1988 944S loss of power going downhill - Bad AFM?
06-22-2012, 12:54 AM
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1988 944S loss of power going downhill - Bad AFM?
I have a very strange issue with my car. When going downhill coasting in 2nd or 3rd gear say at 3K RPMs, if I step on the gas, the car has zero power, after 2-4 seconds on the throttle, it returns to normal. If I depress the clutch, the RPMS would drop to almost stalling, hunt around and then stabilize again.
It doesn't happen going up hill, or on level ground...just downhill. Could this be a AFM issue, fuel pickup?
Any help would be appreciated.
It doesn't happen going up hill, or on level ground...just downhill. Could this be a AFM issue, fuel pickup?
Any help would be appreciated.
Last edited by bay924s; 06-22-2012 at 01:13 AM.
11-28-2012, 09:13 PM
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No responses earlier this summer, but I am having the exact same problem. 
Anyone have any ideas?
I just put an S2 manifold and throttle body on my 87 944S, and I was thinking maybe one of my splices for the AFM was bad, but they all seem good. Something clogging up my gas tank when the car points downhill? I'm going to change my fuel filter as soon as I get a chance.
bay924s, did you figure it out on yours?
At least it isn't when I'm going uphill...
Anyone have any ideas?
I just put an S2 manifold and throttle body on my 87 944S, and I was thinking maybe one of my splices for the AFM was bad, but they all seem good. Something clogging up my gas tank when the car points downhill? I'm going to change my fuel filter as soon as I get a chance.
bay924s, did you figure it out on yours?
At least it isn't when I'm going uphill...
11-28-2012, 11:26 PM
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No responses earlier this summer, but I am having the exact same problem.
Anyone have any ideas?
I just put an S2 manifold and throttle body on my 87 944S, and I was thinking maybe one of my splices for the AFM was bad, but they all seem good. Something clogging up my gas tank when the car points downhill? I'm going to change my fuel filter as soon as I get a chance.
bay924s, did you figure it out on yours?
At least it isn't when I'm going uphill...
Anyone have any ideas?
I just put an S2 manifold and throttle body on my 87 944S, and I was thinking maybe one of my splices for the AFM was bad, but they all seem good. Something clogging up my gas tank when the car points downhill? I'm going to change my fuel filter as soon as I get a chance.
bay924s, did you figure it out on yours?
At least it isn't when I'm going uphill...
11-29-2012, 05:03 AM
#4
Information for fuel pressure and fuel flow test
http://www.clarks-garage.com/pdf-manual/fuel-01.pdf
http://www.clarks-garage.com/pdf-manual/fuel-20.pdf
http://wwhttp://www.clarks-garage.co...al/fuel-07.pdf
http://www.clarks-garage.com/pdf-manual/fuel-19.pdf
http://www.clarks-garage.com/pdf-manual/fuel-01.pdf
http://www.clarks-garage.com/pdf-manual/fuel-20.pdf
http://wwhttp://www.clarks-garage.co...al/fuel-07.pdf
http://www.clarks-garage.com/pdf-manual/fuel-19.pdf
11-29-2012, 01:11 PM
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Okay, I've read those, but still nothing explaining why it would only happen while pointing downhill. Unless the ball bearing in the fuel rail moved to a point where it might restrict flow when the car is tipped forward? I'm still not certain about the purpose of the bearing, or its function. While I was removing the fuel rail at the beginning of my manifold swap, I pulled all the injectors out with the rail, except for the injector furthest forward on the manifold. That one stayed in the manifold. Could this have moved the ball bearing into a position where it would restrict fuel flow? Like I said, I don't quite understand this fuel rail bearing, so that may be a stupid question, but I don't particularly want to take my fuel rail apart and open it up if I don't need to.
I'll clean the strainer when I'm in there for the filter. I've been meaning to get an adjustable FPR and gauge, but I've been short on funds for the car lately. I'm feeling that should help the car's overall function post S2 manifold/TB swap, regardless of whether or not it helps the downhill throttle response issue. I've put an intake (manifold all the way out) for a 3.0L on a 2.5L, without upgrading the fuel side of things, so I guess I shouldn't be too surprised that there's an issue. Its running great aside from this issue, and pulls nicely in the flats.
I'll clean the strainer when I'm in there for the filter. I've been meaning to get an adjustable FPR and gauge, but I've been short on funds for the car lately. I'm feeling that should help the car's overall function post S2 manifold/TB swap, regardless of whether or not it helps the downhill throttle response issue. I've put an intake (manifold all the way out) for a 3.0L on a 2.5L, without upgrading the fuel side of things, so I guess I shouldn't be too surprised that there's an issue. Its running great aside from this issue, and pulls nicely in the flats.
