1990 f150 4.9 300-6 cyl laggy
#31
08-06-2012, 09:01 PM
#32
08-07-2012, 04:44 PM
Elder User
i really appreciate all teh help guys, ive been very busy as of lately, and finally got into teh truck engine saturday, though i didnt crack open the computer and the auto parts store tested my ECM and said it was good., i went after the other part that came up on the computer scan, the MAP , it got replaced ,as well as teh coolant sensor, the mass air sensor, and new plugs and thermostat. oh yeah, a few weeks ago teh TPS got replaced too. now heres a kicker. ok, the mystery continues, the truck is running worse.... well was runnign worse. i cant get it to idle at all now. and if you barely touch the pedal itll kill it.. when it was idling saturday night, i found that if I remove the brake booster vacuum line, and cover most of the hole, it idles like nothing is wrong.... so my new question is, "what type of problem is the result of a vacuum leak making an engine run smoother?" could this be the idle air control module??? is there a stupid reason why my engine would needs massive amounts of vacum??? there was ALOT of air sucking from that vacuum, is that normal???? *sigh* this is neverending, im ready to give up... as for me checking hte EGR, i cleaned it, checked teh plunger for wear crakcs, bad rubber, no carbon, put a multimeter on teh sensor and it had no skips or misses on it while pushing and pulling hte needle. so in m yeyes, its not he EGR, especially since the EGR only operates while at running temp, this wont efect a cold enging not starting at all... im not being stubborn about hte computer, i cant imagine finding a new one is even possible.. and my stress levels on this truck is going to kill me. i think everything under the hood should be considered long before the computer comes into question, so ive double checked to pdead center and im positive im in time. had another question? when your at top dead center.... shouldnt the timing mark on the harmonic balancer be at 10 degrees btdc? ive manually rotated teh crack many times and not once did it align at TDC... this sems odd to me, am i crazy??,
Couple of things here.......
I'm still a little confused as to why you still won't even "crack open the computer". It's not a magical, mystilcal thing that you have to avoid like the plague. It's just a COMPUTER.......a circuit board with some electrical parts soldered on to it, period, plain and simple.........
Second thing........your auto parts store DIDN'T check the ECM. The ECM does not have a self-diagnosing ability, they only store information about the sensors and the environment they function in. They scanned it for stored codes.
Your next sentence confirms this: " i went after the other part that came up on the computer scan, the MAP , it got replaced ,as well as teh coolant sensor, the mass air sensor, and new plugs and thermostat."
oh yeah, a few weeks ago teh TPS got replaced too. now heres a kicker. ok, the mystery continues,
Well, I'd say if it's still a "mystery" you might want to take the advise given and "crack open the computer" and see if the computer is bad instead of throwing money at parts that may be working correctly and quite possibly solve the "mystery".
There are remanufactured computers out there for around $ 100-$200 dollars.
I'll bet you have thrown at least that much money into your truck on parts that didn't need replacing and you still have "the mystery continues", right ?????
the truck is running worse....
Yes, it will with new parts untill the computer readjusts to the new parts you keep putting in it.
this is neverending, im ready to give up...
Just take the advise given here and open up the ******* computer and see if there's any visible capacitor leakage or other problems. I'd be willing to bet my left ******** that once you "crack open the computer", you'll see some obvious visual problem.
im not being stubborn about hte computer,
Yes, you are being stubborn about the computer !!!!!!!!
i cant imagine finding a new one is even possible..
Yes, they're out there. A well known parts supplier out there on the internet has a good "ROCK" solid price on 'em for about $ 100-$200 dollars. (think that was subtle enough
)and my stress levels on this truck is going to kill me.
Well, that's your decision if you want to believe that your computer is absolutely infoulable and couldn't possibly ever have or develop a problem.
i think everything under the hood should be considered long before the computer comes into question,
We (everyone that has participated in this discussion) all pretty much agree on that point.
You, after all, started this topic and said " so im at a loss, ive been sratchign my head over this for a month, i need help, please? anyone have any experience?
Well yeah, I have the "experience" of knowing that a failing or failed computer will make a truck run like crap. Mine does !!!!
There's even others that have participated in this topic that have confirmed this same thing.
Why cant you go with this ???????????
It's your choice, keep throwing money and parts and "my stress levels on this truck is going to kill me", or do a zero cost visual inspection which will most likely reveal the reason your truck is running like crap.
That's just my advise.....take it or leave it.
Bob
#33
08-07-2012, 09:34 PM
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ok, your the first and only person i have ever came across tellign me my computer is prolly bad. your persistance in telling me its the cause is rather disturbing, you must always be right. or at least to the point at wich people just stop asking, how many other threads here in the forums have you suggested the computer is the cause to the other peoples problems? I have been working on vehicles my whole life, and I have only had one computer go out in a nissan car... it was 20 years old then. still drove it with a bad module on it... but i guess since my truck is 22 years old its just iem to throw in the towel, remove teh thing ,and crack her open.... dont yhou think that after 20 years, a swelled up and prolly leaking capacitator is going to exist??? i have a 26 inch monitor in fornt of me that had one after 2 years... so im pretty sure there could be an issue there, but I will do what i have always been taught, and that is to make sure that everything in the engine compartment is troubleshooted before i take a guess at a 200 dollar part. and to update my post, thankyou to all teh helpers, you suggestions have been noted and looked over. as for what i have found out, the electronic gizmo that opens and closes my IAC is bad, its not even working, sticks wide open all teh time, allowing way too muc hair into teh engine, thus CHOKING it out. guess the stored codes missed that one. it will be getting a replacement his weekend, small price to pay to keep my truck up and going for another 22 years.
PEACE
PEACE
#34
08-07-2012, 10:17 PM
Guessing is NOT the way to properly diagnose and fix a problem, you should know that.
#35
08-08-2012, 04:30 PM
Elder User
ok, your the first and only person i have ever came across tellign me my computer is prolly bad. your persistance in telling me its the cause is rather disturbing, you must always be right. or at least to the point at wich people just stop asking, how many other threads here in the forums have you suggested the computer is the cause to the other peoples problems? I have been working on vehicles my whole life, and I have only had one computer go out in a nissan car... it was 20 years old then. still drove it with a bad module on it... but i guess since my truck is 22 years old its just iem to throw in the towel, remove teh thing ,and crack her open.... dont yhou think that after 20 years, a swelled up and prolly leaking capacitator is going to exist??? i have a 26 inch monitor in fornt of me that had one after 2 years... so im pretty sure there could be an issue there, but I will do what i have always been taught, and that is to make sure that everything in the engine compartment is troubleshooted before i take a guess at a 200 dollar part. and to update my post, thankyou to all teh helpers, you suggestions have been noted and looked over. as for what i have found out, the electronic gizmo that opens and closes my IAC is bad, its not even working, sticks wide open all teh time, allowing way too muc hair into teh engine, thus CHOKING it out. guess the stored codes missed that one. it will be getting a replacement his weekend, small price to pay to keep my truck up and going for another 22 years.
PEACE
PEACE
I'm not here to engage you in a wizzin' match, but, you've neglected to let us know some important facts (namely history) regarding your on going truck problems.
Way back in September 2011 you had posted this message on the Missouri Chapter Board:
"I have a 1990 f150 with a c6-4.9 300-6 combo. I had the trans rebuilt and the mechanic told me i had a vacuum leak, so i looked over the vacuum diagram, and apparently almost all of my vacuum were in hte wrong places. so i rerouted everything, and now they are where they need to be, I pulled the clip out of the harness next to the distibutor and reset he timing according to the manufacture specs, disconnected the battery and then put it all back together... test drove it, it seriously lacked power at akeoff, so i adjusted the time by ear while it was running... test drove it again but wasnt much beter... is it possible the way the vacuum was before was fine???? or maybe i should keep going with adjusting the distributor by ear???? and what does a bad EGR smell like??? there is a wierd smell coming from the motor... its not mothballs or sulferic, so im sure its not the catylitic converter... , im soo lost right now, if anyone has any ideas, please let me knopw, i read somewhere that blocking off the egr is better..."
Sounds to me like you were smelling the circuit board (in the computer) toasting itself.
All the more reason to "crack it open".
Oh, and one more thing.
You might want to have your alternator checked first. Somewhere out there (I'm not going to go back and search out where it was) you were complaining that you were burning out $ 12.00 light bulbs in your truck.
To me it sounds like the voltage regulator within the alternator was or has failed causing more than 12 volts to go into your electrical system..............maybe toasting the "computer" ??????????
But then again, what do I know.
Bob
#36
08-08-2012, 07:13 PM
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really? that was what 2 - 3 years ago???? I HAD THE TRUCK RUNNING AS SMOOTH AS A TOP IN JULY. I was geting 15-18 mpg with it. I had zero issues with it back in july, maybe the computer gave up and decided behave for a couple years.... am I right??? you must think im fairly ignorant to not know the difference between a clogged cat smell versus a burning electrical smell. the smel lwas neither the egr or the exhaust, it was the transmission, which got rebuilt .
PEACE
How many people in these forums have had computer problems with a 1990-ish models fords with 4.9 300-6 motors? if there was alot of them, then there would be a common issue causing the problem inside the said computers am i wrong? and the problematic computers would cause issues under the hood, so there would be a list of stuff.... id love to see it. and im not talking about just your experience with your computer. that would be nice. If i run out of options and it turns out to be the computer, you can say i told you so, ill post it here just for you that you was right and i was wrong.
PEACE
How many people in these forums have had computer problems with a 1990-ish models fords with 4.9 300-6 motors? if there was alot of them, then there would be a common issue causing the problem inside the said computers am i wrong? and the problematic computers would cause issues under the hood, so there would be a list of stuff.... id love to see it. and im not talking about just your experience with your computer. that would be nice. If i run out of options and it turns out to be the computer, you can say i told you so, ill post it here just for you that you was right and i was wrong.
#37
08-08-2012, 07:19 PM
PEACE
How many people in these forums have had computer problems with a 1990-ish models fords with 4.9 300-6 motors? if there was alot of them, then there would be a common issue causing the problem inside the said computers am i wrong? and the problematic computers would cause issues under the hood, so there would be a list of stuff.... id love to see it. and im not talking about just your experience with your computer. that would be nice. If i run out of options and it turns out to be the computer, you can say i told you so, ill post it here just for you that you was right and i was wrong.[/QUOTE]
It's not about right or wrong , you asked for help he (we) offered compelling information that pointed to a (inspection) of the PCM . To me there is a disconnect here I'm sorry you're frustrated if you were local I'd shoot by and give you a had , after all that's why we are on this forum ; to ask for help and offer assistance when we can ....
How many people in these forums have had computer problems with a 1990-ish models fords with 4.9 300-6 motors? if there was alot of them, then there would be a common issue causing the problem inside the said computers am i wrong? and the problematic computers would cause issues under the hood, so there would be a list of stuff.... id love to see it. and im not talking about just your experience with your computer. that would be nice. If i run out of options and it turns out to be the computer, you can say i told you so, ill post it here just for you that you was right and i was wrong.[/QUOTE]
It's not about right or wrong , you asked for help he (we) offered compelling information that pointed to a (inspection) of the PCM . To me there is a disconnect here I'm sorry you're frustrated if you were local I'd shoot by and give you a had , after all that's why we are on this forum ; to ask for help and offer assistance when we can ....
#38
08-08-2012, 07:28 PM
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thankyou twisted, i guess i am getting a bit upset, and its stupid i know... if it comes to the computer, il lgladly open it, but not until i know all the cheaper stuff isnt bad. im not afraid to replace parts cuz i cant afford payments on anything else right now, or prolly anytime soon. so, if its 35-80 bucks here or there, it would benefit me to change them first. at least hen, i would know for sure that those parts have been troubleshooted and changed if needed.
i appreciate the help guys, i really do... im sorry for geting upset.
SALUTE
i appreciate the help guys, i really do... im sorry for geting upset.
SALUTE
#39
08-09-2012, 10:54 AM
Elder User
It's not about right or wrong , you asked for help he (we) offered compelling information that pointed to a (inspection) of the PCM . To me there is a disconnect here I'm sorry you're frustrated if you were local I'd shoot by and give you a had , after all that's why we are on this forum ; to ask for help and offer assistance when we can ....
I'm going to back off from this topic and let it play itself out.
Sometimes you just have to walk away.
Suburban B Gone and Twistedwrench please let ALL of us know what your outcome was with either repairing or replacing your computers.
After all, as of right now, there are almost 800 views about this topic.
It'll be important information that others can use.
Bob
#40
08-09-2012, 11:26 AM
#41
08-10-2012, 02:16 PM
Elder User
Well, taking my own advise about posting "important information that others can use", I spent a little bit of time revisiting my computer last night.
I was having a problem with the EGR valve functioning while the engine was cold.
I found what I think were a couple of problems and corrected them.
First, one of the tantalium (I believe to be) capacitors legs was bent in such a way that it was contacting other circuitry on the board. I'm pretty sure the coating that was used to coat the circuit board during manufacturing would insulate any stray current or voltages, but none the less, I re-positioned that capacitor just to be sure.
Second, I did another visual inspection (under magnification this time) while back lighting the circuit board and found a very tiny solder bridge to a neighboring circuit that I created when I did my first repair. It was easy to correct, just a little scuff with a needle to pop off the bridge.
I did some pin-out checking and verified good connections then re-installed it back in my truck. As per my Haynes manual, I checked the coolant temp sensor and the air temp sensor and voltages, (to verify they and the temperature circuit were working correctly) which passed, then started the truck.
Viola' the EGR valve DIDN'T open while engine was cold.
After the truck warmed up a bit, the EGR valve started functioning like it's suppose to.
Because it was getting late in the evening, I didn't get a chance to drive my truck around for the computer to re-learn itself.
I'll do that this weekend.
So, hopefully I found my "cure".
More to come.
Bob
I was having a problem with the EGR valve functioning while the engine was cold.
I found what I think were a couple of problems and corrected them.
First, one of the tantalium (I believe to be) capacitors legs was bent in such a way that it was contacting other circuitry on the board. I'm pretty sure the coating that was used to coat the circuit board during manufacturing would insulate any stray current or voltages, but none the less, I re-positioned that capacitor just to be sure.
Second, I did another visual inspection (under magnification this time) while back lighting the circuit board and found a very tiny solder bridge to a neighboring circuit that I created when I did my first repair. It was easy to correct, just a little scuff with a needle to pop off the bridge.
I did some pin-out checking and verified good connections then re-installed it back in my truck. As per my Haynes manual, I checked the coolant temp sensor and the air temp sensor and voltages, (to verify they and the temperature circuit were working correctly) which passed, then started the truck.
Viola' the EGR valve DIDN'T open while engine was cold.
After the truck warmed up a bit, the EGR valve started functioning like it's suppose to.
Because it was getting late in the evening, I didn't get a chance to drive my truck around for the computer to re-learn itself.
I'll do that this weekend.
So, hopefully I found my "cure".
More to come.
Bob
#42
08-13-2012, 09:29 PM
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Success: Repair Complete
I could not repair the damage on my F150's ECU. So, I began the search for the correct replacement. I found, and purchased a used rebuilt unit on ePay for less than $50.
Tonight, I inspected the unit. The capacitors had been previously replaced, and epoxy applied around the repair sights. I suspect that this was the rebuilding process.
In less than 30 minutes, I had my old unit out and the new unit ready to power up, and test. SUCCESS. My nonstop fuel prime problem, my hard start problem, and my intermittent cut out while driving problem were all gone during a 25 mile test drive.
I struggled with this for over a year. Now, I am quite satisfied with my truck again. I am glad this arduous journey is finally over.
Thank you, again, for pointing me in the right direction.
Truckin Bob, Reps sent!
.
Tonight, I inspected the unit. The capacitors had been previously replaced, and epoxy applied around the repair sights. I suspect that this was the rebuilding process.
In less than 30 minutes, I had my old unit out and the new unit ready to power up, and test. SUCCESS. My nonstop fuel prime problem, my hard start problem, and my intermittent cut out while driving problem were all gone during a 25 mile test drive.
I struggled with this for over a year. Now, I am quite satisfied with my truck again. I am glad this arduous journey is finally over.
Thank you, again, for pointing me in the right direction.
Truckin Bob, Reps sent!
.
#43
08-14-2012, 11:50 AM
Elder User
I could not repair the damage on my F150's ECU. So, I began the search for the correct replacement. I found, and purchased a used rebuilt unit on ePay for less than $50.
Tonight, I inspected the unit. The capacitors had been previously replaced, and epoxy applied around the repair sights. I suspect that this was the rebuilding process.
In less than 30 minutes, I had my old unit out and the new unit ready to power up, and test. SUCCESS. My nonstop fuel prime problem, my hard start problem, and my intermittent cut out while driving problem were all gone during a 25 mile test drive.
I struggled with this for over a year. Now, I am quite satisfied with my truck again. I am glad this arduous journey is finally over.
Thank you, again, for pointing me in the right direction.
Truckin Bob, Reps sent!
.
Tonight, I inspected the unit. The capacitors had been previously replaced, and epoxy applied around the repair sights. I suspect that this was the rebuilding process.
In less than 30 minutes, I had my old unit out and the new unit ready to power up, and test. SUCCESS. My nonstop fuel prime problem, my hard start problem, and my intermittent cut out while driving problem were all gone during a 25 mile test drive.
I struggled with this for over a year. Now, I am quite satisfied with my truck again. I am glad this arduous journey is finally over.
Thank you, again, for pointing me in the right direction.
Truckin Bob, Reps sent!
.
I too am glad your "arduous journey is finally over".
Nothing better than to have your truck back.
Good on you Suburban_B_Gone on sooo many levels.
Life just got a little better, didn't it ???
Bob
#44
08-14-2012, 01:26 PM
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It certainly did.
I drove the truck to work today. I haven't trusted the truck for my work commute in quite awhile. It was raining this morning. I don't normally even try to start it in the rain. It fired up; no problem.
Back on the road.
.
I drove the truck to work today. I haven't trusted the truck for my work commute in quite awhile. It was raining this morning. I don't normally even try to start it in the rain. It fired up; no problem.
Back on the road.
.
#45
08-25-2012, 04:34 PM
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Heres a suprise, i opened the computer, but thats not the suprise, the suprise is, its ok, no bent capacitators, nothing, damn thing looke to be fairly new, no burns marks, no swelled up components. guess your hunch is not soo good. hope your happy i opened it up, was easy to do i give it that, not that i was afraid or anything, i just knew from the get go it wasnt the issue.
repalced the EGR and egr position sensor, also changed out the IAC, and yes, the ICM on the side of the distributor is goos as ORIELLY DOES check these. so, anyone else got any ideas??? once it warms up, its not half bad to drive, still laggy but driveable. Ill be yanking the accell injectors this eveninf and purging them, hope that does the trick. yall drop an idea if you have any.
have a nice day.
repalced the EGR and egr position sensor, also changed out the IAC, and yes, the ICM on the side of the distributor is goos as ORIELLY DOES check these. so, anyone else got any ideas??? once it warms up, its not half bad to drive, still laggy but driveable. Ill be yanking the accell injectors this eveninf and purging them, hope that does the trick. yall drop an idea if you have any.
have a nice day.