New problem at 5700rpms

[cheezmonta]

Mine actually started to shudder around 5K rpm and I just thought it was detonation from running 12psi on a hot day. On my way to work I couldn't boost more than 10psi without it happening. So I turned down the boost to 8psi. It didn't solve the problem but the next day it started to get worse.

My problem seemed to just keep getting worse and worse each day to the point where I couldn't boost more than like 2-3 psi without the car shuddering.

Try resetting your AVCR and starting from scratch to see if that fixes the problem.

[mark86t]

Ok how do I reset my AVCR? Disconnecting the battery doesn't do it as I have done that many times and still have the same settings. (thank goodness) I know I could read the manual but if you already know how to do it that will save me boring time reading through the manual. Thanks!

[300zxt]

If I were you I'd be doing this yourself, I always read manuals for any electronic bs I install in my car.

[mark86t]

300zxt wrote: If I were you I'd be doing this yourself, I always read manuals for any electronic bs I install in my car.

There inlies the problem. I didn't install my AVCR or my AFC or my wideband (ok I welded the bung & installed the O2). Nor did I set them up in my car. I have a friend who knows much more about this than I do so I have him do these things for me. Guess I'll have to call him up now. lol

[craZed]

craZed wrote: That sounds familiar.
Try bypassing the EBC all together.

[cheezmonta]

In the main menu screen scroll down to "etc". Scroll down to #7 "initialize". Click over to "yes" then press the "next" button and turn the ignition off. wait a few secs then turn the key back to Run to power up the unit. If done right it'll be back to factory settings.

[mark86t]

How about if I just bypass the solenoid & link the vacuum hoses that are connected to it? That would have me running without the AVCR & just getting wastegate boost. This way if the sputtering went away I would know it is the AVCR and would then reset it. If it acts the same then it isn't the AVCR & I didn't have to reset it & lose my settings. What do you think?

[cheezmonta]

mark86t wrote: How about if I just bypass the solenoid & link the vacuum hoses that are connected to it? That would have me running without the AVCR & just getting wastegate boost. This way if the sputtering went away I would know it is the AVCR and would then reset it. If it acts the same then it isn't the AVCR & I didn't have to reset it & lose my settings. What do you think?

From back on page 1...
"I actually removed the hoses from the boost control actuator and ran the hose like stock (off the turbo output fitting to the wastegate)."

Yes do that and see if the problem goes away. If not then you have other issues. If it does then reset the AVCR as described.

[craZed]

mark86t wrote: How about if I just bypass the solenoid & link the vacuum hoses that are connected to it?

If it is internally gated then yes.
If it is externally gated, and is hooked up correctly then no.
My external has two fittings.One on the side for mannifold pressure,
and one on the lid for the controlled pressure sent from the controller.
If that is how yours is set up then just remove disconect the hose from
the top fitting. If you connect that to straight mannifold pressure then
you will overboost.

[mark86t]

[quote]craZed wrote:

How about if I just bypass the solenoid & link the vacuum hoses that are connected to it?
If it is internally gated then yes.
If it is externally gated, and is hooked up correctly then no.
My external has two fittings.One on the side for mannifold pressure,
and one on the lid for the controlled pressure sent from the controller.
If that is how yours is set up then just remove disconect the hose from
the top fitting. If you connect that to straight mannifold pressure then
you will overboost.

I have an internal wastegate with 2 nipples on the actuator. Checked all hoses today & nothing seems to be wrong with anything. Guess I will reset the BC. Thanks for the info on reseting it. Will try it tomorrow & see what happens.

[mark86t]

Ok I reset my BC today. Same problem. I added two ground wires to my car today as well. I am really stuck. This is annoying that my car won't pull past 5700 rpms.

Could it be my lifters are losing pressure at that rev & the valves are floating? Cuz when I shift to the next gear I have the same sputtering for a short period of time then it clears out. Almost like the lifters take a sec to build pressure again. I'm reaching here, not sure what else to check.

I have a Toga high flow oil pump - 3 months old. Lifters are Nissan with only 28,000 miles on them.

Should I try a thicker oil to see if it changes anything? I run 10w30 right now.

[Jason84NA2T]

mark86t wrote: Ok I reset my BC today. Same problem. I added two ground wires to my car today as well. I am really stuck. This is annoying that my car won't pull past 5700 rpms.

Could it be my lifters are losing pressure at that rev & the valves are floating? Cuz when I shift to the next gear I have the same sputtering for a short period of time then it clears out. Almost like the lifters take a sec to build pressure again. I'm reaching here, not sure what else to check.

I have a Toga high flow oil pump - 3 months old. Lifters are Nissan with only 28,000 miles on them.

Should I try a thicker oil to see if it changes anything? I run 10w30 right now.

Not sure if you have tested or not... does AFR/timing have any effect at all on the issue?

If not at all, then I would sure suspect a mechanical deficiency. You may have something as simple as a coil broken off an intake valve spring. Hyd lifters should not have issues at that low of RPM.

[mark86t]

Jason84NA2T wrote:
Not sure if you have tested or not... does AFR/timing have any effect at all on the issue?
If not at all, then I would sure suspect a mechanical deficiency. You may have something as simple as a coil broken off an intake valve spring. Hyd lifters should not have issues at that low of RPM.

Put timing back to stock(20 degrees) from the 25 degrees I was running. Worked with AFR recently with no change.

5700 is not low rpm. I only see the sputtering at high rpms. Even though it does carry over to the next gear for a brief amount of time.

I have checked everything I can think of.
wires
plugs
boost leaks
timing
cap/rotor
AFR
boost
fuel pressure
oil pressure

Car runs perfectly below 5700 rpms. Too weird. Since it only started doing this after I installed the new 3" cat back I am tempted to put my HKS 2.5" cat back on to see if the problem goes away.

[mark86t]

Things I already checked:
-plug gap
-turned boost controller off - tried lower boost levels
-timing checked
-plug wires/cap/rotor are new
-compression checked
-no boost leaks


Ok new updates on this problem:
I tried another (known to be working) stock coil. No change.

I checked that my boost referenced FPR was increasing fuel with boost. It does. No change.

I took off my testpipe & ran open from the downpipe. (loud as h*ll & :twisted: mean sounding) No change.

Car still loses power & sputters at around 5700 rpms & then sputters briefly when shifted to the next gear before clearing out & pulling hard again. This is killing me as I can't seem to figure out what is wrong.

[Firehawk]

Might try replacing the valve springs. Seems like you have checked everything electrical.