Is a DIY CPS install possible?

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alternative
Posts: 41
Joined: Tue May 10, 2022 10:51 am
Your car is a: 1980 Fiat 124 Spider Fuel Injected

Is a DIY CPS install possible?

Post by alternative »

I want to install either a crank or cam position sensor for my new customizable ECU that I bought for this car. The only problem is the ECU requires a CPS sensor to be present on the car, I know these cars don't have one so does anyone have a way to get one on the car? Or even a workaround to use the spark pulse as a CPS signal? For reference I am going to install the Speeduino, an open source community project that works amazingly for me.
Nut124
Posts: 748
Joined: Wed Oct 25, 2017 6:39 pm
Your car is a: 1978 124 Spider 1800

Re: Is a DIY CPS install possible?

Post by Nut124 »

Cannot use spark as it's timing varies.

A sensor on the cam is not reliable as cams can be out of time. Something custom either on the FW or the front pulley. There are kits sold for this purpose.
TX82FIAT
Posts: 1814
Joined: Mon May 03, 2010 11:04 am
Your car is a: 82 Fiat Spider 2000 CSO
Location: San Antonio

Re: Is a DIY CPS install possible?

Post by TX82FIAT »

An option is to use a trigger sprocket wheel attached to the crankshaft at the bottom front of the engine that has one or two missing teeth depending on your program. For example, you can run a megasquirt 2 on a 36 tooth wheel with one missing tooth. My system has two missing teeth. You would create and bracket and mount a crankshaft position sensor at the right spacing to the wheel so it can read the missing tooth and alter the pulse signal for the mapping. I had the folks at Vicks Auto Sports create and install the system back in 2009. It is still working great today.
Buon giro a tutti! - enjoy the ride!

82 Fiat Spider 2000
03 BMW M3
07 Chevy Suburban
ORFORD2004
Posts: 1119
Joined: Wed Mar 17, 2010 9:48 pm
Your car is a: 1983 PININFARINA
Location: Sherbrooke, Qc, Canada

Re: Is a DIY CPS install possible?

Post by ORFORD2004 »

And you can use a Ford crank sensor
alternative
Posts: 41
Joined: Tue May 10, 2022 10:51 am
Your car is a: 1980 Fiat 124 Spider Fuel Injected

Re: Is a DIY CPS install possible?

Post by alternative »

I recently discovered I can use the speeduino as a "slave" to the distributor, all it needs is the factory spark signal and it'll work fine.
gandyrail
Posts: 47
Joined: Wed Jun 17, 2015 12:39 pm
Your car is a: 1981 2000

Re: Is a DIY CPS install possible?

Post by gandyrail »

my solution is more expensive than being lucky and finding ford edis in junk yard, plus I did not want an iron crank; I did not want the trigger wheel in front of the crank pulley either.
Used AR's alu crank pulley, a 36-1 trigger wheel (5mm thick), lathed 4.5 mm off the back face of pulley not touching the "shaft", (4.5mm is the most that can be removed still keeping the inner v-belt even though I dont use it), install on pulley with 3 machine screws below pulley slot, insure trigger wheel clears aux pulley turn motor over by hand by hand. (I machined the belt keeper lip on the aux pulley by +/- 3mm, it was touching here and there during the motors complete cycle) ... Also went hall sensor with supplied voltage; Im getting a good trigger signal.
...
I fiddled around and put the pick-up on the timing mark arrow metal.... there is a hole that lines up to the trigger wheel and is almost the right size ... I made it work for the pickup bought at DIY. Dont recommend this but it worked. Had to cut plenty of shims from abs plastic and a couple from alu sheet, somebody can likely figure a way to adjust easier.
.....
For a cam pickup only needed during starting?) install half moon plate behind cam wheel w/ hall sensor pick up installed thru new hole in back of safety "trim" tin. Goal to get rid of anything in the dizzy hole above exhaust
gandyrail
Posts: 47
Joined: Wed Jun 17, 2015 12:39 pm
Your car is a: 1981 2000

Re: Is a DIY CPS install possible?

Post by gandyrail »

UPDATE to earlier older post
The crank trigger and pickup has been bulletproof; the ABS epoxied together with alum top and bottom has been a good encasement for my crank sensor pick-up. The sensor goes in the +\- half inch hole found towards the engine on the ignition timing pointer on my 2 liter, also there are factory machined threads in the pointer used to secure the encasement to the timing pointer. (Really, did Fiat fool around with this, it seams all set up?) This location is above oil pan so is protected from road crap . It is right on top of the trigger wheel I placed behind the crank pulley.
NOW About the Cam Sensor;
The half moon on the cam wheel was a Flunk. Well the half moon worked and looked good but the back tin holding the sensor pickup flexes (slightly), and I also missed the pickup placement by 2 - 3 mm so the sensor would hit the cam wheel edge sometimes and yep screeech new sensor.
NOW: I have modified a Jeep TJ 4.0 Cam Sensor by cutting off the drive-shaft end and welding drive gear splines on cut from my old oil pump shaft. I made all measurements with a micrometer, and used a drill press and mig welder. .This cam sensor fits great in the oil pump block off hole. I had to move my dipstick a wee bit to install, either that or remove it install the sensor and reinstall the dipstick...
NEXT:
I will probably move this unit to drive off the exhaust cam gear with some more engineering it might be a ford sensor next time for lower profile although I think I can cut this one down substantially more ...... Not sure why but Tbelt tracks different now... maybe putting a load on the aux pulley it is not designed for anymore?
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