I just got done doing another turbo motor in my prelude, and all has been great. I am running a MSD 6AL ignition box with MSD cap, wires, coil, and 2 step and my car has been doing excellent until two nights ago. I get a miss at 3000-4000rpms. It feels like the soft touch rev hitting. After that it pulls hard all the way to redline. It feels totally normal from idle -3000rpm and then 4000-8000. The map sensor is good, and it could be tuning, but I have had no issues like this before, and I have not altered the tune. I am running 11.4 a/f in that area as my turbo is just starting to come on, so I don't think I am too rich. I am curious if anyone thinks that it might be my ignition box, while it only has about 3000 miles on it, it is about 7 years old, and hasn't seen the best life in that 3000 miles. The other reason I suspect the MSD is it does it under load, and free revving, but only at WOT. I am baffled. Let me know what any of you guys think. Thanks, Steve

 

I've had similar issues with my MSD setup (new 6AL, coil, wires) on a Civic with SC. I later restored back to stock ignition and the problem went away. I was still not convinced at the time and bought another new 6AL to test, and the similar problem came back. No more MSD for me.

 

11.4 is really rich for part throttle.

 

Maybe I didn't word it right, sorry, it's 11.4 at WOT through that range. It only does it at WOT which makes me think a little bit that it might not be the MSD. My thought on that is if it's the MSD it should do it regardless of throttle position, but maybe not. It definately feels, and sounds like something timing related. It sounds and feels exactly like when I use the 2 Step, or hit the rev-limiter. Thanks

 

how much boost are you running?

what is your plug gap?

how old are the plugs?

11.4 is still pretty rich. Mostly, its just the high output engines that run that kinda AFR

 

what kind of boost are you running? i had problems with sparks blowing out, but didn't have anything aftermarket in the ignition...

also check your plug gap...

 

you check tps

 

I'm only running 12lbs right now with Aeromotive A1000 pump and regulator, Aem fuel rail, 620cc injectors. Plug gap is .045, tps voltage seems right, about .04 at idle, and climbs to 4.3 at WOT. The plugs have about 60 miles on them, so fairly new. As far as 98vetec's comment about the high output engines, I am shooting for 850hp, and the shop that built my short block is making anywhere from 650-1100hp on the same setup. He told me that on pump gas he tunes for 11.4-11.6 a/f, so that's why have been setting it there. I haven't checked the plugs since this started happening last night, I will check them, but prior, They showed good at idle, mid-throttle, and definately rich at WOT. The timing was a bit retarded (color change on grounding strap happening about 1-1.5mm from apex of bend), but not bad at all, had brownish red color to them. I'm open to any recommendations on plug gap....... Could a sluggish TPS cause it. I think I know the answer to that question, but the TPS reads correct voltage, but at times seems that I can hold same throttle position, and voltage takes a while to come up. I guess to that note, how should the voltage react to throttle body movement. Thanks

 

**wrong tread**


Modified by SHPrelude00 at 12:11 PM 9/13/2007

 

decrease the plug gap to .030. yea, 11.4 is good for that 850hp....but is too much, IMO, for roughly 300-350whp. Could be a mix of the fuel and turbo putting out the flame.

 

I'm only running 12lbs of boost right now, and yes I do have a big turbo, and nitrous,eventually I'm planning to be in the 30-40lbs of boost range on ethanol, right now just small injectors, and low boost on pump gas. I'll try the .030 plug gap, and leaning it out a touch. What do you think about the TPS. Should the voltage increase instantly with throttle movement? Thinking back, I have had a few times that dropping from a 40 mph roll in 3rd gear to 2nd gear to "launch" on someone, that it would do the same thing. I just dismissed it as tuning, and maybe it is, but it would make sense that if my TPS was going bad, that I would be getting 1/4 or 1/2 throttle voltage at WOT.

 

yea... sounds like a strout setup... was looking at another tread sorry...

 

no problem man!

 

checked the dizzy and the button?

 

as long as the voltage is ~.45 at idle and ~5 volts at WOT then your tps is fine.

 

Thanks!