Resolved Cranks but still doesn’t start. Ran through the checklist and still doesn’t start.

[reddy351]

Finally got the 5.0 swap up and running. Sort of. It will start and run but I need to "work" the throttle to get it to stay running. Pulled the codes, first one out of the box is #22. BAP out of range. (The others are clutch switch and some EGR codes.) The BAP that was the one in the car from before. (E6EF-12A644-A1A) I have since purchased a proper E7EF-12A644-A1A sensor and still get the same 22 code. Even after having the battery disconnected for several hours. Do I still not have the correct calibration BAP? (It calls for a E7EF-12A644-A2A sensor. It looks like they do interchange but I'm still getting the code.)

 

[AeroCoupe]

Picture of how you have it hooked up please.

 

[reddy351]

What do you mean? It’s just plugged-in.

The engine harness is a brand new Painless standalone one.

 

[General karthief]

What do you mean? It’s just plugged-in.

The engine harness is a brand new Painless standalone one.

I think he may be wondering if you attached a vac line to it, speed density has vac line, MAP, mass air does not, BAP.
Make sure the nipple is not plugged up.

 

[Mustang5L5]

You are running this with an A9L correct (based on other threads). You have the sensor plugged in and NO vac line in the port right?

Technically the E6 and E7 sensor are MAP sensors, meant to measure manifold vacuum level. The BAP sensor was part number E8EF-12A644-.

There are some slight programming differences (References page 296 of Charles O. Probst Ford Fuel Injection & Electronic Engine Control) but many folks have used them interchangeable without differences. Physically the E8 sensor has a little bell where the vac port connection would be. Your current sensor should work but do not connect to vacuum.

It's hard to test a BAP/MAP. They do make a tester for them that I have, but it may not be necessary at this point. I would start testing for 5V vref and sensor ground continuity (to pin 46 at ECU) at the harness to make sure you have a connection and power to the BAP

 

[reddy351]

You are running this with an A9L correct (based on other threads). You have the sensor plugged in and NO vac line in the port right?

Technically the E6 and E7 sensor are MAP sensors, meant to measure manifold vacuum level. The BAP sensor was part number E8EF-12A644-.

There are some slight programming differences (References page 296 of Charles O. Probst Ford Fuel Injection & Electronic Engine Control) but many folks have used them interchangeable without differences. Physically the E8 sensor has a little bell where the vac port connection would be. Your current sensor should work but do not connect to vacuum.

It's hard to test a BAP/MAP. They do make a tester for them that I have, but it may not be necessary at this point. I would start testing for 5V vref and sensor ground continuity (to pin 46 at ECU) at the harness to make sure you have a connection and power to the BAP

Yes. It is not connected to the manifold in any way.

According to the installation manual, the A9L requires the E7EF-12A644-A2A sensor. Is that not correct?

When did Ford stop using this type of sensor?

 

[Mustang5L5]

According to the installation manual, the A9L requires the E7EF-12A644-A2A sensor. Is that not correct?

When did Ford stop using this type of sensor?

It can be used. I'm currently using one on my Mass air swapped '88 with an A9L. Whatever differences there are are minor (if any) and these sensors were used in many diffeent fords. Technically the part number you are using is a 4-cyl Mustang BAP sensor. The 5.0 didn't come with a BAP until 1988 in CA, and 1989 50 state. So that part number would be an E8 or E9 part number

Really the main difference is the port. Left sensor is used as a MAP as it has a barb for a vac line. Right is a BAP as it prevents a vac line from being installed. So you probably want a sensor lke the right one.

I wouldn't sweat the sensor P/N however. like i said, i'm using a MAP sensor with the BAP ecu and it runs nicely. Many others have done this as well. I'd test the wiring connections going to the ecu.

 

[reddy351]

It can be used. I'm currently using one on my Mass air swapped '88 with an A9L. Whatever differences there are are minor (if any) and these sensors were used in many diffeent fords. Technically the part number you are using is a 4-cyl Mustang BAP sensor. The 5.0 didn't come with a BAP until 1988 in CA, and 1989 50 state. So that part number would be an E8 or E9 part number

Really the main difference is the port. Left sensor is used as a MAP as it has a barb for a vac line. Right is a BAP as it prevents a vac line from being installed. So you probably want a sensor lke the right one.

I wouldn't sweat the sensor P/N however. like i said, i'm using a MAP sensor with the BAP ecu and it runs nicely. Many others have done this as well. I'd test the wiring connections going to the ecu.

Mine has the little plastic piece that keeps a hose from being connected. There was not one connected in the previous application, so I figured it would work.

The problem is that now, even with the battery disconnected for a couple of hours, it still has the code for the BAP. Even after I swapped the “correct” BAP.

Is there something extraordinary that I need to do to clear the code? Or is this BAP bad and popping the code as soon as the ignition is turned on?

 

[Mustang5L5]

Likely a hard fault.

You can use a THEXTON 127 tester to test the BAP, but I’d suggest testing the wiring first.

Pin 46 is sensor ground and pin 26 is your 5v vRef. Do you have that on the two wires at the sensor with key on and the sensor disconnected?

I would then test continuity from center pin on wiring plug down to pin 45 on ECU to make sure the wiring is connected properly.

If all that rings out, you’ll have to test the sensor using one of the above tools. Fairly cheap on eBay. Given that you have 2 “bad” ones, I’d suspect wiring here

 

[reddy351]

So, is Sig RTN the “ground” for the sensor?

 

[Mustang5L5]

Correct. You want to test for 5v between vref and sig return

 

[reddy351]

Correct. You want to test for 5v between vref and sig return

And then simple continuity from the “MAP” in the drawing down to pin 45 on the computer? Got it. Will return shortly.

Edit: With the key on and the BAP socket disconnected, I have 6v between vRef and RTN. When I put the probe from my meter in the socket and probe pin45 on the computer (key off), I read 30 or so ohms. It’s not “0” ohms but it’s also not “infinity” either. I’d call that continuity.

 

[Mustang5L5]

I agree.


Where did you source the sensors from?

 

[Bullitt347]

So, is Sig RTN the “ground” for the sensor?

Sig RTN is a ground at/in the ECU. Not a normal chassis ground.

 

[reddy351]

Sig RTN is a ground at/in the ECU. Not a normal chassis ground.

That’s understood. That’s why I put quotation marks around it.

 

[Bullitt347]

That’s understood. That’s why I put quotation marks around it.

Fair enough.
I did not get that from the quotation marks.
I thought you were referencing any ground.

 

[reddy351]

I agree.


Where did you source the sensors from?

One was in the car and was operational just a few weeks before the swap. (As mentioned, it’s technically not the “correct” calibration code but I’m told “they’re all the same”.) The other was a “known good” used part that was purchased from an eBay vendor and IS the correct calibration code.

Should I buy a new Motorcraft BAP sensor at this point? Or, actually test the ones I have?

Could the computer, itself, be the culprit. I bought it used.

 

[reddy351]

Using the Ford Fuel Injection and Electronic Engine Control book, it says to test VREF to SIG RTN. Should yield between 4-6vdc.

I had 6vdc.

The next test is from BP SIG (center wire) to negative batt post. Should read between 4-6vdc.

I measured 2.6vdc on BOTH BP sensors that I have.

The book says “BP sensor may be faulty”.

Both are faulty? One was working when I drove the car in on the 2.3. Both read the same bad voltage.
‍
Not sure whats next because i dont have a breakout box to check the harness.

 

[Mustang5L5]

The book is incorrect. The output wire on the map sensor will always be around 2.6ish volts. What changes is the frequency. That’s why you really need an oscilloscope to test them

Short of that.

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[Mustang5L5]

I have one. Never used it but here are the directions. Looks like they test by voltage, and it’s a lower range.

I don’t buy that both your sensors are bad. What are the odds? I still think it’s wiring but it checked out. We have to have missed something