Help. Engine chokes at 5k

[jteuton]

So i just got through rebuilding the topend of the a20a3. Engine had 100k miles on it. Never new what it ran like normally. So i get in it and crank it and everything sounds and runs good....until you open it up to full throttle. Its particularly slow up to 3k but i expected that will hardly no power down there but when it hits 3k it takes off and i do mean with a force and pulls hard as hell to about 5k where it proceeds SLOW as hell till it shifts at about 6250. I mean it takes about 4 to 5 sec for it to cross this span. It has less power at these upper rpm's than the lower. Does everybody's car pull hard all the way to redline or is this a problem with stock intake manifold? Basically i'm getting a ....2k bog...3k zoom....5k bog.. It doesn't seem normal. I have new ngk's and nology wires and cap and rotor. Regrinded cam and polished remachined head (Compression tests good so its no head gasket leak)..new accel coil, cold air intake, dcsports header to a dynomax with no cat,...aem fpr (air/fuel ratio looks good on my gauge), 50 shot nitrous which i haven't used cause i'm trying to fix this problem first. Does anybody have any suggestions? Thanks cause i'm outta ideas....jteuton

[dj99]

Both fuel filters?

[jteuton]

its fuel injection and only has one filter which is brand new

[ACCORD EX]

timing ??

MIKE

[shepherd79]

i have the same problem on my carb.
around 2-3K my car is slow as hell, 3-5k zoom zoom and after that it pulls but not as hard.
so far i found out that if oil level is too low, around 3K my car feels like it got NOS or something. I putt oil in it, and boom everything is smoth again.
check your oil level. may be it is your oil sensor.

[POS carb]

I think you have a combination of cam timing and a weak/dirty fuel system, doule check you cam gear and flywheel marks

[dj99]

What exactly happens if you slip up and put your timing belt on a notch this way or that? Would you have interference problems or would it still run "ok"?

[rocky2]

I'd have to say To also recheck valve adjustments since you had to be there. But I suggest to run engine modestly for a period. Then check adjustments. And maybe even recheck torque values on head to while your there after engine has cooled and expanded a few times. Then these adjustments will be dialed.

[POS carb]

oops I didn't see the note of the a/f ratio being ok. It's gotta be cam timing. I don't think the car would idle if the valve clearance was bad enough to cause such an odd power band, that's my opinion anyway. plus it never hurts to double check it. Turn the motor over so that the TDC mark is perfectly aligned with the pointer, then make sure you line up the 2 marks on the cam gear so that they are parallel to the edges of the head. Depending on how much they milled it may not line up perfect on the head any more (the cam will end up a tiny bit retarded) but it would be obvious if you were off by a tooth or two, one of the marks would not be visible at all.

[jteuton]

well everything else seems to check out ok so maybe its the timing. I do know i eyeballed it and lined the top cam gear up with the T on the flywheel so it look like its in time and it runs smooth with no miss at idle and nothing binds but i haven't actually checked it with a gun. Maybe even though my air fuel gauge is reading correctly i still need to clean my injectors. The car sit up for about a year will i fiddled with different things. I hate to take it to a shop cause i wanted to do this all myself (except the machine work)...thanks for your replys...jteuton

[dj99]

What about the vacuum advance? You could time it with the vaccum ports plugged (suggested method) to TDC, and check it when you plug #2 primary advance back in. It should move to the red mark. The secondary advance is for higher RPM's. You could check it by providing vacuum to it and seeing if it moves the timing 3-4 degrees more. The advance units often fail on these cars.

[jteuton]

ok the first upper port has no vaccum but the second lower one sucks like a 2 dollar whore on main street. which is which? Fuel pressure comes in at 38 psi? Is this too low? I checked the timing with both hoses undone from the dist. but not plugged. The white T was about a half inch away from the pointer ,,,,took about a 1/8 to 1/4 turn to correct. I fixin to retest drive it but i don't think the problem is fixed. Somebody clue me in to the the hoses and which is which and i'll buy you a sixpack....thanks....jteuton

[jteuton]

I hate to keep going on and on but this car isn't going to win....i am....so i was thinking maybe it has to be the cam and it just doesn't produce power past 5k. If thats the case i'll have to get another. It was a stock cam regrinded to int. 268degrees, .383l ....ext. 272degrees, .402l......is this a wild cam or not? Cause i have no clue....i know nothing about cams except how to install and remove...and position them. I know a .402l seems high for stock valves so i don't know....Anybody else with this grind experiencing problems????.....jteuton

[POS carb]

Originally posted by dj99
What about the vacuum advance? You could time it with the vaccum ports plugged (suggested method) to TDC, and check it when you plug #2 primary advance back in. It should move to the red mark. The secondary advance is for higher RPM's. You could check it by providing vacuum to it and seeing if it moves the timing 3-4 degrees more. The advance units often fail on these cars.

The secondary advance is for a cold engine, it runs smoother, it's supposed to stop advancing after you reach normal operating temp.

[dj99]

#2 hose on the primary, or the one closest to the distributor has vacuum all the time. You really have to plug both off to set your timing to TDC (the white mark). The engine won't run right without it being plugged. Also you should be at normal operating temp, and your idle should be to the spec on the label under your hood, or very close to it.