won't rev past 4500

[sts76]

won't rev past 4500 91 240sx with ka24de. rebuilt engine with great compression. No ECU codes. Cleaned MAF, checked MAF with multimeter, checked TPS with multimeter. Checked all vaccuum lines. Checked cam timing.

Engine starts and idles fine. Does not pull very well through the rev range and cuts out completely between 4500 and 4800 rpm. Will pull past this point if done at part throttle. Cruises nicely at 85 mph, just doesn't accelerate worth a crap.

Has anybody experienced this and have specific suggestions? The next step seems to be fuel filter. I have a feeling that is not it though. I doubt the fuel filter would clog up while the engine was being rebuilt. I'm sure it's something I did, just don't know what. I have checked and rechecked every electrical connection and vaccuum line.

Thanks,Jeff Parker

[Nismo_Freak]

Fuel Filter or Fuel Pump... sounds like there isnt enough fuel.

[sts76]

changed fuel filter today. No change.

[manny's 240]

check ur spark plugs!!

[sts76]

plugs, wires, cap and rotor have all been replaced

[zachosz]

Maybe you have a bad ECU

[sts76]

checked fuel pressure today and it was 38psi at idle raising to over 40 when opening throttle. still no change. Tried revving in neutral with no load. Can ease revs up to about 6500 rpm. At that point it cuts out and drops to 4500 and starts surging between 4500 and 5500 with throttle held wide open.

[MaineExport]

Does this happen ONLY during load (in gear) or does it also happen when revving out of gear?

P.S. I just read your last post (sorry I didn't see it earlier), but is it the SAME problem under load as it is out of gear? (I'm confused)

[sts76]

Yes it's the same problem under load or in neutral.

[MaineExport]

This may be a stretch, but have you tried disabling the rev lmiter? Even if it's toast it wouldn't send a trouble code to the ECU, but it could send the wrong signal.

However, this wouldn't explain your lack of acceleration BEFORE it cuts out. Ah, whatever, it might be worth looking at. Other than that, it sounds like a fuel delivery problem. But, it looks like you have already covered that possibility

[johnsharpe]

Check your exhaust system? Is the cat plugged?

I had a similar issue with mine when I bought it, turned out the cat was completely clogged and the resulting backpressure caused the engine to run like poo-poo above 4000rpm, if it made it there at all. Did it in all conditions (load or no load).

Check it out.....John

[sts76]

Replaced cat with test pipe today. Still no change..

[manny's 240]

did you check your spark plugs? this happen to me, when i change them on my car, it also happen to one of my friends.so take them out, and check the tip of all four, make sure they have the same shape!!

[sts76]

Gave up and took it to a shop. Diagnosis: cam timing. Even though the silver links were lined up with the dots the cams were not in the correct position. Got home tonight and set #1 to TDC. The links were 1 off the dots. Moved the cams 1 tooth each and TA-DAAA!! It's finally fixed.

[Trppen37]

how did you do it? i mean timing the cams?? cause thats what i need to do..

[scruffy63]

hey guys sorry to bring up an old thread but I'd like to know how to do this.