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-   -   Can't solve this detonation issue (https://www.miataturbo.net/e-manage-10/cant-solve-detonation-issue-43931/)

messiahx 02-15-2010 03:01 PM

Can't solve this detonation issue
 
This is a problem that I've gotten nowhere with since I bumped the boost past 6psi. My setup is as listed in my sig.

I can get the car to detonate, even with rich AFRs (10-11:1) and severely retarded ignition timing. This is how I can get detonation to occur and it is reproducible. Get to 5K+ RPMs or higher, in second or third gear, and punch it. There will be a small bit of audible ping immediately and that's it. Afterwards it'll pull like normal.

Doing a pull in third for tuning doesn't reproduce the issue. It is only when transitioning into boost rapidly at high RPM. Here's my current timing map (MAP sensor wired into TPS, 45% is 5 psi, 55% is 10 psi).

http://lh4.ggpht.com/_xihbDfQlW0w/St...tion%20map.jpg

You can see how far retarded my timing is. I'm really at a loss with this. I will be installing a DO water injection kit soon so I can at least make it to some autocross events, but I know it'll only be serving as a stopgap. Any advice would be helpful. Thanks.

Edit: I think I will check my ignition timing this week (with a light and all). If it were way advanced, that would explain why I keep having to pull so much timing.

gianic 02-15-2010 05:37 PM

Your picture is tiny.

Jeff_Ciesielski 02-15-2010 05:46 PM

My bet is that your ecu isn't compensating properly for the rapid increase in pressure (acceleration enrichment) which in turn is causing a massive lean spike while in boost = knock. By contrast, starting at low rpm and doing a pull in a gear causes a much slower pressure increase which is easier to compensate for.

messiahx 02-15-2010 06:04 PM

I fixed the picture.

I went and got a timing light and the timing was advanced 2-3 degrees. Doesn't seem enough to cause these issues but I went and set it to 10 BTDC anyways.

Jeff, that would be exactly what is happening. I've never had much luck with the EMB's accel enrichment map. Maybe I need to keep trying. I haven't been able to see the lean spike in the emanage data logs or on my AFR gauge. Maybe the greddy software doesn't sample quickly enough.

Here's another thought: I have my MAP sensor and O2 clamp under the dash, tee'd off the line going to the boost gauge. That would put about 4-5ft of vacuum line between the sensors and the nipple on the throttle body. Do you think moving the clamp and MAP sensor out into the engine bay and putting as little line as possible would alleviate the problem?

Jeff_Ciesielski 02-15-2010 06:16 PM

I doubt that the map sensor being in the cabin is the problem. All of the MS guys have their map sensor in the same case as the ECU with vac line coming through the firewall. Can you post some screenshots of the AE tables? I've never used the EMB software so I'm not familiar with what settings to change :).

messiahx 02-15-2010 07:08 PM

http://lh5.ggpht.com/_xihbDfQlW0w/S3...s800/accel.jpg

I'm not sure the AE map will do much with the ECU wired as is (MAP wired into TPS on the EMB). I would have to wire the MAP sensor into the AFM input and reconnect the TPS. The reason I'm not using the normal MAP input is because it's being used for AFR. But if that'll allow me to resolve this problem, I'll do it ASAP.

elderc 02-16-2010 08:25 AM

If you can't resolve the issue your having try these guys, I've gotten alot of infromation off this site all Emanage stuff :

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