#4 cylinder is dead after MsPnpPro install
6 Attachment(s)
EDIT: RESOLVED. Turned out that I had a '93 California-model ECU which had sequential injection by default, so my MS3 set up by default for batch mode was only firing two cylinders. Turned on sequential injection and everything was :winner:
Hey dudes, I've been banging my head against this dead cylinder for a while now, have looked through lots of intertubes and forumz and yuhtubs, and now come in shame to y'all for some help. Here's the sitch: '93 1.6L Miata, installed an MSPnPPro (MS3 Pnp)--including an AFM delete and an IAT install--and now cylinder #4 is dead. I'm running the base map provided with my MSPnPPro + setup steps called out in instructions (e.g., set timing). Innovate MTX-L wideband. NGK Iridium plugs. Magnecor wires. Racing Beat full exhaust. No other remotely engine-related modifications. The car seemed to be running fine on all 4 cylinders before I did the MS-install + AFM-delete/IAT-install + spark-wire-swap (did all three at once). How I know it's #4 that's dead, specifically:
What I've done so far:
Total list of everything I've done that might possibly affect things:
Any suggestions for what to learn / where to look next? I'm honestly not sure what to do next to figure out what's wrong, and don't really want to throw money at replacement parts if I don't know. |
Fuel, air, spark, compression, timing.
Generally you want to run cheap sparkplugs (NGK BRK5E is stock iirc) when tuning so you can take them out and read them. Is your car california spec? Those were sequential injected, the rest were batch fired and the wires have a joint about 3 inches from the ECU plug if memory serve.. MS appears to be set up for batch. Wondering if you're only injecting on cylinders 1 and 2, but there's enough suction to pull fuel to cylinder 3 but not 4. Might try disconnecting injector 3 and see if it behaves the same. 3.0ms is a little low for stock coil dwell, wants to be closer to 4. 5ms/5.5ms for cranking. |
Originally Posted by mopnbucket
(Post 1562890)
Verified ignition components are not the problem (note, didn't say "spark is not the problem"): Popped into injector/spark test mode in Tuner Studio, manually triggered each coil, confirmed that they were all triggering with a timing light on each wire. Then pulled the #4 spark plug out of the car, grounded it, and triggered it via TunerStudio and confirmed that it is in fact visibly generating spark (when outside of the car). So the coil, wire, and plug are all doing their jobs, though I can't confirm that the spark is actually firing inside the engine.
Maybe worth a deep search... |
Check wiring! I had a Hydra installation that would intermittently drop one of the injectors due to a poorly soldered patch harness.
Wiggling the wires at the connection to the stock wiring harness confirmed the problem. Sounds like you have lack of fuel. You could pull plugs to verify. #4 will look NEW and the others will look a little bit dirty. You could swap injectors around and see if the problem followed the injector. My money would be on wiring problem. Did you change injectors at the same time? If so injector could be issue. If not look to wiring. |
Originally Posted by gooflophaze
(Post 1562891)
Is your car california spec? Those were sequential injected, the rest were batch fired and the wires have a joint about 3 inches from the ECU plug if memory serve..
I don't live in CA, so just to double-check I did some Googling and it looks like the part number for the 93 CA ECU was "B6AW..." and guess what it says on my old ECU? Looks like I have a Cali ECU indeed. Man I never would have found this. Thank you, thank you! Popped into my MS3, set up the jumpers as described in the instructions for sequential injection, set up sequential in tuner studio, and VOILA, running like a dream. Seriously man. :bowdown::bowdown::bowdown::bowdown: My hero. Can't thank you enough. I wasted weeks on this.
Originally Posted by gooflophaze
(Post 1562891)
3.0ms is a little low for stock coil dwell, wants to be closer to 4. 5ms/5.5ms for cranking.
Originally Posted by technicalninja
(Post 1562918)
You could swap injectors around and see if the problem followed the injector.
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Just in case other people come along and find this, here's a list of part numbers for the 1993 Miata ECUs. If your ECU says "B6AW," you've got a Cali model.
Edit: image didn't link properly. Re-added it. https://cimg7.ibsrv.net/gimg/www.mia...82b1bb46a4.jpg |
Props for updating the first post and explaining the solution in detail for future searchers.
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