Afr acting crazy...any ideas welcome
So were were both wrong. If pump wasn't running, we will get zero volts on both sides. I must have turn engine on (sorry, my mistake, I forgot)
Attached are pictures of the spark plugs. From left to right 1 - 4 cyl. I spent the day messing around with this thing rechecking my work. I tightened all manifolds, pulled valve cover to check lifters, checked timing, checked cam sensor trigger, did another boost leak test, did compression test, tested the wideband sensor with the rag test, cussed at the car, almost flung a wrench at it, called stm, and called gsc. Compression was 150 - 155 on all cyl. Theyre couple psi from each other. I was on the phone with each tech from stm and gsc for about half an hour. Theyre real nice btw. We could not think of anything else to do. Both agreed that it has to be a sensor or something in the tune. Gsc said if i want to i could change the cams back and if it works fine then theyd happily take the cams back to inspect them but damn i dont want to go through that. They said theyve never had a problem but of course theyd say that. I dont think its the cams but who knows. Fred, youre saying i should clamp the fuel return overnight to see if in the morning the gauge still shows pressure? This would rule out the fuel pump bleeding off right? If i clamp it and still shows zero then the only place it could is out the injectors. Or maybe i should clamp feed and return to make sure. Hell idk. When i shut down the engine sometimes it shows 30 and sometimes it shows 40 or so. It used to always fall to 30 and stay there no matter how long i would let the car sit. I tried 2 fpr and same thing happened. I really really am at a lost now. The tuner said he has some 1000cc injectors at the shop and maybe we can try those tomorrow to see if car wants to cooperate. Any suggestions im all ears guys. If anyone would like to check out the map or something by all means.
Last edited by nor11384; Mar 29, 2018 at 06:05 PM.
If you're only putting the stock cams back on, it's not too much work. Were those plugs new when you installed your head? Those are really black (especially #1), but #4 looks potentially lean.
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From: wisconsin
Put the 1000cc’s on and call TScomp, problem solved.
your tune is off. BC 272’s are basically stock cams, S2’s have 24 degrees more duration at 1mm lift than the 272’s.
More overlap will pull less vacuum at idle/low speed, VE will be much lower with those larger cams at low speeds.
call him I’m sure he will concur.
your tune is off. BC 272’s are basically stock cams, S2’s have 24 degrees more duration at 1mm lift than the 272’s.
More overlap will pull less vacuum at idle/low speed, VE will be much lower with those larger cams at low speeds.
call him I’m sure he will concur.
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From: wisconsin
FYI on fuel pressure dropping after key is turned off. Seems to be a lot of misinformation about this around here, so I’ll clear the air.
This is how how it works, key on and the fuel pump runs for a predetermined amount of time to charge your rail pressure. So waiting a second before cranking to start would eliminate excessive cranking time. After you shut off the engine, pressure may start to drop slowly, this is normal for older vehicles, and not a big deal. Some vehicles will hold pressure for days even a week, again normal. If your pressure drops to zero relatively fast say within 1~2 minutes, then you might have a leaky injector. If it’s not flooding on a cylinder then it’s probably just the regulator and still not a big deal as long as it holds the correct pressure when running.
Stock Fuel Pressure means absolutely nothing on a tuned vehicle. For instance I run 50psi rail pressure, the car has been tuned to run that pressure and runs great.
Tuning with a low compression cylinder and a cam that’s 25 measured degrees less duration, intake and exhaust (huge difference!) is the issue here. A LOW compression cylinder will throw off your O2 sensor bigtime.
This is how how it works, key on and the fuel pump runs for a predetermined amount of time to charge your rail pressure. So waiting a second before cranking to start would eliminate excessive cranking time. After you shut off the engine, pressure may start to drop slowly, this is normal for older vehicles, and not a big deal. Some vehicles will hold pressure for days even a week, again normal. If your pressure drops to zero relatively fast say within 1~2 minutes, then you might have a leaky injector. If it’s not flooding on a cylinder then it’s probably just the regulator and still not a big deal as long as it holds the correct pressure when running.
Stock Fuel Pressure means absolutely nothing on a tuned vehicle. For instance I run 50psi rail pressure, the car has been tuned to run that pressure and runs great.
Tuning with a low compression cylinder and a cam that’s 25 measured degrees less duration, intake and exhaust (huge difference!) is the issue here. A LOW compression cylinder will throw off your O2 sensor bigtime.
Yeah I’m afraid of too much fuel too. It’s seeing 11.3 - 12 idle. Stinks of fuel. I’m here at the shop waiting on these guys. I’m going to start by replacing iac valve then tps sensor from an evo they’re building. Next injectors. If none of this fixes it I’m running this ***** into the local river or the bay. It’s either that or call an exorcist...or another tuner. Heh
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From: wisconsin
https://www.evolutionm.net/forums/ev...d-updated.html
BC 272’s cams are literally stock cams, GSCS2’s are bigger than FP 4R’s you need to look at the 1mm lift figures for duration
your gonna need a new tune because of this anyway. You can lead a horse to water.........
BC 272’s cams are literally stock cams, GSCS2’s are bigger than FP 4R’s you need to look at the 1mm lift figures for duration
your gonna need a new tune because of this anyway. You can lead a horse to water.........
Evolved Member
Joined: Mar 2014
Posts: 816
Likes: 82
From: wisconsin
Yeah I’m afraid of too much fuel too. It’s seeing 11.3 - 12 idle. Stinks of fuel. I’m here at the shop waiting on these guys. I’m going to start by replacing iac valve then tps sensor from an evo they’re building. Next injectors. If none of this fixes it I’m running this ***** into the local river or the bay. It’s either that or call an exorcist...or another tuner. Heh