power "surging" under boost

[ke6960]

89 lebaron gtc t2 convertible

i have a g-valve mbc and have had it set all the way down (like 6 or 7 psi) cause i just finished the car and got it on the road like 2 and a half weeks ago

so anyway the other day i decided to turn it up just a little and see what was what i got it up to 10 ish and it seemed ok.... but

going up a pretty steep hill in 3rd i got a surging at about 9 psi or so and between 3500 and 4500 rpm it started surging... kinda its not a really surging, technically its the opposite like as if i were bouncing off the rev limiter

i checked the codes and only got 12 55 so nothing....
i also have a dawes device af guage and it was blue at the time (my foot was on the floor)

needless to say i turned it back down and no more problems at 7psi under any circumstances

what could it be?
i would like to at least like to be able to run the stock 13 psi....

[ke6960]

maybe my plugs are gapped wrong or worn??

ill check them tomorrow or maybe ill just change em im sure they are pretty old...

[Mopar318]

stock boost is 13psi? I only get 5 psi with the reference line attached right to the wastegate. I thought I was bumping the boost up at 11 pounds.

[Turbodave]

Is it a violent shutdown when it happens? It sounds like an overboost cutout you are describing, maybe it's spiking faster than you can see it on the boost gauge. Things like lower rpm and more load such as when your climbing a hill or passing in a higher gear are more likely to see that.

[ke6960]

its a pulsating (shut down, then power back, then repeat) type thing pretty fast pulsing (im not explaining it very good im sorry)

i was thinking overboost but its a t2 so overboost should be way up at like 14 i only had my g-valve turned up to be a max of 10ish and i dont have any codes, shouldnt i have some kind of code stored if i hit overboost



i should mention that i remember it doing something like this sometimes back when my mom owned the car (not to her she didnt drive it hard, but to me...) but ive owned it for 3 years sence it broke so its a vague memory

[moparzrule]

It could be so rich it's flogging the engine out. Blue on the dawes is super rich. Why is your car running so rich anyway? Are you running the stock cal? Stock injectors? Wierd.

So what were your plug gaps and what plugs are you running?

Are your cam and ignition timing good? You could also be detonating(happens even at 10 PSI if your timing is off enough), you are running high test gas right? 91-93 octane?

[ke6960]

everything is stock except for the g-valve

it dosnt have any trouble at 7psi and its blue when i floor it at 7psi too...


but i am gonna do new plugs today so hopefully they are just worn or something...

[moparzrule]

What plugs were you running and at what gap? I'd run champion RN12YC's up to 15 PSI boost, gapped to .030''.

Your exhaust could also be the problem. A stock CAT will clog easily, making EGT's skyrocket and cause detonation because of the massive backpressure. 9 PSI may be the threshold where the backpressure becomes too much.
Get a decent flowing exhaust on that bad boy.

[ke6960]

i put some champion RN12YC from napa in today the old plugs were gapped wider (or the electrode has receded/worn/melted) than the new plugs so maybe that was the problem

im gonna test drive it in a little while when my son wakes up from his nap on that same hill and see if putting new plugs in helped any

[moparzrule]

What plugs were you running and at what gap?