I just put a new engine in my 87 TII. I had it professionaly rebuilt and they put it back together to the longblock for me. The car runs fine and every thing is cool until when I am driving on the highway and put it in 5th the car dies and the main engine fuse is blown. I have search for the last 4 or 5 days and traced every wire I can, trying to find a stripped wire or loose connection. The car never had this problem before the new engine. If anyone can help please do.

 

Just went and checked and if while it is ideling I put it in fith and let it set for about 1 sec. it blows the fuse. If that info. helps.

 

Under the car on the transmission, there are 2 switches. 1 for the reverse lights, and the other for the 5th gear. I believe the 5th gear switch has 2 green wires coming from it. You may want to start here.

 

Do NA's have this? Mine are dragging on the ground and everything is fine.

 

All of the cars have it. Chances are it's shorted, and is popping the fuse.

 

Thanks I will go check that right now

 

I am pretty sure it is that switch or at least a wire leading to or from it. It is pretty tight working down there, does anyone know where the wires lead to so I can check there. Becuase when installing the new engine I really didn't even touch that area so I am guessing it is somewhere near the engine.

 

IIRC, the 5th gear switch is the one on the right side of the tranny...

If it has Green/Black and Black wires going to it, that's the neutral switch, not the one you want (which should be on the left side).

Best step for now is just disconnect the wiring at the connectors there on the left side of the tranny. Only thing I can see you hurting is your "shift up" light (it might come on in 5th now), and your ACV (split air) functions. Tie-wrap the wire ends up so they don't drag on the ground, and see how that (new) fuse does...If it's all good, then that switch is grounding out in (or on) the tranny.

Also take a good look at the Black/Blue wire while you're under there- follow it up as far as you can, and look for any noticeable chaffing or contact with the metal surfaces...

 

My, my. You guys sure have funny cars or should I say funny configured cars.

I have a 87TurboII and on the left side of the transmission is.....the fifth gear/backup light switch. On the right side of the transmission is the...neutral switch.

And darn, that fifth gear (over the top) switch does not get its power from the ENGINE FUSE. And darn to beat the band, the backup light switch does not get it's power from the ENGINE FUSE.

So why are we crawling under the car looking at switches that have not much to do with the ENGINE FUSE?????

Well Hoppie, its like this. When you put your car in fifth gear what happens??? No not selecting up a gear, I mean you put a ground on pin 1I of the ECU.....and also put a ground on .....the SPLIT AIR SOLENOID.

Since the ENGINE FUSE has little to nothing to do with the ECU......and the SPLIT AIR SOLENOID gets its source of power from the ENGINE FUSE.....which should I expect to be the culprit. That's right. So go get 'em little doggie.

Am I a smart *** or what? Yes, your right.

 

dang HAILERS

you rock

 

That reminds me, Hailers, I've been meaning to discuss this supposed "5th gear activates the split air solenoid" theory. Maybe my FSM is wrong, in which case it would have to be wrong in the solenoid tests, and the cutaway of the ACV, but anyhoose, the way I see it, is the split air solenoid is energized in every gear BUT 5th...
Please take a look at the S4 FSM, page 4A-38, and notice that the split air solenoid is shown de-energized, that is, the plunger is down, covering the port, due to spring pressure.
Now, if you will be so kind, turn to page 4A-38 of this same FSM, which is the electrical test for the split air solenoid. Please pay particular attention to the part that says "shift into 5th gear and observe the voltmeter reading". In 5th gear, the meter reading should be below 2.5v (or 0v- I don't know why Mazda expects stray voltage all the time). In other words, in 5th gear, the solenoid is de-energized, the plunger is down, and NO split air is going to the cats. In every other gear, we should get voltage, in other words in every other gear we should have split air to the cats. Follow?
Now, I must admit you are one of my favorite "gurus" on this forum, and I hang on your every words (along with a couple of others-you know who you are), so, I must assume that the manual is wrong, and just hasn't been revised in the 18 years since its printing. Because there is absolutely no way in hell you could be wrong...

Am I a smart-*** or what? Yes, your right

 

if i was a betting man i'd bet someone is wrong

 

http://www.teamfc3s.org/forum/showth...threadid=31438

He has a TURBO. So you have to go to the TURBO EGI EMISSIONS CONTROL SYSTEM, and you get the jpg above which shows that when you put the car in fifth you also directly put a ground on the Split Air Solenoid.

Now I notice I have Egg on my face. In the jpg above the Split Air is supplied 12v on the black/white wire. Uhhh, errr, ahhh that B/W does not go to the ENGINE FUSE. OOOOps. And the author of the thread did not say his ENGINE FUSE popped. I think it was another fuse and it would help if he described just what fuse. The location maybe??

I still think its the SPLITAIR SOLENOID though. Just remove the plug from it. Its the rearmost screwin solenoid on the ACV. If you removed the ACV then find the wiring that went to it and see if its got a dead short.

 

*****In 5th gear, the meter reading should be below 2.5v (or 0v- I don't know why Mazda expects stray voltage all the time). In other words, in 5th gear, the solenoid is de-energized, the plunger is down, and NO split air is going to the cats. In every other gear, we should get voltage, in other words in every other gear we should have split air to the cats. Follow?*********

When you put the thing in fifth gear...The ECU puts a ground on the SplitAir Solenoid......so you have a voltage drop from approx 12v down to little to nothing.

Unscrew the Split Air Solenoid and pull it out without dropping its plunger and very small spring. Leave the harness connected up. See how the plunger drops out due to gravity? Now put the key to ON and the car in fifth gear. Seee how the plunger is held in the solenoid now and gravity is defeated??? Yes.

This smart *** sure did foul the water with his above post suggesting the SplitAir Solenoid was run off the ENGINE FUSE. What a donkey's butt. I'll get over it though.
Gotta go pull my new rebuilt, better than ever, hybrid tubo now. Seems it likes to act like a oil metering pump bigtime, all the time. Not toooooo happy.

 

You're rambling, Hailers...So is the book wrong, or what? And are the turbos different? I can't go out to my car & check it out, I've got the solenoids (split air & port) disabled, and with some crafty vac routing have split air dumping 100% of the time in the attempt to "tame" my wide open exhaust smell...
If the ECU puts a ground on anything, including our much-discussed split air solenoid, it energizes it...Completes the circuit, if you will. With it energized, you will see 12v at the solenoid wire coming from the power source, and 0v at the wire going to the (in this case) ECU. So yes, you have a voltage drop, but I don't think the book is asking you to check voltage on the ECU side of the solenoid (that wouldn't make any sense)...
So, you're saying that on the S4's, with the key on, if you pull the solenoid, it'll be de-energized until you put the shifter in 5th...Then the book is wrong...I've done some more searching also, and this means the test on page 4A-42 is also wrong (has you checking for air at the split air pipe while NOT in fifth gear)

This is fun, I love conundrums!

Romper Stomper, did you ever fix your prob? I'll bet you're thoroughly confused by now, lol...

Anybody else want to run out to their car (S4) and see if your split air solenoid is de-energized in 1st thru 4th, but energized in 5th?

Another interesting question- what do the S5 manuals say about this test?

Keep on rockin, Hailers

 

hailers is right, and the book is right... you are not understanding how it works

 

Do you guys Down South have problems with over heating at all when its over 100f? Because my temp meter hardly moves off the cold mark here when its in the 60s. but it hit 80 the other day and it was allmost halfway up. and when i turn the A/c on its even worse.

 

Mines the same way here in Houston, Adam (S4).. At night going home (about 75*F out), she'll run at less than 1/4, but during the day at 90*+, she'll run at 1/2, maybe a little lower. Been doing that for as long as I can remember (and at this point, my entire cooling is damn near brand new)

 

FYI-
I had the same problem. New engine and the engine fuse blows in 5th gear.
I disconnected the 2 square connectors next to the tranny(not the round ones for the reverse lights) and problem solved.
.. so far.