'79 CIS TO EFI

[PeterK]

Another cold day in the garage, but fear not, the cold is going but the rain is coming.

Anyway, the plan for today was to place the ECU under the passenger seat and route it’s loom into the engine bay. The expectation being that I could then plan what wires will go where.

Things started strongly and I managed to place the ECU on the floor, under the (temporarily removed) passenger seat (not fixed, just placed roughly in position - didn’t want to peak too soon)


As there is already a considerable amount of ‘stuff’ running through the tunnel, and with the inherent risk of additional loomage being abraded by either the throttle linkage of the gear shift linkage, the interweb wisdom suggests just routing the ECU Loom through the heelboard. So I lifted the carpet and sound deadening


There are indentations around the small bracket with a circly sort of shape to the outside of it, which tally up with what I can see from underneath. So, it looks like here will be the spot


So I drilled a pilot hole.


While I was ‘down there’, I had a little think about main chassis grounds and permanent live feeds. There is a ground behind the fuel filter that I can use, or the main one by the gearbox


Rather than replacing the permanent live from the alternator (that originally ran to the 14 way connector), I could also run a feed directly from the starter

This latter feed could loop across the the loomage that runs above the heater flap valve, join with the earth from by the gearbox, across the tail of the gearbox and follow the main loomage up behind the other heater flap valve ….


… to come out in the rear corner of the engine bay



My plan was coming along nicely



until



The only 2.25” / 57mm hole saw I have is clearly for wood


I enjoyed lots of smoke but unfortunately little cutting action. New hole saw quickly ordered from fleabay.

So, thwarted in my hole making, I unpacked the ECU loomage and had a thunk. I’m now in the warm, working out what cables I can delete from the loom and whether I should bother adding a quick connector into the loom to allow engine removal without having to disconnect every sensor.

Oh, and while I was purveying the under side of the engine, I reckon that I could fit a Clewett cam sync adapter without having to remove the engine. Anyone got a spare laying around, or am I into mega bucks for a kit from the USA, more for shipping and then VAT when it arrived (plus of course, the shippers’ “admin fee”).

[SeanP]

I have just bought the cam sensor kit from Clewett £200 or there abouts delivered.

You have a lathe. I could scan and measure it for you. They are not that hard to make to be fair a bit of aluminium stock and time.. Sensor is cheap Hall effect sensor. It’s the drilling and tapping the cam that may be an issue. I am building a new engine at the moment so it’s easy for me! Right angle drill may be the way to do it

[911hillclimber]

Interesting to follow, nearly did all this about 10 years ago on the 3.2 Lola engine.
With the recent rebuild of the Lola engine using a Clewett kit the hardware from them was really nice, very well made, perfect fits.
The electronics was a very different game.

[PeterK]

A day off yesterday for a surprise visit to the Big Smoke and the Maritime Museum & the Cutty Sark, but given it was too windy and rainy today to take SWMBO for walkies, I was allowed in the garage (after chores). Did I mention the big wind – well that didn’t stop me being sent up the ladder to try and sort a leaking window frame. However, despite a wobble or two in the ladder department, I am still here, so the CIS to EFI saga can continue.

I did spend some pre-garage time looking at the pre-wired MaxxECU loom. There are a lot of unnecessary (for an air-cooled 911) wires, and they can go. I checked over the wiring diagram and identified those that can go bye-byes, but I will keep a pair of digital inputs, a pair of analogue inputs and a pair of general purpose outputs. You never know what may be needed down the road. I will de-pin the other not needed wires, but that brings me to my next impasse. I have a veritable pile of de-pinning toolage, but of course, not one that properly fits the Molex CMC type connector, so a spot of inter-webbing, and that should be sorted within a few days. I will also add a couple of spare 12v and ground wires into the loom. Finally in this area, the MaxxECU supposes that the main 12V supply will be near to the ECU, and includes a nice connector to link at that point. This 12V is then spliced to a feed to the lambda and injectors. My feed for all of this is in the engine bay, so I just need a single 12V supply from the ECU relay. Some minor ’adjustment’ will be made to the supplied loomage.

So, what next. Maybe its time to start adding some new stuff, such as the crank pulley. I checked that I was still at TDC, and that the dissie was indicating cylinder 1 before loosening the bottom pulley bolt, then slackening off the alternator pulley.


I removed the bottom pulley and fitted the new Clewett pulley


I then re-fitted the fanbelt, but another one step back moment – the fanbelt won’t tighten. I guess the Clewett pulley is smaller than my SC one. I do know that early SCs (‘78 and some ‘79) needed a 725 belt, whereas the later ones only needed 710. So, order for 2 710 belts placed and my old 725 goes into the box of ‘can I sell these’ items. It will be joined by the spare (also genuine Porsche) from the froot.

Next it was out with the dissie and in with the bung to block off the resultant hole. Then the Clewett crank sensor holder bolts in using the original dissie stud (sorry about he focus, or lack thereof)


Too early for tea, so what next. Drilling.
The RHS fan blanking plate needs modifying to output air from the engine fan to the RHS heater, so with a hole saw that will actually cut sheet steel ….

And trial fitted the bend

I did intend to cut a slightly smaller diameter hole, slit the edges and bend tabs around the new bend addition. But I forgot, so we’ll just pretend that I always intended to cut an exact size hole and will weld the edges.



Then, while I had the electric drill (rather than just the battery one) out, the SSIs were attacked. I had marked where I wanted the O2 / lambda sensors before I removed the exhaust – as vertical from above as possible but with room for the sensors and their removal if/when they fail.

Drill pilot hole


Holesaw 22mm hole


And trial fit bung


All just need welding up now, but it was time for tea, so that will have to wait.

[jb]

All great stuff
Looking at what you took off I realise that the very early cis was so much simpler.
And off topic - I was also at the maritime museum yesterday in the Polynesian section in early afternoon

[PeterK]

Welding time.
The gap around the new heater take-off pipe was possibly a little large for my (lack of) TIG skills, so I MIG’ed it in


Then I cleaned the SSIs and O2 bungs with acetone


And TIG’ed them in

Not pretty, but my first time welding stainless, plus I am a real new-comer to TIG anyway. Sufficiently glued in, although I did overheat the first bung, resulting in a pile of 5h1te on the inside threads, so an M18x1.5 tap set ordered for cleaning the threads out.


Then (as it’s taken me a couple of days to update this) the postperson came a-callin’.

First came the new fanbelts (thx Matthew at Type911), one as a spare and one fitted.


As it was a new bottom pulley and a new size of belt, I guessed at 3 shims behind the fan pulley. Wrong. Added another, still wrong. 5 shims was about right, but I’ll check after the car has run a while.

Having the fanbelt fitted allowed me to torque the bottom pulley. Or maybe not – can’t fit a torque wrench in there, so using my long spanner, I graunched the bolt up tight, then gave it a thump. That’ll do nicely, Sir (I hope).



The metal cutting holesaw also arrived


And in a flash, the hole appeared in the heelboard


A quick splash of weld through primer (I have some in a bottle, so that was easiest for now) although I need to sand off the edges and do properly with epoxy before I finish.

While I was in painting mode, I primered the heating duct take-off

Then sprayed satin black

Which finally dried satin-ish in the cold weather, but at least it is protected



Also arriving, were my Molex CMC depinning tools


So you can decide that you have a shedload of surplus wires in your loom, make a scribble


Remove all of the cable ties from the connector, removed the cover plate, slide out the locking plate and insert your new tool


And end up with this lot on the floor


In the process, I did end up modifying two wires that looped to the power connector plug (that I no longer have on my loom), which I then shrink-wrapped (the red has insulating tape just to keep things in one place)

I know that this is not good enough, but it will do for now and I have ordered a pair (well 3, 1 as a spare in case of mess-ups) of new terminals and will ‘sort’ these two wires in due course.



Slow, but all progress none the less

[PeterK]

I dragged those 2 wires (see previous post) so that there will be enough slack to cut and recrimp

Then added masking tape instead of the cable ties so that I could feed the loom into the car without catching up on the cable ties.


I routed the loom over the torsion tube and up alongside the existing rear loomage


And out into the engine bay


Here I could roughly determine where the initial braiding would need to run to, and marked this with more masking tape, which I scribed to differentiate it from all the other masking tape.
The length of loomage in the engine bay looked a little short, so I may reposition the ECU to the heelboard



Next onto some sensors.
For my CLT Sensor, rather than drill into the cylinder head or similar, I am replacing the thermo switch. As others have determined, getting an M15x1.5 threaded CLT sensor with a sensible plug ain’t happening, so I Bought a sensible (M12x1.5) CLT and an adapter (M14– M12). The hole in the adapter was about 0.5mm too narrow, so into the lathe and I drilled it out to 7.5mm


I also took a little off the length, although I needn’t have bothered, due to the threaded length of the CLT Sensor.


All fitted nicely and awaiting wires



I have a Bosch combined oil pressure and temperature sensor to feed the ECU, so bought an M10 t-piece to fit between the standard oil pressure sender and the block.



I even had thought ahead and bought new crush washers. My plan fell apart once I’d removed the existing sender – it’s a M14 thread !. I can’t find an M14 t-piece with anything other than a 1/8NPT take-off, so one on order. 1/8NPT is very close to M10x1, but not close enough, so I’ve also got an adapter coming.

Looking for things to do, I shortened the heater flexible hose, ready to attach to the take off (modified blanking plate)

Although I won’t fit it up until I’ve sorted the oil pressure area, as I need access to the oil feeds to the cams and Carrera hydraulic tensioners.


I then mixed up some epoxy paint, sanded the paint around the loom hole in the heelboard, and slapped it on. Hope it dries tonight, as I want to fit the ECU loom tomorrow. Talking of which, here it is with braiding that will reach into the engine bay, plus the rubber grommet.





Another day. I’m not convinced that the ECU loom will reach where I need it to go, and rather than doing a cack-hand job trying to make cables fit or extending cables, I have bitten the bullet and ordered a pair of quick-release connectors. I can run new wires from the connectors to the sensors, etc, without the need to splice anywhere. It will also make life simpler if/when the engine comes out.

Today the postie brought my M18 taps, so following a quick chase, the WBO2 bungs are nicely clear for the lambda sensors


While I wait for the various loomage parts, I moved on to more mechanical events. First I temporarily fitted the ITBs. I did need to drill out the manifold mounting holes slightly, but they now fit.


The sharp sighted will realise that this photo was taken after the next activity, but never mind. Next up was the MAP manifold. I’m taking a MAP signal to the ECU, even though my tuner has no plans to use it. I will also feed the FPR (fuel pressure reguator). So, drill 2 holes


I did plan to use Rivnuts, but as there is insufficient access to get the rivet gun in, I am making do with tech-screws. likewise for the FPR

The FPR is not as on the bonk as it appears in the photo (‘onest guv). I’ll replace the FPR outlet with an elbow version to make the pipework routing a little neater.


I was going to instal the oil catch tank, but it was late, cold and I needed a cup of tea.

[sladey]

Excellent work Peter - thanks for sharing

[911hillclimber]

All great going Peter, but the loom on the agenda would bug me, but not you I'm sure!
Esp looking forward to the mapping game.

[Bruce M]

You do want the map signal even if basing the load on a TPS (which you have to, with ITBs). It depends on the ECU but many use the map signal as a multiplier in the fuel calc. This is due to the flow rate of the injectors changes depending on the manifold vac.

You can also tune using map under 80% or 85% and switch to TPS above that on a secondary table. However it is more complicated & expensive if you aren’t doing the tuning yourself.

[PeterK]

I bought the slightly more expensive MAxxECU Sport, rather than the Street. This gives me bluetooth and I'll set up a display on an old Samsung tablet so that I can keep an eye on important conditions while driving (mixture / AFR, temps, oil pressure, etc)

My tuning process will be
1 - start with map from Phill's (IB) SC, with the enhancements added by GTtwo (current owner). I've had to manually transcribe the settings from MS to MaxxECU, so hopefully no typos. Obvious errors show up when looking at the maps in 3D.
2 - check other maps on Pelican
3 - review comments on set up on the MaxxECU forums / Youtube channels
4 - try to get it started
5 - get Aaron (Brands Hatch) to remotely check / refine / fix my base tune
6 - drive carefully to Brands Hatch and let someone who actually knows what they're doing (who also has a dyno) sort it for me


Thanks Bruce - I'm sure the MAP will come in handy, hence including it

[Bruce M]

If i was doing a base tune purely to drive to the tuner i’d go with a map based table. Its slightly more intuitive & simpler to get in the ballpark. Other opinions may differ

A base table is fairly generic. With injector flow rates set correctly(inc deadtimes) & the basic engine config (capacity).
You start with 50% VE in the idle area (up to 60% map & up to 1100 rpm). Add 100% VE at 95+ MAP across the full rev range. Then taper the VE down to 20% in a linear relationship to map (you can just copy the map value). That will get the engine running.

You can then tune the idle on the driveway with the wideband, just keep the block of idle cells all the same VE & +/- the VE until you get a reasonable lambda reading. Then you gently raise the rev with throttle and tune the cells you can (without load, there are limited number you can access). Guess the nearby cells to smooth out. If you can switch on autotune in the software, it will adjust the VE based on the lambda reading (you do need to set a delay map for the O2 sensor since there is a delay in the reaction but if you move the rpm around slowly its less critical). A few rev outs will enable you to check the high map row & tweek that so it doesn’t fall on its nose off idle. At that point you can fine adjust the ITB linkage & get the balance sorted. Off idle will be a bit rough unless you add some enrichment based on the throttle opening acceleration since there is lag from the injectors increasing flow but it should be good enough for a drive to the tuner.

I did a full tune on the road with autotune. It wasn’t terribly difficult i felt. For light to medium throttle i use left foot braking to hold a speed while I progressively increase the throttle & leave the software to make the adjustments. As long as its only for a few secs the brakes don’t cook. Long pulls in gear give you the upper throttle values. A bit of manual smoothing is needed afterwards. Then a 20min drive around with autotune running will get you to a fairly decent tune. The off idle acceleration enrichment is done on the driveway based on the engine reaction, not the lambda readings.

Ignition timing is the tricky one to do on the road without a dyno. The VE helps since the higher the VE (for a given RPM) the less advance needed. After peak torque (where the max VE values are), you can add a little bit more advance since the flow efficiency is tapering off. Copying a distributor map would do for a base map, until the dyno visit.

With a map based tune & ITBs its very difficult to get the tune smooth at lower revs because the vac vanishes with tiny throttle opening. So cruising around in built up areas is typically annoying. A TPS based tune is the normal approach.

[PeterK]

Cheers

[Gary71]

Not sure if it’s relevant in your case but I had issues with a stable MAP when I ran an ignition only megasquirt setup on my car. I had to add a small fuel filter (one of those clear plastic things) in the line to damp the signal as it was bouncing all over the place.

[PeterK]

That’s a useful tip - never heard of that before