Hi all.

I'm a nomad currently working on this Econoline to use as my RV. Currently, I've been a boondocking for around 7 months and really enjoy spending time in the wilderness. My father recently found out that this old Van was still sitting around and gave it to me so I can fix it up and use it rather than my sedan. It used to be his work van when he primarily did finish carpentry.

He's done some really nice work to it such as the roof rack, Ladder, Step, insulated and carpeted interior.

Several years ago, as he stopped driving the van, it developed a problem.

Flooding at startup.

So, I've done some basic inspection and begun to freshen some things up while working to diagnose this issue.

I am not experienced with Ford EEC IV, but have been reading and familiarizing myself as I inspect and test components.

Upon scanning, I have an active and stored code of "MAP sensor out of range"

During my numerous inspections and replacing some things, I've checked NEARLY the entire vacuum system. The reason I say NEARLY is because I haven't yet made it past the EVAP purge valve to the EVAP cans.

As soon as I read up on the EVAP system, I will inspect.

I tested the MAP sensor with my DVOM and vacuum pump as per directions in service manual.

I checked the voltage between VREF and SIG RTN Terminals on the MAP sensor, with harness connected and it passed that portion with 5.0V (specs listed are 4-6).

However, it failed second portion of test. Second portion of test was to be conducted with KOEO. Measuring voltage by probing MAP SIG, and SIG RTN terminals while applying varying amount of vacuum to sensor should produce varying voltage. It stays at 2.52V... pressure, vacuum... 2.52V constant!

So in desperation, I bought a non OEM and after no improvement, I tested it as well. It barley varied from 2.52 to 2.51.

I'm thinking the sensor is bad. But another thing worries me that I'd like to ask the experts about.

with the key on, and sensor completely disconnected, the MAP/BARO SIG terminal on harness has 5.0V...
that made me initially suspect that there was damaged/ruptured insulation in the harness allowing VREF voltage from ECM to bleed over.

so I inspected harness... good to go no shorts and all insulation is in darn good condition for this vans age.

So I've got several questions:

Do the EEC IV computer and sensor communicate by voltage alone, or is the sensor alternating a frequency back to the ECM?

And, with MAP sensor disconnected, KOEO, should test pin # have 5V? If not, that means my ECM is culprit? I looked at the ECM (replaced approx 10 years ago and found no damage. The 1 capacitor on in had no leakage, bulging, or any detectable sign of failure.

In the meantime, I beat myself up for buying an aftermarket sensor, and got a motorcraft on the way from Summit.

I am incredibly stoked about this Van and it means a ton to me to fix it up since it's from my Dad.

I also look forward to updating this thread as I make progress.

Thank you for your interest.

 

I would quickly check for a ruptered fuel pressure regulator. Pull off its vacuum line and cycle the key a few times. If fuel squirts out of the vacuum nipple, replace the regulator.

https://www.rockauto.com/en/catalog/...regulator,6124

 

Raski, thanks. I checked fuel pressure which was good and it'll hold pressure for several hours... I also removed the FPR vacuum line and found no evidence of fuel in it or escaping regulator.

 

I installed the new OEM MAP sensor, and no change...

Anyone know of someone who can test ECM's?

 

Hellooo Yuba,

Hope we can help you out a little..

First if your service manual tells you to check a Ford MAP sensor with a voltmeter and vacuum pump , THE BOOK IS WRONG !

Why? Ford MAP sensors operate with frequency not voltage. You need a meter that can handle frequency changes.
With no vacuum applied, the frequency should read 159 Hz. At 12 in(Hg) it should read 125 Hz
At 16 in(Hg) it should read 109 Hz
When you say flooding at startup , what do you do to prevent a stall?

Yes , you are correct looking into a possible stuck open purge valve, I wouldn't condemn the ECA before ruling out all other possibilities.

Suggest you verify all readings are correct at the Throttle position sensor, if it loses its ground problems come up.

How does it run when warmed up? Are you sure it is actually flooding , getting too much fuel?

 

Hanky,

Thank you for clarifying that the MAP sensor uses frequency, rather than voltage, to signal the PCM. The new OEM MOTORCRAFT MAP sensor passes the test. Some aftermarket service/repair manuals seem to have low standards and poor quality control.

Your mention of the TP sensor has caused me to suspect it is causing/contributing to problem.

I can barely get it to barely start... but by working the throttle it almost trys to stay running. I haven't got it to run more than several seconds and it's rough... strong gas smell, smoke from tailpipe, and previous operator/user said it would contaminate oil w/gasoline from flooding.

I pulled the TP sensor off and measured resistance between TP and VREF terminals as I rotated the input on the sensor. IT IS NOT CONSISTENT. Resistance values jumping unpredictably as th input is rotated.

Also, it is now providing DTC 23, TP sensor out of self test range.

I Think my next step is now to replace the TP sensor.

I appreciate your informative reply, as I don't have experience working on this system.

 

Replaced TP sensor, and still the same thing...

I've vacuum tested lines, but not the actual throttle body and manifold.

I attempted to make a smoke device, which was ineffective.

I was hoping to fill the entire intake manifold and throttle body with smoke and pressure to find a leak perhaps.

I don't have access to a suitable smoke machine, so I'm just going to try to find a mechanic who is experienced with EEC4.

Hopefully I find one who can efficiently diagnose it.

Other than finding a professional mechanic, I'm at somewhat of a stagnant point regarding progress.