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82 Rx-7 – S4 t2 Swap

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Old 03-18-13, 03:40 PM
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82 Rx-7 – S4 t2 Swap

I have been slowly working on this for a while now. I am at the final stages, but I am not getting spark or fuel injector pulsing at the moment. HELP!!

Here is my Setup:
1988 13bt engine/ign coil/right side wiring harness
Stock N333 ECU
All emissions stuff removed
12a trans, starter
na s4 flywheel +clutch
Surge tank and additional fuel pump added

So now to the problem of no spark and no injector pulsing (Checked spark and injector pulse by key on and spinning CAS. Also held AFM open to check if that made a difference):
  • Fuel pump turns on; (with key on, and afm open)
  • I have power and ground at the ecu (with key on)
  • Resistance of CAS is within spec (checked both at the CAS and at the ECU)
  • Resistance changes when I spin CAS
  • I have power at the coils (12V on both wires; need to check grounding of coils)
  • There is 12V going to the injectors from the ECU when key on.
  • Main relay provides 12V to the injectors on key ON (checked at FEM-02).
  • Tried a N338 ECU sourced from the junkyard (not sure if this ecu is good, but what are the chances my N333 and N338 are both no good)

These are the next things I am going to do to figure out whats going on:
  1. Check voltages at all ecu pins and compare to FSM; This should rule out whether its an ECU issue. Someone please confirm this.
  2. Modify the mounts on ignition coils. I have read that the coils are grounded through the mounts. I need to make sure these are getting good ground connection.
  3. Clean ECU ground.
  4. Pray I don’t get this far.
  5. Clean every ground on the car.
  6. Re-evaluate this whole swap idea. Carbs aren’t THAT bad.
  7. Replace CAS (just in case).
  8. Replace ECU (just in case).
  9. Replace AFM (just in case).
  10. Replace ALL wiring (what else am I going to do).
  11. Give up.

Anybody have any input? Am I going down the right road here?
Old 03-18-13, 05:11 PM
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i'm fairly green at troubleshooting the Gen II stuff, so bear with me if you have already done this, but did you swap over the resistor for the injectors?

definitely revisit the grounds also.
Old 03-18-13, 07:48 PM
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I believe these are high impedence injectors therefore no resistors needed.
Old 03-18-13, 08:43 PM
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I guess that answers that then, eh? well, i'm spent for now. i'll go back to giving it some thought.
Old 03-19-13, 12:06 AM
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Coils are grounded through the mounts, found that out the hard way on the S4 engine I've got.

Pretty sure the stock ECU for S4 TII's was N332 from 87-88, and N333 was for S5's from 89-91. Double check on that, but I thought that was how it went.

I would try with the checking voltages at each pin to verify everything is connecting right so that you know it isn't an issue there.
Old 03-19-13, 09:17 AM
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Originally Posted by diabolical1
I guess that answers that then, eh? well, i'm spent for now. i'll go back to giving it some thought.
Thanks for the thought. every suggestion helps either rule something out or make sure it isn an oversight.

Originally Posted by lindahlish
Coils are grounded through the mounts, found that out the hard way on the S4 engine I've got.

Pretty sure the stock ECU for S4 TII's was N332 from 87-88, and N333 was for S5's from 89-91. Double check on that, but I thought that was how it went.

I would try with the checking voltages at each pin to verify everything is connecting right so that you know it isn't an issue there.
Ive been reading your threads and may have found out about the coil mounts from one of them.

Did a quick search to make sure the ecu was right. here is what i found:
N326 - 86-87 NA
N332 - 87 Turbo
N327 - 88 NA
N333 - 88 Turbo
N338 - 88 Vert
N350 - 89 NA California
N351 - 89 NA
N352 - 89 Vert California
N353 - 89 Vert
N370 - 89 Turbo

So it looks like I do have the right ecu. Also on a previous search I found out that N338 ecu will also work for S4 turbo. Apparently it has something to do with then being able to switch between seetings based on inputs that are supplied tothe ecu. Dont quote me on that part though, I have never successsfully used one on a running t2.
Old 03-19-13, 09:45 AM
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Originally Posted by yardy8301
Ive been reading your threads and may have found out about the coil mounts from one of them.

Did a quick search to make sure the ecu was right. here is what i found:
N326 - 86-87 NA
N332 - 87 Turbo
N327 - 88 NA
N333 - 88 Turbo
N338 - 88 Vert
N350 - 89 NA California
N351 - 89 NA
N352 - 89 Vert California
N353 - 89 Vert
N370 - 89 Turbo

So it looks like I do have the right ecu. Also on a previous search I found out that N338 ecu will also work for S4 turbo. Apparently it has something to do with then being able to switch between seetings based on inputs that are supplied tothe ecu. Dont quote me on that part though, I have never successsfully used one on a running t2.
That's why I have all of those links posted at the beginning of my build thread - for anyone who needs some help (including me) it's an easy place to look. I'll be posting up some more here soon with another list that's almost as long as the first one.

Awesome, I didn't know that there could be interchangeable ECU's. I'm sure it's possible to switch them out, you'd just have to really know what you're doing.

I'd check with the multimeter idea first, even thought it's gonna suck.
Old 03-19-13, 06:59 PM
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Ecu results were not good. Trying to find known good ecu now. This seems to be the issue.
Old 03-22-13, 08:04 PM
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Found the issue. I hadnt hooked up 3I on the ECU to the main relay. Didnt notice it on the wiring diagram until i was reviewing it for the 9440th time. I connected it at FEM-02 and now I have spark and injector pulse.

Didnt have time to connect everything back up and attempt to fire her up.
Old 03-26-13, 03:59 PM
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VA

Had some time to try and get her started with no luck. I knew I had injector pulsing and spark. I checked to make sure there was fuel at the rail and discovered I wasnt getting fuel to the injectors. Traced the issue back to me hooking up the fuel pump lines backwards....duh.

So that issue is now resolved. I was feeling pretty confident this would be it, but still nothing. no start.

Pulled the plugs and the egi fuse, cranked the motor for 10 seconds (hoping it is just flooded). While unflooding I observed nice even puffs from the rotors. I then added a couple drops of engine oil in each leading plug hole and installed brand spanking new spark plugs. While I was at it I checked my timing and it was spot on. This had got to be it. But still no luck. By this point battery was getting a bit weak.

And that is where I stand now. Still no start. where do I go from here?
  • Got Spark
  • Got injector pulse
  • Got fuel at fuel rail
  • Ignition timing is correct
  • Unflooded Engine
  • Added oil to help build compression
  • Changed spark plugs
Old 04-02-13, 04:16 PM
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There was just no reason for the car to not start. I started considering maybe I have clogged primary injectors.Tthat would explain no start, but would I hear the injectors clicking? maybe, dont see why not. Before I went out and bought random parts (new or cleaned injectors) I figured I may as well test if it was fuel related.

So got some starter fluid. Car started and idled fine. Go figure. I still plan on sending my injectors off to be cleaned and flow tested. The engine had been sitting for a while so who knows why it didnt start before. I let it idle for a little bit before discovering a couple leaks.

Need to get new oil cooler lines as well as water pump housing gasket. After which Ill be in business...... not really as I still need some suspension and brake work before its road worthy. Pics to come.
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