RPM 'jitters' around 4600 using EDIS

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spitfire1500
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Joined: Thu Jul 10, 2008 12:02 pm

RPM 'jitters' around 4600 using EDIS

Post by spitfire1500 »

Hi,

MS2 v2.2 release 2.01
LC1
40mm TWM ITB
Spitfire 1300
Stock cam and pistons
EDIS-4
Alpha-N

Around 4600 RPM it starts to 'jitter' - sawtooth RPM, PW and DutyCycle and gets worse if I keep applying throttle. My VR sensor wire is shielded for about 3' with 18" left unshielded and the shield tied into pin 7 on EDIS. Engine works great that point, problem occurs with load or no load.

SAW and PIP to relay board are not shielded to the relay board about a foot away.

Most of the posts I've seen with these symptoms are for v3.0 and the solution is to adjust C31 and C32.

Apologize for no log - it was bigger than 2MB

Any advice?

Thanks,

Doug
Matt Cramer
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Re: RPM 'jitters' around 4600 using EDIS

Post by Matt Cramer »

If you disconnect the SAW and rev it to around 4600 or beyond in neutral, does the timing stay steady or have problems?
Matt Cramer -1966 Dodge Dart slant six running on MS3X
spitfire1500
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Re: RPM 'jitters' around 4600 using EDIS

Post by spitfire1500 »

Sorry for the slow response - I had to change my diff and then we went away for the weekend.

I disconnected SAW and the problem got worse the 'jitters' got bigger but still started around 4600. I even had a system reset.

I wanted to attach the log but now it says max attach file size is 716KB.

Should I be looking at my grounds?

- Doug
Matt Cramer
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Re: RPM 'jitters' around 4600 using EDIS

Post by Matt Cramer »

It sounds like the problem is in the EDIS system itself.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
renns
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Re: RPM 'jitters' around 4600 using EDIS

Post by renns »

This has been reported by others with flimsy VR sensor mounting. Check your sensor mount bracket and be sure it is VERY rigid. If it vibrates at certain engine speeds, the EDIS module will 'see' each tooth multiple times causing all sorts of issues.

Roger.
1979 Mazda RX-7, running MSnSExtra hi-res 09c for fuel and spark control on a turbocharged, intercooled, and (of course!) injected 13B rotary.
spitfire1500
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Re: RPM 'jitters' around 4600 using EDIS

Post by spitfire1500 »

I believe it may be a flimsy bracket - I took my homemade bracket off and found a weld had broken and the sensor had been rubbing on the wheel. It may take a few days to get it repaired.

- Doug
W113
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Re: RPM 'jitters' around 4600 using EDIS

Post by W113 »

Hi ,
EDIS flutter.
Great you found the broken bracket. While you are at it, have a liik at the 36-1 wheel.
It has to sit rigidly on the crankshaft, and not be mounted on a vibration damper.
They are usually attached to the crank thru a rubber spring and are designed to
oscillate!
I did this mistake on a 350 chevy and had very erratic ignition in the range 2500-3200 rpms.

Made a new 36-1 wheel that I welded on to the belt pulley, and all was well!

And I would also definitely shield the entire VR and SAW/PIP wires. The shield for those shall
be attached to the nr 7 pin on the EDIS and be left floating in the other end. Best is to use
real good q shielded wire that has an external insulation.

Ola
If not understood , it will not work
Minami Kotaro
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Re: RPM 'jitters' around 4600 using EDIS

Post by Minami Kotaro »

spitfire1500 wrote:I believe it may be a flimsy bracket - I took my homemade bracket off and found a weld had broken and the sensor had been rubbing on the wheel. It may take a few days to get it repaired.

- Doug
Make sure the wheel is mounted true, as well. My wheel was eccentric and rubbed the sensor. A new, absolutely true wheel mount fixed my problems.

You might get a new sensor while you're at it. If the wheel's been hitting it, it could be damaged. I got one from NAPA for $20.
1967 VW Beetle
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spitfire1500
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Re: RPM 'jitters' around 4600 using EDIS

Post by spitfire1500 »

Thanks for all the advice - I still have the problem but I believe the root cause is at the tooth wheel and vibration from an out of balance engine. My motor is a Spitfire 1300 but the flywheel is from a 1500 and they were never balanced together. I will pull the motor over the winter for balancing.

What I have done since my last post:
- the VR sensor was replaced
- the VR bracket is now reinforced with angle iron and could probably lift the car without flexing
- the alternator was rebuilt because its bearings were worn
- the injectors were replaced with a set known to be good
- the coil pack was swapped and moved to a location away from other engine wiring
- the optional noise supression wire was hooked up
- the VR wire is now shielded
- the EDIS and Relay Board ground wires now go back to the battery

The car is a blast to drive to about 4900 RPM which is more than enough for normal traffic since I have an overdrive unit and cruise at 2900-3300 RPM.

I'll report back in the spring - hopefully with good news.

- Doug
78Spitfire
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Re: RPM 'jitters' around 4600 using EDIS

Post by 78Spitfire »

I hope you are aware that the 1500 flywheel uses larger bolts than the 1300. If you put a 1500 flywheel on a 1300. I believe the 1500 uses 7/16" bolts and the 1300 3/8" bolts. Be sure to use bolts that have a shoulder (no threads) in the flywheel. If there are threads the flywheel/clutch action will mash them resulting in similar play to putting 3/8" bolts in a 7/16" hole (i.e. 1500 flywheel on a 1300 motor. Never have threads going into the flywheel, always a shoulder bolt.

If you put a 1500 flywheel on a 1300 you have a couple of options:

1- Drill out the 1300 crankshaft and re-tap it to 7/16. This is what I did with the engine removed and it went well with a hand held drill. Don't make a mistake or you will be putting in a new crankshaft.
2- Turn down a 7/16" bolt with a shoulder to 3/8" and run a 3/8 die down. Be sure you leave the unthreaded shoulder to fit inside the flywheel.

1300 flywheels are hard to come by as the 1300 is preferred by racers as it can rev higher, take more compression, and is generally more robust from exploding than the 1500 when taxed with race conditions.

Kurt
prof315
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Re: RPM 'jitters' around 4600 using EDIS

Post by prof315 »

You may also want to SERIOUSLY consider updating your firmware. MS2/Extra 2.01 is pushing 10 years old. Lots and lots of improvements and new features in the current 3.4.2 firmware.
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DaveEFI
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Re: RPM 'jitters' around 4600 using EDIS

Post by DaveEFI »

spitfire1500 wrote:Sorry for the slow response - I had to change my diff and then we went away for the weekend.

I disconnected SAW and the problem got worse the 'jitters' got bigger but still started around 4600. I even had a system reset.

I wanted to attach the log but now it says max attach file size is 716KB.

Should I be looking at my grounds?

- Doug
Yes - especially if you are using a relay board. In a log, are all the other sensors showing a reasonably clean signal?

Where is your EDIS module grounded?
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ashford
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Re: RPM 'jitters' around 4600 using EDIS

Post by ashford »

prof315 wrote:You may also want to SERIOUSLY consider updating your firmware. MS2/Extra 2.01 is pushing 10 years old.
so is the origional post
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