Motor won't rev over 5200-5300rpm... WTF???

[Jerryl]

.......... It looks like timing falls off gradually as boost increases, then all of a sudden it jumps up 3 degrees and there is a blip of KR and the motor falls off. It looks like the timing locks on steady at that point.

If the KR is pulling timing, why doesn't it show up in the PL files ?

Does the PL show programmed timing or actual timing ???

I ans answer this ; PL shows prorammed timing only.
I did not look at the log, but if the LV8 changes (drops), it will increase timing.

Ok, scrap that, LV8 looks stable.
I did notice that right at 4900 rpm, O2's jump 846. Maybe too rich and flooding the motor?
I know (as you do) a WB will tell the tale, but the NB is not that warm I am sure, so I am guessing this is about a upper 9:1 ratio. Don't know. Furstrating for sure.

In the end, I am just another set of eyes looking at the same stuff.

LAST edit, I promise! :tongue:
Looks like a very similar issue.
http://www.turbobuick.com/forums/general-turbo-buick-tech/167768-car-breaking-up-above-4900-a-2.html

 

[yullose]

LAST edit, I promise!
Looks like a very similar issue.
http://www.turbobuick.com/forums/general-turbo-buick-tech/167768-car-breaking-up-above-4900-a-2.html

In reading that thread, pacecarta's reply caught my attention:

had similar this week , brand new set of MSD wires and at 20psi felt bucking (pop) or miss , went home rechecked all connections even pulled all the plugs which were fine , hooked up DS took it for a test ride and sure enough it coughed again at 20psi , DS showed that the rpm spiked to 6350 and kr went to 3.0 during the two pops which also sent the injectors static at 106% .
threw the old carquest wires back on ,problems is gone and its clean to 25psi once again

oh and the new wires ohmed out just fine they just dont work

I have MSD wires on my car...

 

[Alky V6]

Isn't that chip tuneable? Can't you adjust that timing step out of there?

 

[QUIP'6']

In reading that thread, pacecarta's reply caught my attention:


I have MSD wires on my car...

i have the same problem and i also heard that these wires dont work on our cars. i also have them. here is my thread.
http://www.turbobuick.com/forums/ge...86499-boost-flutter-wot-along-sputtering.html

 

[bison]

MSD wires here and no problems.

 

[yullose]

i have the same problem and i also heard that these wires dont work on our cars. i also have them. here is my thread.
http://www.turbobuick.com/forums/ge...86499-boost-flutter-wot-along-sputtering.html

Maybe we stumbled on to something...

I actually had these wires on before and they were fine... but who knows. RF interference is invisible and hard to detect... All my MSD wires check good with an ohmeter, but maybe something else is going on with them.

I put the AC Delco wires on the other night, only to pull them off before leaving for the car show because they looked like crap.

Maybe I'll throw 'em back on in the morning and give it a try.

 

[yullose]

Isn't that chip tuneable? Can't you adjust that timing step out of there?

I can adjust the 1/2 timing and the 3/4 timing...

I guess I could pull 3 degrees out of the 1/2 timing and it should stay flat.

 

[Alky V6]

I can adjust the 1/2 timing and the 3/4 timing...

I guess I could pull 3 degrees out of the 1/2 timing and it should stay flat.

You can't do anything with the top end timing? That's where you need to change it. Get it to stay at 19 throughout the high load, and see how it affects things.

 

[Alky V6]

i have the same problem and i also heard that these wires dont work on our cars. i also have them. here is my thread.
http://www.turbobuick.com/forums/ge...86499-boost-flutter-wot-along-sputtering.html

Hmmm.

 

[KevinB]

I'm getting a v-spring tester tomorrow to test my springs out. I have also started the install of my distributor setup today. I will figure this out one way or another

 

[yullose]

I have also started the install of my distributor setup today.

This conversion has crossed my mind too, but I'm not sure how well it would work with my stock ECM...

http://www.summitracing.com/parts/MSD-8551/?image=large

 

[jasjamz]

msd wires here and no problems.

x2

 

[TurboBuRick]

X2

X3 MSD wires here. No problems.

Have you checked the balancer? Has it been torqued to spec?

 

[gunslinger]

Have you checked pushrod length? Is it possible that the rockers are binding on the valve stems at higher RPM?

 

[yullose]

X3 MSD wires here. No problems.

Have you checked the balancer? Has it been torqued to spec?

Balancer is fine. I even had it off for inspecion the other day when I did the crank sensor.

 

[yullose]

Have you checked pushrod length? Is it possible that the rockers are binding on the valve stems at higher RPM?

Valvetrain geometry is perfect. There is plenty of clearence at the pushrod holes, rocker to retainers, etc...

There is definitely no mechanical interference going on.

I'm down to a few possibilities at this point:

1) clogged injector(s) ?

2) bad MAF sensor ?

3) valve springs ?

4) plug wires ?

5) maybe tweak the cam sensor a few degrees ?


The injectors are coming out this afternoon to be shipped out for inspection.

 

[DCVING 6]

Since you have a wideband have you considered Eric's Speed Density chip, or is that what you are using?

How about an aftermarket ECU? You can pick up a classic fast pretty cheap these days.

 

[mjdwyer23]

So did you check the seat pressure or not?

 

[Mike Licht]

is the 3rd dip switch on the translator on?
Mike

 

[KL Mallender]

I've been watching this thread with a bit of humor, all the clues have been given and yet the cause is excaping detection:

The "cause" is a fast ramp hydralic roller cam "launching" the heavy lifter over the nose of the lobe allowing valvetrain seperation to take place, magnified by a higher rocker ratio and you have a classic case of "Valvetrain Float", about the only way you can offset this problem is with a very strong valve spring assembly, and even then you will only gain a few hundred rpm before it returns, if you are serious about 6000+ rpm horsepower, get yourself into a mechanical roller, preferrably a "street roller/tight lash" design, I've never seen a hydralic roller "EVER" make power past 5600-5800 rpm without going into convulsions, rev-kits be dammed, lifters are too damm heavy to control, they have their place, just not in a racing environment. Good Luck.

Kevin.