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efi issues with video

Amac70

ME
Joined
Mar 27, 2002
Messages
3,269
so i have had my efi going for a couple of months now. runs great most of the time after it idles for a few minutes. Here is the issue about min after i start it, it starts to run like crap suputering and backfiring out the exhaust. it will do that for about a min then it will clear up and be fine. it does this almost everytime i start it. if i don't let it go through its little cycle it is undriveable. any ideas what it could be. I get no codes that i shouldn't. and have done balance tests everything checks out. fuel pressure gauge on rail everything is good even when its running bad. Thoughts. roughness starts at about 20 secs then clears up at about 1:20 you can hear both.


[youtube]k1yuzZ4LOW4[/youtube]
 
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Amac70

Amac70

ME
Joined
Mar 27, 2002
Messages
3,269
Happens most times hot or cold. The system is mustang mass air, a9s computer, all stock stuff. Also idle does not change while it is doing it stays steady just sounds like crap.
 
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Amac70

Amac70

ME
Joined
Mar 27, 2002
Messages
3,269
what am i checking for, it has been cleaned and moves freely. and functions i get the hight idle on start then it comes down. also this just doesn't start right away i cut out the first 4 minutes of the video of it just idiling fine.
 

BUCKNBRONK

Sr. Member
Joined
Jun 30, 2011
Messages
521
Loc.
fresno
what am i checking for, it has been cleaned and moves freely. and functions i get the hight idle on start then it comes down. also this just doesn't start right away i cut out the first 4 minutes of the video of it just idiling fine.

I was hopeing it was gummed up, but ifs kicking up to high idle and back down its ok. I wish i had sound at work i cant listen to ur video.
 

BUCKNBRONK

Sr. Member
Joined
Jun 30, 2011
Messages
521
Loc.
fresno
what happens when u give it throttle while its running like a dog s$$ting peach pits. Improve, get worse? black smoke, no smoke?
 

chuzie

Bronco Guru
Joined
Jul 21, 2006
Messages
2,697
In addition to the balance test and KOEO test, have you pulled KOER and CM codes?

I'd say O2 sensors but you say you have no codes. It is adjusting the curves after startup for something that has gone bad. I can't believe you don't have codes.
 
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Amac70

Amac70

ME
Joined
Mar 27, 2002
Messages
3,269
If i drive it before it changes it pops and backfires real bad and has no power. i get codes 82 83 84 85 and 33,44. I checked codes a lot the first 3 weeks i drove it trying to find something to replace. still get the same ones. No smoke when giving throttle. And id say no to vacuum leak cause it runs fine after it adjusts. Under load it pulls great to 5000rpms no problems and sounds good the whole way there and wants to go higher but that is where my shift points are set currently.
 
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Amac70

Amac70

ME
Joined
Mar 27, 2002
Messages
3,269
ill go shoot another video and give it a little gas when it does it.
 

BUCKNBRONK

Sr. Member
Joined
Jun 30, 2011
Messages
521
Loc.
fresno
u got something playing with the ecm's timeing or fuel delivery during that 2 min ruff cycle. check ur o2's, tps, maf, etc..
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,312
It seems to be having trouble when it's still in open loop mode. O2 sensors are ignored in open loop. Once it gets into closed loop it appears to run much better. The dominant sensors in open loop are MAF and ECT. Your problem is there. Since you are not getting an ECT code I would suspect the MAF is dirty or bad or wrong application.
 
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Amac70

Amac70

ME
Joined
Mar 27, 2002
Messages
3,269
well i timed it with the camera while recording and it is almost exact on cold starts 4 and half minutes runs fine then runs ruff for 1 min and clears up. same as first video. codes i got after warm where 81,83,84,84 koeo 29 33 cm and 94,33,44 koer. I cleaned the maf when i installed it. Any test to run on it? would it run fine with a bad maf? once it changes to what ever it changes to it runs great. ect act and o2 sensors and maf are all used sensors map is new. the maf, throttle body and injectors where all off the car that the computer came on. probably a little small for application but seem to be doing fine other then this little hickup.
 

chuzie

Bronco Guru
Joined
Jul 21, 2006
Messages
2,697
You can't have a MAP sensor with a MAF system. I assume you are referring to the Bp sensor.

All your codes look fine.

What did you clean the MAF sensor with? You are certain the vehicle you got the MAF from is correct?

The last time I had a MAF issue it turned out to be a blown fuse on the RJM harness. Of course, it was the last thing I checked after shooting wires for 2 hours. Whoops!

The Mustang guys gave me this. I know you don't have code 66 but if it is a MAF issue and you are sure you have cleaned it with the right cleaner and it is the right MAF for the application, it is a good reference...

Code 66 MAF below minimum test voltage.
Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.

There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.

The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

Changes in RPM causes the airflow to increase or decease, changing the voltage output.. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow.

Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.

At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt

Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.

There should be a minimum of 10K ohms between either pin C or D on the MAF wiring connector and pins A or B. Make your measurement with the MAF disconnected from the wiring harness.
 
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Amac70

Amac70

ME
Joined
Mar 27, 2002
Messages
3,269
Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.


what does this mean exactly? measure pin to pin? not pin to ground source?
 

chuzie

Bronco Guru
Joined
Jul 21, 2006
Messages
2,697
Means pin to pin or from one end of the line to the other instead of checking for voltage from pin to ground or body like you would if you wanted to see if a wire was hot.
 

craigaria

Sr. Member
Joined
Apr 10, 2005
Messages
848
Loc.
Monroe, GA
Check your ground wires and battery/starter cables. I had a similar problem and chased it for a while. I fixed it when I replaced my battery cables. I think the computer just wasnt getting enough voltage. It was weird though how it would start running good after a couple min
 
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Amac70

Amac70

ME
Joined
Mar 27, 2002
Messages
3,269
thought i'd add some conclusion to this. So after replacing various parts, maf, iac valve, niether changed anything other then the maf i put in was bad and gave a code instantly. checking all the other sensors i could for there outputs. couldn't find anything wrong. as i was checking the o2 sensors there was still a labeling tag on the harness. Well it was labeled left. I bought this harness from someone else that had it rewired(much of it which i still rewired again cause they were wrong.) well i went hmm what does left mean. So i swapped the wiring on the o2 sensors from side to side. seems to have fixed the problem. Just wanted to post this cause after reading at least 10 similar story's that were never concluded on any of the other websites i thought i would give this one some conclusion.
 
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