ignition question for my fellow turbo 3gs

[Accordtheory]

I have had the same problem with 3 different ignition setups. It is really annoying..It was the worst when I had the J&S safeguard, a little better when I had my modded stock distributor, and now its still there and I have sean's ecm setup. Basically, under boost, the tach jumps around, lags and then twitches up, accompanied by power killing misfiring. I don't understand this, because the tach signal is driven off the coil, so it seems like the only thing that would cause this is a defective signal To the coil, not a misfire caused by something after the coil, like a bad wire, plug, etc. But then, why the has it done this with so many different setups? The car runs fine when cruising, but misfires a little at idle, (?) and at high boost levels (13-14psi) it does the weird tach/misfire thing. I don't get it. It would seem like I should upgrade my ignition anyway, but if the tach is acting weird from the signal to the coil, then I don't see how that would fix it. Anyone have any ideas?

[According2Me]

I had a 89 LXi turbo a few months back. CarDomain @ 89BoostedAccord...... To start off...if you dont have a separate ignition box...you need to invest in one...I had a Crane, it worked well. Also, you need a nice big battery to power your extra spark and ECM. I had a separate red top 6 cell battery ran in line with the ignition box and electric fuel pump. And since you have all that extra spark, try double silicone 14-20mm plug wires. If you have platinum plugs...get rid of them and stick with a quality copper Splitfire...gapped of course. And to top it off...make sure that you arent running lean(which can cause all of your ignition woes) b/c if you are lean...bubbye turbo and motor. I learned all this the hard way...hope some of this helps.

[smufguy]

Its a weird thing man. I have not heard anyone misfire under idle. BUt the only problem one of the guys at work had was a faulty MAP sensor. There was something wrong with it and weirdly, it made this lil pop pop sound under idling and hard acceleration, once the pressure evened out, there was nothing wrong.

But like mentioned, an ignition box like crane or msd should solve your problem big time. i am even suprised that Sean's kit did not do anything to you.

PS: Check up on all your vaccuum lines and stuff, the regular bs, and see if they are in order. OTher than that, only thing i can possibly think of are hotspots in the camber causing detonation. Getting Denso plugs would be a good choice, since pretty much any aftermarket forced inducted user, seems to have their igntion system happy with those plugs.

[system-f]

Just my experience, but I had a similar problem on my 3G turbo charged Prelude. We tried EVERYTHING to get it working right and it would missfire like crap. Replaced the coil and the problem was solved. The turbo setup with the MSD boost retard would eat stock coils. The only good solution was to replace the coil with an aftermarket model of higher output.

[shepherd79]

your best bet would be to get crane Hi-6 ignition. i had it on my car, it is very small but man it gives a nice punch. second you should get nice coil.

[AccordEpicenter]

whats your ignition gap? I smoked an accel coil in 2 days. Is the coil and the tach setup exactly like stock? If you bypass the internal resistor in the coil to get the tach signal, it tends to bounce and twitch... What plugs are you running?

[Accordtheory]

Well, I was already tentatively planning on the crane hi-6 with the lx92(?) coil, and the denso iridiums. But still, doesn't it seem like if since the tach is powered by the coil's primary side, if the tach isn't working perfectly, then the signal triggering the coil is at fault, and therefore would also incorrectly signal the aftermarket igntion box?? Seans ecm setup is basically a setup out of a late 80s factory gm car (pontiac sunbird gt turbo)? and it uses the gm ignition module to power the honda coil. (the tach remains connected to the coil) Also, the ignition doesn't act like that all the time.. I drive the car daily, and I was hitting the same 13-14psi today with no problems. But I guess it's worth upgrading the ignition system anyway, even if that doesn't solve it.

[shepherd79]

what is your spark plug gap? if it is too large, you will blow the spark right out of the plug with your 13-14psi boost. make it small so it will stay there.

[AccordEpicenter]

you should probably be running around 34-36 gap, stock is like 40-44. Irridiums arent great for boost, you should just stick to a regular plug instead of a plug of the month for durability reasons.

[Accordtheory]

I thought those plugs were specifically designed for that type of shit.. ?