Just for clarification, are you saying that there's a programmed delay event that happens with the EGR valve when the throttle is opened ????

That's not how my truck operates.

As soon as my throttle is opened, the EGR valve starts to open.

I do have, and have used a vacuum delay valve in the vacuum line going to the EGR valve that has "masked" most of my stumble problem.
My "mechanical" vacuum delay valve supports your "The EGR is activated at cruise once the computer detects a part throttle load at speed" statement.

And we all have to remember this.
The trucks we're discussing with the missing, stumble or whatever descriptive term you'd like to use, are MAP systems.
The air/fuel ratio is measured/adjusted AFTER the combustion event (lean air/fuel mixture) happens.

A MAF system measures airflow PRE-COMBUSTION.

An EGR valve that opens too much (in a MAP system) due to an O2 sensor/system that's not working correctly, ie. failing capacitor(s) causing spikey noise etc., can cause a stumble (lean condition), that will be adjusted by the EEC after the combustion "event" happens.

If you put all of these things together, it would explain why the classic "EGR restrictor plate" band-aid repair works.

A little too word intensive, but............hope you get my point.


Bob

 

I am not trying to be testy in any way here , you guys are helping me in a great way and I appreciate all your time regarding this , but I will say this regarding the Capacitors on the ECM .
It seems some are in reality down playing this issue , after looking at the pics of that ECM's board no one should down play this in any way .
Sure Capacitors are used to filter , but does everyone understand why ?
Filtering is a broad term regarding electronic circuits , I think Stabilize or Regulate would be a better way of explaining their importance .
If the intended purpose of the component in the circuit fails or the value changes due to leakage it can change every aspect of the operation of the Processor based computer control , every aspect , noise sounds simple and not a big deal , but noise to electronically controlled or Processor based controls is really translated most times to AC and or Frequency based stabilization , one bad Capacitor can change the regulated voltage for a computer based control , once you change that voltage then every spec that control is designed to monitor and or control changes , this could be in relation to a single function or could be responsible for a chain of functions , like the one pic someone else posted of the metal can type surface mounted capacitor , seeing it is at the base of the Crystal that maintains the clock frequency of the processor , this means if that one cap is failing , out of spec regarding value , this can and will change the stability of the clock for the processor and or change the clock frequency , when this happens , then all functions , all values , ALL TASKS that this entire module controls and or monitors WILL CHANGE , EVERY ASPECT OF ALL FUNCTIONS !
One capacitor can wreck the entire operation of a computer based , processor based control module whether it be from voltage regulation , frequency control and stabilization and or even a single function / circuit that is operating out of spec that the module uses as a benchmark for monitoring and controlling .
And then we get to the leakage part , outside of the fact that leakage will affect the value of the capacitor as well as it rated voltage , which can and will in many cases lead to the capacitor rupturing and or exploding in higher voltage and or current applications , it can even explode at 12V , though the explosion per say is not dangerous , it is the oil in the cap that is the issue getting all over the board , a capacitor leaking in most cases is leading to rupture though again it can be the manufacturing process like anything else that eventually leads to this , I digress , so when the capacitor leaks , especially these older ones which have the PCB based oil in them , yes even if they are paper types they still have the oil , this oil is caustic , it will create traces of build up from the chemical action between it and whatever it touches ( just like acid on metal for example , though not quite that extreme ) , when this build up and or the oil itself crosses traces on the PCB , it cause a capacitive effect and or will outright eat the coating off the board and begin to conduct , once again , this can change every value , every function , every benchmark clock frequency in the entire module .
So while I understand that many go for years and never fail this does not mean it will not fail , I do not care what manufacturer makes it , there are hundreds of minute defects in manufacturing , this is why we are all here on this forum , how many have put in a new part and had it be bad , how many have put in a new part and had it last a month , and then again how many still have original equipment that is running great for 30 years or even more ?
This is everywhere and in everything , the thing that changes when you are using computer based controls is literally one little component can change the entire design specs and operation of any module or system , it could be a weak diode , a bad electrolytic , a bad ceramic disk capacitor , one bad cold solder joint , a weak switching transistor , a crack trace , or bad/weak voltage regulating transistor , just one little tiny component could change all behavior and design specs of a module .
I am not defending anyone or taking any sides here but this is an issue on newer modules as well , harmonics can shut down a processor based module , harmonics are a totally diff animal regarding clock operation for processors and again one tiny little component can cause it and create a problem no one can find , many times because they say , na , it nots that , they rarely go bad , well when something is rare and there may be millions of them , then rare could still equate to thousands if not 10's of thousands of failures , so you have to realize that the thousands of parts the modules are made with all have the same chance to fail , and one of them failing could cause the entire module to fail completely and or intermittently , or you can find yourself replacing everything on the car only to finally replace the module and find it was the cause all along , a failure regarding this module could cause it to generate codes , could cause it to report failures and symptoms that are not even present , could cause it to in my case decide not to communicate with the Code Scanner , could cause it to intermittently die like a waning crank or cam sensor or coil would , could even cause it to report everything is fine while there is a serious failure in it or elsewhere , I know they are reliable for the most part , but I have done allot of reading and read many many war stories regarding these modules and in my days turning wrenches I have replaced many a ECM on Fords , GM's , Chrysler's etc etc .
I understand we have to exhaust all possibilities , but many times we cause ourselves a ton of problems saying , na , that's never is the problem , when in reality that is the furthest from the truth

Ok Preach over

I am now going to remove my ECM , will report back later if I see anything that raises concern .
Also does anyone know of anyone that can bench check these ECM's ?

 

I'm saying the computer opens the EGR valve when it detects part throttle relatively steady load.
The computer fuels based on load and calculated air flow. With a MAF based system, the computer gets a direct air flow reading, then calculates load. With a SD/MAP system, the computer gets a direct reading of load, and calculates air flow based on known engine volumetric efficiency. They both end up in the same place.

The O2 sensor compensates for the variability in cheap, mass produced sensors, as well as gradual engine wear and sensor deterioration.
An over enthusiastic EGR valve in an SD system would cause a rich condition, not lean. There would be less manifold vacuum - causing the computer to think the engine is under more load and there would be less available air. Thus rich.

The EGR valve can't open too much without setting a code. The computer uses a feed-back loop with the EGR position sensor. The EVR solenoid is variable, it can have a duty cycle of 0-100% and the computer will change the duty cycle to maintain a set EGR valve position.

If you want some good reading, check this out: http://www.myo-p.com/Ford-EEC/EEC%20...Files/GFUB.pdf
It's a document from Ford detailing the entire operation of nearly every component and feature of an older EEC-IV. It's filled with tons of technical jargon, but you should be able to get the gist of what it's talking about.

 

Now this is interesting , because I can actually feel the difference in truck when EGR is opening and closing , it is very present and dramatic , this being said , could you provide me with links or further info on the vacuum delay part I would use and also the restrictor plate mod , I need this , it is not a big problem but is surely present in this motor .

Thanks

 

The computer fuels based on load and calculated air flow. With a MAF based system, the computer gets a direct air flow reading, then calculates load. With a SD/MAP system, the computer gets a direct reading of load, and calculates air flow based on known engine volumetric efficiency. They both end up in the same place.
Yes, true, but what if the Known engine volumetric effiency has been compromised by an over enthusiastic EGR valve or a vacuum leak???? Lean Stumble ???

The O2 sensor compensates for the variability in cheap, mass produced sensors, as well as gradual engine wear and sensor deterioration.
I've got to disagree with you on that statement, An O2 sensor is JUST a sensor that ONLY reads what it is presented with in the environment it's placed in. There is NO built in circuitry in an O2 sensor that compensates for wear or deterioration, it's just a sensor.

An over enthusiastic EGR valve in an SD system would cause a rich condition, not lean. There would be less manifold vacuum - causing the computer to think the engine is under more load and there would be less available air. Thus rich.
O.K. then why is it when an EGR valve is opened at idle, the engine will start running rough and die ??? Is that a "rich condition" ???

The EGR valve can't open too much without setting a code.
That's true, but what we're discussing is an EGR valve opening enough to cause a lean stumble. The egr valve doesn't have to open fully to cause a "lean stumble" condition.......thus no codes.

The computer uses a feed-back loop with the EGR position sensor. The EVR solenoid is variable, it can have a duty cycle of 0-100% and the computer will change the duty cycle to maintain a set EGR valve position.
Yes, true again, but, if the computer is recieving a corrupt signal (because of a capacitor failing/failure) in the "feed-back loop", wouldn't the computer try and adjust to the corrupt signal ?????? i.e. O2 circuit with failing capacitors you refered to in a previous post ???

If you want some good reading, check this out: http://www.myo-p.com/Ford-EEC/EEC%20...Files/GFUB.pdf
It's a document from Ford detailing the entire operation of nearly every component and feature of an older EEC-IV. It's filled with tons of technical jargon, but you should be able to get the gist of what it's talking about

Thank you for the link. I'll give it a read here pretty soon.
I do ENJOY understanding how electronic things operate and function.
Perhaps that's why the profession I've chosen involves repair and servicing of electronic office equipment...... for the last 24 years.

Your turn !!!

Bob

 

Well, the vacuum delay valve was purchased from an independent (non-franchise) auto parts store.
It's either a one or a two second delay valve that is used primarily in/with a vacuum style distributor.

The "EGR RESTRICTOR PLATE" is well documented on this site.
My version is a 7/8 inch o.d. fender washer with a 1/8 inch hole, that is slipped in between the EGR valve and the tube nut.
Others have fabricated "plates" that are placed in between the EGR valve and the upper plenum.

Either way works, but as far as I'm concerned, a fender washer is much simpler and easier to deal with.........that is if you don't have trouble loosening the tube nut that bolts up to the EGR valve.

Search this site for "EGR RESTRICTOR PLATE" and do some reading.

Get the EEC pulled out yet ????

Bob

 

I had one heck of a time getting that nut off when I replaced the EGR Valve , I thought I was going to snap the valve casting in half at the upper intake LOL , but I finally got it to budge and then upon replacement I coated it heavily with anti-seize compound for plugs , so in the future it should be a piece of cake to remove , Thanks for that info

Guy

 

Ok , first off , what a piece of cake removing the ECM , Ford gained many points for that , took me all of 10 minutes including disconnecting battery and getting tools .

Got it out and opened her up ( DRUM ROLL LOL ) .
It has one ruptured Capacitor , it is located in the what would be the Processor Clock and or RAM area.
I am going to get on the phone now and talk with my friends at the Motorola Service Center near here I used to work with and see if they have the Caps in stock , theirs would be very high quality , so I am going to try to do that now , also I see this Cap is only rated at 16V , in my opinion that may be why the early death so to speak , that is too low considering many vehicles can routinely approach high 14V and even into the 15's normally when charging or helping under load .
I will shoot for at least 18V but would rather see a 25V to make sure my son will not have this problem after I am dead LOL .
The board was not affected , this PCB has a beautiful coating on it that protected it , the coating in this case was applied after assy and if I am right I believe this coating would also act as waterproofing , another point for Ford , at least they did not encapsulate it in epoxy !
I will replace all 3 electrolytic caps , even thought the other 2 look fine , I might as well update them all .
Also in considering this beautiful coating that I do not want to compromise , I will be cutting the legs of the caps off at the bottom of the caps with some precision nippers so that I will be able to solder the new ones in attaching them to the legs of the old ones , this way I do not compromise the coating .

Sorry I took so long but my wife interrupted me with bacon, egg and cheese sandwiches which were just short of ecstasy

I will have to replace and then reinstall and see if I have communication back with scanner , and then I will be able to further check with a road test if this is my intermittent problem as well

Got to get on the phone fast , will let you know how it goes as it goes

Thankyou again to everyone , all this discussion has really helped me in allot of ways , you guys are great

Guy

 

Anti-seize is your friend on that tube nut.

Bob

P.S. Thanks for signing off as "Guy"......much easier to refer to than n4nu1010

 

And Guy........, this discussion has helped a HUGE number of us out here.

Your persistance and electronics knowledge has,for the most part, changed some of the attitudes regarding EEC's and their failures.

A great big thumbs up to you !!!!!

Keep the updates coming,

Bob

 

The NTE VHT series of aluminum electrolytic capacitors is designed for use in automotive, commercial, and industrial applications. These high temperature, radial lead capacitors are especially suitable for applications that require extended life and higher temperature operation.

• Capacity: 47μf
• Voltage: 25V
• Tolerance: ±20%
• Operating temperature range: -40°F to +220.9°F
• Leakage current: I ≤ 0.01CV + 3μA
• Capacitance tolerance (M): ±20% measured at +68°F
• Load life: 1000 hours @ +220.9°F
• Lead solderability: Meets the requirements of MIL-STD 202, Method 208
  
  
  Ok , had to order these from Radio Shack , went with this Black Version as it has a higher temp rating than the Blue Version , Blue Version is 185*F and this version is rated at over 220*F , thats a tough puppy right there lol .
  The specs shown are for the 47uf Cap , as you can see , went with 25V here , was going to go with 35V but the diameter of the capacitor got substantially larger as the voltage increased , this larger diameter would not have been an issue but 25V is more that sufficient in this case , this one is actually the very same size as the original .
  There was not a available increase in voltage rating for the 10uf 63V , there actually was but it was 160V and that is too far a jump though it would have worked most likely , some capacitors do have working voltage ranges which are generally very wide , but raising the rating 100V is too much of a jump for me , I was hoping for a 75V but there was not any except 160V and up and this particular capacitor is located in a tight spot so really not any room for increased size .
  They did have the exact replacement 10uf 63V so I just got that one , the 10uf 63V is not leaking anyway , but since I am going thru this , it makes little sense not to replace them all .
• Tech Specs <table name="prods" border="0" cellpadding="2" cellspacing="0" width="500"><tbody><tr> <td colspan="4" height="25" nowrap="nowrap" width="250">Dimensions</td> </tr> <tr> <td colspan="4" bgcolor="black" height="1" nowrap="nowrap">
  </td> </tr> <tr><td bgcolor="#F5F5F5" valign="top" width="250">Product Length </td><td width="5">
  </td><td valign="top" width="500">11 millimeters </td> <td width="50">
  </td> </tr> <tr> <td colspan="4" height="1"> <table border="0" cellpadding="0" cellspacing="0" width="745"> <tbody><tr> <td>
  </td> </tr> </tbody></table> </td> </tr> <tr><td bgcolor="#F5F5F5" valign="top" width="250">Product Diameter </td><td width="5">
  </td><td valign="top" width="500">6 millimeters </td> <td width="50">
  </td> </tr> <tr> <td colspan="4" height="1"> <table border="0" cellpadding="0" cellspacing="0" width="745"> <tbody><tr> <td>
  </td> </tr> </tbody></table> </td> </tr> <tr> <td colspan="4" height="25" nowrap="nowrap" width="250">General Features</td> </tr> <tr> <td colspan="4" bgcolor="black" height="1" nowrap="nowrap">
  </td> </tr> <tr><td bgcolor="#F5F5F5" valign="top" width="250">Model </td><td width="5">
  </td><td valign="top" width="500">VHT47M25 </td> <td width="50">
  </td> </tr> <tr> <td colspan="4" height="1"> <table border="0" cellpadding="0" cellspacing="0" width="745"> <tbody><tr> <td>
  </td> </tr> </tbody></table> </td> </tr> <tr><td bgcolor="#F5F5F5" valign="top" width="250">Product Type </td><td width="5">
  </td><td valign="top" width="500">Electrolytic capacitors </td></tr></tbody></table>
  The original capacitors in the Module are Blue yet they are of nice quality as they too are rated @ 220*F .
  So the only thing that is different regarding the 47uf Caps is the Voltage rating which is 25V instead of 16V , this will have no effect on function , at best it will extend the life considerably .
  Also these Black types are specifically made for industrial and automotive extreme use applications ( ie - high temp / extreme conditions ) .
  
  I had to order them , I was really hoping to have a answer for me and everyone today but that is not going to happen , once I get them , it will take a hour or so to get them in , and in the meantime I will find a suitable sealer I can use so when they are soldered back in I can cote the legs and the base of the new caps to replace the moisture protection , I believe I already have something that will work that I used on marine equipment repairs for the same purpose , may not be the same but as long as it has di-electric properties and will seal out water and moisture then it will be fine .
  So will wait for them to get here , install , and then plug it back in and try to check codes first , if that works then I will know I have accomplished something , then a road test and re-check codes , seeing it has been dis-connected it should not be storing codes anyway before I drive , this way I can see it is communicating , take for test drive and see if I have the stumble and hesitation , and then either way come home and re-check for codes .
  Going to be a few days for the parts to get here , I will be anxiously waiting for them , am hoping this will solve my ghost problem .
  
  Guy

 

Don't forget to drive it around 20-25 miles so the EEC can re-learn it's "NEW" self.

Bob

 

Definitely sounds quicker/easier then the 92 ^ models, they slide out to the front side need to undue the inner fender pry forward out of the way to get the box clear of the slot. Did it with my 94 as was not concern with fender/paint not in a hurry do it to my 95 though as that would be a concern, sounds like they should have stayed with original idea. Mounted up higher in the trunk wouldn't been a bad idea either. In my younger day had 78 in mud/water regularly that woulda put a computer mounted in such location well below the water line.
Not real hard to get it out no just gotta get into and do things shouldn't need to do what should be a simple task, remove a computer.

Yea be interesting see what effects it had, what changes seen replacing the capacitor. If restores communication between it and your reader and corrects running issues, time will tell on that one and yea I'll be watching/waiting for results.

Then the question what caused the demise of the cap, age alone or some outside force? No way to know at this point, say someone connected jumper cables back words for example might have fried it time/hot/cold had nothing to do with it. Might be as you suggested rated at 16v not enough "head room" power spike from a faulty VR done it in at some point.

You stated it sat for near 5 years but didn't see where you might have stated more about its history, as in previous owner allowed it to sit for all that time then you bought it? If so might be reason it sat, say gave it a jump one day from that point on it didn't run right all attempts figure out why failed so parked it. Neither here nor there at this point its damaged and that's all that really matters in the end.

I've changed capacitors on a motherboard (desktop computer) did it see if I could fix it. It had no video (onboard video) and it was one of the boards suffered from them china whatever caps many computers of its vintage did.
I replaced that caps on it that leaked and it restored video, old board if I was successful or not didn't matter. I practiced on a couple of add on cards first, think one was a NIC. I removed a cap installed the card in a computer verify it didn't work then put the cap back on, tested again see if card functioned. IIRC it was 99cents for a ten cap sack, the board needed 6 of them.

Edit: almost forgot to include reason mentioned that start with, one of the cards I used for testing I removed one of the caps put in back in a computer to verify it didn't work, so I'd know if my soldering it back on made it work/I was successful or not. Well wouldn't ya know it it worked with that cap removed! I threw it away got out another one to use as guinea pig!

All that was practice for the real work I needed done, wife's car (see sig) It was model included in that GM stepper motor snafu, gauges failing. And yes sure enough shortly after buying it her speedo quit working, I ordered the new updated motors and practiced on that other junk had laying around waiting for them to arrive.
Picked up a small solder pencil, solder tape and of course the correct solder required, couldn't very well use the solder I use to sweat pipe together with now could I LOL! All cheap even the motors weren't bad, 38 bucks for the 6 and they included fresh LED bulbs and few inches of solder. I didn't do the bulbs, they work so wasn't getting into that not until one day I might have too!

Good idea clipping and leaving the legs soldered in, then attaching new to them instead of completely removing from the board. By the sounds of it comments you made you probably already have one, I wouldn't do it again without a solder vac. Solder tape does work its just not ideal IMO for the task, takes to much time/heat to get all the solder out of the board clearing the holes. Couple of them I used the appropriate size drill bit to clear the hole after removing the motor, tad hesitant with the heat unknown to me exactly how much the board would and could take. Drill bit cleaned the holes that tended to solder over after removal of motor nicely. Motor fits down tight to board, pins on the body indexing it in place so wouldn't have been able to do the clip leg trick on those.

I have couple of B2 computers right handy here where in service up to oh lets see couple three years ago or so now one of them been longer then that. I opened them up see how they looked, they both look like brand new inside yet. Both are 1988 IIRC, one for auto one for manual trans models.

 

Also , wanted to add this , the leak of this particular cap did not damage PCB , but what it has done is ruptured , leaked and puddled at the base of the capacitor coating and covering both of the radial leads going to PCB , at the very least this is creating additional capacitive effect by the leakage effectively shorting out the radial leads at the base of the capacitor , it is not like a short you would expect from water so to speak , more so like a resistive short , or if the di-electric properties of the liquid are still somewhat intact ( which I kinda doubt since it is burnt and looks like Indian Head Gasket Cement ) then this would still add a serious capacitive effect changing the value of the cap dramatically , the rupturing and leaking alone have already done that , the puddle at the base only complicates the problem yet even more .

Guy

 

Yeah solder wick is worthless on most newer PCB boards , you can bake the board and traces will start lifting and such , allot of the newer PCB's are layered as well which makes service with primitive tools very destructive , the vacs are nice but still the same problem , allot of heat , depending on the frailty of the board , many time I will heat and blow it out or shake it out , if I am doing processors I will cut the legs with my surgical nippers and address one at a time , when I use to work in the shops we had the cool tools , you could de-solder chips in one shot , it was awesome .
Always use rosin core , lead free solder , the lead in the solder is what causes many issues with cold solder joints , some people use Acid core not knowing that when they are done that moisture and humidity will continue to activate acid and corrode the solder joint and actually eat the legs off of components , I have a special soldering iron , has interchangeable tips , for different applications , I can solder two battery cables together or I can solder sub-miniature components or wiring the size of a human hair .

I really believe the failure of the caps to be Voltage Related in this case , jumping the car would have no effect on these components , too much protection with diodes and such , it would have opened one of them and just shut down long before it ruptured the cap , 16V rating with most cars operating very close to 15V or a tad over , it is just not enough , way to close for comfort in may opinion , but then we do not know what the actual regulated voltage for that circuit is either .
Many times they do this because they have reached the end of their use , the di-electric begins to fail and the capacitor become a power resistor , gets hot and pukes and or ruptures , I may still end up replacing ECM in the end , but we will see , most of these modules have built in safegaurds and or are designed so that the failure of one component will not roast the rest , so I will wait and see , but I am more than optimistic , if I had found nothing I still would have replaced it regarding the on and off communication issue , I surely hope this will rectify the issue , we will all know in a few days .

Guy