AFPR what’s its good for??
Thread Starter
Drifting
Joined: Jul 2002
Posts: 1,273
Likes: 0
From: Olathe, KS USA
AFPR what’s it good for??
Well in my case not much, I installed one hoping to fix a rich idle problem. So having an LT1 and not wanting to spend a lot of $ I purchased the TPIS, LT1 AFPR hat kit for 50$. After installing the kit I set my FP to 38psi at idle with vacuum applied, no vacuum it goes up to 42psi. Before the kit my pressures where 42/47psi.
After driving a week the only difference in the old to new scans is the IPW’s (injector pulse widths) at WOT (wide open throttle) increased from 9.80mS to 10.45mS as a result of the lower pressures. Same thing at idle in gear, 3.3mS to 3.43mS. So the chip compensated for the lower pressure and I ended up with about the same amount of fuel.
I felt the need to post this because IMO a AFPR on a stock or mildly modded ECM controlled car is a waste of $.
After driving a week the only difference in the old to new scans is the IPW’s (injector pulse widths) at WOT (wide open throttle) increased from 9.80mS to 10.45mS as a result of the lower pressures. Same thing at idle in gear, 3.3mS to 3.43mS. So the chip compensated for the lower pressure and I ended up with about the same amount of fuel.
I felt the need to post this because IMO a AFPR on a stock or mildly modded ECM controlled car is a waste of $.
Last edited by C4Crazy787; Dec 17, 2004 at 02:05 PM.
Racer
Joined: Mar 2002
Posts: 498
Likes: 21
From: Maine
How rich at idle is your car now since you put the adjustable fuel pressure regulator on and decreased the pressure?
Are you able to determine what your long term BLM's are?
Are your 02 sensor readings making frequent transitions from 100mv-900mv?
Are you able to determine what your long term BLM's are?
Are your 02 sensor readings making frequent transitions from 100mv-900mv?
Pro
Joined: Aug 2000
Posts: 700
Likes: 1
From: Florida
Waste of money. hmmmm depends.. In closed loop your ECM will compensate for the lower Fuel presure (within reason). But in open loop (WOT) that's where the AFPR will play an important role. You can benifit by lowering your Fuel presure provided you were running too rich in open loop.
Check your O2 sensors. If you have exhaust headers, make sure there sealed tight. Leaky exhust headers can fool your 02 sensors by improperly measuring the oxygen content.
Also contaminated 02 sensors will not properly measure the Oxygen content.
Hank
Check your O2 sensors. If you have exhaust headers, make sure there sealed tight. Leaky exhust headers can fool your 02 sensors by improperly measuring the oxygen content.
Also contaminated 02 sensors will not properly measure the Oxygen content.
Hank
Thread Starter
Drifting
Joined: Jul 2002
Posts: 1,273
Likes: 0
From: Olathe, KS USA
Originally Posted by 93Blackrose
How rich at idle is your car now since you put the adjustable fuel pressure regulator on and decreased the pressure?
Are you able to determine what your long term BLM's are?
Are your 02 sensor readings making frequent transitions from 100mv-900mv?
Are you able to determine what your long term BLM's are?
Are your 02 sensor readings making frequent transitions from 100mv-900mv?
BLM's run 108 unless its PE mode then it runs 128
At idle in gear the o2's run about 850mV hardly transitioning at all.
At idle not in gear the o2's trans are much better. (I have heated o2's)
I've been thinking, maybe my problem is that in gear at idle(850rpm) my car pushes, it wants to go, the engine is making enough torque at 850rpm's to engage the stock converter. The ECM see this load and add's more fuel.
So maybe a high stall converter (comming soon) will fix this??
Thread Starter
Drifting
Joined: Jul 2002
Posts: 1,273
Likes: 0
From: Olathe, KS USA
Originally Posted by 93LT1
But in open loop (WOT) that's where the AFPR will play an important role.
Edit..
Sorry, My first post was confusing I fixed it.
Last edited by C4Crazy787; Dec 16, 2004 at 11:24 PM.
Instructor
Joined: Aug 2004
Posts: 108
Likes: 0
There was no change in the o2 readings after the FP drop.
BLM's run 108 unless its PE mode then it runs 128
BLM's run 108 unless its PE mode then it runs 128
You checked the fuel pressure and that seems not to be the problem. Next thing I would look at is the injectors. Are you running stock or perhaps SVO injectors?
Another possibility is wrong injector constant in you chip. Do you have a stock or custom chip?
Drifting
Joined: Oct 2004
Posts: 1,976
Likes: 0
From: Patchogue NY
After I installed the headers, and other mods, the car was popping when I revved the engine; my mechanic said the car was running lean because of the less restrictive exhaust system, so he suggested I try an AFPR. I put one in and kicked it up to 54 PSI, now the car runs strong, no popping or backfiring problems. I guess they're good (AFPR) if the vehicle is running lean, and you have a stock FPR. My .02.
Joe B.
Joe B.
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Racer
Joined: Mar 2002
Posts: 498
Likes: 21
From: Maine
Originally Posted by C4Crazy787
There was no change in the o2 readings after the FP drop.
BLM's run 108 unless its PE mode then it runs 128
At idle in gear the o2's run about 850mV hardly transitioning at all.
At idle not in gear the o2's trans are much better. (I have heated o2's)
I've been thinking, maybe my problem is that in gear at idle(850rpm) my car pushes, it wants to go, the engine is making enough torque at 850rpm's to engage the stock converter. The ECM see this load and add's more fuel.
So maybe a high stall converter (comming soon) will fix this??
BLM's run 108 unless its PE mode then it runs 128
At idle in gear the o2's run about 850mV hardly transitioning at all.
At idle not in gear the o2's trans are much better. (I have heated o2's)
I've been thinking, maybe my problem is that in gear at idle(850rpm) my car pushes, it wants to go, the engine is making enough torque at 850rpm's to engage the stock converter. The ECM see this load and add's more fuel.
So maybe a high stall converter (comming soon) will fix this??
Thread Starter
Drifting
Joined: Jul 2002
Posts: 1,273
Likes: 0
From: Olathe, KS USA
Originally Posted by Blower91
My EPROM has the BLM lower limit set to 108. If the engine hits this limit usually something is wrong.
You checked the fuel pressure and that seems not to be the problem. Next thing I would look at is the injectors. Are you running stock or perhaps SVO injectors?
Another possibility is wrong injector constant in you chip. Do you have a stock or custom chip?
You checked the fuel pressure and that seems not to be the problem. Next thing I would look at is the injectors. Are you running stock or perhaps SVO injectors?
Another possibility is wrong injector constant in you chip. Do you have a stock or custom chip?
I'm running stock injectors, and a Azzato Custom chip. I pulled the fuel rail/injectors, set it on cookie sheet and pressurized system. Came back 45min's later and one of the injectors had small drop of fuel at the tip.
I've talked to Jesse and he has no problem redoing the chip, I just want to explore all other possibilities before I send it back.
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
I think the value of an AFPR is in getting you used to removing the plenum, runners and injectors when you install it.
And checking the fuel pressure while you adjust it.
All great experience.
I found mine was a pretty much a "set it and forget it" deal.
The REAL fun is in chip tuning.
The factory FPR will be just fine for me, thank you.
And checking the fuel pressure while you adjust it.
All great experience.
I found mine was a pretty much a "set it and forget it" deal.
The REAL fun is in chip tuning.
The factory FPR will be just fine for me, thank you.
