Anybody have info on the layout of an A9L's fuel pump circuit?

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Miller347
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Anybody have info on the layout of an A9L's fuel pump circuit?

Post by Miller347 » Tue Apr 04, 2017 1:52 pm

Hi guys I'm new here and I have some problems with my eec IV ....I want to be able to fix them.... I have changed the capicators just as safety precaution .... My question is does anyone have a good layout on how and how to test all aspects of a a9l fuel pump ? What makes them kick on and off during koeo ? .What makes them keep running ? What makes them not turn on ? Etc ? I have built myself a test box in reference to test them ....But I'm needing a really good layout of go diagram and how and where does it complete the circuit

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Re: Tracking down problems

Post by cgrey8 » Wed Apr 05, 2017 11:45 am

The fuel pump's power is wired to be Normally Closed (NC)...borrowing from relay terminology there.

The EEC actively turns the fuel pump OFF after 1 second with no engine activity. So once the distributor (or Cam/Crank Position Sensor) ceases to indicate engine activity, then the EEC shuts the fuel pump OFF. My guess is this is a safety feature.

However if the EEC is not executing the tune correctly (i.e. bad ROM, no valid tune in chip, some other hardware-related issue, etc), then the portion of the tune's code that is responsible for maintaining the fuel pump's 1 second TURN-OFF counter won't be able to do its job and thus the fuel pump runs indefinitely.

I'm not sure if that answers your question completely or not, but it should at least shed some light on the issue.

BTW, I updated your post's title to better describe your actual question and moved this to the HW Forum.
...Always Somethin'

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Miller347
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Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by Miller347 » Wed Apr 05, 2017 1:56 pm

Tha KS for the reply .... Well very informative read.... But my problem is when koeo mode....The fuel pumps keeps pumping and does not kick off in 2 seconds like it's supposed to..Make any sense ? My question is what makes the fuel pump turn off and turn on ? See where I'm going with this ?

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Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by cgrey8 » Thu Apr 06, 2017 5:46 am

If you are looking for info on processor pin numbers, board traces, or hardware component that are in the circuit between the processor and the EEC output pin, then I'm not going to have any info there. Others here might have more if you can be more specific as to exactly what it is you are wanting info on.
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Miller347
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Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by Miller347 » Thu Apr 06, 2017 11:14 pm

cgrey8 wrote:
Thu Apr 06, 2017 5:46 am
If you are looking for info on processor pin numbers, board traces, or hardware component that are in the circuit between the processor and the EEC output pin, then I'm not going to have any info there. Others here might have more if you can be more specific as to exactly what it is you are wanting info on.
Ok....Let me see if I can get this close.... I'm not very good with the termanlogy ..... Power is received thru pin 37 and 57 I think.... This power run thru the board and somewhere on the board it complete the circuit and turns the fuel pump on for 2 seconds if it's working correctly.... In the case where the fp will not cut off.... Or some is not receiving signal.... I need a trace down where and how the fuel pump is turned off and on

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Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by cgrey8 » Fri Apr 07, 2017 6:06 am

Ok, I can clarify 2 points that may help here.

First off, the fuel pump is not powered by the EEC. It is powered via a fuel pump relay. Power goes to the relay and the EEC is switching power to the relay. The relay is wired to the fuel pump NC so even if the EEC wasn't present, the fuel pump would still run if the ignition was turned ON. This is what I meant by the EEC has to actively turn the pump OFF, not turn it ON.

Now another concept worth understanding is the EEC never "powers" things. It either senses them or grounds them. Whether it be sensors that require power, injectors, or any other I/O component, 12v power is generally wired directly to the device if 12v power is required by the device to function. The EEC is then only responsible for sensing the device (i.e. sensors) OR grounding the device (i.e. injectors, relays, solenoids, etc).

The EEC has dedicated ground pins so it can use some as current-sinking grounds or as sensor-reference grounds. The HEGO ground pin comes to mind. The ground used to reference HEGO voltage is not the same ground pin (or ground lug physically on the car) as the pin (and lug location) for injectors. The lugs are significantly distanced so the HEGO voltage, as measured by the EEC, isn't influenced or affected by the current flow of the EEC grounding the injectors. And I'm here to tell you bad ground systems can wreak havoc on the EEC's ability to read sensors. In the early days of my project, I had trouble with the EEC properly reading my HEGOs. When electrical loads were low, the EEC could see the HEGO voltages. However as I increased electrical load, the perceived voltages went down. I could run a datalog and turn the blower motor and/or headlights ON and watch the datalogged voltage of the HEGOs change. It would drop them so low that the EEC wouldn't see them actually switch (they have to get above .42v to be sensed as ON. With the blower motor and headlights ON, they wouldn't go above .3v so the result was the EEC kept enriching the mix until the engine wouldn't run right. Eventually, it would consider the HEGOs as bad and force Open Loop. It took me a while to figure out why this was happening, but it was clearly a grounding problem. So I started beefing up the grounds and in the process of doing that, I found a body ground wire meant to be connected to the battery had corroded and broken off. After repairing that broken ground lug, the HEGOs never misbehaved again. So bad grounds are not just something you hear people talk about but that never really happen. They can happen and can cause real problems that are hard to explain, witness, or catch because things "kind of" work and the problems they cause are often perceived as intermittent.

Now newer EECs blur these lines a bit. From what I understand, the newer EECs can logically treat outputs as inputs and do so simultaneously. For example, if the EEC is trying to drive an ignition coil, it can do so and measure the draw from the coil to know if a spark plug associated with that coil is misfiring. My guess is the actual circuitry of the EEC is that an output has an input wired into the circuit so at the processor level the output and input are actually separate. But from the outside world looking at the EEC like a black-box, logically some outputs (probably not all) are sensed to determine if the intended device connected to that output is behaving as expected. I don't think any EEC-IVs or EEC-Vs do this, but I could be wrong. If I'm wrong, I suspect someone will chime in and correct me.
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Miller347
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Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by Miller347 » Sat Apr 08, 2017 7:37 am

Ok... I remember now that someone told me long time ago the ECU sends grounds. Thanks for reminding me of that lol.. great reading there.. very helpful thanks..... Ok so I have one ECU that when I test it pin 22 does now cut the fuel pump off like it's supposed too after the 2 second .I have traced and traced to no avail. I'm trying to find out where and what point does pin 37 and 57 meet pin 22 for the fp . So I can Mabe replace a chip or subcapicators or something that would repair the ECU.

ECU number 2..... They are no power being sent to the fuel pump from pin 37 and 57 to turn. The FP on. Pin37 and 57 sends power to the fp ....Then pin 22 pulls the ground to cut it off during koeo .. but pin 22 is Eather stuck ground or power is not being sent to the fp....Sorry for being all over the place with my questions....

decipha

Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by decipha » Sat Apr 08, 2017 4:10 pm

power doesnt go to the fp output only ground

thus 37/57 never go to 22

if the ecu isnt turning the pump off then the rom is screwed up

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Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by Miller347 » Sun Apr 09, 2017 11:20 am

decipha wrote:
Sat Apr 08, 2017 4:10 pm
power doesnt go to the fp output only ground

thus 37/57 never go to 22

if the ecu isnt turning the pump off then the rom is screwed up
Ok... If the room is screwed up.... How can I fix it ? I understand what rom is.... I just want to know if it can be fixed

decipha

Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by decipha » Sun Apr 09, 2017 11:38 am

easiest way is to put a chip on the j3 port and bypass it, otherwise you can desolder it buy a rom chip and a burner write it one time only and solder it back on

unfortunately, if the rom died from a spike it prob took out the processor too

Miller347
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Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by Miller347 » Sun Apr 09, 2017 7:51 pm

decipha wrote:
Sun Apr 09, 2017 11:38 am
easiest way is to put a chip on the j3 port and bypass it, otherwise you can desolder it buy a rom chip and a burner write it one time only and solder it back on

unfortunately, if the rom died from a spike it prob took out the processor too
Any way to double check if it is the ROM chip ? Also can a processor be wiped and reloaded with different program?

decipha

Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by decipha » Mon Apr 10, 2017 2:07 am

read the first line of my reply you quoted

no

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Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by sailorbob » Mon Apr 10, 2017 2:49 am

An LSO output from the 8061 cpu is used to control the fuel pump. Its output it fed into a 2 line to 1 line data selector for limp home mode functionality. The output from the selector switches a transistor that grounds the coil of the fuel pump relay.

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Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by cgrey8 » Mon Apr 10, 2017 9:49 am

Miller347 wrote:
Sun Apr 09, 2017 7:51 pm
Any way to double check if it is the ROM chip ?
As decipha said, the easiest way is to put a J3 chip on the EEC and see if this fixes what ailes it. If it does, then the on-board ROM is bad.

See, the J3 edge-connection on these older EECs is LITERALLY the same traces that go to the onboard RAM and ROM along with some additional control lines to do things like DISABLE the onboard ROM so a J3 device can assume that responsibility. Many people assume those connections are just serial connections of some kind. No. The interface is FAR more sophisticated and exceptionally time-critical...far far more complex than an RS-232 connection ever thought about being.

The tunes that we modify are literally a binary dump of these factory ROM chips. We then modify key data portions of the tune via software, and write those modifications to a J3 device. Some J3 devices are not much smarter than the ROM chip Ford put on the board. However others are more sophisticated, like the Moates Quarterhorse (QH). The QH emulates the ROM as well as allows for custom programming to relay certain pieces of info back to an attached PC for the purposes of datalogging. Unfortunately it doesn't do this through feats of smarts itself. There's lots of hand-holding done by the software as well as definition files that the software uses.

Point being, if you are wanting to get into the business of repairing these EECs, then you'll really want to invest in a J3 device to make ROM diagnostics a bit easier...if anything just to eliminate whether it's only the ROM that is bad or if the EEC being tested has more wrong with it than just a bad ROM chip.
Miller347 wrote:
Sun Apr 09, 2017 7:51 pm
...Also can a processor be wiped and reloaded with different program?
The processor is not what's reprogrammed. If you were going to reprogram something, it'd be the ROM chip. These old EEC-IVs are not reprogrammable by any other means thatn desoldering/resoldering a ROM or by just overriding the onboard ROM with a J3 chip.

The newer EEC-Vs are capable of being reprogrammed via their OBD-II connection. Although depending on the hardware and software you use to perform the write procedure, it might be a time consuming process. A 256kb write to a Moates QH can be done, over USB, in roughly a minute (around in that time range anyway). Writing to the factory flash on an EEC-V over the OBD-II, I've heard, can take as long as 45 minutes! I don't have personal experience with this so double-check that before making any decisions. I've heard there are devices that can make this faster, but I don't know what those devices are or exactly how much faster ti is. I'm sure others here on the forum that have done this many times can clarify this point.
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Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by Paulie » Mon Apr 10, 2017 11:51 am

Reprogramming an EEC V PCM with the factory Ford scan tool takes 2-10 minutes. The early EEC V take longer than later ones.
1990 Mustang 5.0, HCI, Vortech S-trim, FRPP 42# inj., PMAS MH95, A9L, Moates Quarterhorse, BE/EA, Innovate LC-1.

decipha

Re: Anybody have info on the layout of an A9L's fuel pump circuit?

Post by decipha » Mon Apr 10, 2017 3:07 pm

I can write a full 256kb to the QH in less than about 30 seconds or so, you can too, if not check your latency is set to 0 in device manager

flashing a 4 bank ecu over obd2 takes me 158 seconds on average, flashing a 2 bank is a touch shorter, thats based on using my mongoose pro

flashing a 4 bank ecu over the j3 using a modified QH takes just under a minute

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