bottlefedb16

ok I'll try to make this short and to the point. My car is a 91' Civic DX HB I'm running a OBD 1 B16 that I converted to OBD O running a PR-3 ECU. Here's the problem I'm running into a mis-fire / hesitation and it only happens at 1/4 throttle or less and only till about 4,000 RPM. I had a similiar problem back when I had my turbo ZC but it only did it when the motor was cold now with the B16 it does it all the time from the day I did the swap.

If I reverse the TPS's wires so it reads backward like the original DX should it runs better but you can still feel it alittle. If I disconnect the TPS it'runs alot better but I can't tune my car with the nitrous I use now with the TPS disconnected. Here's also something if I Disconnect the ECU the car will drive fine for about 3 days then the misfires slowly come back and get worse and worse. Here's a list of everything I've tried and check. I think that the wires for the dizzy are shorting out or grounding out somewhere i.e. for the cyclinder position sensor or something. THE CAR WILL NOT THROW ANY CELS's I've driven the car about 20 miles once only at 1/4 throttle missing it's *** off the whole time and would never throw a cel.

Here's what I've done :
-Replaced and tried a million different TPS sensors and voltage is fine at idle and WOT. I tried hard wiring the TPS wires straight to the ECU and still had no effect.
-Replaced Fuel filter , FPR , and changed fuel pump to a Walbro 255lb and cleaned sock at pump really good.
- Replaced whole engine harness from the strut towers foward and re-checked all wiring for DPFI-MPFI conversion.
-Tried swaping different ECU's. MAP sensors and every freak'in sensor under the hood. If it's under my hood it has been changed or replaced and IO mean everything.
-The distributer on the car is BRAND new I found a company in canada that makes OBD O B16 Dizzy and these are new not re-man.ed.
- I've tried different injectors and even swaped in some RC 255 cc's but it seemed the 255's made it worse.

I've tried everything and talked to alot of people and no one knows who to fix it. The 255cc's made it worse so it seems I'm loosing spark not fuel. And I don't know why clearing the ECU works but for only a couple of days. I work at a shop so the only parts I've had to pay for were a dizzy and the fuel pump so I haven't had to spend alot of money on parts the problem is just getting on my nerves and I'm ready to junk the car and swap everything out into another 88'-91'. I've done this swpa and DPFI-MPFI conversion on a bunch of customer cars and nevr had this problem mines the only one. I could any help right now I can get. Thanks for your input guys.

StanB

The following could also cause the car to stumble on acceleration:

1. Spark plug fouled
2. Incorrect ignition timing
3. Intake manifold air leak
4. Fuel injection system faulty

Hope these help solve your problem.

tranceminister

StanB's got some good sugestions as to what could cause that misfire/stumble. For the longest time my mini-me's had what I thought was misfire very similar to what your describing. Just yesterday I was doing some tuning and discovered it wasn't getting enough fuel at low vacuum/low RPM (ITB's are fun to tune), I made the correct adjustments and guess what? that strange misfire feeling is gone I went through 2 distributors to find the problem with no luck there. It had nothing at all to do with the ignition system.