'95 f150 cutting out in reverse only???
#16
09-10-2012, 09:38 PM
#18
09-11-2012, 12:39 PM
Elder User
Well it was a shot worthy of quick test, missing badly/missing when in reverse rather then dead stall suggests an electrical problem over anything mechanical in nature. Such as the filter dropping off.
Computer gets input from MLPS when shifter is moved into reverse, something in the switch directly or effecting something else on that same circuit when in reverse.
No help so question is whats next, what else happens when in reverse but not in any forward gear? That is the question at this point, that is if you're are sure of "reaction".
You say it misses bad, you're sure its a miss and not just struggling?
Missing suggests spark issues, spark cutting in and out in one or more cylinders. Based on your comments sounds like all cylinders.
Have a timing light handy? If so hook it up and move it to various plugs aiming light at dark area like under side of hood. Watch the light as it flashes, should be steady beat, no variation in on|off|on|off not hit and miss now and then or every other hit missed. Or hit once miss next three then hit one miss next two any way think you get the idea.
Do so with it idling in park, idling in drive and then with it idling in reverse.
Note any differences in flash pattern, basically checking for sporadic hit miss flashs while in reverse but yet nice steady flash pattern in drive and park. Be sure and cross check few plugs get a good over all picture.
Knowing for sure the issue effects spark should/would make it easier to narrow down the cause.
And only take few minutes to verify or disprove that as the resulting condition of placing it in reverse.
If it disproves it then move on, check fuel pressure under same conditions.
If spark is not disrupted nor is fuel pressure then check/test injector pulse with a noid light same test conditions.
If no issues are apparent, no difference noted in drive verses reverse at idle, in any of those three? I guess it be time to drop that pan, verify the filter is up in place where it should be.
Find what is effected, then find its cause.
Computer gets input from MLPS when shifter is moved into reverse, something in the switch directly or effecting something else on that same circuit when in reverse.
No help so question is whats next, what else happens when in reverse but not in any forward gear? That is the question at this point, that is if you're are sure of "reaction".
You say it misses bad, you're sure its a miss and not just struggling?
Missing suggests spark issues, spark cutting in and out in one or more cylinders. Based on your comments sounds like all cylinders.
Have a timing light handy? If so hook it up and move it to various plugs aiming light at dark area like under side of hood. Watch the light as it flashes, should be steady beat, no variation in on|off|on|off not hit and miss now and then or every other hit missed. Or hit once miss next three then hit one miss next two any way think you get the idea.
Do so with it idling in park, idling in drive and then with it idling in reverse.
Note any differences in flash pattern, basically checking for sporadic hit miss flashs while in reverse but yet nice steady flash pattern in drive and park. Be sure and cross check few plugs get a good over all picture.
Knowing for sure the issue effects spark should/would make it easier to narrow down the cause.
And only take few minutes to verify or disprove that as the resulting condition of placing it in reverse.
If it disproves it then move on, check fuel pressure under same conditions.
If spark is not disrupted nor is fuel pressure then check/test injector pulse with a noid light same test conditions.
If no issues are apparent, no difference noted in drive verses reverse at idle, in any of those three? I guess it be time to drop that pan, verify the filter is up in place where it should be.
Find what is effected, then find its cause.
I'd concour that there's an electrical grounding problem in the reverse circuit.
That's why I think it could be within the EEC.
Perhaps Dhughes1 (the OP) should try running a temporary ground from an alternator mounting bolt to the battery ground or to the fender ground to make sure the alternator isn't trying to use a ground circuit within the EEC as it's best ground source.
A poor alternator ground could wreak havoc with the EEC's grounding circuitry (transmission grounds, injector grounds, spark, etc).
Just a thought........I've been shot down before..........
Bob
#19
09-11-2012, 12:45 PM
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#20
09-11-2012, 12:49 PM
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#21
09-11-2012, 01:00 PM
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I don't know if this will work or not, but heres the video again.
<a href="http://s1183.photobucket.com/albums/x466/Danielhughes/?action=view¤t=D4E0E034-BA81-454E-A425-2F7AEADA3BA7-1777-000001B623CE9743.mp4" target="_blank"><img src="http://i1183.photobucket.com/albums/x466/Danielhughes/D4E0E034-BA81-454E-A425-2F7AEADA3BA7-1777-000001B623CE9743.mp4" border="0" alt="Photobucket Pictures, Images and Photos" /></a>
<a href="http://s1183.photobucket.com/albums/x466/Danielhughes/?action=view¤t=D4E0E034-BA81-454E-A425-2F7AEADA3BA7-1777-000001B623CE9743.mp4" target="_blank"><img src="http://i1183.photobucket.com/albums/x466/Danielhughes/D4E0E034-BA81-454E-A425-2F7AEADA3BA7-1777-000001B623CE9743.mp4" border="0" alt="Photobucket Pictures, Images and Photos" /></a>
#23
09-11-2012, 06:25 PM
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#25
09-11-2012, 06:47 PM
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#26
09-11-2012, 06:53 PM
Not sure might be the video but doesn't look or sound like its missing to me. Its fighting itself yea but not what I'd call any kind of a miss, sounds like its hitting on all eight like it should just under high strain.
Unplug the VSS, test see if any change. No change plug the VSS back in.
If no change with VSS unplugged, flip the glove box all the way open, if you squeeze the sides in a tad it will open hang straight down.
Reach in unplug the RABS module, test again see if any change.
No change with RABS module unplugged, leave it unplugged and unplug the VSS agian, retest with both unplugged.
Somethings really screwy there!
Unplug the VSS, test see if any change. No change plug the VSS back in.
If no change with VSS unplugged, flip the glove box all the way open, if you squeeze the sides in a tad it will open hang straight down.
Reach in unplug the RABS module, test again see if any change.
No change with RABS module unplugged, leave it unplugged and unplug the VSS agian, retest with both unplugged.
Somethings really screwy there!
#27
09-11-2012, 06:56 PM
The alternator is grounded via its brackets to the engine block, if you have a bad ground its the where the ground cable connects to the block.
The engine starts, the starter cranks the engine over, pretty safe bet the ground is making fairly solid contact with the block.
If you think you have a bad ground, clean the existing cables connection rather then run another new cable over.
The engine starts, the starter cranks the engine over, pretty safe bet the ground is making fairly solid contact with the block.
If you think you have a bad ground, clean the existing cables connection rather then run another new cable over.
#30
09-11-2012, 07:45 PM
Ok again was worth a try a minute.
Have you tried moving the shifter up or down a tad from the reverse's detent point, see if the motor smooths out doing so either direction?
Know what I mean, Move shifter to reverse then while holding the sift lever pulled toward you move it slowly up and down slightly away from that position. See if engine smooths out but yet still has reverse, go as far as you can or need to but still have reverse.
Have you tried moving the shifter up or down a tad from the reverse's detent point, see if the motor smooths out doing so either direction?
Know what I mean, Move shifter to reverse then while holding the sift lever pulled toward you move it slowly up and down slightly away from that position. See if engine smooths out but yet still has reverse, go as far as you can or need to but still have reverse.