MattSapp95_T/A

iTrader: (35)

UPDATED!!!


OK so I have been having High Rpm issues with my car now for about 6 months

I thought it may be fuel so I replaced
Regulator
Fuel Filter
255 Fuel Pump
42lb injectors

Put it on the dyno and the fuel was not an issue and like usual it stared missing at 5800 rpms ...Hp and Torque fall off exactly the same

fuel stayed in the mid 12s...

So i bought a Dynaspark opti and checked all the measurements before I put it on (dowel pin and all)
New MSD coil
New Taylor Wires
tried 2 different Icms
Added and checked grounds
ICM cooling Mod done
NGK TR6 plugs (gapped at .39)
MSD Digital 6 box (does it with or without it)

New Patriot Valve Springs shimmed between 1.780 - 1.800
Push rod length looks great
1/4 turn past zero lash on valve adjustment

Compression check showed good


Car still misses at 5800 rpms but will pull until the shift light at 6400...

Once it starts missing the check engine light now comes on and the car don't want to idle.. Turn the car off and back on and the light is gone and it idles fine...

Car went 11.9 @ 112 shifting at 5700 so in know the motor is strong just need to figure this high rpm miss out!!

Could this be an Harness or PCM problem??? What about a Cam issue??? I am at the end of the road with this damn car...

wrd1972

iTrader: (12)

Post the dyno graph.

MattSapp95_T/A

iTrader: (35)

I am going to asap..I am waiting for them to email me the file...

Or I may be able to scan my paper copy an post it

it looks a lot like the dyno sheet you posted in an old thread where you were showing valve float...hp and tq fall off at 5800 the exact same and a/f stayed pretty good...

Matt

joelster

I would have said opti all the way since that is what mine did, but I see that you swapped it out. A cheap solution would be to run a set of 918 beehives and see what happens. The 918's will easily handle that cam. Whatever pressure those springs put out is only part of the equation. They might be too heavy for your application and aren't designed for high rpm use.

fergymoto

iTrader: (129)

Probably the valve springs if they are that old. Have they been run this long or were they just purchased in 2002?

MattSapp95_T/A

iTrader: (35)

Yea I was blaming the opti for the longest time too...but after all the optis and now a brand new Dynaspark I am ruling it out..as well as the coil and ICM plugs wires and anything Fuel related...I have been through all of it multiple times with several different parts...

The car never regains power once it starts to miss...even if you stay on the gas it just sputters and hits a wall...

I don't want to run Dual springs so beehives are prob what I will go with... are the 918s good?? up for opinions...

Thanks everyone!

joelster

I run the 918's on my car. My cam is the XFI 468, 242/248 with .584/.579 lift. I shift at 68-6900rpm, smooth as silk. They are the recommended spring for the cam I run. I'm sure they will handle your cam quite easily. Here's the cam "kit" right from comp:

http://www.compcams.com/Cam_Specs/Ca...csid=1112&sb=0

They are pretty cheap too if you shop around:

springs for $187.95 http://www.summitracing.com/parts/CCA-26918-16/

retainers for $26.95 http://www.summitracing.com/parts/CCA-787-8/

locks $22.95 http://www.summitracing.com/parts/CCA-648-16/


Maybe one of the vendors in here could get you a package for $200ish?

speed_demon24

iTrader: (6)

Valvesprings on aftermarket cams don't last anywhere near as long as the stockers on the stock cam. I would definitely swap out the springs if they are 8-9 years old before you drop a valve.

MattSapp95_T/A

iTrader: (35)

Thanks joelster for the info! I will be ordering the above this week for my car..

I know I don't know what I was thinking...I just had the motor out of the car and I know i should of changed them I guess I just assumed they were ok..


i am still working on getting the dyno posted...

Besides the obvious that the springs are old and need to be changed...Does the symptoms I described sounds like valve float would be the culprit?

joelster

Sounds exactly like a valve float issue. You are lucky that no damage occured. When pistons touch valves, bad things can happen, lol.

MattSapp95_T/A

iTrader: (35)

Ok cool Well I will get those springs ordered...I am going to see if I can order them through one of the sponsors no here...

Thank god I haven't had one slap a piston yet... I am pulling the car down tonight because I don't want to push my luck..

Thanks everyone for taking time to post!

Thanks joelster for all the info!

Matt

MattSapp95_T/A

iTrader: (35)

Updated with dyno sheet....SMOOTHING IS ON 0.... Valve Float???

joelster

Yep it very well could be valve float. It looks like float or spark scattering, but you already addressed the spark issue. Your air/fuel is pretty conservative too. It starts off around 13.1-1 then it gets richer and richer. Around 5800rpm it's just above 12-1 which is pretty conservative.

wrd1972

iTrader: (12)

Might be float.

Here is what float looked like on mine:

MattSapp95_T/A

iTrader: (35)

Yea we quit making pulls and tuning on it because of the high rpm issue...

It has a new Dynaspark (all specs measured and good), MSD Coil, ICM (cooling mod done), Plugs .39 gapped TR6s, Taylor Wires, checked all grounds, checked wires in harness, with or without Digital 6 box does it

Fuel wise...New lines, Regulator, 42lb injectors, 255 pump.....

so I am def leaning towards valve train...

wrd1972

iTrader: (12)

Definitely get some new springs. When I installed the Patriot extremes in mine, all float was history as seen on the graph above.

MattSapp95_T/A

iTrader: (35)

That is def my next step...car is apart in the garage already...

I am going to double check my push rod length too while its apart...

is there ANYTHING else yall think I should check while I am in the motor??

Matt

joelster

Roll the pushrods on a flat surface, make sure none of them are bent. Maybe do a compression check while it's all apart.

MattSapp95_T/A

iTrader: (35)

push rods are good... I did a compression check a few weeks ago and it turned out pretty good too...

I believe my car just hates me...lol

wrd1972

iTrader: (12)

I have reached this conclusion many times myself.