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Yes, a vacuum leak of sufficient size can cause all sorts of problems. The FSM lists it as one of the things that could be causing your problem.
It can also keep you from idling.
If you don't have any boost leaks, you probably aren't going to have any vacuum leaks. You probably applied several times more pressure than your engine would apply as vacuum. So, I don't think a smoke test will tell you anything.
Did you test the injectors by hitting them with battery voltage, or by trying to start the car?
The question I have isn't whether the spray pattern is perfect, but rather whether they are actually firing when you try to start the car.
Come to think of it, does it matter which way the primary connectors go? I can't remember...
I would think it did, since the rotors are opposite of each other, and I am pretty sure they fire opposite of each other.
If they are directional, I can see how the primaries would easily get reversed. It's been a while since I've had to mess with my fuel system, though. I also only have two or three solenoids left on my car. Haha.
I did not at all take the injectors out of their housing since ownership. here is the clip of them spraying. I didn't care if they made a mess, but I shielded the alternator as you will see in the clip. https://www.youtube.com/shorts/D29FRb4ZPFI
The injectors spray down onto deflectors or diffusers that sit in the cavity below the injectors. The deflectors are actually quite fragile bits of plastic. If you try to fish one out it is likely to break. Lord knows where the plastic bits will go.
(This page gives us a further clue how the FPR functions.)
Lord knows where the broken bits will go.......
Last edited by Redbul; May 27, 2023 at 12:37 AM.
Reason: added info.
I Have pictures of when I took the injectors assembly out the very first time, I checked and everything is in the correct order. I left the diffusers in when disassembling/building the engine. I don't plan on trying to take them out as I can already see them falling in the engine.
Also a way to tell (On my car at least), is the injector connector with the white tag on the wire is closest to the front of the car, for future reference.
I am going to check my spark wires again tomorrow, since the coils are out of the car at the moment.
I keep mentioning the change of coil positions on and after version 4 JDM. Because it likely cost me an engine. Version 1~3 JDM had coils mounted in the same order as USDM Version 1~3 (Series 6). But Mazda switched things around starting the end of 1995. In the diagram below, the old position in shown on the top and the new position shown below. Although it is unlikely that you have a Version 4 set of coils, it is something to mind. Another twist is that the short harness that connects the coils to the Engine (aka starter) Harness is also different for version 4. I lent a random short harness I had to my friend only to discover it was a version 4 harness and he had a version 3 car.
Change of coil mounting positions on Version 4 cars (1996 +)
Above the coil for the leading plugs is located in the middle between the trailing plug leads. On the bottom the leading plug coil is located on our right.
I keep mentioning the change of coil positions on and after version 4 JDM. Because it likely cost me an engine. Version 1~3 JDM had coils mounted in the same order as USDM Version 1~3 (Series 6). But Mazda switched things around starting the end of 1995. In the diagram below, the old position in shown on the top and the new position shown below. Although it is unlikely that you have a Version 4 set of coils, it is something to mind. Another twist is that the short harness that connects the coils to the Engine (aka starter) Harness is also different for version 4. I lent a random short harness I had to my friend only to discover it was a version 4 harness and he had a version 3 car.
Change of coil mounting positions on Version 4 cars (1996 +)
Above the coil for the leading plugs is located in the middle between the trailing plug leads. On the bottom the leading plug coil is located on our right.
The coils are all clearly marked, so it's pretty hard to screw up unless you don't know which rotors are which, and the difference between trailing and leading. Also, the car will start without the trailings.
Though the connectors might be hooked up to the wrong coils!
I think what happened in my case, the local garage used the USDM FSM as a guide to hook up my leads. The car was running funky. It is only when a more aggressive friend took a few pulls over 6000 rpm that I got detonation. Probably the reversal of the leads was less critical at lower revs.
After four detonations I lost compression. I still cringe whenever I approach 6000 rpm.
I think what happened in my case, the local garage used the USDM FSM as a guide to hook up my leads. The car was running funky. It is only when a more aggressive friend took a few pulls over 6000 rpm that I got detonation. Probably the reversal of the leads was less critical at lower revs.
After four detonations I lost compression. I still cringe whenever I approach 6000 rpm.
I think maybe the connectors were color coded? My memory is a bit fuzzy here…
My car is a Ver. 4 (“chuki”), so the US spec FSM isn’t all that much help. Thankfully, I can read Japanese… Every US spec car is an early-model FD (“zenki”), which should be the case here, even if his car is actually a 94 model year (since Japan doesn’t do model years the same way).
One easy way to tell off everything is connected correctly would be to see if your front and rear trailing spark and injectors are basically synchronized.
Test the injectors a few more times just to see if it always starts with the same rotor. Then ground both of the trailing spark plugs and see if it always starts with the same rotor. If not… something is misconnected.
One easy way to tell off everything is connected correctly would be to see if your front and rear trailing spark and injectors are basically synchronized.
Test the injectors a few more times just to see if it always starts with the same rotor. Then ground both of the trailing spark plugs and see if it always starts with the same rotor. If not… something is misconnected.
Today I checked the spark wires and they have continuity. So I plugged the coils in to test spark once more, and after cranking in noticed a light crackling sound coming from the coils. I saved a YouTube video on diagnosing this a I think this is abnormal.
Today I checked the spark wires and they have continuity. So I plugged the coils in to test spark once more, and after cranking in noticed a light crackling sound coming from the coils. I saved a YouTube video on diagnosing this a I think this is abnormal.
You don’t want just continuity, you want resistance that is within spec.
Test the coils and wires using the procedure in the FSM.
Crackling might be a spark between the coil and the wire… make sure the wire is all the way on, and isn’t deformed or something.
Or, take the wire off and see if the coil still makes a noise.
Okay I will try both of your suggestions. Also I have found a thread on this noise, which comes from BACV and will not allow a car to start.
The idle control valve shouldn’t prevent the car from starting, unless maybe it’s stuck wide open. Apparently they can get stuck partially open, and you can clean them to fix this. You will need a new gasket, though.
Did you ever check your TPS?
Also, I’m curious if you cleared your codes after fixing the coolant sensor and before checking to make sure the code was gone. Or did you not have to clear the codes to make the code go away? Maybe check them again? Don’t be surprised if there’s another code…
I turns out the noise was not the BACV, it was the rear most leading coil when wire was on. I didn't make noise when wire was off . I checked the harness as well but found the leading wire was in spec at 6 ohms, until the wire was slightly twisted/ played with . I am going to order new wires now. After fixing that sensor before trying starting, I attempted to get a code but there were on faults. I don't know how to refresh the computer.
Friend was struggling struggling with runability issues lately. Ran through the list of things to test and try. Finally bought a Power FC off Buyee. It arrived within a week. Installed it. Car idled well for 10 minutes then crapped out.
Ran the compression test and the back rotor failed to register any compression.
Surprisingly, front rotor had compression still in the teens. Interesting given the rebuild was ten years old.
The new NGK wire that I tested before putting in the car where a different spec than what Mazda says. I remember my testing my short new wires at 3.23 ohms. I still tried them any way and the car would not start still. I got them from sakebomb, part number RC-ZE30
The new NGK wire that I tested before putting in the car where a different spec than what Mazda says. I remember my testing my short new wires at 3.23 ohms. I still tried them any way and the car would not start still. I got them from sakebomb, part number RC-ZE30
the brand new NGK wires are probably fine...
make sure your car isn't just flooded at this point.
