This is a pic from Jon. I think terminal M was active on the '88 models and terminal N was active on some of the earlier years. In this pic, looks like M isn't connected to anything but N is.
I was gonna test these terminals tonight, but i have 3 buffer boards and NONE of them have any circuits connected to K, L, M or N .
LOL I guess I forgot about the letter "N"! Sorry it was a long day yesterday. Oh well, if you do find a circuit board trace going to a terminal that doesn't appear to be used I would give it a try anyway.
Blacktree Thank you. How do I delete the cold start injection system exactly ?
I'm not using the fan switch now, so i can just unplug the connection (?) I'd probably remove the sensor and plug the hole anyway.
Right now, the car seems to start and idle fine, but the idle jumps between 900 and 1200 after it warms up and sometimes the car starts to surge and buck. Is this an IAC issue ? Maybe Throttle POsition Sensor ?
I wanna re-read about where you installed the knock sensor .... I saw where ryan said it was needed, but did not see where it could be deleted in the programming. Must be better to have it (?)
How did your stalling problem turn out ?
[This message has been edited by PaulJK (edited 04-02-2008).]
When I deleted the cold start injection system, I replaced the thermal switch (in the intake manifold) with a pipe plug. And I replaced the tube fitting in the fuel rail with a short (stainless steel) bolt. I couldn't think of an easy, effective way to plug the injector hole in the intake manifold, so I just left the injector in there. You can also delete the wiring, if you want. It's just dead weight, anyway.
The 7730 ECM takes over the function of the fan switch. So you can remove it, and plug the hole. You can trace the wire back to a splice in the harness, and snip it there. The fan switch plug fits the knock sensor. So you can re-use it.
Speaking of knock sensors, mine is located on the trunk-side of the engine block, almost exactly in the center of the block. There's a coolant plug there that has the same size threads. The knock sensor replaces that coolant plug.
By the way, the fan switch and cold start switch both use 3/8" NPT pipe threads.
My stalling issue was caused by a faulty throttle body. The throttle plate sometimes didn't fully close at idle. The inconsistent readings from the TPS were confusing the ECM. After adjusting the idle stop screw, the stalling ceased.
I should also mention that the 7730 ECM seems to be more sensitive to sensor input than the old Fiero ECM. It's very important to have all your sensors in perfect operating condition. When I first installed the 7730 ECM, I had a problem with the engine bucking and hesitating during acceleration. After some investigation with an OBD-1 scanner, I found that my MAT sensor was reading high. As a result, the engine wasn't getting enough fuel during acceleration. Replacing the sensor fixed that problem.
When I deleted the cold start injection system, I replaced the thermal switch (in the intake manifold) with a pipe plug. And I replaced the tube fitting in the fuel rail with a short (stainless steel) bolt. I couldn't think of an easy, effective way to plug the injector hole in the intake manifold, so I just left the injector in there. You can also delete the wiring, if you want. It's just dead weight, anyway.
The 7730 ECM takes over the function of the fan switch. So you can remove it, and plug the hole. You can trace the wire back to a splice in the harness, and snip it there. The fan switch plug fits the knock sensor. So you can re-use it.
Speaking of knock sensors, mine is located on the trunk-side of the engine block, almost exactly in the center of the block. There's a coolant plug there that has the same size threads. The knock sensor replaces that coolant plug.
By the way, the fan switch and cold start switch both use 3/8" NPT pipe threads.
My stalling issue was caused by a faulty throttle body. The throttle plate sometimes didn't fully close at idle. The inconsistent readings from the TPS were confusing the ECM. After adjusting the idle stop screw, the stalling ceased.
I should also mention that the 7730 ECM seems to be more sensitive to sensor input than the old Fiero ECM. It's very important to have all your sensors in perfect operating condition. When I first installed the 7730 ECM, I had a problem with the engine bucking and hesitating during acceleration. After some investigation with an OBD-1 scanner, I found that my MAT sensor was reading high. As a result, the engine wasn't getting enough fuel during acceleration. Replacing the sensor fixed that problem.
I had a hard time finding a short 12mm x 1.25 bolt to fill the fuel rail were I removed the cold start from and end up using a 12mm oil drail plug from Orchelins. Use a cooper washer with it as well. On plugging the CSI on the intake I used a 7/8" shallow freeze plug w/ a little RTV. Mike
Sounds good. Instead of changing all the hardware right off the bat, is it possible to just disconnect the wiring to the cold start injection system and leave the hardware in place to test the ECU upgarde installation ? Will leaving the dis-connected hardware in place hurt anything ?
Does the knock sensor come with a connector to splice into the harness ?
Yes, I did this very thing. Just left everything in place plugging the holes. I did verify the CSI did not leak under pressure. I also disconnected the wires and left them hanging. Not really needed as the other end of the wires are not connected to the ECM anymore.
The knock sensor uses the same type connector as the old fan switch on the intake. Since you will not be using the fan switch anymore just reuse the connector on the knock sensor. You will need to splice a new wire to run to the ECM for the knock sensor circuit.
I have a question. Remove the fan switch cut the wire out of the harness and plug the hole?
I read the instructions to be .....move the D8 (egr diag sw, pin C at egr) to GE8 and then cut the wire FROM the fan sw and connect it to the old egr at pin C. Now the fan sw goes to GE8. Is this an option to use this if you don't want to have the ECM control this circuit?
Also I have not installed my knock sensor yet but I thought the knock sensor went above the oil filter. Is that only true for the 3.4 block and the 2.8 does not have this boss?
What is right?
Ed
[This message has been edited by Fino (edited 04-04-2008).]
I'm kind of confused as to what you are asking. You can remove the fan switch and plug the hole, yes. Now you have 2 options: Run a digital EGR or none at all. The 7730 is not compatible with the Fiero 2-wire analog EGR solenoid. It needs a 4-wire digital EGR. On mine I wanted to run the digital EGR so I left my stock EGR wiring alone. I cut the fan switch wire a couple of inches above the fan switch connector, spliced a new wire to the wire from the C500 end of the fan switch wire, then ran that wire to the cooling fan control pin on the ECM (YE8 on my 7730). If you wanted a cleaner install then find the cooling fan wire where it comes through the cabin from the front fan relay and splice it there. It is just a ground wire anyways as that is what the fan switch does, goes to ground when the temp goes above it's set threshold.
I believe Darth's instructions are just a nice way to reuse/repurpose the Fiero's original EGR wires for a nice clean install. My method leaves an extra wire running through the engine compartment that you need to deal with. As it stands now, I had Darth disable the EGR so I don't get a Check Engine Light.
[This message has been edited by Hudini (edited 04-04-2008).]
On your 2nd question, here is a picture of the stock 2.8L block, rear side as mounted in the Fiero. There is a plug in the middle of the water jacket that can be removed for the knock sensor:
I'm kind of confused as to what you are asking. You can remove the fan switch and plug the hole, yes. Now you have 2 options: Run a digital EGR or none at all. The 7730 is not compatible with the Fiero 2-wire analog EGR solenoid. It needs a 4-wire digital EGR. On mine I wanted to run the digital EGR so I left my stock EGR wiring alone. I cut the fan switch wire a couple of inches above the fan switch connector, spliced a new wire to the wire from the C500 end of the fan switch wire, then ran that wire to the cooling fan control pin on the ECM (YE8 on my 7730). If you wanted a cleaner install then find the cooling fan wire where it comes through the cabin from the front fan relay and splice it there. It is just a ground wire anyways as that is what the fan switch does, goes to ground when the temp goes above it's set threshold.
I believe Darth's instructions are just a nice way to reuse/repurpose the Fiero's original EGR wires for a nice clean install. My method leaves an extra wire running through the engine compartment that you need to deal with. As it stands now, I had Darth disable the EGR so I don't get a Check Engine Light.
Ok I looked at the Fiero wiring digram and it makes more sense now. GE8 is the output of the computer to control the fan relay (I was thinking GE8 was an imput looking for the sensor) that one is OK now. The knock senser in the Beretta book shows it to be on the right side front. Got that now.
I am all better now. I should be done shortly now. Thank you Ed
EDIT: I was typing while you were posting
[This message has been edited by Fino (edited 04-04-2008).]
On your 2nd question, here is a picture of the stock 2.8L block, rear side as mounted in the Fiero. There is a plug in the middle of the water jacket that can be removed for the knock sensor:
Thanks Hudini
I got this out of the Beretta book because I am using the 1991 Beretta computer and need the knock sensor for that engine. I do have the 3.4 in my car and this boss is on my car.
[edit to add] Notice that my engine has the boss for the knock sensor like in the Beretta photo, but I didn't use it because it would interfere with my headers.
Below is a photo of the pipe plugs in the intake manifold, where the cold start switch and fan switch used to be.
[This message has been edited by Blacktree (edited 04-04-2008).]
[edit to add] Notice that my engine has the boss for the knock sensor like in the Beretta photo, but I didn't use it because it would interfere with my headers.
Below is a photo of the pipe plugs in the intake manifold, where the cold start switch and fan switch used to be.
That looks great a lot cleaner. I got the knock sensor installed and wanted to make sure the wire did not pull loose so I wraped it around the exhaust manufold three times for safety. Don't want that to come disconnected.
Ryan - is the knock sensor absolutely needed or will the car run OK if the knock sensor is simply deleted in the ECU programming ?
On a stock Fiero 2.8 engine, no; the knock sensor is not absolutely needed -- but if you don't install it the chip will have to be reprogrammed as such.
If you are running a modded 2.8 or different engine, then yes you should be using a knock sensor. The reason why it isn't critical when you are using a stock 2.8 is because that engine has low enough compression that it's hard to get it to detonate anyway and besides that we can transfer the stock timing tables from the stock 2.8 programming over to the 7730 ECM.
Also wondering - the 5 speed trans (isuzu and getrag) have a lower final gear ratio than the 4 speed automatic (?). Therefore they should get even better gas mileage in "highway mode driving" than the 4 speedo auto did with this ECU upgrade (?)
Also wondering - the 5 speed trans (isuzu and getrag) have a lower final gear ratio than the 4 speed automatic (?). Therefore they should get even better gas mileage in "highway mode driving" than the 4 speedo auto did with this ECU upgrade (?)
Not exactly. Your typical 440T4 / 4T60 came with a 2.84, 3.06, or 3.33 final drive; overdrive ratio for this trans is ~0.70:1. The only manual trannys that had a similar final drive would be the econo 4-speed munice (84 only?) which had the 3.32, and the 5-speed isuzu used on the 4cyl engines which had a 3.35 final drive.
The 5-speed getrags had a 3.61 final drive and the 4-speed muncies that came with the V6 had a 3.65 final drive ratio.
Pretty much all GM computers that have removable chips use EPROMs - Electronically Programmable Read-Only Memory. These types of chips need to be erased with a UV lamp before they can be reprogrammed. EEPROMs are basically the same thing as flash-memory chips; they get erased electronically.
I have my 7730 installed and the digital cruise and the engine started up first time. I have only driven it for about two miles so I cannot tell if there any problems.
Pretty much all GM computers that have removable chips use EPROMs - Electronically Programmable Read-Only Memory. These types of chips need to be erased with a UV lamp before they can be reprogrammed. EEPROMs are basically the same thing as flash-memory chips; they get erased electronically.
Thaks Ryan.
I have another thread going about aftermarket ECU's, but I guess what I'm really after is a DIY tuning solution. I currently use HPT for the GP, but since it won't work on a OBDI computer and HPT doesn't support these older calibrations, I'll need new tuning software/hardware.
After having read through this thread, it sounds like using the 7730 may be the way to go since certain calibrations are compatible with distributor ignitions and it will support a knock sensor. Just need to figure out what software to use. I'm looking through TunerProRT (not quite as user friendly as HPT and will require me to dust off some assembler and hex knowledge that I haven't used for 25 years) and hardware requirements for data logging, chip emulation, and chip burning.
Thanks for posting the links to TunerPro and Moates.
ok so what MAP sensor do i need to get for running 12psi? what car do i need to steal it from lol. i think the 3800sc has a good one but what gen and what car?
ok so what MAP sensor do i need to get for running 12psi? what car do i need to steal it from lol. i think the 3800sc has a good one but what gen and what car?
2-bar is all you need to accurately read up to 15psi of boost. The 1996-up 3800 Series 2 SC engines all had a 2-bar MAP sensor.
I just wanted to put in a good word for marc at TRU Mension Mfg. If this adapter works anywhere near as good as it looks, ohhh boy The copper color in the pics is just a reflection of an overhead light. By the way, I'm planning to use the stock fiero gasket on the flange, adapter plate on top of it, digital EGR gasket onto the adapter, then the digital EGR. Seem OK ?
[This message has been edited by PaulJK (edited 04-12-2008).]
I have had a chance to drive my car now after installing the 7730 computer. The driveability of the car is like a NEW car. Well worth the install of the computer. I have the EVAP, digital EGR and knock sensor installed.
Thanks Ryan Ed
------------------ Fino www.feroce.net Member National Kit Car Club www.kitcarclub.com Lifetime Member CFOGi (Lot of good that does me)
finally getting back to work on my 7730 swap. almost there. now - ran into a Q: the speedo. the re-wiring instructions have me splicing the speedo feed, so the ECM can piggy back off it. now, if I wanted the speedo feed to come from the ECM - there is only mention of switching 1 line. what about the 2nd? does the "low" remain? is it like a ground?
and, will this allow me to make speedo adjustments for tire size?
finally getting back to work on my 7730 swap. almost there. now - ran into a Q: the speedo. the re-wiring instructions have me splicing the speedo feed, so the ECM can piggy back off it. now, if I wanted the speedo feed to come from the ECM - there is only mention of switching 1 line. what about the 2nd? does the "low" remain? is it like a ground?
and, will this allow me to make speedo adjustments for tire size?
The low (purple) VSS wire -which is a ground- coming from the Fiero speedo won't be used if you are running the VSS wiring thru the 7730 ECM. All you will be using is the "hi" (yellow) VSS wire coming from the Fiero's speedo which hooks to the speedo conversion circuit then connects to the 4000ppm output comimg from the 7730 ECM. I don't know how much adjustment the 7730 ECM allows for speedo calibration because I didn't need to get into that in the conversion I did.
Originally posted by Darth Fiero: The low (purple) VSS wire -which is a ground- coming from the Fiero speedo won't be used if you are running the VSS wiring thru the 7730 ECM. All you will be using is the "hi" (yellow) VSS wire coming from the Fiero's speedo which hooks to the speedo conversion circuit then connects to the 4000ppm output comimg from the 7730 ECM. I don't know how much adjustment the 7730 ECM allows for speedo calibration because I didn't need to get into that in the conversion I did.
can ya re-explain this? sorry - when I look at the wiring & the schematics/pinouts - its not falling into place....
and, is there a circuit I need to add to this thing? I saw on page 3? a small circuit (basicly, a filter) which is needed to drive the speedo from the 7730?
[This message has been edited by Pyrthian (edited 05-01-2008).]
can ya re-explain this? sorry - when I look at the wiring & the schematics/pinouts - its not falling into place....
and, is there a circuit I need to add to this thing? I saw on page 3? a small circuit (basicly, a filter) which is needed to drive the speedo from the 7730?
The Fiero speedometer head contains the main VSS buffer circuit used in all stock Fieros. This means the Fiero speedo interfaces directly with the speed sensor (VSS). So it has to supply a ground to the sensor (purple wire) and it reads the return signal from the sensor (via the yellow wire). When using a 7730 ECM, you no longer need to have the Fiero speedo send that ground signal to the speed sensor because the 7730 ECM will do that for you (therefore you don't need to hook up the purple wire coming from the speedo to anything). All you need is to hook the 7730 ECM up to the speed sensor as I direct you to do in my wiring instructions. Then the 7730 ECM will output a 4000 pulse per mile signal that you can use for the digital cruise control and the Fiero speedometer. In order for the Fiero speedometer to understand this output from the 7730 ECM, you need to build that "fiero speedo conversion" circuit I have posted on my website. The speedo conversion circuit connects to the 4000 ppm output from the 7730 ECM, the yellow speed sensor wire going to the Fiero speedometer, and a 12v + (hot in run) power source.
Does anyone that has done this conversion used a scan tool software with it? I thought I had read in this post that you could use FreeScan. I am trying to use it with my 3.4(DIS)new build. Unable to start engine yet. Software (selected 3.1 engine)on the sensor scan page has a line that is called crank postions =0 is this saying I am not getting feedback from my crankcase sensor? Is there any other software to use? Mike
P.S. I think I may have flooded it and is the cause for it not starting will know more tomorrow. I have spark, fuel at the shrader valve (psi? will check as well tomorrow) and i have a pulse at the injector connector Just would like to understand the software a little better.
.
I should be done shortly now.
