Tps function in EEC IV
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Tuned
Joined: Mar 2005
Posts: 373
Likes: 1
From: Calgary
Tried it, no dice. Checked for resistance between PCM and EDIS today, clean. Thought I had it when I noticed the bolt that fastens the coil pack mounting plate to the cyl head was missing, removed the plate and polished all contacting ares and the bolt as the spark must reurn to the coil thru the ground. Nada.
Interesting thing on the PCM grounds, #20 0 ohms #40 + #60 2 ohms. This to the polished ground on the inner fender by the PCM mounting area. To a jumper wire from neg post of battery, values are reversed. There are stray voltages at work here it would seem. Too cold to continue tonite will soldier on tomorrow.
Interesting thing on the PCM grounds, #20 0 ohms #40 + #60 2 ohms. This to the polished ground on the inner fender by the PCM mounting area. To a jumper wire from neg post of battery, values are reversed. There are stray voltages at work here it would seem. Too cold to continue tonite will soldier on tomorrow.
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Tuned
Joined: Mar 2005
Posts: 373
Likes: 1
From: Calgary
Is it right for the BAP sensor to have 5VDC at 2 connections? I am getting reference voltage on my brown/white wire and my light green wire, sensor unplugged, koeo. Would anyone with a 91 be so kind as to see if their X is wired the same? Thank you.
Postmaster
Joined: Dec 2001
Posts: 3,742
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From: UT
It might, can't say for sure. The thing with Ford MAP's/BAP's is that you can't test them with a voltmeter. Their output is a frequency signal, so you either need to get a MAP/BAP tester that converts the frequency to a voltage or a use a DMM with a frequency counter. The MAP on my BII (I believe your '91 should be the same) outputs 0.16 Hz at ambient pressure (5000 ft elevation).
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Tuned
Joined: Mar 2005
Posts: 373
Likes: 1
From: Calgary
Awesome thanx for answering mrshorty, but with myBAP unplugged I'm measuring 5VDC at the connector koeo at the br/w (vref) wire and at the l/g wire in the center of the connector. So I was wondering is this right or are the two wires shorting together somewhere in the harness?
Senior User
Joined: Nov 2003
Posts: 478
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From: ut
I read somewhere that you can use a digital tach for a frequency counter. It requires a math conversion. As I recall, it wasn't very complicated. I just tried to find the book it was in, but no luck. It's gotta be in my messy garage somewhere!
Anyone else heard of this?
Anyone else heard of this?
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Senior User
Joined: Nov 2003
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From: ut
Found it. It's in a book by Ben Watson..."How to tune and modify Ford fuel injection".
With the tach on the 4 cylinder scale (regardless of how many cylinders you have) connect to either the ground side of an actuator circuit, or in this case, a sensor output wire, and a good ground. Observe the reading, divide by 30. That should be the reading in Hertz.
The book says the 6 or 8 cylinder settings work equally well, but the math is more complex. I haven't tried this, (all I have is an analog tach and the book says they don't have enough precision), but it sounds reasonable that it should work.
Hope this helps.
With the tach on the 4 cylinder scale (regardless of how many cylinders you have) connect to either the ground side of an actuator circuit, or in this case, a sensor output wire, and a good ground. Observe the reading, divide by 30. That should be the reading in Hertz.
The book says the 6 or 8 cylinder settings work equally well, but the math is more complex. I haven't tried this, (all I have is an analog tach and the book says they don't have enough precision), but it sounds reasonable that it should work.
Hope this helps.
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Tuned
Joined: Mar 2005
Posts: 373
Likes: 1
From: Calgary
Egg on my face, 'twas a bit of resistance across ig switch contacts. The car stayed dead this time which helped and I measured under 10.5 v key on and 8.2 cranking. Hot wire confirmed it. One new switch later and a huntin' we will go. Thanx for all the help guys, happy exploring.
Senior User
Joined: Nov 2003
Posts: 478
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From: ut
Test lights still have their place. The other night, while troubleshooting a circuit, there was the proper voltage shown on the Fluke, (28vdc) but when the circuit was "loaded" with the test light, it didn't light up. With the Fluke re-attached, and the light was simultaneously applied, the voltage dropped to zero. Apparantly the wiring had broken down within the insulation. The wire was replaced, which fixed the circuit. The same thing could have been seen with an analog meter with a lower "ohms per volt" rating than a Fluke. Since Flukes have a very high "ohms per volt" rating, they are more sensitive to the presence of voltage, but not necessarily the quality of the voltage. Someone with more electrical education than I might be able to elaborate, but from what I've seen, this seems to be true. That's why I use both types of meters (analog and digital) along with test lights...depending on the situation.
Anyway...glad to hear you fixed your problem. I must say that the ignition switch is something that I probably wouldn't have considered, at least for a long time.
Anyway...glad to hear you fixed your problem. I must say that the ignition switch is something that I probably wouldn't have considered, at least for a long time.
Posting Guru
Joined: May 2002
Posts: 1,574
Likes: 1
From: Phoenix
You're right Woody - took 3 trips back to the dealer in 1993 to have them finally fix the trailer lights. They used a volt meter and said - pigtail has 12V so problem must be customer's trailer. Finally, I talked to the technician and said drop your meter and jumper a bulb and put a load on the circuit. He tried it and said hey, it don't light up.
Issue was a factory ground not connected under the dash. tech had to remove insulation that the connector was crimped onto. Crimped on copper wire and wolla - now grounded. Gotta love it "Ford - quality goes in before the name goes on!"
Issue was a factory ground not connected under the dash. tech had to remove insulation that the connector was crimped onto. Crimped on copper wire and wolla - now grounded. Gotta love it "Ford - quality goes in before the name goes on!"
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