Datalogging RPM

Anything not covered in the other forums.
Blocmi
Posts: 26
Joined: 2021 Feb 16, 11:13
Location: Connecticut
Vehicle Information: 1995 Mustang GT, CBAZA, 11:1 306, Ported Windsor Sr. aluminum heads 2.02/1.60, Trick Flow Track Heat, 24lb injectors, Comp cams 294/306 (2,800-7,000), Shorty headers, X-Pipe, Reverse Manual VB C4, 4100 stall converter, 4:10, MT ET Drag 26-10-15

Datalogging RPM

Unread post by Blocmi »

When looking at data, my RPM data is not very smooth. 2nd and 3rd gear WOT pulls show a repeated 200 rpm drop or increase between data points while accelerating. I did replace the original distributer that had worn bushings with a Spectra FD22, but I did not see any difference.

Is this just the nature of the beast, or should the RPM trace be consistent and smooth?
decipha
Posts: 4952
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: Datalogging RPM

Unread post by decipha »

That's not uncommon. You can try grounding the distributor housing to help smooth it out a tad.
Blocmi
Posts: 26
Joined: 2021 Feb 16, 11:13
Location: Connecticut
Vehicle Information: 1995 Mustang GT, CBAZA, 11:1 306, Ported Windsor Sr. aluminum heads 2.02/1.60, Trick Flow Track Heat, 24lb injectors, Comp cams 294/306 (2,800-7,000), Shorty headers, X-Pipe, Reverse Manual VB C4, 4100 stall converter, 4:10, MT ET Drag 26-10-15

Re: Datalogging RPM

Unread post by Blocmi »

I tried adding a ground from the distributer housing to the block but it made no improvement.
It appears to be jumping around enough to make perload and injector pulswidths inconsistent.

Is it possible to install a tach signal filter to smooth the signal to the ECU?
decipha
Posts: 4952
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: Datalogging RPM

Unread post by decipha »

nope

only other option is a new distributor or pickup
Blocmi
Posts: 26
Joined: 2021 Feb 16, 11:13
Location: Connecticut
Vehicle Information: 1995 Mustang GT, CBAZA, 11:1 306, Ported Windsor Sr. aluminum heads 2.02/1.60, Trick Flow Track Heat, 24lb injectors, Comp cams 294/306 (2,800-7,000), Shorty headers, X-Pipe, Reverse Manual VB C4, 4100 stall converter, 4:10, MT ET Drag 26-10-15

Re: Datalogging RPM

Unread post by Blocmi »

Distributor is pretty much new. Under 500 miles.
I changed the original for this same issue, so I should probably be looking elsewhere.
Unfortunately, class rules prohibit me from changing to EDIS.

Attached is a pic of how rough RPM is compared to the MAF signal.
RPM vs MAF.JPG
decipha
Posts: 4952
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: Datalogging RPM

Unread post by decipha »

graphs do nothing for me im more of a numerical value person

if its not giving you any trouble then i wouldn't be concerned with it. Otherwise you could have some resistance in the wiring.

oh and just because a part is new doesn't mean its working correctly
Blocmi
Posts: 26
Joined: 2021 Feb 16, 11:13
Location: Connecticut
Vehicle Information: 1995 Mustang GT, CBAZA, 11:1 306, Ported Windsor Sr. aluminum heads 2.02/1.60, Trick Flow Track Heat, 24lb injectors, Comp cams 294/306 (2,800-7,000), Shorty headers, X-Pipe, Reverse Manual VB C4, 4100 stall converter, 4:10, MT ET Drag 26-10-15

Re: Datalogging RPM

Unread post by Blocmi »

It seems to run OK, but load and perload can jump 5%-8% between data points due to the MAF being stable while the RPM data is fluctuating.
Keep in mind, as this is a bracket car, I'm looking for consistency, every little bit counts.

I hear ya on the new parts being bad too. I replaced the original worn distributor, that had an Echlin pickup in it, due to worn bushings. Like I said the new distributor acts the same. Maybe it's a pickup issue, I don't know what pick up is in the FD22.

I believe it was previously stated that the ford sensors were of the best quality, is that still the case?
Any difference between the Motorcraft DU-50 for sale everywhere and a E9TZ-12A112-A pickup straight from a dealer?

I also measured the teeth on the OE and Spectra distributer. The Spectra was out of spec by 5-6 thousandths, but it was consistent on every tooth. The OE was within spec, so I'll swap that to the new dizzy.
decipha
Posts: 4952
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: Datalogging RPM

Unread post by decipha »

As with all ford ignition components from 1980s to 2021 there isnt a single aftermarket upgrade for anything. All aftermarket ford ignition components are far inferior to the oem stuff.

all motorcraft pickups are usually fine.

yeah I wouldnt expect much from spectra
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