Dltreezan

iTrader: (3)

ok guys, doing a swap on my cousins car and the negative terminal is hot as hell, and the temp gauge rises to the top, and the engine wont start. It also stopped cranking though the main fuse looks fine. You guys think i hacve a shitty ground somewhere or a loose wire and blew main relay?

funkjaw

iTrader: (3)

Sounds like a short. Check to make sure the alternator is not grounding out on something like the top mount intercooler.

Dltreezan

iTrader: (3)

that part is fine, check. It was doing the same thing when I had the other NA swapped in it trying to get it to run, as far as the hot terminal. What the hell would make the temp gauge jump like that?

Dltreezan

iTrader: (3)

behmp.

HAILERS

You real sure the battery cables are on right?

After leaving the batt, the neg cable attaches to one of the bolts that hold the transmission to the engine. Thats the main gnd for the engine/car.

After leaving the batteryh, the positive cable attaches to the solenoid of the starter.

KusImmak7

Mmm well make sure to do something about that ground wire today.

KusImmak7

cables are on right. why would the temp guage go up??

HAILERS

Is this a non turbo to turbo swap using the turbo em harness instead of the stock non turbo em harness? That would explain why.

KusImmak7

no were using the harness from the turbo jspec

HAILERS

The car has always been a turbo car? Never been a non turbo car? Matters.

KusImmak7

no its always been a non-turbo s4.

HAILERS

That's what I'm getting at. You put a turbo EM harness on the engine.

When you did that, do you remember how you had two ORANGE colored plugs you connected up inside the passengers foot well to connectors on the Front harness? Say yes, I remember.

Well the wire pinouts on the Turbo EM harness are not the same as the wire pinnouts on the non turbo EM harness.

Some small alterations need to be made to the Turbo EM harness to make things work. Small changes, not significant. Are you already aware of these small changes? Like the alternator on a non turbo has two small wires that run thru the non turbo EM harness. Well on the Turbo EM harness those wires do not exist. So you have to either run two new wires from the alt to the Orange plugs or make other plans to excite the alternator.

Dltreezan

iTrader: (3)

No we are not aware of these changes. Some of the threads we have read did not have this on there. If you have a link that would be awesome.

As for the temp gauge there might have been wires on the main harness (battery harnes) there might be something plugged in wrong. I have a few extra connectors loose after everything obvious was plugged in and I plugged the oil pressure sensor to one of them and it might be wrong (the plastic part was broken and just the metal tab was sticking out so I stuck it in an extra open female connecter).

Another odd *** thing on this car is there is no relay by the trailing coil pack near the clutch MC. I was like WTF? The car is an 86 gxl.

I am going to reground the main negative wire to the chassis itself and try giving it a start.

HAILERS

Actually that does not explain the hot water temperature wire. Because that wire should be Yellow/White in color. It travels inside the harness to the ORANGE in color plug with 15 pins in it.

Now that 15 pin connector will connect with its mating plug on the Front harness........but there should be no wire in that mating plug at all........therefore there's no way the yellow/white wire at the water temp sensor should be *hot* at all. Odd.

The wire that is yellow/white for the water temp is going to have to be moved to the OTHER ORANGE plug (13 pin plug) so it can mate up with the yellow/black wire in the front harness that leads to the water temp gauge. By the way, there's already a Light green/Black wire already in that hole where you need to put the yellow white.

AH, HA. That's your problem. If you remove that Light green/black wire from the thirteen pin orange in colore plug, then the water temp gauge won't read high anymore. The Lg/B wire is in the upper corner of the thirteen pin plug of the turbo EM harness.

Attached is a jpg of someones EM harness laying on the floor. I think I pointed out where the two ORANGE in colore plugs are in that jpg. Those two orange plugs connect to the FRONT harness inside the car on the passengers side. Far right of the foot well, up high.

The two Orange in color plugs are shown in the last two jpg attached. The wire colors with ( ) around them are TURBO peculiar.

Dltreezan

iTrader: (3)

awesome. So that will take care of that problem. Hopefully regrounding everything will get rid of that hot terminal and ten I can get the thing to at least crank again and then figure out why it wont start.

KusImmak7

ok, fail. No matter what the car will not start without the turbo boost control box in the passenger footwell. Need to get one of those.

Also found out why the s5 na motor i put in before it would not start when i put the s4 manifild and deleted the OMP. Without a signal from the OMP the ECU goes into limp mode and will not start.

HAILERS

The hot battery terminal is a worry. Then again, in the past when I've had a bad starting problem, I have found the connector not on the battery good or the cables in the connector corroded causing the hot condition.


The other end of this batt cable goes to the LONG bolt on the starter or one of the bolts that holds the transmission to the engine. Make SURE you don't have it going to the starter solenoid.

If your turn signals work and wipers work with key to ON, then you have power to the ignition key........so power to the starter solenoid would also be there at the igniton switch. IF those two items do NOT work.......I'd guess the power to the key is not there and that explains why the starter does not turn over.

Also you need to pull apart the two orange in color plugs. Find the fifteen pin plug that is the half attached to your trubo EM harness. EXTRACT the two wires that are colored (BrR) and (BrB) from the plug and tape the ends over and tie back to the harness. You DO NOT want these wires in the harness. IF you leave 'em in there, then you'll be backfeeding batt voltage to pin 2B of the ECU and that pin should not see more than ?? 2-3vdc.

I'm writing ALL the above thinking this is a series four car of the 1986-87 vintage. If series five.........forget anything I said.

KusImmak7

hailers this is all series 4. one thing we were missing was the knock control box which the car will not run without. that was fine two days ago when the car would turn over but i cant even see if that will work.
so i figured that it was simply the erlay. let me replace it and i will be fine. i have been in this situation before.

i went to replace the main relay and it doesnt exist. wtf?? there is a smal harness there with a plug that routes it to itself and another that goes under the trailing coil and plugs into a dummy harness. looks like a ground, or where the ground would be on the shock tower. If i could find the main relay that would be awesome then i could be on my way....

where the hell is my main relay????

KusImmak7

oh and i regrounded the starter wire and put a different starter on it. the starter ground is now going to the subframe.

satch

iTrader: (1)

The main relay passes voltage from B/G which comes from the engine fuse box to B/Y and W/L which also comes from the same fuse box (different fuse) to B/W. If you are trying to work on the car to get it working you could temporarily connect these wires and effectively bypass the relay altogether but in doing so the B/Y and B/W wires will receive constant voltage and so will everything connected to these wires. This will likely drain your battery so if done it needs to done on a temp basis.

EDIT: Chances are the wiring is already set up to do such but the main relay accomplishes nothing more but to control when the voltage is passed or not, and nothing else.

HAILERS

I have a 1986 non turbo with a turbo engine in it. You do not need the Mazda Knock Control Unit to run this car. Not at all. Ever. No Knock sensor either. I used the stock non turbo EM harness on the engine with very minor changes to the EM harenss. Like extending the TPS wires a few inches so they connect to the TPS on the turbo engine.

See the jpg attached. It's of a blue jumper connector. That connector is installed on series four cars that do not have a Starter Cut Relay (theft cars only device). That blue jumper passes power from the START circuit on to the starter solenoid.

I don't have a jpg of the Main Relay. Should be there outboard of the Trail Coil assy.

I'm confused about your starter talk. The starter gets one small wire on its solenoid. That is the trigger wire from turning the key to Start. Then there is one large cable on the solenoid. That comes from the batterys positive post. Then there was/is on a stock RX, the large batt neg cable that is attached to the long bolt on the starter (on on one of the bolts that holds the engine to the transmission). The starter gnds thru its case being mated to the transmission/engine. The engine/transmission is grounded to the battery via the large neg cable I just now mentioned.

MAIN RELAY should be seen in this thread somewhere: https://www.rx7club.com/showthread.p...hlight=sensors JPG attahed of it near the clutch master cylinder.

HAILERS

See that blue connector under the TRAIL COIL assy????? If one pulls that blue plug off, and jumpers a wire from the batterys positive cable to the large black/white wire in the connector the blue jumper was attached..........then engine should turn over. Make sure the car is out of gear doing this.

What good does that do??? Assures you that the starter is not the bad actor and that the starting issure is caused by a bad circuit from the key to the blue connector BLACK/GREEN wire.

Dltreezan

iTrader: (3)

alright cool I will try that when I get back home. I still don't have a relay by the master cylinder over there. It is freaking me out. I have the bronze little box but all of my other fc's have a relay there and this one doesn't, however it does have that little blue dummy plugged into the harness. I will jumper that and see what happens.

Where the hell else on this car could that main relay be????

Dltreezan

iTrader: (3)

where is my main relay if it is not by the trailing coil/clutch MC??

satch

iTrader: (1)

If you found B/G jumpered to B/Y and found W/L jumpered to B/W located by the trailing coil then there is no main relay. The "only" job of that particular relay is to jumper those wires internally when the key is turned to "on."