Thread: No power at 5700 rpm. Just falls flat on its face.

So, in a nutshell, after circa 5700 rpm, the car literally falls flat on its face and all I am hearing is noise. No pull and it struggles to rev to anything close to 7000 rpm. Now, I am leaning towards the JWT tune (its from over 6 years ago) and possibly the fact that the stock cam profiles are hampering its ability to rev and hold boost all the way to past 7K (the car does not get flogged to these sort of revs on the street, mind you. But I bring it up to over 6K atleast once a month to blow out all the carbon buildup)

Setup info:
98 SER with a 97 B14 ECU with a JWT tune
T3/TO4E garrett turbo 57 trim
550 CC RC injectors
Warlboro pump
Stock Cams

Has anyone else have or noticed such issues?? Its comparable to having heat soak and the ecu pulling loads of timing. Just feels gutless above 5700 rpm

Thanks

Have u to trying seeing if gas is flowing well into the injectors.... had the same problem n i melted a piston.

do you have a wideband on the car?

Boost leak, maf sensor, fuel cutout from pump. Try checking for a boost leak. Under idle feel around the couplers for a feel of cold air. Inspect the piping. And intercooler. If not sure borrow a smoke machine and try again. For the maf check voltage. There is a write up about it. Also, on that note, check your tps voltage. On the fuel, buy a $20 gauge from summit or jegs.com, and install it. Check the fuel pressure 3 bar ~43 psi /4 bar ~58. Hope it helps.

Let me delve into the issue(s) and try to give a bit more detail.

I changed the (air) filter as the old one was in terrible shape. I also grabbed some CRC MAF cleaner and sprayed it down on both sides (as per instructions) and allowed to dry in open air wrapped in a towel for circa 1 hour.

The problem(s) still persist. I am realizing that heat might also be an issue as when "just" warmed up, it will rev fairly cleanly in 1st to 7000 rpm quiet easily. However, once I try to do the same in second gear, it hits this seemingly phantom rev limiter at 6000 rpm and gets progressively worse from there forth. If I part throttle it under load (while driving with almost zero or circa 1psi boost pressure) it will rev (albeit slowly) to redline if I wish. It is only under boost, WOT and heavy load conditions does the phantom rev limit become apparent. And it is not the same for each gear give the same throttle conditions.

Also, if at 2500rpm in gears 3,4 and 5 and cruising, and I decide to go WOT, it has an immediate bog or misfire (read: backfire) right before it gets on song. Its almost as if the tune for boost transition at that RPM is completely off...........Odd to say the least.

OK, guys, thanks for all the recommendations and I will be tackling each one by one


On my list of things to do:

- Check MAF voltage and if it all checks out, I will move on to regrounding it.

- Remove and check spark plug gab

- Check and adjust TPS

- This weekend, I will hopefully attack the boost pipes (as they need to be re-done, regardless), however, I am leaning towards this not being the issue as the I have a hunch it is more along the lines of MAF or ignition or TPS (which, I will be checking the plugs when I get home from work today).

- I also had a fuel pressure gauge installed and it read a rock steady 43 psi under idle (which is 3 Bar)

Any other recommendations??

And sorry, to answer, the car is in the process of getting the wideband installed. I am currently calibrating it off the car with an independent power supply to make sure everything is in working order before full complete installation

Dude, do a boost leak test, I had the same problem and had a huge boost leak.

^^^ What was your vacuum at idle?? I have a little over 20 currently.

check ur wastegate and make sure its functioning correctly. that might be causing the back fire

Not discrediting your theory (and I will check just to make sure), but why would the waste gate cause such an issue?? Its a pretty straight forward mechanism that runs soley off exhaust energy that either
a) Stuck closed (tons of boost......which both me and my gauge would have picked up on immediately, not to mention blown couplers)
b) Stuck open (no boost what so ever)