Chris Boots

I have a completely rebuilt a TII engine that I have put into my NA body for a swap. It has a 1988 TII ECU and boost sensor etc. and Everything on the engine is S4 turbo, except for the wiring harness (heard it was easier to convert) Everything plugged in fairly easy but I now have a few questions cause its not running right:

First is the knock sensor. The directions on how to hook it into the wiring harness have been pretty vague. The only thing I have heard is that you splice/connect it into the Light green with black stripe that usually plugs into the powersteering wire near the leading coils/under the fuse box. So its plugged in there for now. Is this right? I know a lot of people have come across this question in their swaps so this answer should be easy...

Second is starting. Cold it doesn't rev up after about 4 cranks and idle at 1250 for a while like my NA did. HOT it doesn't start easy at all. I have to either wait a while and give it a little gas to get it to fire or sometimes I have to turn my fuel pump off and crank till it idles up and then turn it back on. BTW it has a S6 fuel pump so thats not a problem.

I haven't boosted it at all yet cause the engine needs to break in, Oh and the ECU won't throw a code like it should. What are some ways you guys get a code out of it? I have another ECU I will try for it tommorow (N332 instead of a N333) I'll see if that makes a difference. Until tomorrow or Tuesday it will have a NA MAF in it but I'm told that it won't make much of a difference in getting it to start normally.

Any help with this is appreciated. Its taken a long time to get this far only to find I have more problems Thanks

HAILERS

For the knock sensor to work on a series four, you need a Knock Box/Controller. Do you have that?

Guessing a bit here. Just throw the na pump in the tank and see if the starting when hot etc is better or not. After all, you said your not boosting right now and it will only take thirty minutes or so to do.

The codes should work. I've a turbo in a 87non turbo car and the codes work normal. It did with N332 or N333. It's odd that you can't read faults.........unless there are none. Then that would make sense.

arghx

iTrader: (3)

a good thing to always check/replace when it comes to cold starts and cold running is the water thermosensor on the back of the water pump housing. Are you using your old one, or one that came with the engine? OEM replacements are about 40 dollars, and parts stores sell them for like 20

Chris Boots

I don't have a knock control box actually. Describe to me what and where it is/goes/plugs into and I'll get it off my parts car. I ran the S6 fuel pump in this car when it had a NA engine in it and it started/ran fine so I don't think that could be much of a problem. Lemme see if I'm doing this right... To test a code you either make the LED style checker and plug it into the connector or use the Mazda Tester. To check for a code you turn the key on and engine off and it should throw a code, Or does the engine have to be running? I know there would be a code if I could check for one.

Thanks for the tip on the Thermo sensor, I'll replace it today.

HAILERS

It's located in the passengers foot well. Up and to the right near a couple of orange elect plugs. It's within a few inches of the item in the attached jpg. Also near the ATP sensor.

Chris Boots

Ok, I'll try and get one. But how do I plug it into the NA harness? Or, could I just disable the entire Knock Sensor System and have no problem (ie Turn the wheel and the ignition retards). I replaced the Thermo Sensor and that made no difference. Could the NA MAF be the reason it not starting right up? I should be getting one tomorrow. There's no problem having a NA gauge cluster right? It won't mess anything up?

Chris Boots

Anyone have anymore thoughts on this?

TehMonkay

iTrader: (-1)

It was just rebuilt it still has low compression, expect hard starts for a while.

Are the injectors cleaned?

Chris Boots

When I mean low compression we're talking over 80psi and under 95ish. Still it shouldn't be this hard to start.

TehMonkay

iTrader: (-1)

95 is what is reccomended by mazda to rebuild at, at least since the 3rd gen came out.

Did you clean the injectors?

HAILERS

Just pull the plug off the TPS or even easier, the boost sensor and a code should arise.

The wire from the knock sensor goes to the Knock box, not the ECU.

A water thermosensor will not cause a hot start problem, only a cold start problem (ECU defaults to 180* when the sensor is open or a wire is open b/t it and the ECU), and it's easy to check out if it's any good or not. When hot the input to the ECU should be approx a half volt (0.50vdc).

Hot start problems are caused by too much fuel on a car with low compression. You can only overcome this by interrupting the Start signal to the ECU during hot starts. Fuel during starts is by a preset Start map internal to the ECU. The afm is not used during Starting. If the ECU never sees the Start signal, Then it will use the afm signal for fuel. That fuel amount WILL be much smaller than the preset Start map internal to the ECU. Pin 3B is the Start signal to the ECU.

Well you can overcome it with a fuel cut switch and help wear out the starter. humor.

Engine does not rev to approx 3000rpm duing cold starts and then drop to 1500 and slowly drop to the idle of approx 750rpm? Partly a BAC problem and partly a bad rig of the water thermowax device imho. Get some miles on the engine before doing anything. But I'd check the BAC to see if it's doing anything at all. You should have had to lengthen the BAC plug to reach from the left to the right side of the engine bay. Mabe the problem lies there?????

The engine will start and run fine without the knock sensor seeing as how your not boosting right now anyway. I'd disconnect the knock sensor output wire from where ever it's going now.

The BAC goes full open duing START. After the engine starts, it stays at a high duty cycle for 17 seconds causing a high idle during cold engine starts.

The Knock Box........personally I'd forget it for a while. But once you decide to mess with it, it's easy to get working. It has only for wires to it. One is ground. That's easy to make. Just go to a gnd point with that wire. Another is 12vdc. Easy again. Pickoff from the small plug of the ECU the 12vdc. Pin 3J, a white/blue wire.
Another wire is the output from the knock sensor. And the last wire is the output from the knock sensor to the ECU.

Like I said, run NO wire from the knock sensor for right now til you get things sorted out.

The gauge cluster matters not at all since your using a non turbo EM harness. It would be a problem if you uses a Turbo EM harness.

A chart is attach showing how Starting fuel is used during .......Start. By Start I mean under 500rpm and the key HELD to Start, just like the attachment shows.

Once you get the engine running where you have faith that it is a good engine, then consider someday buying a RTEK2.0. It has some features like the ability to control the fuel amount used During Starting, to prevent flooding when the engine is hot.

EDIT: I was just rambling above and there is no order to the comments.

Chris Boots

Thanks for the info Hailers. I did in fact lengthen the wires connector going to the BAC. I'll test it again today. I have heard that the knock system is not even very reliable and isn't used much or even at all, so I'll just leave it off if it won't throw a code or change the way this engine starts. I have been thinking about getting a Rtek2.0 for a while now. A friend of mine has one in his car and it starts perfect at 70 psi of compression so I know that that ECU helps a lot. Oh and he doesn't even have a knock system in his car anymore and it is fine. I'll get the right AFM today and test all my systems for a problem, that and get some miles on the engine.
But for some reason I can't get a code no matter what I do. I have even used two different ECU's (N332 or N333). Still same symtoms and no codes. Is there any way to test the code connector? maybe I have a short?

HAILERS

Are the two led's your using any good? Try them in the TPS check connector and see.

When in the six socket diagnostic connector, and you just turn the key to ON, do the lights light up for a second then go out?

The really should work especially since you used the original na harness.

Chris Boots

I'm using the SnapOn Modis to check the codes. It has the same connector and everything just like the Mazda Checker does except when it finds a code it stores it in its memory and Identifies it and tells you how to correct the problem or test the deffective part. I've been using this on other rx7's and it works great... but not so much this car. I will however have the actual Mazda code checker in my hand tomorrow and will try that. I just need to know if there is a problem within the harness or something that would keep it from working right. The FSM doesn't tell you how to check the code check connector

HAILERS

Well, neither do I. But we KNOW the black/white wire should have 12vdc to power the LED'S or tester, and the other wires go to the ECU. The other three wires on that connector go straight to the ECU with no other connectors in the harness in between.

So I'd go out to the car and see if that black/white wire has 12vdc or not. Key on. Odd problem. I'm looking at a 1987 FSM wiring. I'll look at 88 wiring and if I see something different I'll say so.

EDIT: Looked at the 88 FSM and there are no differences. All three are a straight shot to the large plug on the ECU.

HAILERS

Only two wires on the ECU are diff b/t the two ECUs. Pins 1R and 2K. The 2K is twin scroll solenoid signal outputed from the ECU to the twin scroll solenoid. You have to install a extra solenod for the twin scroll to work (just use the EGR solenoid if you have a series four. Just the solenoid of the EGR, not the wires to it).

1R is the knock sensors output signal TO the ECU. Just leave the wire off the knock sensor for right now. It will go to a Knock Box if you decide to use the stock knock box. Right now, if your car has no pwr steering, you have to do nothing with the 1R wire. IF you DO have pwr steering, then it's best to remove the 1R from the ECU plug for right now.

In other words if you have a turbo afm, pressure sensor, ECU then the engine should run just as good in your chassis as in a turbo car chassis.

Chris Boots

Thanks for the info. I'll check for power on the connector after work today. I'm not using a twin scroll system so I'll leave that disconnected and tied back. I'm probably not going to use the Knock system cause its pretty useless being its already too late by the time it kicks in, so I'll leave it disconnected and unpinned.

Chris Boots

Well i fixed the code test connector and it works perfect. But. The problem remains. I unpinned the wires you told me to and still no difference. Could a bad BAC valve be the problem. Or will a non turbo BAC valve work...

HAILERS

Hold a BAC in your hand. Either BAC will do. Connect it to the harness. Key to ON. USUALLY the BAC will start vibrating (doing its duty cycle). If not, then reach over and move the throttle a bit (moving the TPS) and then see if it's vibrating.

No vibration? Do this. Hold it in your hand and look into it while someone turns the key to Start. The plunger/valve should go full open (moves only about a quarter inch when going full open) when the key is held to Start. I've done this by myself by removing the small wire from the starter solenoid (the one on the blade connector) and then put the BAC up where I could see it from the drivers area while going to Start.

No movement ever. None at all? Bad transistor in the ECU maybe. Put the non turbo ECU in the car and repeat the above. Make sure the two wires to the BAC do not touch each other. OR look at the BAC plug and make sure one of the two sockets isn't pushed back in the plug. I'd do that first. No contact......no worky.

Non turbo BAC is not adjustable. You'd have no way to adjust the idle in a Normal way.

Don't ever force anything internal to the BAC with a screwdriver etc. No touch.

Chris Boots

Thanks, I'll try that right now. As for the idle... I have a Jspec upper intake which has a different idle adjuster than you guys are used to seeing. You've probably seen one hailers. Anyway, A Turbo BAC is not needed to adjust the idle on this intake

Chris Boots

Well you were right Hailers. I checked the BAC valve circuit with a New N326 BAC valve and it vibrated and opened when I would tap the key. Then I took off the BAC valve that was on the engine and tested it the same way and it did Nothing at all. So I'm going to put my new BAC in tomorrow (when theres light out) and hook it up and see what happens, maybe it will run normal
On another thought, I have just created another post asking where the wires to my Water temp switch could be. I have the switch on the bottom of my radiator but no wires going to it. Maybe I haven't looked hard enough but I can't find them. Maybe they didn't use the switch on Manual trans?

HAILERS

Series four manual cars have two black bullet connectors in that general area where the switch on the bottom of the radiator is. I don't know what else to say. Just fish around. Their part of that Front harness that runs on the left side of the enigne bay. They ought to be somewhere b/t the engine fuse box area and that water temp switch area.

It's an emissions switch. Below a water temp of approx 65* it's contacts are open. Over that temp they close and put a gnd on a pin of the ECU. It has some control over the Relief solenoid when the engine is colder that 60* in the radiator.

Soooooo.........if you ever have a bad switch in the radiator, just connect both the bullet connector together to make the ECU see what a normal car sees when the water temp is up above 65*. One bullet goes to the ECU. The other bullet goes to gnd.

Chris Boots

Alright, I'll look for the wires after work today. If I can't find them I'll probably just jump the ECU wire close to where it plugs into the ECU. So... this doesn't effect they way this thing starts?

Chris Boots

OK after a long search I finally found the wires. (they were underneath the battery box) My switch that they would go to is broken so I jumped the wires. I got all the parts for this swap and put them in. The car starts right up when cold but not so easy when its warm. To start it warm I have to turn the fuel pump off (with the switch I wired in long ago) and crank till it starts and revs a bit then turn the fuel pump back on immediately. Its kind of a pain but its better than it not starting at all. It idles at 750 perfect, the TPS is tuned right and everything apears to be functioning. But somethings wrong or else it would start right up. OH, when you start to drive it, it won't rev smoothly above ~3000 rpms or higher unless I floor it or ease off the gas as it accelerates. Thats the biggest pain. I changed the fuel filter in it and it still has the same problem. I'm outa ideas.

TehMonkay

iTrader: (-1)

You still didn't say if the injectors have been cleaned or not yet.