89 Iroc Z

We don't know that for a fact, I haven't been able to find any info on anyone cracking the case open to see whether it does or doesn't have a driver. Or what the unused pins connect to

89 Iroc Z

....

ULTM8Z

I'm going to "crack" mine open tonight and compare against a spare 7730 that I have laying around. See if I can see anything obvious.

The hall effect swap should be piece of cake, so if the IAC issue gets put to bed, then it's a definite go. Even if it doesn't, there are likely some work arounds for the IAC. I was thinking maybe some sort of mini throttle cable, but for the IAC motor. Instead of attaching the Caddy IAC motor directly to the throttlebody, simply rig up a throttle cable so you can mount the IAC motor remotely, but still actuate the throttle blades.

89 Iroc Z

When you open the PCM up look for a chip with a labeled 16034993 or 34993, that is the delco IAC stepper motor driver IC. The 7730 has it mounted up against the "heat sink" so it takes a little work to get at.

Also the caddy 4.9L has the same firing order as a gen-I SBC so that makes life easier in terms of wiring the injectors and figuring out the cam sensor in the distributor.

JPrevost

https://www.thirdgen.org/techbb2/sho...hreadid=269230
That is the precursor to this pcm/bcm, whatever you want to call it. It had the same throttle opening motor driver in place of the IAC stepper driver. I doubt you'll find an IAC controller in this bcm. If it was there, then GM would have used it in some application... but none of the listed vehicles have a normal stepper IAC .
If you do find it, I'd be suprised, and happy

JPrevost

Be really careful with relocating a throttle actuator. With cruise control it's not a big deal because the throttle is usually open a decent amount but if it's controlling the idle the resolution needs to be HIGH. Just a little bit of deformation and slop in the relocation could turn into a big issue. Just a heads up on that. I'd try and mount it just like GM did with as little slop in the system as possible (no cables).

89 Iroc Z

This took a lot of digging to find but the Cadillac Alanate had a long tub runner setup and a TPI style TB. Cadillac just mounted the ISC motor on the throttle body as seen in the pics below.

89 Iroc Z

From the picture it looks almost as though the computer controls the second throttle valve entirely.

You could build a external IAC passage and mount the ISC motor to a small butterfly valve and plumb that into your stock IAC passage in the TPI throttle body.

Another pic of the Allante TB:

ULTM8Z

Well, I opened it up and can't see a bloody thing. The Cadillac ECM actually has a daughter card above the main PWB (see picture below). This is why the PROM protrudes above the top of the ECM case. This daughter card is covering everything up and is fastened down in such a way that I'm fearing I'll break something if I attempt to dislodge it.

Anyway, if you look in the next post, I believe the location of the 34993 chip is circled in red. The corresponding location in the Cadillac computer has a different chip there. Unless someone wants to get hold of a Caddy computer and do a destructive analysis on it, it's impossible to tell whether it has this type of driver in it without a ECM schematic.

ULTM8Z

The Caddy ECM...

ULTM8Z

The 7730 showing the IAC driver....

ULTM8Z

Geez... leave it to GM to develop the biggest kluge job for an IAC... It's no wonder they're in such trouble these days.

In the same years, they had the TPI IAC that they could have integrated into that throttle body. For a crying out loud, it's as if Chevrolet and Cadillac were part of two different companies when looking at the IAC setups!

Grumpy

25 years ago when it was designed it wasn't considered a kluge.

Alot of divisions within GM operate seperately. The code teams work on different floors, and don't share much, since the objectives are so different. Not to mention that under different leaders the deveoplement process, can *demand* that they approach some codes in sometimes 3 or more way.

GM's issues are alot more involved then just the ecm/pcms. The current design of PCMs, seem to be about as well thought out as possible, IMO. Might even say borderline genius, and GM is still in trouble.

RBob

iTrader: (1)

The ISC motor driver number in the '2240 is 28763.

ULTM8Z, remove the two screws, one on each end of the little board. Then loosen the the posts from the coating (posts are opposite the screws). Can use a little acetone, goof-off, or an xacto to free them from the coating. The little board then just lifts off.

RBob.

ULTM8Z

Yeah, I know. Just a little hyperbole...

89 Iroc Z

Wow, that thing is packed with drivers and I/O chips. As far as GM PCM's they did have communication problems in the early 90's between departments but I still think they made some great ECM's. There's a reason they are so popular. Also the new PCM's are pretty much universal now instead of 100's of different models.

ULTM8Z

Rbob, it worked. DIdn't see anything interesting under it though. I'm e-mailing you a picture of it. It's high resolution enough to see part numbers on the various device packages. I can't post anything that large on this site. Take a look and see if you see anything...

If anyone else wants to see it, let me know... I'll e-mail it to you as well.

Z69

Looks like some one who is electronically inclined will have to make an adapter board to drive a tpi iac.
Then mod the code to control the 2240 isc pins like 8D.

JPrevost

and then fabricate the cam position sensor, make or modify the crank sensor, run the extra wires for the injectors, hack the code itself so there is at least some tuning.
It's a lofty project but one well worth the effort. You would have a SEFI OBD-I computer for a v8.
I still think the ISC is going to be the stopper .

89 Iroc Z

The caddy ECM doesn't use a crank sensor, all that needs to be added is a cam sensor in the dizzy.

ULTM8Z

Which the Cadillac HEI distributor already has (per my previous posts and pictures).

To me, this ISC thing is not a show stopper.

JPrevost

From the first page;
It needs the missing tooth to know where the engine is else it would have no way of distinguishing between the cylinders.

JPrevost

I think he was refering to the standard SBC dizzy... which doesn't have the missing tooth on the reluctor! Which means you would need to either adapt ALL of the caddy dizzy internals to the sbc's OR add the cam sensor AND modify the reloctor in the sbc dizzy.
I don't think the ISC is a show stopper either... but there is still the code that needs to be covered and look at how long it's taking people to source the $8D .

jwscab

the missing tooth is most likely not a form of detection. its only for assembly purposes. the other 'teeth' line up with the reluctor and generate the pulse. You probably only really need one tooth, but the generated signal would be much smaller (its a magnetic field/flux intensity thing). having multiple poles line up give a nice strong pulse that works in the noisy real world.

you just need the cam position sensor added to the distributor.

all this stuff you guys are trying to accomplish has already been done and hacked in the 94-97 PCM's. Flashing them is not THAT big a deal, just use a radio shack DC supply and plug the lap top AC/DC supply in. And real time tuning is a luxury, not a necessity.

I applaud the effort, and can appreciate the drive, but there is a simpler way out of this. The hardened PCM might even be of benefit retrofitting into a 2nd gen camaro ( by the way, I hope to update my '73 at some point. Where did you mount your ecm, ULTM8Z?)

don't take this the wrong way guys, I love seeing the unknown ecms taken apart and learned about, I just think in this situation, there are alternatives that are more common, and available without months of legwork.

ULTM8Z

Yes, the code could be the impediment. Without the ability to recalibrate, it's pretty much dead on arrival.

I e-mailed Tunercat the bin file the other day. Hopefully, he can come up with a definition file for it.

ULTM8Z

I mounted the ECM behind the glove box. It's fastened to the air distribution box.

I actually wrote a paper on swapping TPI into 2nd gen Camaros. You can get to it through my website.

FieroAddiction

Hey guys. I've received a few emails from one of the members here regarding the Cadillac 2240 ECM. I've been working with 4.9s for several years in Fiero V8 engine conversions. A few years ago I worked with the creator of the GMEpro editing software to develop an editor for the 2240. As far as I'm aware, it is the only working editor, and it is not publicly available. I have over 25 stock Cadillac 4.5/4.9 bins on file. The Fiero community is by far the largest segment of the Caddy 4.9 aftermarket, and they have not been able to get TunerCat to produce a definition file, I just don't think there is enough demand to hack a 15 year old luxury car code that was only used for 3 years. The 2240 code is not typical GM, it's not like hacking a 7730.

I'm going to do my best to talk you out of using a 2240. First of all, the ISC... as you've already found out, it is a linear actuator, not the stepper motor that you're familiar with. They are slow to react and are somewhat difficult to set up without the Cadillac climate control panel and BCM connected. The 2240 throttle follower function can be troublesome and very dangerous if the ISC is not properly set up or if the PROM is not properly calibrated. I've been in cars that will push you right through a stoplight while you're standing on the brakes. It is also not well suited for manual shift cars, and there is no manual code for a 2240. Unfortunately the 2240 does not have the hardware to control a stepper motor ISC.

Second, the sequential injection will offer no more high-RPM WOT power than batch or bank to bank injection. I've dynoed a few 4.9s with both the 2240 and a 7730, they normally come up within ~2 hp of each other. The primary advantages of sequential is lower emissions and smoother low-RPM operation. The benefits of sequential are not worth loosing the much better IAC system. There is no individual cylinder trim, only right/left bank trim when using the dual O2 code. It is the most primitive form of sequential injection.

The distributor-mounted cam sensor is a hall effect type and is in no way compatible with the LT1 optical sensor.

There is no crank sensor.

There is no knock sensor!!!!

There is code for either single (C cars) or dual (E/K/V cars) O2 sensors. '94-95 were all dual sensor.

The IAT, CTS, TPS, and MAP are all electrically compatible with 7730 parts. The TPS polarity is reversed.

Summary; It's not worth losing the IAC and knock sensor and spending many hours hacking and tuning just to get sequential injection. I've converted several 4.9s to run on 7730s just so I could get a decent IAC, and a knock sensor.

Jon from FieroAddiction.com

ULTM8Z

All of a sudden, the LT1 swap is looking more attractive...

jwscab

i saw someone yesterday on the classifieds selling an LT1 ecm and wiring harness. Might want to check it out.

JPrevost

I don't think so.
http://www.pe-ltd.com/products.htm
All missing a tooth for a reason!
Trust me, the tooth is missing for a reason other than mounting the sensor. The electronics expect to see 7 pulses and a missing pulse. Put 8 uninterrupted pulses on and you would need a CAM position sensor with a missing tooth... which isn't on the caddy cam pick-up meaning it uses the missing tooth as an interrupt.
Which brings me back to my original decloration that you would need to modify the stocker or swap the caddy's guts over.

69 Ghost

iTrader: (1)

If only somebody could figure out how to either replace the opti code with something that a GENI motor could use the LT1 bins offer everything that people want. SFI, Individual fuel trim, tranny control, dual O2's, BOTH MAF and MAP control. Large extended tables, etc. Take a look at a 94-95 bin. There are guys running a second puter just for a tranny control on older cars. The PCM's are flash with dual setups one for the motor the other for the tranny. Figure out how to use the code in a older setup and it's all there. I would even lose the SFI for a bank fired setup with all of the above. Think about it everybody would go because nobody gets left out.

ULTM8Z

Just looked at the $EE code... apparently you can run "Speed Density" mode by enabling switch in the switch tables. At least I won't have to get a MAP sensor.

Dave_Jones

Nah, it's still an 8X sensor even with the missing tooth.

Maybe it's hard to tell from the pictures, but the missing tooth isn't an interrupt at all, because the other 7 peaks all line up every 90 crank degrees (or 45 cam degrees). So that part is functionally identical to a regular large-cap HEI.

(Edit: For some reason, the words "pick up coil" escaped me when I was originally typing this. That's all it is, and just like a regular HEI you get 8 pulses with each rotation of the distributor shaft.)

There is a separate Hall effect switch for the cam position sensor.

JPrevost

Well then, I stand humbly corrected. Your right, I couldn't tell from the picture. When I was replying I was also thinking that the "crank" wheel/sensor isn't that at all. It's driven off of the cam so it's a cam sensor. The 2nd cam sensor is the interrupt for the electronics to know which cylinder is where. Or am I still getting it wrong? Making this nearly identical to the Lt1 opti which used both of it's internal sensor pickups to do the SEFI in 94-95 where as 92-93 only used the "course" optical pickup needed for batch fire . Do I have that correct?

JPrevost

So who's going to start hacking the $EE and form up some source for it?

FieroAddiction

The 4.9/2240 distributor and spark timing works in exactly the same way as any other computer controlled GM HEI. The cam sensor that happens to be mounted inside the distributor is used for injector timing only and is totally separate from the ingition system. There is no other crank or cam position sensor.

89 Iroc Z

FieroAddiction,
Does the later PCM that comes in the 94-95 4.9L (Not northstar) Deville have individual cylinder trim? (Part numbers: 16196347, 16197426, 88961139).

Thanks for stoping buy and giving some more infomation.

89 Iroc Z

For the sake of completeness I think every option should be mentioned and discussed.

For that reason I am going to bring up another PCM. The Cadillac Northstar PCM. It has a regular IAC driver to start, it is SFI, and has DIS. I picked up a Northstart coil pack for $25 at the junkyard and they are everywhere and low cost. The PCM is also readily available and low cost. This PCM also has a mem-cal so an emulator could be used easily.

A great befit of this PCM is DIS. Though this would require more work it would definitely be worth it. The Northstar PCM needs a crank trigger, which I have a crank sitting at home waiting for the trigger wheel to be CADed out for use on a possible 730 DIS conversion. The Northstar PCM also uses a cam sensor that could pretty easily be mounted inside a small cap HEI distributor and gutting all the other parts.

Here is a picture of the ECM.

ULTM8Z

I'm looking at the LT1 wiring schematic...

It appears as though I could simply repin my 7730 harness over to the LT1 ECM connectors (albeit adding a few more wires for sequential injection). The color coding seems to be the same for all of the circuits too. Hmmm... would make the install MUCH easier, and I'd have an in-the-car PCM too. Not to mention MUCH less expensive.

Going to see if I can find a junk opti-spark someplace and see how to retrofit the guts into my HEI...

FieroAddiction

The 16132240 ('90 4.5/4T60 '91-93 4.9/4T60E) and the 16196347 ('94-95) appear the up-to-date numbers. As far as I can tell all other numbers have been superceded by one of those two. Those are the two that you will likely find, they are the only ones I can recall ever seeing, having been through nearly 100 of these cars.

The ECM pinout for the '6347 is the same as the '2240, and a '2240 memcal and calibration will work in a '6347. As far as I can tell they are identical in operation, but there must be some minor difference, possibly something to do with hardware for the BCM data comms or some other function that I haven't investigated. I don't have any '94-95 manuals to read up on the operation of those units. Individual cylinder trim would require a fairly complex crank position sensor to be able to monitor slight changes in engine RPM during a single revolution, and the 4.9 has no crank sensor at all. And it still leaves you with a ****ty ISC and no knock sensor.

The '93-95 Northstar PCM sounds like a great deal, but you will have even more trouble finding an editor for that one. Same deal as before, it's a luxury cruiser that was used only a few years, there is not enough demand for it to be hacked to the extent that we would need to be able to use it for another app. The Fiero guys (myself included) have been trying to get a hack for years. It is also an extremely complex code. It has two 512k EPROMS, double what the 4.9 uses. It's operation is dependent on all of the other vehicles systems (trac control, ABS, etc..). Northstar swaps are stuck running in limp home mode, GMs engine-only dyno chips, or an aftermarket ECU like I run on mine.

I am aware of one guy who converted an HEI distributor to use optispark components so he could use the LT-1 ECM. I'll see if I can get his contact info.

69 Ghost

iTrader: (1)

The 92-93 LT-1 cars are virtually the exact same wiring but would need to be repinned. The boxes are the waterproof types.

69 Ghost

iTrader: (1)

Posted this on the 8d great ideas link:

OK here goes some links on a Opti in a HEI. Speartech is the place that has done it if we can get a group effort here we may have something:

http://img.villagephotos.com/p/2004-...1_HEI_02_w.jpg

http://img.villagephotos.com/p/2004-...1_HEI_01_w.jpg


and the link where where it came from:

http://www.ls1tech.com/forums/archiv.../t-258251.html

here is speartechs page:

http://www.speartech.com/

JP84Z430HP

Ok, I think we have a winner! Since, from everything I have researched but still have yet tom implement, the Northstar DIS module should work with a '730, is there any reason the Northstar code could not be made to run with a distributor? They both use the same signals to the ECM/PCM.....

I'd have to look over some wiring stuff, but I think it may even be possible (some code work?) to make this PCM run a 4L60E trans! I know the later 4T60E's used a force motor similar to the one in the 4L, so maybe?????

Does anyone have a Northstar bin lyiong around? Are there any hac's, def, or other editor files out there for them? I really don't have time to look, but I am willing to help out with the few minutes I get each day of free time!

As a side note.....I really have very little interest in SFI, or most of the other stuff that this will offer, but, I am VERY interested in making a 4L60E work with a P4 era PCM, with port injection. The SFI would just be a plus for the low RPM performance....

Feedback??? Bueller????Bueller????

JP84Z430HP

Sorry, but due to past experiences with Speartech on this board, I would NOT expect ANY sort of info to come from him..... This is not meant to be negative to him in ANY way, other than expressing the amount of info gain in previous endevours that he chimed in on.....

Look at this post:
https://www.thirdgen.org/techbb2/sho...hreadid=193531

JP84Z430HP

Ok, one more post tonight....

I think the ideal situation would be to retrofit the Northstar DIS on to your V8 application, and it's looking like we may have a solid SFI platform using the Northstar PCM.

Looks like I REALLY need to finish up my work on the Northstar DIS to work with the standard GM ECM...... I need to get back into CAD....... I should have some solid stuff by the end of the long weekend (provided I can keep my head straight )

89 Iroc Z

JP84Z430HP,
I have been trying to get my roommate to CAD out this Northstar crank trigger I have had sitting here forrrevverr. Maybe after the thanksgiving break he will have time to do it.

Also the transmission on the northstar is a 4L80E.

32V_DOHC

The northstar uses an ISC for OBD1. I do not see the IAC driver on the board.

As far as hacking either goes, neither are hard. The truth here is that no one has been willing to spend the time and then share. The 2240 I have about 8 hours in and already know where the main VE, checksum, main spark, ALDL code, and climate control code interface code is among other things.

I have many more hours in the northstar code.

Any of it is doable.

John

69 Ghost

iTrader: (1)

I didn't know. I would have never mentioned it. SORRY "he who helps others helps himself" Now where did I hear that from????

ULTM8Z

So what's the deal with the Syclone/Typhoon ECM's? They were sequential EFI..

http://www.sportmachines.com/magrack/hot_rod_10-90.html

Is there something in the code that can make it work with a V8?

What would it take for a conversion to this one? Seems that it has the conventional distributor and it uses an L98 throttle body. Knowing GM, the circuitry is likely almost identical.

JP84Z430HP

While not the end of the world, the ISC puts a dmaper on me working on the Northstar stuff. Rather than deal with the mechanics of mounting it to the TB, I'd rather just run $8D and be done with it. The other option would be to disable idle control and just set the throttle screw for Idle and run whatever computer you want.