95 Civic, just did a swap from a D15B7 1.5 to a D16Z6 1.6 VTEC. I got everything done, got the timing set, and took it around the block. Everything runs good, idles good and drives good, no check engine light. My problem is...everything runs great at partial throttle, but when I punch it good it falls on its face. It studders, bogs, and bucks. As soon as I ease up it runs perfect again. Then when I try to punch it it just bogs down. Doesn't matter what gear its is. Is this a fuel problem? What do I need to check? Any suggestions would be greatly appreciated.

 

When you punch it does it just die(stall) or does it just rev & not go anywhere?

 

it definitely doesn't rev. It just bogs down. Now if I'm in the driveway, without the car under a load moving....I can rev it as high as I want to go. But when I get in the car and head down the road...it drives good as long as I don't floor it. If I floor it, it just falls on its face.

 

Fuel filter is my guess. It's a quick job and if that isn't the problem, it's good maintenance if it hasn't been done recently. Good luck.

 

If the misfiring is worse flooring it at low rpm (in a high gear), suggests a spark problem. Worse flooring it at high rpm (in a low gear) suggests starving for fuel.

 

Changed the fuel filter, didn't help.

if I ease into the gas....it runs fine. Its when I floor it (in lower gears) it just does nothing. Realy doesnt even buck or anything. I floor the pedal and its just NOTHING. I need to check the fuel pressure somehow, and see what that looks like.

 

When there is general poor performance and no CEL, check the timing. Both the cam timing and the spark timing. You need to put the jumper in to put the ECU in test mode in order to set the spark timing properly.

 

I think I may have a TPS problem. I noticed it would do nothing when I had the pedal all the way down, no matter what speed I was at. When I got back home, I put the car in nuetral, in the driveway with no load. When I would rev all the way to full throttle, it would cut out as soon as I got the pedal all the way down.

I unplugged the TPS and MAP sensors and plugged them back in. All of the sudden the car would rev all the way, even with the throttle all the way open. When I sat back in the car it had a check engine light. I ran the self diagnostic, and I believe its a 7 and a 41. The 41 I had when I first put the motor in and I had a bad O2 sensor. I replaced it, and the CEL went away until now. So I pulled the 7.5amp fuse under the hood to let it clear, then undid the negative battery cable for a little bit. I put all of that back on, started the car, no CEL, but now I'm back to cutting out at full throttle. Any ideas?

 

Make sure you didn't swap the plugs for MAP and TPS. They are both the same type of plug and can be plugged in to the wrong sensor. The MAP plug has a wire that is solid white.

To test the TPS, connect a voltmeter between the center wire (sensor still plugged in) and engine ground. Turn key on but don't start engine. The voltage should be about 0.4 volts with the throttle closed and increase smoothly to about 4.5 volts as you move the throttle to wide open.

And double check the timing.

 

Thanks, I'll give that a try.