86 no start
Thread Starter
Instructor
Joined: Jun 2003
Posts: 176
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From: Columbia SC
86 no start
1986 stock L98: Engine turns over, battery 9 months old with fresh charge (12.4 volts), engine turns over freely but does not catch. Spark was checked on #1 & 3 cylinders and was good, those plugs were pulled and had no gunk on them. Replaced cooant temp sensor and harness as the cooling fan comes on with the ignition and the fan relay is getting a 12.43 volt signal from the ecm on the green/white wire. This relay was also replaced one month ago. There is no voltage at all on either wire going to the cooling sensor. the only code is 54, low fuel pump voltage. Fuel pump replaced in March. If I power the fuel pump throigh the ALDL, I can hear it run, but the engine still will not catch, although it does sound "beefier". I am starting to question the ECM itself and am tempted (as much as my pride screams NO) to send it to an electrical shop. Any suggestions? And thanks, even if all you did was read this post.
Racer
Joined: Nov 2002
Posts: 471
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From: Queens NY
Re: 86 no start (loflyin)
you might want to check if the ECM fuse is ok and check for voltage down there
that's really the only thing that comes to mind if the fuel pump is good.. it whines when you turn the key, right?
[Modified by CarAteMyMoney, 6:30 PM 6/22/2003]
that's really the only thing that comes to mind if the fuel pump is good.. it whines when you turn the key, right?
[Modified by CarAteMyMoney, 6:30 PM 6/22/2003]
Thread Starter
Instructor
Joined: Jun 2003
Posts: 176
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From: Columbia SC
Re: 86 no start (CarAteMyMoney)
no hum from the fuel pump unless I activate it through the ALDL, then it has a perfect whine. Dash tells me low voltage at fuel pump. Not sure where to check, could this be caused by faulty fuel pump relay? Fan is activated by ECM when engine is dead cold, even with new sensor in place. Timing chain and gears were relaced in December, as well as water pump and harmonic balancer (inner and outer rings had actually separated). Am getting closer to using the mother of all tools (hammer). Please help.
Thread Starter
Instructor
Joined: Jun 2003
Posts: 176
Likes: 0
From: Columbia SC
Re: 86 no start (CarAteMyMoney)
Update, twist your brains on this one. Fuel pump works fine, if I disconnect the fan relay or the IAC connector. With IAC disconnected, the fan does not come on when cold and the fuel pump works the way it is supposed to. Any thoughts on this? What is the electrical relationship?
Thread Starter
Instructor
Joined: Jun 2003
Posts: 176
Likes: 0
From: Columbia SC
Re: 86 no start (BILLYD)
Is there a test for the coil, before I replace it? Oh, btw, the fan comes on with IAC disconnected (my bad), but I found that of the 4 wires at the IAC, the light green ones have battery voltage and the black ones both have 0.33 volts. Are the black supposed to be grounds with 0 volts?
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