Hello all,
Ok, I have to gather up and post more info on my settings and problem, but since I am in front of the computer at the moment, I figured I could start the question process

Setup:
I have a '88 13B Non-Turbo installed in my off-road vehicle.
Here are some pics and more info on the rig: http://www.luciexyz.com/4x4/Slinky2/Slinky2.htm
Note: motor in photo was the old one that the prior owner burned up.


Scenario:
We wheeled all day into a trail on Saturday. It had no problems firing up and running all day, but it ran really rich (I could feel a raw throat from breathing in the exhaust all day). It also has a very slight stumble(misfire?) when it runs that I have never got rid of.

Sunday morning I go to fire it up and it wouldn't start. I heard a couple of pops like it wanted to start, but then nothing. So we began the long process of checking spark at the plugs, metering all control wires to make sure there wasn't a break anywhere, checking the distributor to make sure the magnetic pickups were working, checked power to the coils which was fine.

What we found was that the Leading coils weren't firing off during cranking. Only the trailing coils were firing. However, when some "criteria" was met the Leading coils started to fire. I am trying to find out if there is some setting in my Microtech or a sensor reading that is causing the Leading plugs to not fire during cranking.

We noticed that the signal is making it to the Microtech controller from the distributor, however, it is not coming out of the Microtech controller going to the coils to fire off the leading plugs. So this is why I am curious if it is a setting of some type or if I lost a sensor.
(i.e. some temp sensor fails giving false overheat scenario which tells the leading plugs to not fire to reduce engine temp.)

Also while troubleshooting, the plugs would get fouled up pretty quick which goes back to the performance issue the day before where it smelled like it was running rich. While this is a problem, it did start and run in this rich condition which was only 8 hours prior. The temp outside did fluctuate from a 0 degree C up to 19 degrees C by the time we gave up troubleshooting.



Do you have any thoughts on this? I will gather some program setup detail, but is there anything else I should look for or provide as information? I am new to rotarys so I have little knowledge on how they "should" run.

Thanks in advance for any help on this.
-Sam

 

Distributer?

Looks like you have a TII engine in there. I can't quite tell but the pictures shows the CAS...

What version of the Microtech?

How are you checking for spark at the leading coils?

 

what computer have you got?

 

Sorry guys for not getting more info yet. I have been too busy as of yet to work on it. Hopefully tomorrow. To answer a couple of the questions you had:

Distributer? - Like I said, I don't know much about rotarys and/or terms, so the distributor that I refer to may be called something else since it doesn't have a standard cap or rotor. It's located on the front driver's side of the motor. It appears to be just a timing shaft with a Hall sensor for each bank of coils. One with 2 pickups which I presume is for the leading spark and the other with several which I presume is for the trailing spark. Both appear to open and close their circuits just fine.

Looks like you have a TII engine in there. I can't quite tell but the pictures shows the CAS... Unfortunately like stated earlier, the pictures shown on the other page are the previous motor. I will have to take a more recent photo of it.

What version of the Microtech? LT-8

How are you checking for spark at the leading coils? Pull the coil wire out of the coil and watch the light show .

what computer have you got? Microtech LT-8


Thanks for the help guys. I should have better details soon.

-Sam

 

My guess is that the leading ignitor failed (or is failing). If you have a scope you can check the signal at the input of the ignitor to verify that the Microtech is firing it, but the easiest troubleshooting is to just swap the ignitor.

 

Thanks for the suggestion Aaron. Very appreciated. Just so I have my terms correct since I am not an engine guy, the ignitor is the same as the coil correct?

If so I think we accomplished testing the microtech trigger in a similar way as you described by pulling the plug from the Microtech and reading the output signal straight out of the microtech itself. The signal from what I call the "distributor" or hall sensor goes into the controller ok, but never comes out.

So that is why I was wondering if there is a sensor or setting of some type that tells the leading to fire or not fire under certain conditions.

Also, I need to find a good place to read what all the codes do. Does that exist here or somewhere on the web or should I get in contact with Microtech? If you happen to have a link that would be awesome.

Thanks again for the help.
-Sam

 

The igniter is the little silver box the coil mounts to. It's what actually provides the current to fire the coil.

There's no sensor to tell the coils when to fire or not. That is determined by the ECU, which measures the engine position using the crank angle sensor.

By codes, are you referring to the flashing error light? The best way to figure it out is to connect a laptop or hand controller and read them directly.

 

Ok, got it. I will check that.

I am not getting any error codes on the hand controller or through blinking lights. The codes I am referring to are what I am programming. Such things like mixTRM, etc. I am just curious what each of the parameters in the Microtech are.

Thanks again
-Sam

 

Ok, I got a chance to play with the rig today (finally). It has been a while, so now I am trying to dive in and get it running again.

Just to recap, the motor cranks over, but I don't seem to get any kick. It doesn't want to fire at all.

The first thing today I was plugging in the controller and I found that there were 2 errors that came up. First was a "Ref" error and on the next page an "RPM" error. I figured that would be the CAS (Crank Angle Sensor) went bad somehow. I had checked it before to see if it was working fine and it was, but just to be sure, Paul over at "RotorSport" hooked me up with a test CAS and I checked it as well and plugged it in. Same problem. I searched this forum for similar errors and the result was similar with the CAS being being the suspect.

So if that was fine, I went and checked my wiring. I traced the wires back to the ECU and they seemed fine. They traced out ok.

HERE is where it gets weird. So my buddy stopped by and I started describing everything I went through. I then wanted to show him that my Leading coil was working fine, but my Trailing wasn't (per what we troubleshot on the trail). I pulled the Back Leading (rear rotor leading spark plug) coil wire from the coil just to show it could jump across. I asked first if he wanted to feel what the spark felt like, but he laughingly declined the offer.

So, I started to crank and it didn't fire off at first (weird), but then it started to spark and the motor started to kick and fire up. Shocked by this, I plugged it back into the coil and tried again. Nothing. I pulled it out partially, the same exact scenario happened again. It started to fire up with the coil wire pulled but the spark jumping across to the wire.

So I am trying to understand why it would fire up with the coil wire unplugged and not plugged in. Here are some thoughts:

Could that be a sign of the coil going bad? My initial thought, maybe with the wire pulled the coil is only able to release charge half the time and has more time to charge up and make a higher discharge for the single firing then once going can work normally?

Could it be a bad plug wire that is grounding out somehow and pulling the charge from the coil even though I am not hearing it pop anywhere?

I am not engine wiz and am learning as I play with things, so any help you might have on this would be great. Before I go buying and replacing things, I wanted to hear opinions first.

Thanks guys.
-Sam

 

If you're not getting sufficient spark, you should be smelling fuel, or see fuel on the tip of the spark plugs when you take them out.

If it was running before, could be fouled plugs. Try throwing some new ones in to see if it'll fire up.

 

So up to this point I have done the following:

Changed plugs
Changed plug wires
Relocated coils closer to motor to shorten distance so that I can run stock length wires
Verified CAS is working
Verified that CAS wires going to Microtech are not broken

I read somewhere else on this forum that one set of plugs don't fire (as of this posting I can't recall if it was trailing or leading) on cranking when using the LT-8. So that might, if it's true, explain why I was seeing that out in the middle of the trail when troubleshooting.


I will keep playing with it and start all over from the beginning. Verify spark, fuel, grounds, etc. The only thing I am unclear on is if my map settings are causing a big problem in this.

Thanks for the help
-Sam


Here is my current map in case you see anything weird there:
Idle Map
Screen 1

30" 1.33
25" 1.48
20" 1.93
15" 2.38
10" 2.48
5" 3.48
0" 4.00
2-20PSI 4.95

Load Map
Screen 3

30" 1.76
25" 1.86
20" 1.95
15" 2.24
10" 2.90
5" 3.90
0" 4.81
2psi 5.62
4psi 6.10
6psi 7.14
8psi 7.86
10psi 8.49
14psi 8.71
16psi 9.00
18psi 9.48
20psi 10.00

RPMwot
0% all

RPMcrs
0% all

Pump Map
Screen 19

Pump2Start 2000
Pump1Amt 10
Pump1Pulse 2
Pump1Trig 14
Pump1Stop 0
Pump1Adv 5

Pump2Amt 10
Pump2Pulse 30
Pump2Trig 16
Pump2Stop 0
Pump2Adv 5

PumpDwell 3
PumpTimers No
PumpSync No
PumpSpare 0
PumpCold 0

WaterMap
Screen 20

-25 0
-17 70
-9 60
-1 55
5 50
11 50
18 45
24 35
31 30
38 20
46 15
60 12
68 8
82 0
99 0
124 0

Air_tMAP
Screen 21

-25 0
-17 8
-9 6
-1 5
5 4
11 3
18 3
24 0
31 0
38 0
46 0
60 0
68 0
82 0
99 0
124 0

Cank Map
Screen 22

-25 72
-17 72
-9 72
-1 67
5 62
11 57
18 50
24 41
31 31
38 26
46 20
60 15
68 5
82 0
99 0
124 0

t*rpm
Screen 23

Idle 0
1000 10
1500 15
2000 20
2500 25
3000 25
3500 25
4000 25
4500 25
5000 25
5500 25
6000 25
6500 25
7000 25
7500 25
8000 25
8500 25
9000 25

t*Map
Screen 24

Idle 0
25 5
20 4
15 3
10 2
5 0
0 0
2psi 0
4psi 0
6psi 0
8psi -2
10psi -3
14psi -4
16psi -5
18psi -6
20psi -6




t*gap
Screen 26

500 15
1000 15
1500 15
2000 14
2500 12
3000 10
3500 10
4000 10
4500 10
5000 10
5500 10
6000 10
6500 10
7000 10
8000 10

t*Inj Map
Screen 27

500 120
1000 150
1500 150
2000 150
2500 150
3000 150
3500 180
4000 180
4500 210
5000 210
5500 210
6000 240
6500 240
7000 270
8000 270
9000 270

t*wat Map
0 All

Option Map
Screen 30

Af_StE 10
Dwell 3 set at Time Base no Duty Cycle
REVstg 3000
MAPstg 5"
%stg 50

Aux
RPM_ON 60
Map_ON off
Fan_ON off
FanAdd 0.10
Fanair 0.10
AirMin 10
AirMax 10.52
AirWat 0.80
Airafs 0.10
RPMset 2820
pwmLOW 0.76
pwm_HI 7.62

Imp
RPMlim off
Air add 0.19
Enrich 0.14
Timing 5 degrees

Opt
mix trm 0.23
opt tpscal 14
Tim Trm 7
Static 5
Tim Max 35
RPMwot 4
rpmCRS 17
Af_STE 10
RevLim 7180
RevCut off
BSTcut off
Rev stg 5"
%stage 50
Decel off
Dwell 3.50

 

set your mixtrm to 0.00.

verify that your getting an orange light flashing on crank.
make sure you have spark on your leading. trailing wont have spark crank.

verify you have fuel pressure.

and if it still dosnt start.
tow start it.

 

Interesting. I actually get spark on my trailing and not my leading during cranking. It has been this way since I have owned it. Could they have actually wired that up wrong?? It looks ok going into from the CAS to the ECU from what I saw. I will now have to verify somehow from the ECU to the coils. If that is correct, thanks for the tip. I also have the blinking orange light as well when I crank.

I tried playing with the mixtrm, but didn't see any difference, but then again I didn't play with it long. I was hunting down the no leading spark problem.

I seem to have fuel, but I have yet to verify fuel pressure. I will have to find out what is normal. I haven't checked because it seems that I get plenty of fuel since I get a lot of fuel out the pipe after cranking for a while.

It's an auto tranny so tow starting isn't much an option in my case. I actually tried while we were on the trail

Thanks for more tips on what to look for.

-Sam

 

LT8 doesn't fire trailing during cranking...

If you are not getting leading spark even after a coil replacement, then something is wrong with the wiring or Microtech.

Make sure that you have 12V at the tan wire (on the ignitor) and at the coil + with the key on. If that checks out, find a scope and probe the pink wire (I think grey/blue on the Microtech harness but check the diagram) and make sure you have a series of pulses while cranking.

 

Thanks for the additonal help Aaron. I don't get much time to play with it right now, but here is what I gathered tonight. I quickly ran down the wiring and wrote down what I have. Here is what it looks like. I couldn't see the wires going into the leading coil because it got dark before I checked.

Click on the thumbnail below to see the ignition portion of the schematic that I traced:


I haven't changed the coil out because I don't currently have a spare to throw in there. However, I saw it would fire off if I pulled one of the plug wires out from the coil. However as stated above in a previous posting, it doesn't seem to fire off when I plug it back into the coil. Odd?

I am seeing 12V at the tan wires with the key turned on. I didn't get a chance to probe the pink wire while I cranked it yet. What should I be set to on my meter? Would I just set it to DC volts and watch for spikes?

I tried finding the wiring diagram for the LT8 to RX7 (88 non-turbo motor which I believe is a FC? if I recall correctly) on the microtechefi.com website, but found only a MTX8 diagram which has different wiring colors. Does anyone have a link that they know of off the top of their heads? I will do a search here on the site as well to see if I can find it.

Thanks again for the help
-Sam

 

So I did a bit of searching again and I know the following links which I saw before:
http://www.microtechefi.com/pdf/LTX8...ries6FDign.pdf
http://www.microtechefi.com/pdf/LTX8...3BTS4-5ign.pdf
http://www.microtechefi.com/pdf/LTX8MAZDA13BT.pdf
http://www.microtech-efi.com/downloads/17.pdf

These all seem to be different than what I have per color codings, but maybe if I get the colors noted I can use them.


I found part of my wiring question here:
https://www.rx7club.com/newreply.php...te=1&p=7237064

Which was this:
Coil Green/yellow ----- Grey/blue
Coil Blue/yellow ----- Grey/red
Coil Brown/yellow ----- Grey/black

I have that correct so far. Time for work so more hunting when I get home.

-Sam

 

The LT8X diagram is different from the LT8 (or LT8s).

With the grey/blue wire on the green/yellow wire at the leading coil things should work. You'll need to scope the wire and see if you have a signal from the Microtech.

You can also test the coil/ignitor assembly by applying 12V to the black/yellow wire, and then using two AA batteries in series (ground the - to the chassis) to pulse the green/yellow wire. When you tap that wire and let go, the coil will generate a spark.

 

Just got home and there is little to no light. Grrr... Time for head lamps again.

Anyone have a link/copy of the LT8 wiring diagram by chance?

I will check to see if I have signal from the microtech and if I am getting spark from the coil which I am pretty sure I am since I watched it fire off several times. But just to make sure, I will check it with your trick.

The confusing part here is that I have seen it said that I should not see trailing spark when I crank, yet I do and I don't see leading spark when I crank. How could that be if it appears to be wired up properly? Is there something in my settings somehow causing this or a bad sensor that could make this happen?

Thanks again for any info.

-Sam

 

A quick FYI, I just tested the Green/Yellow (Gray/Blue) wire and I am seeing about 1.7 volts as I crank. I am not sure what it should be, but at least I am seeing something.

Sounds like a bad coil or one that is flaky (ignitor most likely?). Time to hit up RotorSport and see if I can try one out.

Still doesn't answer the weird question of why I am seeing spark on the trailing as I crank. Piculiar eh?

-Sam

 

So I had some time yesterday and noticed some ugly wiring. So I decided to clean it up while troubleshooting my other problem. As I did that I noticed even more. So out comes the book and I start tracing all the wires and recording it all down because as I can see, this thing needs a lot of wiring help.

Luckily I did this because I found some creative wiring techniques not used in any other traditional wiring methods that I have seen before. At one point I had at least 6 wires intersecting each other but through various means all within 4 inches of each other. I should have taken a picture.

Anyway, I was able to find another problem. The wires going to my MAP sensor on my intake were actually damaged. There were two splices in a row going to the plug before the MAP and just beyond the splices on the brown wire, it was broken off. I am not sure what these 3 wires do, but I can only presume help make the vehicle run. So I have that to fix.


So here are the list of questions thus far:
1) Is the 1.7 volts that I saw during cranking the right voltage to see for the Leading spark signal from the Microtech to the coil?
2) Any ideas on why the trailing coil would want to fire during cranking when I have read that it isn't supposed to?
3) Does anyone have a link to the MT-8 wiring schematic by chance? I found others, but not the MT-8.

Thanks
-Sam

 

I've never measured the voltage at the ignitor during cranking. What you are measuring is probably the average of the pulses the Microtech is delivering. If you had a scope you would see a square wave.

On my LT8s unit, trailing fires during cranking. On other LT8 units, I've never seen it fire. So my guess is that it's a software change.

Sounds like you have a bit of a wiring basket case. I've dealt with cars like this and always found that it is far easier and faster to just rewire the whole thing instead of figuring out what the previous person did.

 

Cool thanks for the thoughts once again.

I am not a car nut or an electrical guy, but I can tell that something wasn't right when it looked like a pile of wires stuffed into a kitchen drawer. You know that 1 drawer that everyone seems to have in their house full of stuff that no one knows what to do with. If you can imagine that drawer, then you can imagine the wires I am following. Now, on top of that, the oil pressure guage leaked over everything making it nice and "lubricated"

Thanks again.
-Sam

 

So I went downtown and got lucky. No not that kind of lucky. I actually went to a wrecking yard to get parts which are either damaged in my cluster of wires or would be great spare parts for when I am on the trail in the middle of nowhere.

So I went to this one yard that I knew of a long time and went car shopping. The problem is, what is the liklihood of finding an RX-7 in a yard that is of the same year and model of what you run... AND... still has parts in it that are in good condition.

Oh yeah. Bingo!!!. Talk about luck. I found an 88 non turbo with the motor and parts still there. I can't believe it!! Considering the coolness of these motors, I would have thought it to be gone. The injectors were gone out of it, so somebody knows it is there. However, I was able to get the Leading & Trailing coils, the CAS (just the hall sensor portion), the TPS assembly, and several of the plugs that are damaged. I also cut a few of the plug connectors out from different parts of the car so that I can make some quick connects for my wiring in the console. The nice thing about the Mazda connectors, although they are hard to remove the wires from, they use what look to be standard flat blade connectors which are easily replaced.

So if anyone in the San Francisco Bay Area needs a 13B non-turbo motor core, it appears to be mostly all there and in pretty good shape.

Time to go fabricate a wiring harness.
-Sam

 

Hey Sam, have you posted in the West section of the forums yet? I'm sure they'll drop their jaws when they see your bitchin' crawler!

Besides that, there are alot of great people in your area you can meet, and I'm sure they'll help you out no problem. Drop by sometime.

 

You either have two problems. Your computer is faulty. Or your wiring.
Id start with wiring seeing as you can fix that locally.

This is what id do. Id remove the 6 pin(3 wire loom) from the car. strip it down. check for damage or cuts etc.

ID then get a multimeter and check that the coil packs both leading and trailing are getting 12v whether its all the time or on ignition(usually ignition). You need to test the Tan wires(ignitor, not car(plug side)). Their are two on the trailing and one on the leading.

Then lets go back to the microtech loom.(for future reference use this wiring diagram for your ignition side of your computer http://microtech-efi.com/downloads/17.pdf ).

Grey blue must go the leading ignitor. and onto the pink wire(again ignitor side not car(plug side)).

Grey Red goes on the pink wire on the traling ignitor
Grey black goes on the white wire on the trailing ignitor