quote Originally posted by Lou6t4gto: I was in the bonetard today, grabbed a dist "half shaft ". At the 5- 3.4 engines I looked at, NONE of them is using a crank "sensor" ! Where is the "Stock DIS" getting the "signal From ?

Camaro 3.4's do use a crank sensor AND a cam sensor (the cam sensor is not needed in our Fiero's though). It is in the middle, bottom of the block on the passenger side. Looks like a little black connector. Unbolt it and it comes right out.

I just installed DIS on my 3.4 turbo car and it is amazing. Took me a while to get the new tune close enough to run but the new ignition is definitely an upgrade and well worth it.

It helps that I already had the 7730 ecu running and I had all the parts lying around from a 3.4 camaro engine I pulled.

good luck all

quote Originally posted by Lou6t4gto: I was in the bonetard today, grabbed a dist "half shaft ". At the 5- 3.4 engines I looked at, NONE of them is using a crank "sensor" ! Where is the "Stock DIS" getting the "signal From ?

Isn't the sensor on the side of the block and the timing wheel on the crank itself?

quote Originally posted by Lou6t4gto: I was in the bonetard today, grabbed a dist "half shaft ". At the 5- 3.4 engines I looked at, NONE of them is using a crank "sensor" ! Where is the "Stock DIS" getting the "signal From ?

the crank position sensor is on the side of the block. you'll see 2 things: the crank sensor & the knock sensor. the wheel is actually part of the crank, square in the middle. which is actually very sucky design, if you consider rotating mass.

I'm SOOOO Stupid ! I have the 3.4 on the engine stand, the crank out. someone took out the sensore & put in a "Plug" . So I can use That instead of putting the sensor above the balancer ??? & it will work with the stock ECM ?

quote Originally posted by Lou6t4gto: I'm SOOOO Stupid ! I have the 3.4 on the engine stand, the crank out. someone took out the sensore & put in a "Plug" . So I can use That instead of putting the sensor above the balancer ??? & it will work with the stock ECM ?

I have doubts the stock ECM can do DIS.
I brought this up in the old 7730 swap thread, because I too thought the stock ECM could do it, because it used the same wiring & signal names.

edit to add: link to 7730 swap thread - near the end of the page - the discussion on why the stock ECM wont work
https://www.fiero.nl/forum/F.../HTML/000088-12.html

[This message has been edited by Pyrthian (edited 02-05-2010).]

quote Originally posted by Pyrthian: I have doubts the stock ECM can do DIS. I brought this up in the old 7730 swap thread, because I too thought the stock ECM could do it, because it used the same wiring & signal names. edit to add: link to 7730 swap thread - near the end of the page - the discussion on why the stock ECM wont work https://www.fiero.nl/forum/F.../HTML/000088-12.html

I did some reading on the subject:
http://www.megamanual.com/ms2/GM_7pinHEI.htm
http://www.megamanual.com/ms2/GM_DIS.htm

These are my conclusions, in brief, on the feasibility of using the stock ECM with DIS:

HEI sends a continuous stream of reference pulses to the ECM, with no phase information - all pulses are identical.
DIS sends a continuous stream of reference pulses to the ECM, with no phase information - all pulses are identical.

In both cases, the timing reference appears to be on the falling edge of the reference pulse.
The only important difference appears to be the pulse frequency.
Pulse duration may vary - but it is the falling edge that is important.

I believe that a divide-by-n counter should do the trick.
The reference pulse signal line is named "3X Reference", however, I'm 99% sure that that n=2.
So, it should be a divide-by-2 counter.

This is 5 volt logic at relatively low frequency.
Any off-the-shelf TTL stuff should work. I would mount the interface inside the car - not the engine compartment.

the 7730 can run DIS ignition while running a distributor-based code mask.

i think the ref signal is inverted with the DIS module. the code $59 guys reported having to change the kref angle in tunerpro by about 60*, which is about the difference between the rising and falling edge of the signal on a 6 cylinder engine.

simple RTL inverter should do the trick. if not, it should only be a matter of moving the pickup to compensate for the difference in reference angle. you'd have to disable the bypass, since it would no longer fire the coils automatically at 10*, but that's not that big an issue.

it's just a matter of getting the signals to line up. it's certainly not impossible.

I've been reading this thread with interest. Ideally there would be an easy way to keep the stock ECM.

I was wondering how much interest there might be for modified dampeners. I could set myself up and run a few.

What would be a fair price?

Dawg

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You Dream it Up -- I'll Build it

[This message has been edited by Dawg (edited 02-07-2010).]

Dawg, WHY are you not pumping out a pile of upper Fiero intakes with larger "Necks" ? seems there would be a larger Call for those !

PM sent

quote Originally posted by Lou6t4gto: Dawg, WHY are you not pumping out a pile of upper Fiero intakes with larger "Necks" ? seems there would be a larger Call for those !

quote Originally posted by Lou6t4gto: Dawg, WHY are you not pumping out a pile of upper Fiero intakes with larger "Necks" ? seems there would be a larger Call for those !

having done the "neck expansion" on my stock intake - I will say to anyone planning on doing this:
do what WCF did. MUCH easier.

quote Originally posted by Lou6t4gto: I was in the bonetard today, grabbed a dist "half shaft ". At the 5- 3.4 engines I looked at, NONE of them is using a crank "sensor" ! Where is the "Stock DIS" getting the "signal From ?

Its there, but its in the side of the block, not the front like you'd expect. I think you'd call it the "left" side in longitudinal cars.

Kurt, Yes, I found it & posted that 4 days ago. Pyrthian, Just WHAT was it WCF did for the upper manifold? I don't know what you are refering to. Thanks

I'd like to try to use this approach with my 3500 swap using the 7730. Anyone have input on any changes due to the fact the 3500 is a true FWD application?

quote Originally posted by KurtAKX: Its there, but its in the side of the block, not the front like you'd expect. I think you'd call it the "left" side in longitudinal cars.

quote Originally posted by Lou6t4gto: Kurt, Yes, I found it & posted that 4 days ago. Pyrthian, Just WHAT was it WCF did for the upper manifold? I don't know what you are refering to. Thanks

A little late to the "party" on this, but just thought I'd help illuminate where the 3.4PR crank sensor is located.
From my old 3.4 build pics:

Red arrow is the crank sensor location.
Green arrow is the knock sensor.

[This message has been edited by randye (edited 02-10-2010).]

1984-1988 GM DISTRIBUTOR-LESS IGNITION SYSTEMS OPERATION AND DIAGNOSTIC PROCEDURES

this is also useful. i think some credit is due

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First LX9 Fiero GT, 1987 | My Fiero Fuel Economy | MPG Display for OBD I
Youtube Videos of My GT | modernize your fiero with technology!
If you can't fix it with a hammer, you've got an electrical problem
Fiero's are people too. We pay just as much attention to them, if not more than our loved ones
screw paying those bastards. im not going to become rich by paying for things.....

[This message has been edited by americasfuture2k (edited 02-10-2010).]

Very useful documentation. Thanks!

.

quote Originally posted by mattwa: Camaro 3.4's do use a crank sensor AND a cam sensor (the cam sensor is not needed in our Fiero's though). It is in the middle, bottom of the block on the passenger side. Looks like a little black connector. Unbolt it and it comes right out.

Actually, there are 3 sensors, one for the cam at the top front of the block, one at the front of the crank, and CPS on the side of the crank.

To effect DIS, all you need is the one in the side of the block, as long as you are running the 3.1/3.4 crank which has the 'bump' it senses. Late 80s ECMs used OBD 1.0 and could handle the DIS

You need to use the front sensor AFAIK if you use an OBD 1.5 PCM, and you need the cam sensor for any SFI implementation - batch fired doesn't require it..

The one in the side of the block for use with late 80s ECMs can be fitted simply to the Fiero 2.8 block - remove the blanking plug and screw it in.

quote Originally posted by BillS: The one in the side of the block for use with late 80s ECMs can be fitted simply to the Fiero 2.8 block - remove the blanking plug and screw it in.

The sensor will not function, the Fiero crank does not have the reluctor wheel to trigger the sensor.

That leads back to the original post of modifying the 88 harmonic balancer and using a ford sensor to see the notches.

[This message has been edited by flimbob (edited 02-16-2010).]

This looks like a great writeup on the "how". Now how about the "why"? I think I know why you'd want to do this, but I'd like to hear from others (maybe those who have done this) on the benefits (other than no more pickup coils to replace).

Better power?

Better mileage?

Better driveability?

Better maintenance?

Better reliability?

Yeah I'm gonna have to ask the same ? This is a nice how too write up cool info! But why would I put in the hours of work to accomplish this? For a firebird intake ? That neck goes out the other way toward the drive belts anyhow right? Or can it be flipped around?

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Say no to socialism communism marksism maoism and say yes to Freedom! God Bless America!
1986 black gt fast back 4 spd recently rescued. 1987 gt fastback 5 speed! Hopefully swapped before end of summer.

[This message has been edited by ozzy83 (edited 04-14-2010).]

this is compared to stock ignition:

Better power? yes, in the upper RPMS, due to the original stock Fiero coil falling off at higher RPMs - a good MSD coil fixes this

Better mileage? maybe - but not noticable

Better driveability? not really - not when compared to a stock ignition system in new condition. tho again - upper RPMs is where DIS really shines over a distributer.

Better maintenance? yes. no dist cap replacements, or timing coming undone

Better reliability? yes - fewer moving parts, and none which take direct wear.

and - to add in - something I ran into immediatly after doing a 7730 swap + DIS:
can I adjust the timing? NO. timing is set by the ECM & the programming, so to adjust the timing a few degrees - gotta get a chip made. yes, there are bolt-ons you can get to adjust.

Thanks, Pyrthian.

One more question. Is the timing more stable? On stock 2.8 w/distributor, the timing bounces around ±1° or so. I'm guessing that this system would be rock solid. If so, then I would think that it would allow the 7730 ECM to advance the timing slightly more before knocking would occur. More timing without knocking = good.

quote Originally posted by americasfuture2k: 1984-1988 GM DISTRIBUTOR-LESS IGNITION SYSTEMS OPERATION AND DIAGNOSTIC PROCEDURES this is also useful. i think some credit is due

Credit is due to who?

quote Originally posted by flimbob: Does anyone know how to get ahold of Tim( Gravitic Anomaly )? He seems to be out of touch. I need to get the files he posted on Fileden. Any help would be most appreciated.

Last time I saw or heard from him was the Tyler project...

[This message has been edited by carbon (edited 04-15-2010).]

quote Originally posted by Formula Owner: Thanks, Pyrthian. One more question. Is the timing more stable? On stock 2.8 w/distributor, the timing bounces around ±1° or so. I'm guessing that this system would be rock solid. If so, then I would think that it would allow the 7730 ECM to advance the timing slightly more before knocking would occur. More timing without knocking = good.

yes, it is. for a standard setup, the timing comes from the crank, not the cam, so there is no timing chain, or timing chain slack. so, no timing bouncing around.

tho, thinking about adjustability - the setup shown in this thread, where the reluctor wheel is on the pulley, and the pickup is on a bracket - there would be adjustability by moving the pickup on the bracket.

quote Originally posted by Pyrthian: yes, it is. for a standard setup, the timing comes from the crank, not the cam, so there is no timing chain, or timing chain slack. so, no timing bouncing around. tho, thinking about adjustability - the setup shown in this thread, where the reluctor wheel is on the pulley, and the pickup is on a bracket - there would be adjustability by moving the pickup on the bracket.

Yup, similar to the kit that is sold at WOT Performance for the new 60* motors to be used with older ECMs...

[This message has been edited by carbon (edited 04-15-2010).]

Anyone has the .DXF and .PDF files mentioned on this thread? This DIS setup takes me one step closer to doing a top en swap to aluminum with minimum parts.

I have modified a balancer for my 3500 LX9 swap. I have yet to make the sensor mount though. Got too many other Fiero issues with my 86 and 88 so the swap is currently on hold. vEnOm, I sent you an email with the pdfs I got from Gravitic.

[This message has been edited by flimbob (edited 04-16-2010).]

Regarding the use of the stock ECM:

Base timing is set by the Prom. I don't have access to my home computer now, but getting this to work should be a matter of changing a few bytes and Burning a new Prom. Or am I missing something?

Best regards

Oliver