HELP WITH HP POWER ISSUE over 15psi
Thread Starter
Staging Lane
Joined: May 2013
Posts: 97
Likes: 5
From: Blackwood NJ
Is your second pump on a hobbs switch? Is it possible that a vacuum line going to the hobbs switch that runs the second pump some how got disconnected? That happened to us out of the blue and car nose dived. We thought the pump went bad. It just came loose so no signal to turn it on.
I agree. Bob
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ATI ProCharger and Moser Sales 260 672-2076
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ATI ProCharger and Moser Sales 260 672-2076
PM's disabled, please e-mail me
E-mail: brutespeed@gmail.comob@brutespeed.com
https://brutespeed.com/ Link to website
If the new plugs gapped tighter don't fix your issue, then it's most likely a valve spring issue. I think it's just a coincidence that it happens around 14.7 psi, but then again, you were having issues above 6300 rpm before. There's no reason a motor with a decent cam can't rev out to 6800 rpm or more and be stable. Springs have changed quite a bit over the past 7 years, so it might be something to look into.
Thread Starter
Staging Lane
Joined: May 2013
Posts: 97
Likes: 5
From: Blackwood NJ
Re dyno'd the TA again today. Plugs BR7ef gapped at .023. Same exact problem. I guess its valve float. Im going to pull a spring and check the seat pressure. Im sure there dead. Any recomendations for a set of dual springs for a boosted application on 243 heads. im all ears. I was thinknging 160# seat pressure would be good.
Thread Starter
Staging Lane
Joined: May 2013
Posts: 97
Likes: 5
From: Blackwood NJ
I called Brian Tooly today. Super nice guy gave me an education and set me up with some springs and retainers that should do the trick. He also feels the current springs are staged from siting compressed in the engine for years. Should have them installed by next Tuesday and back on the dyno.
Thanks for the help guys. Stay tuned !!!!!!!
Thanks for the help guys. Stay tuned !!!!!!!
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Thread Starter
Staging Lane
Joined: May 2013
Posts: 97
Likes: 5
From: Blackwood NJ
Well the spring made no change. I can't believe it. I'm going to swap back to the larger pully I had when it made 600 Hp. I want to see if the power comes back and it will rev past 5100 clean threw to 6500. Boost will be under 15. I'm leaving the 120# injectors in for now. If I still have the problem I will swap out the 120# for the 84# I made the 600 with. Also installing new plug wires. I need to figure this out I'm loosing sleep over it at this point. Nobody seems to know where the power is going.
So you changed springs, and plugs, with a tighter gap, and still no change? That's really strange. Definitely check plug wires if you haven't. I know when I was running msd wires, I could never really tell if they were fully seated or not, and this would cause an issue higher in the rpms.
TECH Enthusiast
Joined: Jul 2008
Posts: 577
Likes: 1
From: League City, Tx
OHM out the spark plug wires and check for high resistance, you'd be surprised the screwy **** that will cause.. Also make sure they are 100% seated/clicked on the plugs.
Looking at your logs in HPT, are the O2 readings the same on both banks? The graphs should mirror each other..(the factory O2s, not your wideband).. If one jumping around more then the other, that is the side that is misfiring.
Your chart definitely looks like a valve spring issue but... Since you changed springs that eliminated that.. It's an ugly graph for sure after 5400..
What are the IATs at that point? It almost looks like its getting some hellacious timing being pulled... Either from KR or from high IAT/retard.. Is the timing holding steady after 5400?
That probably is definitely one that will make you sick...
Looking at your logs in HPT, are the O2 readings the same on both banks? The graphs should mirror each other..(the factory O2s, not your wideband).. If one jumping around more then the other, that is the side that is misfiring.
Your chart definitely looks like a valve spring issue but... Since you changed springs that eliminated that.. It's an ugly graph for sure after 5400..
What are the IATs at that point? It almost looks like its getting some hellacious timing being pulled... Either from KR or from high IAT/retard.. Is the timing holding steady after 5400?
That probably is definitely one that will make you sick...
Springs do no wear out from being full compressed unless compressed beyond their yield point. They wear out over time from a number of cycles (heating and cooling). Valve float will wreck a set of springs in a hurry though. I had a very similar issue and I tried all sorts of things, several plugs, plug gaps, new valve springs, plug wires and finally coils. I had MSD plug wires which caused part of the problem but the main problem was my stock coils. They would get really hot on the dyno, swapped to a set of my buddies LS2 coils and all my issues went away. I'd try another set of coils and wires. What rockers are you running?
Springs do no wear out from being full compressed unless compressed beyond their yield point. They wear out over time from a number of cycles (heating and cooling). Valve float will wreck a set of springs in a hurry though. I had a very similar issue and I tried all sorts of things, several plugs, plug gaps, new valve springs, plug wires and finally coils. I had MSD plug wires which caused part of the problem but the main problem was my stock coils. They would get really hot on the dyno, swapped to a set of my buddies LS2 coils and all my issues went away. I'd try another set of coils and wires. What rockers are you running?
Some springs out there are junk after 5000 street miles, poor spring quality. This has nothing to do with sitting for long periods of time. 20,000 miles is alot of miles with an aggressive aftermarket cam, no doubt they would be weak. How many sets of springs have you measured seat pressure on to confirm your claims? What mileage intervals?
Ok, I'm now confused because it looks like the run with the small pulley and 84# injectors was fine, then when you stepped up to the larger injectors it broke up at higher rpms.