ITB bug

[Tippy]

I kept the DME harness intact and used one of the pins for my tach trigger. I filed down a common spade connector, plugged it in, and taped in place.

It's ghetto, but works.

Didn't have the heart to strip the harness out.

[Pehlen]

I wrestled with the idea of keeping the harness installed; but I've decided this is a one way journey at this point and it just does not serve a purpose. I'm retaining the portions of the harness (installed) that fit my plan - like the fuel pump lead and to your point, the tach lead.

It was a little bit of a leap, but as of now I'm happy I did it.

Hopefully more progress and more pictures soon.

[Ferrino]

I think that with an off-the-shelf kit like you have, abandoning the vestigial DME components is a great idea to keep everything tidy.

[al lkosmal]

Phil,
I have a big box... 1 of 2....with your name on it.......and the contents will replace your stock DME nicely. Headed your way today/tomorrow and box #2 will follow mid-next week.

regards,
al

[Pehlen]

I was surprised with a Sunday delivery of package 1 of 2 from Al!

Unpacked and ready to begin phase 2 - AEM installation.

[Taxi!]

Originally Posted by Pehlen

I was surprised with a Sunday delivery of package 1 of 2 from Al!

Unpacked and ready to begin phase 2 - AEM installation.

Christmas came early! (Lucky bastard)

[emcon5]

Originally Posted by al lkosmal

That is approximately a 12% increase in HP and a 15% increase in TQ with no other changes except replacing the CIS with EFI/ITB.........

Hmm. Any other details on the engine? Original ports? Do you know if it started as an early or late SC?

Thanks,

[Pehlen]

Originally Posted by emcon5

Hmm. Any other details on the engine? Original ports? Do you know if it started as an early or late SC?

Thanks,

Up until last week it was a perfectly functioning stock 1988 Carrera. I had replaced the cat with a pre muffler and replaced the muffler with a de-baffled stock muffler with and extra out (so now 1 in, 2 out) - and I had a Steve Wong chip for that setup.

Now it's time for the next step.

I'm aiming for a late model street hot rod - a frisierterwagen

It took me a while to get over thinking it was an investment (I bought it over six years ago). I enjoy working on it almost as much as I enjoy driving it.

By the way, I've pulled the harness this evening. That was a workout!

[Pehlen]

Just realized your question was directed to Al - that was not so apparent on my iPad!

Originally Posted by Pehlen

Up until last week it was a perfectly functioning stock 1988 Carrera. I had replaced the cat with a pre muffler and replaced the muffler with a de-baffled stock muffler with and extra out (so now 1 in, 2 out) - and I had a Steve Wong chip for that setup.

Now it's time for the next step.

I'm aiming for a late model street hot rod - a frisierterwagen

It took me a while to get over thinking it was an investment (I bought it over six years ago). I enjoy working on it almost as much as I enjoy driving it.

By the way, I've pulled the harness this evening. That was a workout!

[Pehlen]

More progress last night on the Porsche hot rod build #frisierterwagen

Motronic ECU is out, along with its wiring harness (from earlier). The AEM ECU is located, but not mounted and its wiring harness has been painfully run. I've added to the mounting stand, so it now supports the vacuum plenum/manifold, the fuel pressure regulator and the MAP sensor - all trial-plumbed to the vacuum manifold. Some, all of these may need to be relocated once I receive and test fit the ITB units.

The distributor has also been gutted and retrofitted with an AEM engine position sensor. This takes the place of several other sensors I would have had to mount, otherwise, for crank and cam position data that is fed into the ECU - that's pretty trick. Of course, I won't need the distributor with the new ECU and the Coil on Plug approach I'm taking with this build. More on that later.

[Techno Duck]

On your bottom picture; if that is a ground wire attached to the heater shroud, perhaps use something on the engine block instead.

[Pehlen]

Originally Posted by Techno Duck

On your bottom picture; if that is a ground wire attached to the heater shroud, perhaps use something on the engine block instead.

I appreciate the extra eyes - it's the CNT lead.

I have a quick question in to Al regarding the Rasant instructions that have the CNT (sometimes labelled CLT) lead - which I am assuming is the coolant temp sensor lead - grounded to the fan shroud.

While I want to confirm that, I also would like to understand why / how that works. My assumption is that the AEM ECU requires a figure for this and we are just shorting it to provide a constant value that will be ignored or factored out?? Or is it a thermocouple of some sort?

[Tippy]

It probably has a 2 point slope with low ohms generated equaling a given temp and then a high ohm giving another temp.

It's generating resistance based on temp.

[cmonref]

In the upper left corner of the left chain cover is the thermotime switch on the 3.0 L engine. It provides an oil-temp based temp signal to the CIS which switches the cold start injector off when the oil temp is hot enough. On my 3.0L, I replaced the OEM thermotime switch with one with a different ohm-temp curve and fed it to the ECU as CLT.

Do not know if that threaded boss is on the 3.2 L engine, but it might be.

[al lkosmal]

The CLT lug should be installed using one of the bolts that fastens the fiberglass (fan/engine) shroud to the engine case.

Typically these sensors are RTD (Resistance Temp Detector) or a thermistor ( when I use Megasquirt..I make these temp sensors using thermistors and ring lugs) The CLT will change resistance with changing engine temps....so mounting it to the bolt that is directly connected to the engine case provides an engine temp signal to the ECU.

This signal is typically used for start up (added fuel +/- based on temp , idle control etc.




Everything you wanted to know and more in the full AEM Infinity Users Manual

http://aemelectronics.com/files/instructions/Infinity%20Stand-Alone%20Programmable%20Engine%20Management%20Syste m%20Full%20Manual.pdf

regards,
al

[Pehlen]

Thanks guys - understanding that it is some type of a thermistor makes sense (hard to tell in the Rasant harness - which is very nice by the way). I have it fastened to the fan shroud.

I've read the 300+ pages of the AEM manual and am looking forward to playing with it a bit.

Wideband O2 sensor is installed and I plan to be mounting the ECU, fastening the through-body grommet and getting the wiring routed well and tied down underneath, tomorrow.

[al lkosmal]

Phil,
It was not clear from your post.......did you move the CLT from the hot air duct to the fiberglass shroud mounting bolt?

[Pehlen]

Originally Posted by al lkosmal

Phil,
It was not clear from your post.......did you move the CLT from the hot air duct to the fiberglass shroud mounting bolt?

Thanks - I did relocate it after your note.

[Pehlen]

It's been a little slower than anticipated over the holidays, parts wise. So I took on a couple of tasks a bit earlier than maybe would be prudent and started another project: plasti-dipping the fuchs.

It took a little digging to find the correct sized thread for the Mahle fuel filter inlet - M14 x 1.5. I removed the pre-existing pipe to compression adapter and installed the new M14x1.5 to AN6 adapter. I also ordered a 90 degree AN6 thread to hose fitting and installed it on the AN6 fuel line and did a test fit. Should be great.








I also did some digging on plasti-dipping wheels - tons of great info out there on this. I did some tests and then jumped in and painted one of the rear wheels. Like most things, spending time on the prep really pays off in the end. One word of warning - even the most mild painter's tape will create issues with the base plasti-dip coat. I think I've resolved this by using ~1/4" of tape to wheel for masking, with pre-cut contractor paper masks under that instead of directly taping the whole petal. Still, even with touch up after having tape residue and some pull-up issues with the antique gold plasti-dip, I think the result is quite good - up to about 2 feet for my eyes.

[Clay.0]

Looking good. Keep it up