Hall effect sensor ??

[ecm911]

A friend of mine has a 93RSA that is having a frustating problem.
Car runs fine until pushed hard at the track. Even had it run on a dyno for 3+ hours and could not replicate the problem.

The problem- feels like hitting rev limited @ 5000- 5600 rpms.
Very frustating - What has been done:

Changed ECU ( new box)
Changed coils ( both)
Check fuel pressue/pump


Car is highly modified but very low miles <5K - mods - light wieght fly wheel, headers, but not engine modifications. Did try a Cyntex chip customed for the car and the prob still exists, but less of it.

Anyway any suggestions, would be appreciated.

Long story, someone at the track made a commment that it could be the "Hall effect sensor intermittent"

What is this?

TIA

Earl

[anewbill]

Earl,
I am not an expert by any means, but I believe the Hall sensor is a sensor that the DME uses to determine where the crank is and which cylinder is firing. My 91 C2 gave me a Hall sensor code when I changed my distributer caps and rotors a while back. It turned out one of the caps was a bit loose. I screwed it back down and have not had the problem sense.

[ssetek]

hall sensors can be affected by heat most dme cars use 2 hall sensors 1 for cam angle and crank angle ,
question was the dyno you were testing on a loading dyno or a inetia dyno ?

[Bill Verburg]

I will need to look it up but the 964 has a separate crank sensor wich takes its input from the teeth on the flywheel and a separate hall sensor in the distributors.

Search Ingo Schmitz, he had a hall effect sensor issue and did a really nice write up.

[ssetek]

yes the 964/5 and up have a 58tooth pattern flywheel and a cam sync in the distributers for sequential injection to tell what stroke the engines on

[ecm911]

Thanks All!

I beleive it was a load dyno - ssetek.

Thanks, we are following up on these points.

appreciate it!

[FrayAdjacent911]

Well, Hall Effect Sensors are basically a switch that detects a magnetic field. Lots of laptops use them to sense when you have closed the display, rather than using a physical switch that can break.