So I've been trying to figure out this problem for the longest time. Heres the background. My '93 accord runs and idles great in the lower rpm's, around 2.5k rpm's or less.

However once it reaches about 3k on a hill, or 4k on flat ground, it just looses all power. Makes it very hard to get up to speed on an uphill freeway, or reach about 40mph on a steep hill. On flat ground I can go 80+ no problem as long as I shift before about 3k rpm's.

On flat ground it gets a little jumpy when it looses power like its misfiring a bit, but on a hill it doesn't get jumpy, just looses all power.


Heres all I've tested.
-The fuel pressure is great, even at high rpm's
-The timing is right on, freshly adjusted.
-Good Compression
-K&N filter cleaned recently
-Brand new plugs (correctly gapped)
-Brand new spark wires
-Distributor cap&Rotor only about 6 months old and look good.
-Ignitor only about 6 months old (last one died).

I was told it might be a clogged cat however the cat does not look like it will budge, the bolts don't even look like bolts anymore, they are so corroded down there, I doubt any amount of trying and penetrating lube will get it off. So I ran a vaccum test because I was told you can diagnose a clogged exhaust component with that. And to be honest I'm not sure if I did it right, didn't know which vaccum hose to attach it to, so I chose one of the ones right after the throttle plate, where there are about 3-4 identical ones going into that controller box.

Heres the results I got from that test

About 17-19 at idle, nice and steady, not jumpy. When I mash the gas it drops down below 10 and slowly climbs back up to almost as high as idle. When I release the throttle it jumps up about 2 higher and then back down. To be honest, I'm not sure what those results indicate, its my first time doing a vaccume test and those results don't match any of the other problem exhamples I had read, so I don't know if they indicate a clogged eshaust or not, maybe you can help.

I have an aftermarket exhaust, I can see its not clogged. I tried running the car without the O2 sensor in (well I actually disconnected it completely, thinking it would run fine in open loop mode). I thought if it was a clogged cat, it would run better with an extra place for the exhaust to escape, however the car ran so poor with it out, that test didn't help much. I think it still seemed to not be able to exceed 4K rpm's though.

Well sorry if this is so long winded, but I wanted to point out exactly what I've done so nobody tells me to do the same things I've already done. Right now I'm pretty baffled, I don't really know what to do next, and don't want to take it to a mechanic. Any help?

 

done anything to it recently?

done a compression test?

possible that it needs a tune-up?

auto or manual tranny? if it's an auto, it could be a torque converter or downshifting problem.

getting any check engine lights (CEL)? if so, pull the code

a clogged cat will usually show up across the board. it will feel stuffy pretty much the whole time you accelerate.

those bolts are commonly shot to hell, and you basically just have to cut them/torch them off. a muffler/exhaust shop can do that.

you could do a few things that probably won't help, but it's possible. you can always check/clean the EGR.

a good site for the cb7 (90-93 accord) is cb7tuner.com

 

Yes, I did do a compression test, it was good.

I do not get any check engine lights.

It's a manual transmisson.

I didn't do anything to it recently to make this problem happen, it just happened, and as far as I know, it came on pretty fast. It wasn't long ago that I could run it to redline no problem (not that I ever did that often, but I would go 5K often), all of a sudden I just lost the power.


The EGR system is one thing I haven't looked into, and don't know much about. Are these the same symptoms of a clogged EGR system?