ainadude None
Jan. 6, 2012 11:48 a.m.

Hi guys ... first-time poster. Did some trolling yesterday and swapped some e-mails with Mr. Joshua, who suggested I post my question here.

Like Josh (at one point, anyway), I'm in the process of installing a Mazda engine into a Triumph Spitfire. Unlike Josh, I'm going the four-cylinder Miata engine route.

Physical installation is done but my mechanic has run into a wall: Despite several different wiring configurations (he's mated the Miata fuse block to the Spit's ignition circuit), he can't get the engine to run correctly. He says it runs and idles well, but has a nasty off-idle hesitation he can't fathom. (Josh suggested the problem might be that it's running in limp-home mode.) My mechanic's regular stock in trade is mostly doing American V8 conversions on Jaguars, but this is his first job on an LBC. He seems damn good at what he does and I think we're probably just a week or two from having it back on the road if we can just get past this issue.

All that being said, the installation of the motor and tranny looks good: He cut into the firewall and did some innovative notching of the frame and reconfiguring of one of the crossmembers in order to place the engine back to a point where no tweaking of the hood was necessary (the front of the motor is at the same position as the original Triumph mill). Beyond that, he's using the Miata radiator, too, with its twin electric fans and also came up with a creative intake plenum/K/N filter setup.

Meanwhile, he was also inventive in placing/configuring the transmission. He reworked the linkage in such a way that the shifter lever is in the original position -- something I've never seen in a conversion like this. Finally, we're using the Miata driveshaft, which is considerably lighter and narrower than the standard Spitfire componet.

When we finally get everything buttoned up, the interior will look almost completely stock, apart from the newly re-covered Miata seats we'll be plugging in (unfortunately, these weren't the ones with the built-in speakers).

As you can probably imagine, I'm eager to get the car back on the road -- I live in SoCal, so it's actually perfect convertible weather right now. So I'd greatly appreciate any input from you Miata guys, especially if you've done a similar conversion. Thanks in advance and I look forward to meeting you guys.

mndsm SuperDork
Jan. 6, 2012 11:54 a.m.

What ECU is it using? Any way to get a scan-tool on it? While it would normally throw a CEL if it went into limp mode, obviously the LBC car isn't going to have that. Car could still be throwing codes tho, if it's using a Mazda ECU.

ainadude New Reader
Jan. 6, 2012 12:01 p.m.

We're running the regular Miata ECU (it was a'93 or '94 with the 1.8L). The engine was running and driving fine before we pulled it (I bought the entire car for the swap -- it had been lightly T-boned but was somewhat driveable). My guy ran a scanner but I don't know what codes he got. I'll ask him next time I talk to him. If the motor is running in limp-home mode, any thoughts on what we're doing wrong?

mndsm SuperDork
Jan. 6, 2012 12:17 p.m.

Could be any number of things. Horrible off idle hesitation tells me vac line or shot MAF/o2, both of which could be easily damaged in a non factory swap, especially with a fabricated intake tract. I'd start there. I could be completely wrong though.

ainadude New Reader
Jan. 6, 2012 12:27 p.m.

Sounds like a good place to start -- thanks, man.

MrJoshua SuperDork
Jan. 6, 2012 12:50 p.m.

Welcome-I'm glad you posted! You should post the pics!

ainadude New Reader
Jan. 6, 2012 12:54 p.m.

Thanks, Josh -- good suggestion to post. Re pics, I clicked on the link to do just that but it seems like it's only set up for photos that are already online somewhere. All my stuff is just on my hard drive. Is there a way to upload from disk?

ransom Dork
Jan. 6, 2012 12:58 p.m.

In reply to ainadude:

You'd need to get set up with an account at someplace like photobucket, imageshack, picasa... You can load your images there and then link to them here.

You're correct in your observation that there's no facility for uploading image files to this site.

mw HalfDork
Jan. 6, 2012 4:00 p.m.

A 94 won't have the flappe door afm. As a side note, most miata seats have space for speakers in the headrest even if they didn't come stock. You can put your own in (better ones)

ainadude New Reader
Jan. 7, 2012 10:10 a.m.

OK, created a photo account and am posting some pics. The first are from several years ago, when Mrs. Peel was still ambulatory. The second set shows some in-progress pics, one of which displays what I'm assuming is the MAF (I'd appreciate it if someone could confirm this).

Larger pics and in sequence








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