rceron

Guys not sure if the following is directly relevant to the PFC, but in light of the discussions on advance timing issues and maps I'd like to hear some thoughts on my dilemma.

For starters I'm breaking in a new large street ported motor (2mm Hurley seals) and have been using fuel maps (ignition unchanged) from individuals on this forum with similar mods. Well, just recently my car started to idle real awful. I immediately thought I blew an apex seal. From a recent post you may recall that I noticed some clicking noises from the engine when accelerating under high load and low rpm. At the time I assumed it was some form of detonation, although I really have no idea what detonation sounds like (some say like popcorn though). So, I immediately added something like 3-5% more fuel to the PIM Volt at the 10 and 12 boost range. Please note that I have only been running about 11 lbs of boost (just passed 1200 miles in the breakin period and I wanted to slowly add boost). Well, the clicking noise didn't go away when accelerating, but the power was still good (which isn't uncommon for an engine with a blown seal). I thought even if it wasn't detonation it probably couldn't be good. So I decided to do the observational compression test that Dave at KD recommended in lieu of a formal compression test. Basically, I didn't want to drive it anymore (it's resting on jacks for the winter now). Well, I pulled the rear leading plug and I heard (real loudly) at least 3 consecutive blasts of air. I did the same with the front rotor with the same result. I again was surprised at the how loud the air blast was. So, did I blow an apex seal. Not sure. Watcha think?

Interestingly enough I took a picture of both the front and rear leading spark plugs. The picture is below. Two things: neither plug has the symptoms of detonation (i.e., no white specs) and the front rotor spark plug is extremely blackened (running too rich). These were new plugs when the engine was put in.

Any input?

Other relevant mods: I/C, intake, dp, mp, cb, HKS ignition and running NGK 9's. I haven't put new spark plugs to see if that is the problem. But somehow I don't think that is the problem because of this clicking noise that seems to be coming from the right rear of the motor (passenger side).

So sorry for the long post.

Ramon

Rx7@Rocketship.com

Mind telling us WHICH map you used?

Map 8 is mine.

David Ieroncig

Dragon

Your plugs are definitly junk, the center electrode is gone, when it's rounded off like that it is time to change the plugs, that may be your whole problem...

Also did you check your coils, maybe you lost one of them...

rceron

Thanks for the input guys.

Well, I checked the ignition system the best I could. At first I was convinced it was the coil to the leading plugs, but unfortunately we saw current (plugs grounded but not put in the engine) from the spark plugs when we turned the car over. Then we suspected it would be one of my 10mm Magnecor wires that was shorting or loose. I put everything back--making sure all connecting were correct and well situated and put new NGK 9's in--but to no avail.

My vacuum reading was still only 24 mmhg at 750 rpms with a vibrating engine as well.

So, I guess I have a blown seal (again). Not sure if this was my fault in anyway. Only thing left is the fuel system. The fuel filter is brand new and I have no idea how my injectors would be impacting my vacuum at idle if they were damaged or malfunctioning in anyway. I'll be bringing back to KD again sometime this winter.

Next time around I will also send my PFC to XS engineering to make sure it is set up correctly. The sharing of maps has left an awkward feeling with me.

Later,

Ramon

weaklink

does it smoke? what else makes you so sure you blew a seal? go ahead and get a compression check, they're what $50? I thought hurley seals were supposed to be THE ****!

Jonesboro

I was looking at your spark plug pictures. Are you saying these plugs have only 1200 miles on them? Take a close look at the plug pictured on the right. It appears that the electrodes have partially burned away. I'm new to rotary spark plugs but for conventional spark plugs I recall that burnt electrodes are a telltale sign of pre-ignition. You mentioned modifying the PFC fuel maps but my guess is the culprit was timing.

Tim Benton

iTrader: (1)

This is generic info and you more than likely checked it already. The line running to the MAP sensor near the driver side firewall might have came loose. My friends did, idles likea blown seal, mazda dealer was all set to replace the engine for him until I looked at the MAP sensor. thats just damn ignorant on Mazda part. Nice job, map sensor line comes off, replace the damn engine. I wonder how many people got suckered by this and help to build the FD's reliability problem. pathetic. sorry for the rant.

Check it and see.

Tim Benton

Jonesboro

I would like to amend my post above to say that after further consideration I believe the problem with your engine is "detonation" and it resulted in an apex seal failure. Furthermore, the cause of the detonation could be advanced timing, lean mixture, and/or a number of other factors and not just timing as I originally suggested.

Clearly your spark plug pictures show damaged plugs. However, since the plugs were new with only 1200 miles on them, it was the detontation and/or accompaning preignition that caused the spark plugs to fail. It was not a matter of faulty spark plugs failing prematurely and then causing further engine problems.

Finally, let me say I am not an authority on this subject. It is a subject that I am in the process of learning about because I intend to make modifications to my FD. Here's a link to a detailed discussion of detonation and preignition that I found very helpful. It focusses on piston engines but is directly applicable to rotaries.

http://zhome.com/ZCMnL/PICS/detonation/detonation.html

Take Care

rceron

Hey, thanks for all the responses. At this point I believe it was detonation as well. The alarming question is how. If it was the timing maps on the PFC I will lose it.

I haven't done the compression test since the MI dealer I went to last time charged me $165 to do a test (something KDR says takes 20 minutes). I guess I'll be hauling it out to KDR in a month or so.

Hopefully, I can have the car up and running before Spring MADS.