Check Engine light is on

BroncoJoe19

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I made a home depot run to pick up some mulch, and a piece of sod. I'm getting tired of seeing dog urine brown spots on my lawn, and then having to wait for the grass to grow back. So as it goes, I got the mulch and they were out of sod.

Before I left home, I noted that the check engine light CEL stayed on longer than usual, but it went out. I wasn't sure if the truck seemd to be lagging a little, and maybe hessitating if I slightly depressed the throttle. If I more aggressively pressed the throttle, it seemed ok, but just not quite right. While at the traffic light leaving the parking light the truck stalled, but started right up. My CEL came on, and stayed on.

Now the hessitation with slight throttle was more obvious, but not consistant. There seemed to be a little more pronounced lack of throttle response. The trans started making hard shifts. I typically drive gently, and noted the shifting got a bit harder, once when I got on it a little bit I was surprised at the hard shift. Also when I was cruising along, and suddenly got off of the throttle, to step on the brake, it hard shifted out of OD. That was surprising!

OK... so I started thinking what could this be?

Poor idle and stalling... IAC?

combined with lack of response and shifting? vacuum leak(s)

hard shifting TPS (replaced less than 1,000 miles ago)

VSS Trans shift points.

So of course I would pull codes as soon as I got home.

KOEO

22 on demand

22 continuous

KOER

98

22

Now the odd thing with the KOER, is that I did not get the initial 4 flashes identifing an 8 cylinder, nor did I get a signal for the throttle test. IT just started sending codes.

So. Actron lists 22 as Manifold Absolute Pressure (MAP) sensor or Barometric Pressure (BP) sensor

 

miesk5

96 Bronco 5.0
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yo Joe!

some quickie's for you now;

Operational Description, pic & Parameters (click on Sensors; MAP sensors are only used in Speed Density systems

Source: by Ryan M

Most significant:

"To prevent the replacement of good components, be aware that the following non-EEC areas may be at fault:

*Unusually high/low barometric pressure. *Kinked or obstructed vacuum lines (MAP). *Basic engine (valves, vacuum leaks, timing, EGR valve, etc.). ..."

so, your prev. vacuum leak may also be evident elsewhere.

and Ryan has a schematic for a 91..should be sim...

Have not found a DIY test yet on a Ford MAP sensor tho; need a 'scope it seems; see my site under ELECTRICAL; EEC/PCM, Self-Test, wiring diagrams... -> Sensor -> Manifold Absolute Pressure (MAP); for waveforms, etc.

and this by Chilton;

http://www.autozone.com/az/cds/en_us/09008...irInfoPages.htm

Code 98-Hard fault present or Electronic pressure control driver open in PCM (E40D)

DTC 98 KOER - found this and I never heard of this Joe!

Failure Mode Effects Management (FMEM)

FMEM is an alternate system strategy in the PCM designed to maintain vehicle operation should one or more sensor inputs fail.

When a sensor input is perceived to be out-of-limits by the PCM, an alternative strategy will be initiated.

The PCM will substitute a fixed in-limit sensor value and will continue to monitor the faulty sensor input. If the faulty sensor operates within limits, the PCM will return to the normal engine running strategy.

Engine Running DTC 98 or 998 will be displayed when FMEM is in effect.

The Malfunction Indicator Lamp (MIL)/Message will remain on when FMEM is in effect..."

so, "sensor inputs fail"; address the MAP first... then see what's up

or;

98 - That would probably be an EPC circuit failure. If this circuit fails line pressure should go to full at all times. The full line pressure puts a good deal of extra load on the engine, and will usually effect the idle. It is especially noticeable if your engine is already in need of a tuneup. You will need to check the electronic pressure control solenoid and its wiring. Either of these could be causing the EPC code...

Open circuit causes maximum EPC pressure, harsh engagements and shifts.

EPC Solenoid/WIRING OR MAP SENSOR

 

miesk5

96 Bronco 5.0
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here ya go!

MAP/BP Sensor Testing w/ DVOM!

UPDATE

The most accurate way to test this sensor is to measure output using a DVOM (digital volt-ohm meter). In this case the meter must have a frequency measuring ability.

Wonder if autozone has this in their lend proggie?

Or, take it to an auto electric shop in area.

 
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BroncoJoe19

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here ya go!MAP/BP Sensor Testing w/ DVOM!

UPDATE

The most accurate way to test this sensor is to measure output using a DVOM (digital volt-ohm meter). In this case the meter must have a frequency measuring ability.

Wonder if autozone has this in their lend proggie?

Or, take it to an auto electric shop in area.
My Haynes manual states that there are two types of MAPs early ones are voltage varying type and later frequency varying type. They list a testing method for each. Ones uses a volt meter, or tach depending, and a vacuum pump to pull 20mm Hg.

SO I guess at the least I will have to get a vacuum pump, and hope that I have an earlier model MAP :) /emoticons/[email protected] 2x" width="20" height="20" />

 

BroncoJoe19

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Miesk5,

Thanks once again!!!

I hurried up and did a quick check of the MAP sensor, and I have 4.99 volts to it. 4-6 is accceptable.

Unfortunately it seems that I have the variable frequency type, and I don't have a tach to test it.

Just for the hell of it I threw my old MAP back in to see if it was the variable voltage type, and it was not. For the heck of it I decided to start her up. The CEL was out!

I warmed her up and pulled codes, and got a pass both KOEO and KOER!!!

I don't have time to test drive her, but sitting here scratching my head.

joe

 

miesk5

96 Bronco 5.0
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MAN!

well that's great!.. the No Code thAng... and now, I'm here scratchin' my _____ (edited by miesk5)

and some of these parts stores ... I give up sometimes and walk out w/stuff on da counter... last time was about a month ago when the guy who was prob my age told me emphatically and loudly and smiking that my 96 does Not have 4wABS... he told the entire store that I should buy a Haynes and study it so I can get da right parts next time.

I'd buy the electr stuff from Ford... never from da Zone,, esp da Zone!

anyway, GL!

 

BroncoJoe19

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MAN!well that's great!.. the No Code thAng... and now, I'm here scratchin' my _____ (edited by miesk5)

and some of these parts stores ... I give up sometimes and walk out w/stuff on da counter... last time was about a month ago when the guy who was prob my age told me emphatically and loudly and smiking that my 96 does Not have 4wABS... he told the entire store that I should buy a Haynes and study it so I can get da right parts next time.

I'd buy the electr stuff from Ford... never from da Zone,, esp da Zone!

anyway, GL!
I'm here scratchin' my _____ (edited by miesk5)

LOL... that's funny :) /emoticons/[email protected] 2x" width="20" height="20" />

You really pointed me in the right direction to go after the MAP FIRST!!!

I appreaciate it. Can't wait to get home to give her a little test drive.

Yeah, its a little frustrating dealing with people behind the counter sometimes. Especially those know it all types. Little does that knucklehead know that when the Haynes manual doesn't give enough information, that's when people come to you!

Oh well... I appreciate you my friend :) /emoticons/[email protected] 2x" width="20" height="20" />

joe

 

BroncoJoe19

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OK... so I got home and took her for a test drive. She started right up and I drove her a couple of miles up and down a hill, and in and out of a parking lot. No CEL, but she just wasn't quite right. THen I pulled into the driveway, and shifted her into park, and the CEL flashed! I put her in drive and the CEL flashed. I put her in 2nd, and the CEL flashed. Back into park, and the CEL flashed. Whaaat is going on?

OK.. I guess I'll pull codes and see what I get.

SO I go to my workbench expecting to find my little 4" piece of wire. but instead grabbed my 6 inch one. I popped my hood so I could set the jumper to pull codes, and there was my 4" piece, still connected!

I pulled that bugger out, and took her for a ride. No more flash of the CEL when I shifted gears, proper throttle response, no stuttering idle, or stalling.

Good as NEW! :) /emoticons/[email protected] 2x" width="20" height="20" /> Hey... and I still have a full head of hair!!! :) /emoticons/[email protected] 2x" width="20" height="20" />

Miesk5 thanks again for all the help!

Happy Father's day to ya,

joe

 

Lonnie's 88custom

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OK... so I got home and took her for a test drive. She started right up and I drove her a couple of miles up and down a hill, and in and out of a parking lot. No CEL, but she just wasn't quite right. THen I pulled into the driveway, and shifted her into park, and the CEL flashed! I put her in drive and the CEL flashed. I put her in 2nd, and the CEL flashed. Back into park, and the CEL flashed. Whaaat is going on?
OK.. I guess I'll pull codes and see what I get.

SO I go to my workbench expecting to find my little 4" piece of wire. but instead grabbed my 6 inch one. I popped my hood so I could set the jumper to pull codes, and there was my 4" piece, still connected!

I pulled that bugger out, and took her for a ride. No more flash of the CEL when I shifted gears, proper throttle response, no stuttering idle, or stalling.

Good as NEW! :) /emoticons/[email protected] 2x" width="20" height="20" /> Hey... and I still have a full head of hair!!! :) /emoticons/[email protected] 2x" width="20" height="20" />

Miesk5 thanks again for all the help!

Happy Father's day to ya,

joe
Joe,

That is a great story. I actually caught myself doing the same thing just as I was closing the hood after pulling codes. I have made it a habit now to place the connectors back into their little cover when I'm done so I don't forget the wire. I'm still curious though, it sounds like you just put your old MAP sensor in and it worked? Let me know. LOL> great story.

Lonnie

B)

 

BroncoJoe19

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Hi Lonnie,

Yeah, I put the old one in and it worked!

The truck had an intermittent problem, and when it finally threw a code it was a MAP code. I didn't have the ability to test it, so I just replaced it, and the truck ran fine.

So it seems that I have a problem that is causing MAP sensor inoperability and codes, but it gets fixed when I probe the connection, replace the MAP and disconect and reconnect the vacuum line.

I'll take a close look at the connection, use some CRC electronic contact cleaner on it, and then a little dielectric grease. I'm pretty sure I had done that in Jan when I originally replaced it. Also... I spend a little more time looking for a slight vacuum leak, and this time check to make sure that the line is not partially clogged.

Knowing how to pull codes, and getting a little help from my friends let me fix her in a matter of minutes, and for free! otherwise it could have been down for weeks.

At any rate, I put 120 miles on her today, in and out of the woods.

Had a great time!

:) /emoticons/[email protected] 2x" width="20" height="20" />

 

Lonnie's 88custom

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120 miles. Nice. I've got a bit of work to do before I get to where I can trust mine to go that far. LOL. That goes to show you how sensitive the EEC system can be. That is the reason I keep all of my old parts. The wife doesn't understand it yet, but this story will help. LOL.

Later.

Lonnie

B)

 
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BroncoJoe19

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120 miles. Nice. I've got a bit of work to do before I get to where I can trust mine to go that far. LOL. That goes to show you how sensitive the EEC system can be. That is the reason I keep all of my old parts. The wife doesn't understand it yet, but this story will help. LOL.
Later.

Lonnie

B)
LOL... I just renewed my AAA Plus membership allows a tow up to 100 miles!

Overall, she's been pretty darn dependable. I hope you get your's to the point that you have full confidence in her.

BTW, I do throw out old parts that I *know* are bad. As far as the MAP sensor went, I wasn't sure, cause I had no way to test it, and the bronco had an intermittant problem, so when she ran fine with the new replacement, I didn't know for sure if it would hold up, or if it was just one of those times that the truck ran well. Now it appears that it was the latter.

I'm confident that I will nail this down.

joe

 

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