texasviany

I was testing our 1983 944 on the track for the first time. After about an hour, we started to push it...but still keeping it to the self-imposed 5500 RPM limit...and on a long right corner the dropped about 1500 RPMs....no dash lights came on...its like it starved for fuel for a second. Gas was full. Any suggestions?

We also had lock up on the right rear...I may need to re-bleed (I think)

Thank you for the help!

txhokie4life

Kurt,

Do you have an oil pressure gauge?
Just wondering if your oil pickup is an issue?

obviously a fuel pressure gauge could give you ideas whether
the fuel pump was keeping up.

I can't remember exactly where the pump pick up point is.
Lower left -- so even with a right hander, with a full tank you should be good to go.

You do know of course the tank is built in two sections, and the center hump is pretty huge.

I'm also told there is a grate/filter in the fuel tank -- there is a chance that
it is being covered/clogged on right handers.

My tank knowledge is limited, as that was worked on by one of our other mechanics
on our Chump car.

I'm told there is already a front rear blender for 944's or you can get one easy enough.

Ours car tends to push, and when push comes to shove :-) we lock the fronts.

mike

Lemming

Fuel pump pickup is on the right side of the tank and therefore right-hand turns can be problematic when the fuel is low, but should not be an issue when full.

texasviany

Oil pick up is fine. New PU and windage tray added.

I am going to check fuel filter and pressure.

M758

That 5500 rpm Limit is something we 944 spec guys have seen fairly often. I have never had that issues, but know others that have. First thing to check electrical system. Cap and rotor can do that also low battery voltage. Worse case is bad inner vavle springs simply not working at high RPM.

The 1500 rpm issue could be full starvation. I have seen this happen from 2 diffrent things. I had part of the fuel filler neck float break off and fall in the bottom of the tank. On right turns it would plug the surge tank in the bottom of the car and run the car out of gas at the end of long right turns. It would always come back to normal on the straights. I pulled the fuel sender and poked around with long grabbers and picked out a white plastic cap. It was the bottom of the fload to close the fapper in the fuel filler neck. It also explaind why the fuel tank leaked out the cap on long left turns. I have steel tank car (83-85 and 924S models).

The other issue was the fuel sock on plastic tank car. (85.5 and later). This had collapsed and needed to be replaced. The sock is part of fuel tank to fuel line feed system. Jrichard who sometimes posts here had that issue and resolved it.

txhokie4life

I'm guessing the 5500 limit was self imposed :-) The new car on the track REV limiter.

We did the same thing, and when racing still try to keep it well below 6k. These are $500 20+ year old
endurance racers -- turtles trying to survive.

Last time we were on the track we had a 5000-5500 RPM back fire issue.
If you could (or dared) to fight through it -- you could pull to redline after 5500rpm.

Over the winter break I pulled the cam tower and found two weak lifters
and I have also replaced the plug wires. They sort of exhibited the
chem stick glow light phenomena. You know every time you touch them
they sort of give you that snap/crack sound/feel -- probably glow as well
but we hadn't actually observed that :-)

Got to love crap can racing -- pick your poison. You've got major budget constraints
and when an oil change is nearly 10% of your race budget -- when some things
have to bide their time getting addressed, what a hoot!

Kurt -- post a picture!

Mike

StoogeMoe

I can give some insight on the locking rear. I had the same problem. I rebuilt my calipers all around. It was probably the first time they have been done. There was quite a lot of crud at the bottom of the bores and on the back of the pistons. After cleaning and installing new seals and dust boots, they have been working great.

As to your rev dropping problem, it does sound like a fuel starvation problem, but could be an electrical problem as well. I had a loose connector on the AFM that didn't have the wire tethered tightly, and on sharp turns would cause the engine to cut out. And it only did it on right hand turns also. Just a thought.

dillon410021

I have heard about the power loss problem before.

texasviany

Thanks guys. The rev limit is self imposed. As a team we will keep the car at 5k and we should make it to the end. Due to varying skills of our drivers we don't have a shot at winning anyway. We just all want to drive instead of staring at an engine bay in the pits!

User 52121

Our Lemons car had the same issue once we got below 1/2 tank when we ran a test day with it. Long sweeping right hand turn (T3 at Blackhawk Farms), the car would run out of fuel halfway through. As the fuel level got lower, it got to where it would run out of fuel on ANY right hand turn. Car had just a hair below half tank in it, so we found it odd that it was starving for fuel with as much fuel as we had in the car still.

Took the tank and pump apart, found nothing obviously wrong, put it back together - problem never returned.

If you find out what the problem is with yours - post it here. I'm paranoid that our car will start doing it again during a race.