87 5.0 headache

T

TRIT0N

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Jun 9, 2004

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Jun 9, 2004

#1

• Jun 9, 2004

• #1

ok lets start at the beginning, 87 5.0 with aod
runs fine for 10 mins each morning and quits half way to work, restarts, sputters and dies, continues to do this for any whereb from 10 mins to half an hour, we have replaced the module, pick up coil, coil, tested for codes and at first we came up with a few but upon retesting only came up with a code 18 which we understand to be spout connector.
after the car sits for anywhere from 10 mins to half an hour it will restart and more ofetn then not make it the rest of the way to work. although sometimes when it does restart it runs like crap.
one contact suggested the air bypass valve. does this sound reasonable?
any help would be appreciated
oh and yes we here the fuel pump running and have pressure at the rail to eliminate those right off

 

stangbear427

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Nov 11, 2002

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Jun 9, 2004

#2

• Jun 9, 2004

• #2

Do you let it warm up, or just start it and cruise? If so, on a cold start in the morning, how long will it idle before exhibiting problems?

 

T

TRIT0N

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Jun 9, 2004

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Jun 9, 2004

#3

• Jun 9, 2004

• #3

i generally wait until it idles down before i start driiving it. I can usually get about 5 minutes of driving befiore it stalls

 

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87GTPrimer

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Sep 12, 2002

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Jun 9, 2004

#4

• Jun 9, 2004

• #4

Sounds like maybe an O2 sensor, because before it warms up it runs in open loop mode and ignore's the sensors, then when it gets warm it runs in closed loop and uses tht sensor to adjust A/F ratio, if the harness of sensors are screwed it could really that up. Try disconnecting the battery for at least 1/2 hour, i would do for an hour to let the ECC reset, then disconnect to O2 sensor harness and driver the car and see if the problem occurs agian.

 

T

TRIT0N

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Jun 9, 2004

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Jun 9, 2004

#5

• Jun 9, 2004

• #5

thats what we thought too
hence we did both sensors

 

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87GTPrimer

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Sep 12, 2002

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Jun 9, 2004

#6

• Jun 9, 2004

• #6

Try resetting the computer, whenever I get weird problems like that that are ECC related I flush the thing by disconnecting the battery for about an hour, and sometimes it works.

 

stangbear427

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Nov 11, 2002

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Jun 9, 2004

#7

• Jun 9, 2004

• #7

To satisfy my curiosity, don't just wait for it to idle down and then take off. Hit the key and get out. Let it warm all the way up to normal operating temp (180 or so) before you move it at all. Let me know what it does.

 

stangbear427

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Nov 11, 2002

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Jun 9, 2004

#8

• Jun 9, 2004

• #8

Oh- you don't have to let it sit an hour disconnected to clear the memory- just disconnect the battery and hold the + and - cable ends together for a few seconds and it will clear it out instantly.

 

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87GTPrimer

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#9

• Jun 9, 2004

• #9

really, cool. I was always taught to just disconnect the bat for atleast 1/2 hour, maybe I'll try that next time. I usaully reset my computer after I do any major mods, and it normally seems to work pretty good.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Jun 9, 2004

#10

• Jun 9, 2004

• #10

stangbear427 said:

Oh- you don't have to let it sit an hour disconnected to clear the memory- just disconnect the battery and hold the + and - cable ends together for a few seconds and it will clear it out instantly.

Click to expand...

Jess, nice info - i had not heard or thought of that (im not smart enough to think of things like that).
some folks like to turn the headlights on once the batt is disconnected (point being to discharge any juice in the puter circuits, etc)..... same difference, right? there is something about touching the cables together (disconnected or not), that does not seem right (in terms of how it makes my gut feel, not your technique or the result, SB). touching the cables together just grounds out (discharges) any residual juice, right....?

 

iwannarace67

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Sep 24, 2001

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Chicago, IL

Jun 9, 2004

#11

• Jun 9, 2004

• #11

possibly a bad crank sensor...I've seen this happen before same exact scenario.

 

T

TRIT0N

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Jun 9, 2004

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#12

• Jun 9, 2004

• #12

ok we will try resetting the comp and see what happens
thanx for the info

 

S

sublime29

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Mar 18, 2004

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Jun 9, 2004

#13

• Jun 9, 2004

• #13

Have you checked for spark when the car will not start.I would replace the pip(profile ignition pickup) if you have not its under 15 bucs.It is the piiece inside the distributor under the rotor.Check to see if the spout connector is pluged in.Its the connector that jumps the two wires that is in the bunch of wires going to the distributor.That is the connector you pull to set timing.Take your code scanner with you and when it won't start check for codes.It sounds like a iintermitent problem.You can set the code scanner to check for wiring problems.I forget exactly how too but its easy after you run the code scanner you start wiggling wires and try to find a short or open somewhere if you find one thw scanner will beep.Read the scanner for directions.Then go to town going all over every wire and connection.

 

T

TRIT0N

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Jun 9, 2004

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Jun 9, 2004

#14

• Jun 9, 2004

• #14

yes it definitly has spark as it will sputter and fire but won't catch
and the spout connecter has been monkied with every way imaginable to no avail
as for codes we are pulling them with test light and a jumper wire so no beeping here

 

stangbear427

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Nov 11, 2002

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Jun 9, 2004

#15

• Jun 9, 2004

• #15

HISSIN50 said:

...there is something about touching the cables together (disconnected or not), that does not seem right (in terms of how it makes my gut feel, not your technique or the result, SB). touching the cables together just grounds out (discharges) any residual juice, right....?

Click to expand...

I agree, it feels a little strange the first few times. However, one must remember that it's the terminals on the battery that aren't supposed to touch, not the cables. Incidentally, while there's more to it than this and it isn't really accurate, think about it this way if it makes you feel better (just don't tell anyone, it isn't true): all the battery does is connect the two cables- so theoretically they are always touching anyway, in a manner of speaking. What we are doing is removing electricity from the equasion. How exactly this clears the computer isn't for me to explain, but I think there's more to it than simply grounding. If I had a better understanding myself maybe... I just know it works, and is more reliable than just disconnecting and waiting around- not to mention much faster

 

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87GTPrimer

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Sep 12, 2002

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Jun 10, 2004

#16

• Jun 10, 2004

• #16

The thing is that the computer and the air bag (if equiped) have a bakcup power supply that is isolated from the normal power supply so the power is not drawn to other devices. This backup supply, in the computer's case, keep they computer memory backed up for up to 1/2 hour, and the airbag's supply does the same thing, except the air bag can deploy for up to 1/2 hour after losing power

 

HISSIN50

"How long does it take to get help in here?

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Nov 29, 1999

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Jun 10, 2004

#17

• Jun 10, 2004

• #17

iwannarace67 said:

possibly a bad crank sensor...I've seen this happen before same exact scenario.

Click to expand...

not on a 5.0 stang, you have not.
(we have dizzies, not cam/crank sensors and coil packs).

 

iwannarace67

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Sep 24, 2001

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Chicago, IL

Jun 10, 2004

#18

• Jun 10, 2004

• #18

duh shoulda caught that one....TFi module maybe then

 

T

TRIT0N

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Jun 9, 2004

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Jun 10, 2004

#19

• Jun 10, 2004

• #19

ok we have reset the comp. and we also found that somehow the o2 sensors were plugged in wrong, (right for left and left for right) dunno if that matters but now the car seems to be running great
thanx again for all the help
next to dump money into improving rather then keeping it running, always more fun

 

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87GTPrimer

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Jun 14, 2004

#20

• Jun 14, 2004

• #20

Glad to here the computer trick worked. Somethimes when you do major changes it ****s with the computer, and it just goes haywire.