Going to be taking off the uim as there’s wires in between that smoke/spark when trying to turn the car on and will try to figure out the problem, if anyone knows anything about it or has had the problem before if you could pass on the knowledge thank you! I do think it could be oil in there causing a short or something as there’s a bit of oil everywhere due to blowby.

Question is, anything j should do before taking it off? I know to unplug the battery but that’s pretty much it, maybe drain coolant? Any help would be great, oh and also is there anything else I should look to replace while the uim is off?

thank you!

 

Check the FSM starting around F-76 or so. Use your phone for lots of pictures is the biggest suggestion. It helped me the first time…and a couple times more after.
Disconnect everything around the T-body. Underneath toward the middle of the manifold they’ll be a connection for the IAT and vacuum hoses. The pictures and labeling with tape can really help with those.
Thing(s) I can think of underneath the manifold that would spark are the coils, plug wires and coil harness. Once you’ve got the leak dealt with and cleaned up, it’s a good time for new plugs, plug wires and maybe even a new harness if it’s stiff and crispy. I’d stay with stock NGK unless you’re heavily modded. Change them one at a time.
Sources of oil under there that come to mind are from slopping oil while filling during maintenance, leaking filler neck, PCV or OMP lines.

 

It's pretty straight forward. You shouldn't have to drain all the coolant, just a little if even that. Since the TB is a high point, the coolant is above the radiator so most should drain back (make sure it's not pressurized). There may be a little left regardless of draining which will probably spill so be prepared for that (if that's something you'd be concerned with). Once you get it off, you'll want to cover the LIM intakes. I'd also plan for a new gasket.

And there's a whole choice of options available on what you should do when you have the UIM off that may end up in a $30k build.

 

Pulling the UIM isn't too hard, get used to it since you end up having to do it a lot.

- Disconnect battery since you're going to be doing some electrical during the process
- Undo throttle cable, 2 12mm nuts hold it to the bracket, slide it up
- Remove throttle body elbow
- Remove vacuum lines on front side, left side, and rear
- Remove ISC and TPS connections and ground wire to firewall
- Remove 4 nuts and 1 bolt holding UIM to LIM
- Loosen 12mm bolt holding it to bracket near oil fill neck
- There are 2 turbo solenoids bolted to the front. Undo the 2 10mm bolts holding it on, don't try and undo the vacuum hoses, you'll probably break the nipples off
- Lift up a bit and unplug air temp sensor underneath manifold. Also AWS if your car has it
- Carefully remove making sure nothing else is hanging up

A stock car won't have a problem with a short under the intake manifold. Something happened - either someone damaged the harness or did something to it. Take your time and look around everything thoroughly.

Dale

 

2 VERY important notes here. Do NOT...I repeat DO NOT do ANYTHING until you've physically covered your LIM intakes. The last thing you wna do is drop anything into your engine, no matter how small.

And the second point is also very important. My advice if you are running the stock TT, is to replace all of those old crusty vacuum lines under there. You could fall down a $30k project rabbit hole easily (ask me how I know), but as long as you go into it with a plan, you should be fine. it's a very simple job, just be patient with that sensors on the underside and on the back of the UIM (I always struggle with this and I've done it at least 100 times) and you'll begin to feel comfortable with disassembling engine accessories.

 

And this is where the slippery slope starts. If stock, the vacuum lines are indeed probably crusty, but left alone they might be fine. Once you start messing with them, you'll probably break solenoid nipples. And, you might as well test your solenoids. And while your at it, your actuators. Then there's the fuel hose (it's old too), and the hot water hoses. Then you start thinking about all the emissions equipment and whether you should ditch it and there goes the LIM to get to the EGR. And while you're down there, may as well port the wastegate and put on a DP (if you don't already have one). Now you need to upgrade to a PFC (if you don't already have one). Then there's the suspension. And so it goes...

 

^All good points. The big thing is to limit project creep, it's probably going to be a big enough project as it is, don't add to it.

Dale

 

I agree, don't let project creep get to you. If you can, limit what you touch. If there are easy to replace vacuum lines with silicone, you can do that. However, limit what you touch if everything is working. Taking the UIM isn't hard. Dale's steps are what you need to do and just make sure to take pictures as you go so you don't forget where things went. It can be tricky to remember sometimes if you aren't familiar with the rats nest.

 

Lots of info, very much appreciated guys. Will definitely make use of it. The car is not stock, po had it rebuilt and is now single, and a couple stuff that aren’t stock. I’ll take the UIM off first and let you guys know of what I find and have replaced, anything of that sort. I wouldn’t have thought of covering the LIM which could’ve ended bad haha and also I actually don’t see that many vacuum lines going, a lot of it is capped off and some off the connectors aren’t even connected so I’ve got a lot of stuff to look at but I’ll take my time, thank you!

 

Got it off, wasn’t that hard I think since it’s modified there wasn’t much, going to attach some pictures I took. There’s a bunch of wires just bundled together with electrical tape, just tried to move the wires out of the way so it doesn’t make contact with other parts for now while I decide what to do and see if it turns on in a bit and if the sparking/smoke is gone. Definitely need new gaskets for the TB though. Also, where can I get replacement wiring for these parts? Sorry if I’m not making sense, still a big newbie to rotaries, and cars in general haha

 

At this point, I would just throw on a new engine harness and let it be a reliability mod.

 

Definitely, once I get the funds, hopefully this month I'm thinking of getting new engine harness, specifically this . Question is, what's the difference between tucked and the regular harness that I have?

 

That is the original paper gasket between the throttle body and UIM, Mazda updated it to a metal gasket that lasts forever. Get one. That paper gasket is crap. Make SURE all the old gasket and RTV and crap is off and both sides are clean and flat and you are good. The new gasket shouldn't be much from Mazda.

Since they went single they probably cut all the connectors for the twin turbo and emissions solenoids out and did a crap job of it. There's a few people that do some really nice single turbo wiring harnesses, it will cost you some money but you'll have a lot easier time of it than trying to fix a ratty harness that someone has hacked up poorly.

The red RTV on the throttle body gasket is all I need to know. The previous owner did some VERY sloppy work.

Dale

 

Don’t forget to re-cap the oil filler neck and keep those lower intake runners covered.

 

Can you still get an OEM harness? Mine is really crispy.

I see Rywire makes a tucked, single turbo harness only
Wiringspecialties also seems to make one.

 

OEM still available. About $1k.

 

I actually just ordered a gasket from atkins and I’m not sure if I got the updated metal one, is there anything I need to add or just add gasket and just put the tb back? Any other sealant I should add? I’m planning on buying the rywire single turbo harness soon

Yes sir capped it off and kept it covered thank you

 

The metal gaskets are self sealing. That's the only one available.

No RTV or anything, just get both surfaces TOTALLY clean - scrape all the old gasket and RTV off. It's going to be some work but you have to do it or you won't have a good seal and you'll have a vacuum leak.

OEM harness is nice but if you're single turbo there's no sense paying for all the connectors that won't be used. Many aftermarket options. I wouldn't go too crazy, just get a good quality single turbo one.

Dale

 

Okay I’ll definitely make sure to scrape it off clean, guess I got the right gasket then if there’s only one, thank you sir.

as for the wiring harness, I gotta find out what injectors I have first I believe might as well replace them though not sure yet, is it difficult to redo the wiring myself? Does the engine or anything hard need to be pulled out? Will probably get the single turbo one

 

It's not super bad to pull and replace a harness on a single turbo car. You don't have to pull the engine. Big thing is making sure you know where all the connectors need to go and getting them plugged in where they should.

Dale

 

Okay! Sounds good, will probably just need to do a couple searches while I do it. Thank you!

The car turns on now, replaced the battery with a little bit bigger powersport battery from autozone and it cranks up right away, gasket hasn't come in yet just wanted to test it out to see if it would turn on and it did but revs up and down by itself which I'm guessing is because of the leak caused by having no gasket.

 

Gotta love those LIM Gasket changes. Easy rabbit hole.

 

the paper gasket hasn't been available since 1994, which shows what a job the P.O. did....

the metal gasket goes with the little tab toward the rear, the gasket is not symmetrical, although it is very close

 

thank you! That helped haha was trying to figure it out and I got it all in, car was fine until some of the wires got moved and it shut itself off, tried turning it back on and something popped. Definitely need a new wiring harness before anything.

Does anyone know how I can find out what fuel injectors I have primary/secondary? Need to find out for the wiring harness

 

Post up a picture.

Dale