Running Rich/Black Smoke/Power Loss Fixed!
08-12-2007, 11:18 PM
#1
8th Gear
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Join Date: May 2007
Location: motor city
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Running Rich/Black Smoke/Power Loss Fixed!
86 951 Running Rich/Black Smoke/Power Loss Fixed!
Hey all,
I wanted to share a fix for what so many of us encounter with our 944/951.
I was experiencing a real rich running situation that would come on under WOT, accompanied by black smoke, power loss, etc...super frustrating! With info on this board and Rennlist I began to hunt it down. New plugs, rotor, checked TPS, AFM, vacuum lines, and NOTHING was fixing the problem.
I finally took the car to a local garage, and they went further into the investigation including DME, KLR, Turbo hoses, more...long story short it ended up being the Fuel Pressure Regulator...which by the way tested fine at idle and under medium throttle, but is near impossible to check at full boost. From what I understand the internals of the FPR deteriorate over time, and are excelled by ethanol in gas that eats rubber. So the FPR would work at normal driving, but gobs of gas were being dumped on WOT. The car is now running incredible not a puff of smoke and FULL POWER, runs as new with all of the checking and rechecking of all other parts. It has also greatly improved the vehicle starting and gas mileage. Just wanted to share! Check your FPR!
Kudos to autoeurope in Bham Michigan, great to work with and really worked with me on this fix.
Hey all,
I wanted to share a fix for what so many of us encounter with our 944/951.
I was experiencing a real rich running situation that would come on under WOT, accompanied by black smoke, power loss, etc...super frustrating! With info on this board and Rennlist I began to hunt it down. New plugs, rotor, checked TPS, AFM, vacuum lines, and NOTHING was fixing the problem.
I finally took the car to a local garage, and they went further into the investigation including DME, KLR, Turbo hoses, more...long story short it ended up being the Fuel Pressure Regulator...which by the way tested fine at idle and under medium throttle, but is near impossible to check at full boost. From what I understand the internals of the FPR deteriorate over time, and are excelled by ethanol in gas that eats rubber. So the FPR would work at normal driving, but gobs of gas were being dumped on WOT. The car is now running incredible not a puff of smoke and FULL POWER, runs as new with all of the checking and rechecking of all other parts. It has also greatly improved the vehicle starting and gas mileage. Just wanted to share! Check your FPR!
Kudos to autoeurope in Bham Michigan, great to work with and really worked with me on this fix.
08-12-2007, 11:42 PM
#2
Lazer Beam Shooter
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Rennlist Member
What kind of gas mileage were you getting? My car runs so rich and has the same symptoms and im getting terrible gas mileage. How bad were you getting?
08-13-2007, 12:30 AM
#3
8th Gear
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Join Date: May 2007
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Rock,
You know I never actually documented the mileage, just seemed to eat gas at an alarming rate. Since the fix I am halfway through a tank and can tell already it has improved. Do you lose power at the same time you are smoking? it was basically flooding the engine, the power loss was really bad, but only noticeable at higher RPMS.
You know I never actually documented the mileage, just seemed to eat gas at an alarming rate. Since the fix I am halfway through a tank and can tell already it has improved. Do you lose power at the same time you are smoking? it was basically flooding the engine, the power loss was really bad, but only noticeable at higher RPMS.
08-13-2007, 12:42 PM
#4
Burning Brakes
Was this the "stock" FPR??? I have the same problem right now, using an adjustable unit I purchased from Lindsey. Had to cut my fuel pressure down to 28lbs and it still maxes out the wide band from 4K to 5500 rpm. Maybe I will try a 3 bar unit and see what happens.
08-13-2007, 01:25 PM
#5
Lazer Beam Shooter
Rennlist Member
Rennlist Member
Well it used to hesitate at higher RPMS, it does feel like its loosing power though. I think im gonna grab a 3.0 bar and see what happens. I know its not the 02 sensor, I was messing around with that and when I unplugged it, it went from smelling rich to super rich.
06-28-2010, 11:14 AM
#6
Burning Brakes
86 951 Running Rich/Black Smoke/Power Loss Fixed!
Hey all,
I wanted to share a fix for what so many of us encounter with our 944/951.
I was experiencing a real rich running situation that would come on under WOT, accompanied by black smoke, power loss, etc...super frustrating! With info on this board and Rennlist I began to hunt it down. New plugs, rotor, checked TPS, AFM, vacuum lines, and NOTHING was fixing the problem.
I finally took the car to a local garage, and they went further into the investigation including DME, KLR, Turbo hoses, more...long story short it ended up being the Fuel Pressure Regulator...which by the way tested fine at idle and under medium throttle, but is near impossible to check at full boost. From what I understand the internals of the FPR deteriorate over time, and are excelled by ethanol in gas that eats rubber. So the FPR would work at normal driving, but gobs of gas were being dumped on WOT. The car is now running incredible not a puff of smoke and FULL POWER, runs as new with all of the checking and rechecking of all other parts. It has also greatly improved the vehicle starting and gas mileage. Just wanted to share! Check your FPR!
Kudos to autoeurope in Bham Michigan, great to work with and really worked with me on this fix.
Hey all,
I wanted to share a fix for what so many of us encounter with our 944/951.
I was experiencing a real rich running situation that would come on under WOT, accompanied by black smoke, power loss, etc...super frustrating! With info on this board and Rennlist I began to hunt it down. New plugs, rotor, checked TPS, AFM, vacuum lines, and NOTHING was fixing the problem.
I finally took the car to a local garage, and they went further into the investigation including DME, KLR, Turbo hoses, more...long story short it ended up being the Fuel Pressure Regulator...which by the way tested fine at idle and under medium throttle, but is near impossible to check at full boost. From what I understand the internals of the FPR deteriorate over time, and are excelled by ethanol in gas that eats rubber. So the FPR would work at normal driving, but gobs of gas were being dumped on WOT. The car is now running incredible not a puff of smoke and FULL POWER, runs as new with all of the checking and rechecking of all other parts. It has also greatly improved the vehicle starting and gas mileage. Just wanted to share! Check your FPR!
Kudos to autoeurope in Bham Michigan, great to work with and really worked with me on this fix.
I will write back to let people know.
06-28-2010, 01:02 PM
#7
Do you have a Wide Band 02 meter? I was having the same issues. I still need to change my idle control valve but once I put the SMT-6 on and a new TPS I was able to tune it all out.
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06-28-2010, 09:56 PM
#8
Burning Brakes
PROBLEM FIXED.
IT WAS THE FUEL PRESSURE REGULATOR. 150$. INSTALLED IT MYSELF (I'M NO MECHANIC BUT THANKS TO CLARKS GARAGE).
And yes I'm screaming of happiness.
The problem used to happen when the engine was hot.
I just installed the FPR and went for a ride right after.
4 min. after departure, I had a backfire switching in 2nd gear (bigger than before).
But then, my car was just running like a new baby. Went on the highway, went up to 200km/h,
then got back home doing all does stop, going at 30km/h (it was always on that street where I had does backfires, going really slow) and nothing, just a clean, smooth 951 engine noise.
I also noticed a bit of a difference on performance, but maybe that was just all in my head, I felt like I was driving a new car.
Thanks Turbopilot
IT WAS THE FUEL PRESSURE REGULATOR. 150$. INSTALLED IT MYSELF (I'M NO MECHANIC BUT THANKS TO CLARKS GARAGE).
And yes I'm screaming of happiness.
The problem used to happen when the engine was hot.
I just installed the FPR and went for a ride right after.
4 min. after departure, I had a backfire switching in 2nd gear (bigger than before).
But then, my car was just running like a new baby. Went on the highway, went up to 200km/h,
then got back home doing all does stop, going at 30km/h (it was always on that street where I had does backfires, going really slow) and nothing, just a clean, smooth 951 engine noise.
I also noticed a bit of a difference on performance, but maybe that was just all in my head, I felt like I was driving a new car.
Thanks Turbopilot
06-29-2010, 02:26 PM
#9
Burning Brakes
PROBLEM FIXED.
IT WAS THE FUEL PRESSURE REGULATOR. 150$. INSTALLED IT MYSELF (I'M NO MECHANIC BUT THANKS TO CLARKS GARAGE).
And yes I'm screaming of happiness.
The problem used to happen when the engine was hot.
I just installed the FPR and went for a ride right after.
4 min. after departure, I had a backfire switching in 2nd gear (bigger than before).
But then, my car was just running like a new baby. Went on the highway, went up to 200km/h,
then got back home doing all does stop, going at 30km/h (it was always on that street where I had does backfires, going really slow) and nothing, just a clean, smooth 951 engine noise.
I also noticed a bit of a difference on performance, but maybe that was just all in my head, I felt like I was driving a new car.
Thanks Turbopilot
IT WAS THE FUEL PRESSURE REGULATOR. 150$. INSTALLED IT MYSELF (I'M NO MECHANIC BUT THANKS TO CLARKS GARAGE).
And yes I'm screaming of happiness.
The problem used to happen when the engine was hot.
I just installed the FPR and went for a ride right after.
4 min. after departure, I had a backfire switching in 2nd gear (bigger than before).
But then, my car was just running like a new baby. Went on the highway, went up to 200km/h,
then got back home doing all does stop, going at 30km/h (it was always on that street where I had does backfires, going really slow) and nothing, just a clean, smooth 951 engine noise.
I also noticed a bit of a difference on performance, but maybe that was just all in my head, I felt like I was driving a new car.
Thanks Turbopilot
I was so happy last night that I couldn't sleep. So I sneaked out of bed (my wife was sleeping) and went for another midnight drive. The car had a huge backfire when pressing on the clutch to switch on 4th gear (about 6000rpm), and when I came back, going really slowly, I still could hear small puf puf sound pressing on the clutch to switch in 2nd gear.
The good news, it seems like the fuel/exaust smell as disappear, or almost. And the car seems to have a bit more performance.
Did more research and found this on http://www.clarks-garage.com/
''Fuel System leakdown failures can be caused by a leaking fuel injector(s), a bad fuel pressure regulator (FPR), or a leaking fuel pump check valve. When this happens, the fuel rail voids and the car is difficult to start when it's been sitting for a while. When the engine is turned over, if the fuel rail is voided, it takes the fuel pump a while to refill and clear the voids from the rail so that the car will get enough fuel to start.
Normally, if fuel rail voiding is caused by a leaking injector, you'll see lots of black smoke on subsequent startups. The following guide is intended to help you isolate fuel system leakdown problems.''
09-03-2020, 12:24 PM
#11
I'm curious too about my FPR. My new to me, 1986 951 recently has noticable black smoke when started and going down the road. We haven't been driving it much but it seems to be starting to run richer and richer. It has a tune, header and other mods the previousd owner wasn't sure of so i'm still trying to figure out exactly what I have in this car.
Chris
Chris
09-04-2020, 12:20 AM
#12
Three Wheelin'
I'm curious too about my FPR. My new to me, 1986 951 recently has noticable black smoke when started and going down the road. We haven't been driving it much but it seems to be starting to run richer and richer. It has a tune, header and other mods the previousd owner wasn't sure of so i'm still trying to figure out exactly what I have in this car.
Chris
Chris
Short of that, if the fuel pressure is not much above the rating of the fuel pressure regulator, then you rich condition lies elsewhere, either with the tune or a faulty sensor/wiring . . . .
09-04-2020, 10:46 AM
#13
Rennlist Member
One way is to check your oil, when the FPR goes it dumps fuel and will land in your oil. It will smell strong like fuel and be thinned out. You can also check your vacuum line to the FPR if it is wet with a fuel smell (to me it smells like fuel even when not wet so wet is the key) then there is a leak in it.
