My ignition is failing WHY... HELP ?

O.K. I have a 91' Civic HB Dx model. Now I do everything myself to my car but I bought my car back when I was 16 and right after I bought it I had a "so called " performance shop " Did the Dx-si DPFI to MPFI conversion which was a hack job and a ZC swap. Now this was done 5 years ago and I knew nothing about cars back then. Now I've learned and know what to do but I've had this problem for ever and EVERYBODY knows of this problem but no one knows how-to fix it. This problem i have ALOT of DPFI to MPFI supposelly have this problem. O.K. When I'm driving down the road cruising at 20-30 % throttle ONLY and this only does this between 3,500 RPM to 4,500RPM my car hesistates , misfires, falls on it's face. as soon as I hit over 4,500 RPM bame it runs fine almost like VTec is kicking in. I had this problem back with my zc , during my turbo ZC phase . And for some reason back when I had my ZC I went threw dizzy like hot cakes never knew why but the bearing kept going up.

My car was running fine for the last couple of months and I now turbo'd my B16 and the problem came back just three weeks ago so I took my turbo off cause I'm loosing spark and didn't want to detonate and blow the motor up. Just to le t you all know the turbo's have nothing to do with the problem. I took a friend ( fellow mechanic ) for a ride to show him and he says it feels like I'm loosing ignition... which I can smell raw fuel when is mis-fires real bad on it's bad days so I know it's not fuel. I jknow what throttle percent is does it cause I'm reading my AFC. I've tried EVERYTHING and nothing has fixed it. I have a feeling it's a problem in thw iring conversion that the shop did back in the day but I've used diagrams after diagrams and checked everything and everything seems o.k.. I don't know WHY I'm loosing ignition cause I have a FULL MSD ignition. External Coil , 8MM wires , and a MSD SCi-Plus ignition box. I think my dizzy might be taking a dump. PLEASE I need some feed back alot of people have seen this and kow of the problem and all say it's from the DPFI to MPFI conversion but nobody knows the solution. Here's a LIST of what I've replaced and checked .

-TPS ( some say it could be a TPS since it only does it at 1/4 throttle ): I've switched and tried using 3 different TPS's all checked o.k. and niether one made a difference.
-Conversion wiring- I've checked all the injector wiring and TDC/ crank sensors and all are going to the right pins and no breaks in the wires and everything seems to be wired correct. Also when they wird it they used butt connectors... I took every one off and sodered all the connections.
- Injectors- I tried changing injectors just because I thought maybe they were just old and sticking... No change and injectors looked fine.
- Tune up- I bought Stock MM brand new wires... changed the plugs. Changed the MSD external Coil. Changed the Rotor. I changed the dizzy but I had to use a used OBD 0 B16 dizzy and it was making a squeeking noise but the bearings in my old stock dizzy was bad so I had no choice but to use this one.

Well thats about it. I think my Dizzy could be taking a dump just cause it's a used one but I tried swaping ignitors and it made no difference. since I'm running a OBD 0 B16 I can't exactly goto Pep Boys and get a new one. Some people say you can modify a LS dizzy but I tried that and it didn't work the holes don't line up even after hacking the one arm off like they said. I can't see how I'm loosuig ignition with all this MSD crap I have unless it's something internally in the dizzy. If anyone has had this simuliar problem or know what the solution is I could really use some help. Thanks and sorry this is sooo long

just wondering, but do you keep your timming advanced all the way, cause my friend has a B18a1 crx, and he went through3 distributers in about 5 months, then we relised it is cause he keeps his timming advanced, now he only advances it when he races, and the distributer has held up for the past year almost

Well I set my timing to 18 degrees advance TDC. I went threw like literally 8 dizzys when I had my ZC. I thought maybe I have it too advance but when I put my B16 in i set my timing at 16 degrees and still having the same problem. People keep saying it has to do with the DPFI to MPFI conversion but that can;t be right since I've done DPFI to MPFI converisons on customer cars and have had no problems. I don't use my MSD box to advance or retard my timing I just turn the dizzy. Plus it's wired cause once I hit 4,500 RPM the cars runs fine but anywhere below that range at 1/4 throttle it mis-fires but as soon as I hit 4,500 even at 1/4 throttle it starts to run fine.

maybe your ecu is screwed, i doubt it is your dpfi to mpfi

I had this problem. I went through dizzy's like mad crazy. it was because my timing. If you are turbo you need to retard your timing. Also try retarding it some and see if it helps.

Although you said it is definitely not fuel I wouldnt overlook it. Have you ever run your fuel pump dry? Your symptoms sound similar to mine on 2 different cars i have owned. Might be fuel pump/fuel filter or 0/2 sensor.