns the Mazda yard) if there was a change for the '88-'89 and after some fumbling in the manual he said there were "no significant differences" which I later found out meant "there are no significant similarities but I don't have a '90-'92 and I want your money."

Now onto the swap:

Saturday I started with the fuel pump. There were about 7 gallons of fuel in the tank so I decided to lift the bed rather than drop the tank. The horizontal 4x4 is only there so my face isn't the widest thing between the frame and the bed



There's the culprit right there:



Mazda eschewed the traditional ring setup for a silly lock plate and philips screws. I replaced the screws with proper hex bolts due to my annoyance removing these:



I didn't get any pics of it but the Mazda uses a low-pressure electric pump for the carb. It is small and useless and mine had no sock on it which may have been a big part of the lean issues, but whatever.

All EFI imports from that time period used basically the same pump. The Carter pump I bought had hundreds of applications listed in the catalog. The upper clamp was too low so I zip-tied it all together. This is the new pump in the old (carbed) pickup:



You can see the size vs. the old pump:



Carb removal was fairly uneventful until a nut froze on one of the studs and rounded off. Figuring that no one in their right mind would want to buy a Mazda intake manifold (and considering what scrap aluminum is going for) I got out the Milwaukee and "fixed" it:



Yup, fixed it good. I'm subtle like that.



LIM goes on:



Injector prep (Vaseline FTW!):



Rail on and harness routed:



UIM on and airbox mocked up:




That was Saturday night. Sunday was a lot of boring soldering, studying harness diagrams, unwrapping tape, probing the a multimeter, and so forth, so I took no pictures.

Sunday night after I took the video of it starting I realized why it wouldn't stay running. See, Mazda engineers didn't really design things with any sort of logic, they just sort of did stuff and it worked so f**k it ship it over to America!

For instance: instead of having a normal fuel pump relay triggered by the ECM like everybody else on the planet, Mazda decides to have two relays both triggering the pump. The first relay is triggered by the motor stud on the starter (hot on crank) thus causeing the pump to run any time the starter is cranking. Of course you need to run the pump once the motor starts so there is a second pump relay that is grounded out as soon as the air meter door opens! I had wired the relays correctly but then forgotten about them when it kept stalling out. I jammed a screwdriver in the air meter door (remember, I'm subtle ) and it started right up.

Today I finished up the intake piping, made up of the intake from a 1986 Isuzu Impulse (yeah! ) an exhaust adapter and a no-hub sewer pipe connector. Then I went brodying around in the rain. Throttle response is a night-and-day improvement. Top-end power seems about the same but that's to be expected on a 25-year-old Japanese four-banger with 200K on it.

I still need to re-wrap the harness, figure out where the heck to put the ECM, and finish a lot of little stuff.

[Twilightoptics]

Crazy A-Hole.

I've been rolling the 4bbl Nikki for many years now. It... runs.....

Mazda in the 80's didn't really know about electronics. Hell, my entire car was run through the ignition switch - wipers, power windows, alternator, everything! No relays at all. Atleast your truck HAS a relay or two lol.

There is a reason I'm not using the stock Mazda ECU stuff I have and going straight to squirt. lol

Good work there Captain Insano.





When we gonna work on that "other" other project?

[aaron_sK]

[iansane]

Beautiful.

Any chance you want to do this again? A guy who comes into my work just bought that exact truck with something ridiculous like 40k miles on it and it does the same thing you described. He wants to swap a rotar'd into it. Not a big deal but he has very little mechanical skill.

[aaron_sK]

No rotaries in trucks, that's just silliness.

Mazda actually tried it in the 70's. Google "mazda repu" They sold them as a "sport" truck. It didn't go over well.

The issue with the swap is that it is not economical. I am probably into this twice what a Redline-brand Weber swap kit for this truck would cost. I did it because I must be unique (or nearly so) and I am crazy.

[Twilightoptics]

And EFI is better period.



Repu's have a major cult following. They are badass little trucks. I think they may be lighter than the RX7 too. Just don't USE them as a "TRUCK"

[iansane]

[Alphius]

I would buy and drive a RePu in an instant. They are amazing. Then I would LS swap it and piss some rotards off.

I'm glad you're happier with the Mazder. Does it fry a tire up yet? Time for a 5-speed swap next.

Did you sell the Cavvy yet? You better get going on that Camaro. Wanna work on it this weekend?

[Twilightoptics]

[QwkTrip]

It's not fair. Your truck has less rust then my new truck will have in 1 month.

[aaron_sK]

[Quasi-Traction]

a little non-related, but that mazda yard....if he's got a tailgate handle for a 91-92 Mazda B2200 pickup (not the pot-metal and chrome one, this one is like ABS plastic or some shizzle). my Aunt's truck (which I use for scrap and dump runs quite often) needs one.

[aaron_sK]