Jump to content
HybridZ

misfire or running out of fuel pressure?


Guest Nissansforever

Recommended Posts

Guest Nissansforever

I have a 1994 that has upgraded turbos, motor, 555 nismo injectors, stillen ecu, and loads of suspension updates. The problem I am having is at WOT it seems to lose power at about 5000 rpm's! I have the number 7 iridium NGK plugs in it....they are very black right now. Now, when I first got the car back together, it ran fine, no problems. Is my stock fuel pump not keeping up? Or is it getting too much fuel? I have never hooked up a boost guage to see what it is running at with the stillen ECU, but I know it's more than 14 psi. Anybody else have this problem? Please don't tell me to check the archives. a guy could read for weeks and still not get an answer specific to a problem. Please help, I love spanking corvettes on the road!!! LOL!!!

Link to comment
Share on other sites

Put the right plugs in it. NGK PFR6b-11b. Throw the "iridium" crap out the window. If they're black, you're running rich, which is pretty normal for the Stillen program.

 

Are you getting any codes? Are you in safety boost (is the boost gauge going up to about half way and no farther)?

 

The Stillen ECU is about the same as any other "ECU" you buy (which is to say, a stock Nissan ECU with a socket soldered in to accept a reflashed chip). It won't boost beyond the stock Nissan levels without the addition of boost jets or a boost controller. Boost jets prevent the manifold pressure from opening the wastegates by putting a restriction in before the solenoids.

Link to comment
Share on other sites

Guest Nissansforever

Hey, thanks for the reply! Do you think it's really just the plugs? Now the 6's will be slightly hotter then too, right? Also then do you know what timing should be set at? Can it be set where the car runs good or should it be set to a certain spec no matter what? My car especially when it's warm...well, I guess it does it cold too, but it idles fast, then it slows, then it idles faster again, then it slows down. I had changed the timing a while back and then that went away, now a year or two later, it's doing that again as well. Is that just the nature of the beast? Well, thanks tons for the info, I got the plugs on order today. Thanks!

Link to comment
Share on other sites

You can set timing by loosening and twisting the CAS, but stock it should be 15 +- 2 degrees BTDC.

 

As for rough idle, there are a billion and five causes for the VG30DETT. I'd start by spraying some PB blaster down the air intake side of the AICV (it's acutally a preventative maintenance thing that I do about once a year).

 

If the car is really falling flat above 5000RPMs, I'd start to suspect vacuum issues (which can cause a rough or hunting idle, as well).

 

My Z32 starts at around 1500RPM, and then settles down nicely to 750, and is rock solid.

Link to comment
Share on other sites

  • 2 months later...
Guest Audioquest

Definitely put the NGK OEM Platinums back in, one heat range colder than stock, and make sure to gap them at .034 not .045 to avoid detonation. Anything other than the stock plugs just doesn't work right in these engines unless you have extreme mods and high horsepower.

Also, make sure your timing is dead on 15 even though the FSM says +/- 2, not hard to do.

Also, is your fuel pressure regulator fairly new?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...