Project 3.4 Camaro

Ok so as some of you might already know I recently swapped my ECU to run DIS, I now finally know the problem causing the car to not run, my injectors are pulsing way too fast, but Idk what would specifically would cause this, my instructor says something in the ECU itself is more likely than a misplaced wire.
If Bl85c is reading this, I need to know the make/model/year car my ECU came from, if you can PM me that or put it here. And I guess whatever mask, or code its running(whatever one calls the programming running things) if its not the original, which I believe is the case?
And of course, if anyone knows what could be wrong to cause the injectors to pulse way too fast like that please chime in, I know the problem now, now I need help figuring out the cause and how to correct it.

Maverick H1L

iTrader: (8)

Only reason I can think of that the injectors are pulsing too fast is that the ECM is still running on V8 code...

You need to post up the numbers on the ECM sticker, particularly the 3-4 digit MEMCAL broadcast code and the broadcast code on the MEMCAL itself.

Project 3.4 Camaro

That's one of the possibilities my instructor mentioned, are said memcal codes listed on the memcal itself or have to be pulled from it with a scan tool? And I'm hoping bl85c chimes in soon here with exactly what the parts I have are from.

Maverick H1L

iTrader: (8)

The silver sticker covering the top of the chip where UV light shines to erase it... Should have the 3-4 letter code and the word DELCO on it.

Bl85 isn't going to be able to help you without the BCC of the chip and the ECM sticker...

Project 3.4 Camaro

Luckily I took the ECU out and with me in case I needed info off it..I have a circuit board type chip with 1L1248 on it, on a blue section of it, the other chip is a black one, and I believe not the relevant one. Thought that is a 6 digit code...

Project 3.4 Camaro

My memcal doesn't have any kind of cover on it, is it possible the bin it had, was erased by sunlight and it reverted to its original bin maybe?

Maverick H1L

iTrader: (8)

The code should be in the form of something like this:

HNL (1987 2.8 manual), HNR (87 2.8 auto), APFU, APFR, AUXW, AUJW...

The BCC is either on the outside of the ECM (unless it's a reman) or on the chip. Sounds like your sticker is gone on the chip. Attached will be a pic of a MEMCAL I pulled out of a 16196401. The silver sticker is clearly shown with the BCC on it, which I pretty much know is from a 3800. This is what the MEMCAL is supposed to look like.

If you haven't removed the chip in the MEMCAL and installed a programmable chip and written the code Bl85 has written to the chip, you probably still have the V8 program.

If sunlight had erased the chip, the engine wouldn't run, period. There would be no instructions or tables on the chip for the ECM program to refer to in order to run the engine.

Project 3.4 Camaro

yeah see, I am missing that cover piece, so I guess I don't have that #...but he sent the ECU as complete ready to run and preprogrammed.

Project 3.4 Camaro

I did just notice on the outside of my case I have "ACWS" in the top right corner of the sticker with the ECU #, is ACWS the code you want to know?

RBob

iTrader: (1)

If that MEMCAL is still being used that is why the injectors are firing too often. The key is whether or not it is that MEMCAL still in use.

It is for a TBI 4-cylinder that will fire the injectors at every spark plug firing. Instead on every 3rd spark plug firing.

Note that the MEMCAL can be modified for the proper firing rate. May need to cut a pin and add two resistors, or just add one. Some research into how the MEMCAL is set up needs to be done first.

RBob.

Project 3.4 Camaro

Unless bl85c messed up and forgot to swap it or something then it should have "memcal out of any 1227730 / 1227727 ecm equipped vehicle w/ a 2.8 or 3.1" I mean pretty much, I have done what this thread details:
https://www.thirdgen.org/forums/diy-...take-look.html
With the exception of bl85c getting the parts together and doing the tuning. Will the memcal have a # on it allowing me to determine what its out of?
If I find a 727 or 730 memcal could I swap into the ECU to try, and see if that sorted it? Is there even an MPFI memcal that runs DIS?

Project 3.4 Camaro

Wait, just so I am clear on this, just realized(undersleeping and overworking a lot lately...) but if I'm reading that last post correctly, the "ACWS" code on my ECU indicates that it originally had a TBI 4 pot memcal, is that correct?

Maverick H1L

iTrader: (8)

Yes, the 4-letter code indicates what MEMCAL the ECM was originally equipped with in a non-reman ECM. Remans only have a sticker with the P/N of the ECM on it (not that you needed to know that, but I figured it might help in the future).

I have to go through my MEMCAL pile (I have about a half dozen of them now), but I know I have a couple FWD 2.8/3.1 MEMCALs laying around.

Project 3.4 Camaro

Is there a way to tell whether this memcal is the original or a different one?
Which chip is the memcal? white or black? The black chip has:
27SF512
70-30-PGE
0808170-C
On it in those 3 lines and order, the white chip only has 1L1248 on it, the ECU case itself has a sticker on it with:
1227165, which is the ECU # of course, "ACWS" Which if I gather correctly from the last post designates which memcal it has/had originally, then on a 2nd line it has, 860141, M529845319. Also what would I need to look at the code in this thing with(equipment wise) and see whether or not its trying to fire a v6 mpfi? And what and where would I be looking for the code that would show that?

Maverick H1L

iTrader: (8)

The 512 is the PROM... It's a similar chip to what was in your old ECM but it's got more memory space and a couple other additions. The other would be the CALPAK, same as the small chip in your old ECM. The MEMCAL is simply both in the same package.

Project 3.4 Camaro

If you have a compatible memcal kicking around you might sell me cheap let me know, if I can't ascertain which one I have or if its programmed right if its the programmable one, then I intend to just swap it out, especially since my camaro can't be sitting up at school too long

Maverick H1L

iTrader: (8)

I have around 3-4 of them. They're on the back table in the garage buried under other car parts (there may be one in the 727 I have, however). I need to dig them all out and figure out which ones are FWD and which one is the one out of the 730-equipped 91. I'll have you pay shipping as I have no use for any of them and want them gone.

RBob

iTrader: (1)

The easiest/best method is to measure the voltage at pin 56 of the MEMCAL. Do this at key-on, engine-off. Obviously with the MEMCAL plugged into the ECM.

If at 4 to 5V then it is a TBI MEMCAL.

If at 1 to 2.5 V it is the correct 6-cylinder MEMCAL.

The FWD 2.3 & 3.1L engines ran DIS.

Note that the TBI MEMCALs I've seen from '7730s didn't have the knock filter. Although it could still be a MPFI 4-cylinder MEMCAL. Which would also fire the injectors too often.

If Maverick H1L doesn't have the correct MEMCAL let me know.

RBob.

Project 3.4 Camaro

What if its a programmable memcal? And maverick let me know when you find them, probably a flat rate envelope or the smallest box should suffice.

RBob

iTrader: (1)

Doesn't matter, the cylinder setting for the injector firing rate is electrical. It is within the resister networks, not the PROM.

RBob.

Project 3.4 Camaro

So if it shows TBI, resistance then its definitely the culprit causing the injectors to pulse to fast?

Project 3.4 Camaro

Also you are referring to the pins on the socketboard, not the eeprom teeth right?

RBob

iTrader: (1)

Yes, the pins on the MEMCAL. They are numbered on the ends. Take a look, then count & mark pin 56 on the top. Plug it back in and measure the voltage.

RBob.

Maverick H1L

iTrader: (8)

I knew there was something I forgot to do today... Had to work most of the day and then my bumper parts (that I've been looking for since last year) finally showed up and I put the front end of my baby back together...

I'll be out of work at 11 tomorrow, and I have anti-static bags and a padded envelope for the MEMCALs. I believe that out of them you'll want to use the AUXW, IIRC... There's also an ATSN (I believe) and another FWD chip I don't remember the BCC on.

:edit: The numbers that RBob is referring to are on the brown side of the MEMCAL... May also be printed on the board in the ECM but I wouldn't count on it.

Maverick H1L

iTrader: (8)

Okay, I went out and got them so I wouldn't forget again tomorrow...

IIRC, the AUJW is from the 91 Bird at the JY, so you won't want that...

RBob, I need you to confirm the following BCC's for me as I have one I'm not sure about: ATSN. AUXW, and BCDY.

Project 3.4 Camaro

Tuesday I will be testing the memcal, so go ahead and send me a PM with shipping cost to 146 whipple st, pittsburgh, PA if you would please, along with paypal info ofc. And on tuesday I will let you know if I need them, but I am fairly certain I will, quick question though, are any of them programmable? They don't need to be since atm I just want the damn car to run, just want to know if I'll have to track one down when I start tuning.

Maverick H1L

iTrader: (8)

I'm only going to send the 2, ATSN and AUXW, because those are the ones I'm sure are FWD V6 MEMCALs. I know the AUJW came from the 91 Bird (still have the ECM with the sticker), and I think the BCDY came from a 3.4 DOHC Beretta (with the 16196396). I'd use the AUXW first because I'm sure that's newer (I think the ATSN came from a 91 Lumina but don't hold me to it as it's been 5 years since I got the 727 for my Grand Prix) as I think it came from a 93 Corsica, IIRC.

:edit: And no, the stock PROM in the MEMCAL is not programmable without special equipment (requires a UV light to erase the chip, which is the reason for the silver sticker on the chip, to cover the erase window).

Project 3.4 Camaro

1.68v...I REALLY wanted it to be the wrong memcal, what else could cause the injectors to pulse too fast???

RBob

iTrader: (1)

Is it that the car won't start? Or is it the car starts and runs for a moment. Then dies out?

The other side is what was done to conclude that the injector pulse too fast. On a MPFI 6-cyl engine, the injectors will generally pulse once per revolution (3 plug firings).

However, many ECMs, dependent upon the code, when cranking, will fire the injectors at a different rate. It is dependent upon DRP count and tables.

Note that SFI ECMs will once the engine is running, fire the injectors each once every two (2) revolutions.

RBob.

Project 3.4 Camaro

It kind of does a bit of both, it will fire and catch, but moment it starts to start it dies off.

RBob

iTrader: (1)

So it is a guess that the injectors are firing too often?

Open the EST/BYPASS and try it.

Pull a couple of spark plugs and see if they are fouled.

RBob.

Project 3.4 Camaro

No, I had a test light on them. Issue is definitely fuel, that much is certain, spark is fine, but I pulled a plug after some cranking and they weren't even wet, which contradicts logic if the injectors are pulsing too fast...going to pressure test it tomorrow just to be certain, I guess there is a chance the FPR on the 3.4 rail is bad, but seems unlikely since the engine ran when pulled.

Maverick H1L

iTrader: (8)

From that statement, it sounds like either a, there is not enough fuel reaching the rail to bring the system pressure up to where it should be, or b, the pressure is leaking down too fast due to either a bad set of injectors or FPR damage. A pressure test would confirm this. If the pressure stays low and doesn't come up, there is probably a clog in the system between the tank and the engine (since I'm pretty sure you replaced the fuel pump recently, right?). Also take out the vacuum line attached to the FPR and check it for liquid gas (and check the intake throat for puddled gas).

Project 3.4 Camaro

Injectors should be fine, ran the engine before on them, leaning towards FPR, going to pressure test it today and see whats what, can you tell me what PSIs it should be at, for primed, cranking, and running? I can't remember offhand, wanting to say 43 for primed, and like 5 lower for cranking/running?

Maverick H1L

iTrader: (8)

Well, you see, the thing is that I have a full set of 3.4/3100 fuel injectors that run just fine (more false advertisement on eBay as they were SUPPOSED to be from a 93 3.1 engine but turned out to be from a 3100)... When you can get the car started due to the fact that they lose fuel pressure. Reason I pulled them was because I was getting tired of having to use starting fluid in the middle of winter (that's friggin cold!) to get the engine started and warming up while I finished getting ready for work.

Fuel system should have no less than 37 PSI at all times with no more than a 1 PSI drop in 20 minutes after the fuel pump shuts off. This keeps the ECM within its calibrated limits, and not much of a drop in pressure will throw a code 44... I believe that anything less than about 28-30 PSI stalls the engine, IIRC.

Project 3.4 Camaro

To better answer, the moment it starts to fire and bring the RPMS up, pulse cuts off completely, and won't come back till I turn the key off.

Maverick H1L

iTrader: (8)

Double check the 7x sensor and the output at the ignition module, and possibly the module itself. The ECM is cutting out because somewhere along the line the reference pulses are getting lost.

Or there is a problem on the EST line... Have you tried starting the engine with the timing bypass open yet? Keep in mind the ignition module controls the ignition until the engine reaches 400 RPM, when there is a signal on the EST line and the ECM takes over ignition control.

Project 3.4 Camaro

Seems unlikely that its a bad connection, Wouldn't it not fire the plugs without reference pulses? And if the bypass is the 1 wire connector by the firewall, then yes.

Maverick H1L

iTrader: (8)

Think you may have it backwards... The plugs MAY fire without reference pulses to the ECM. The injectors won't (and that's a fact). The ECM will think the engine has stopped and will kill the injectors if the ref pulses stop.

To do anything else, you'll need access to a scanner... You need to make sure the ECM sees engine speed before anything else. Unless you can get a copy of the "Engine cranks but won't run, page 1" chart for yourself (for the 165, not that it's much different from the older ECM). Being at school, this shouldn't be a problem (even ALLData has this chart for a reason). And also get the "Ignition system check" chart...

May also help to get the applicable charts for a 730 FWD car to compare...

Project 3.4 Camaro

I have access to a scanner, but without knowing the vehicle the ECU is from, or having a repinned ALDL(impossible since by some fluke freak of nature I don't even have one of the pins that has to be swapped with another) its completely useless...
Can you be more specific about what charts you are referring to, and what they are for exactly? And the reference pulses you are referring to are the same ones that tell the fuel pump to run every 2 seconds correct? I guess I could hook up a multimeter to that wire and test it for 5v(it is 5v if memory serves) while cranking? Cause my original theory was the pump not running, and I think at one point I had my head right over the tank and couldn't hear it run while cranking....so maybe it isn't getting an RPM reading on the ECU end...

Maverick H1L

iTrader: (8)

You'll need to get the charts, should be as I listed (was in the AllData program the idiots at school were using when they couldn't figure out why my engine wouldn't run when they fried my ignition module). You'll need the data from the FWD ignition system in case the information is different (don't see why it would be, but you'll need to know if it is).

Anyways, the voltages are as follows:

1.3V at pins B5 and D4
9.3V at B7
0V (or ground) at B3

This should be while idling and may be different while cranking...

What ALDL wires are you missing? Everything GM ECM specific got pulled from mine and is in one piece... Diagnostic white/black, data orange (2 terminals into one at the ECM), and I think the TCC clutch tan/black.

Project 3.4 Camaro

Instructions say to swap E & M with each other, one of these is in the 2nd row, and I have not 1 single wire pinned to that row...

Maverick H1L

iTrader: (8)

Actually, most cars have one part of the 2-into-1 data line in both of those ports... 90-92 have only M... Guess yours doesn't have the fuel pump test line wired into G either (probably just a connector about 2" off of the relay).

You should try hooking a scanner up to the ALDL and see what happens. Most (if not all) ALDL cables will have both connections for both systems. It won't matter what year car the ECM came from as long as you put the right digit in the 8th spot provided you use either G, H, or J in the 10th (not sure if they used the 165 in 85 or not).

Project 3.4 Camaro

I tried every car the 1227165 came in...

Maverick H1L

iTrader: (8)

Did the scanner say it "device not found"? If so, try swapping the E pin to M (lower right, IIRC)... Although there was a guy on here who couldn't get his 730 to connect (to TunerPro via a Moates cable) through M and when we swapped it to E it connected (required replacing the ECM, however, as it was bad).

Or there is the problem that some of the early systems required a resistor be placed into the data line to enable data transfer. Don't remember just how it worked though, but I believe it was a 10K resistor.

Project 3.4 Camaro

It wasn't able to pull any data, wouldn't unplugging the EST or whatever that wire was throw the ECU into some kind of default mode? And really at this point I don't see a scan tool helping all that much, I already know the problem is the ECU or the way its wired, and specifically related to fuel, and more specifically the injectors, I will have to test for reference pulses tomorrow, though I'm fairly certain I have that wired up fine, since I know I checked it at some point, but the multimeter should tell all..

Maverick H1L

iTrader: (8)

Here's the thing... The engine basically runs itself until 400 RPM, when the ECM takes over. You NEED to make sure the ECM is receiving reference pulses by using a scanner to find out. If the ECM still won't send data, there may be a problem with it... If possible, you may want to make sure it sets a code 12 using the usual paperclip.

Unplugging the EST takes the ECM out of the ignition timing equation. That's it. The ignition module runs the ignition timing instead of the ECM.

Project 3.4 Camaro

So sub 400 rpm the ECU doesn't run the injectors? you sure? And FWIW, one of the instructors said that it could actually run without the EEPROM due to the memcal having a built in failsafe, and when I tried running without the EEPROM, nothing changed, still cranked and fired but wouldn't start and killed off injector pulse. But also the main instructor helping me said the injectors have to be getting a pulse from the ECU, which in and of itself seems correct, my suspicion was that it has a default mode for cranking ie. sub 400 rpm, and didn't pulse till it started to start, which would explain the pulses cutting out the moment its about to start, but he said it would have to be controlling them in order for them to be firing in correlation with the crank, but I'm not entirely sure hes right on that, cause from what I do know of this stuff it seems like GM would do it with some kind of default startup mode thing, I mean hell, the ICM does it with the spark, why not the ECU with the injectors...

Maverick H1L

iTrader: (8)

Okay, I misinformed you, slightly. The ECM does pulse the injectors at startup.

Your problem occurs when EST is supposed to kick in, around 400 RPM. You said it yourself the engine does light off but dies within a moment.

Double check all of your ignition wiring at the ECM. It SHOULD run with the EST disconnected, and it almost seems like the wrong wire is in the EST connection if the EST timing bypass connector does nothing when disconnected, which SHOULD cause the engine to run on base timing (whatever point the CKP is set at, should be 10*, just like the distributor).

Also double-check the mount for the CKP tone ring on the crank. Make sure the ring is positioned as it's supposed to be.

When you removed the PROM, I do hope you put it back in right, or it's fried. They only go in one way. Yes, the engine SHOULD run on the CALPAK (the small chip in the MEMCAL). However, it may not due to your engine setup not being compatible with the settings in the CALPAK (assuming a V8 TBI or the 4-cylinder TBI or otherwise). Talk to the guys on 60*V6... They know more about the BCC codes and can tell you what the MEMCAL came out of if RBob can't.

Again, make sure the ECM will flash trouble codes. It could be that it doesn't like the MEMCAL and will post a "bad MEMCAL" code, 51, or "bad ECM" code 55. If the ECM is posting one of these codes, it may be trying to run on the CALPAK due to a PROM error and cannot due to the incorrect CALPAK being used.

Do you still want the factory MEMCALs?

Project 3.4 Camaro

Probably, I'll check for morse codes, and check that the reference wire is actually carrying a signal first though, but since its me it won't be that easy...nothing ever is....I don't suppose you know the blinking code for 51 and 55? The fact that nothing changed when I DCed the EEPROM, does kind of suggest bad ECU or memcal doesn't it? Is there any way I can test if the EEPROM is good? I mean, if its been firing off the calpak and not the EEPROM, unplugging the EEPROM wouldn't change anything, which is exactly what happens, seems like something different should happen with the EEPROM disconnect, ie. run if correct calpak, or fire differently if not. The EEPROM was kicking around inside the case when I got the ECU, so its possible it was damaged, though it appeared to be fine...
This is why I am pulling my hair out over this, there is like an infinite # of things that my problem could be, and neither I nor anyone with access to my car has the knowledge to pinpoint it....But monday I will check for reference pulse, you never did quite answer, does the ECU run on some sort of default mode/code until the engine actually fires up?
I swear, ever since I got this car its been a case of immovable object(camaro) meet unstoppable force (me) both stubborn as hell, and neither willing to just give in....I want it running again, as much as I like my corsica, walking by 3 rather nice 4th gen mustangs then getting into my corsica while my camaro rusts away is just downright depressing....