Author Topic: est timing issue looking for shorts  (Read 2820 times)

Offline rusty but trusty

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est timing issue looking for shorts
« on: November 15, 2012, 05:04:34 PM »
my truck is a 87 gmc v1500 all stock with tbi if i leave the set timing wire unhooked it runs fine but if i hook it back up and start it it only stays running if i give it some gas and the whole truck shakes back and forth and backfires. if i keep on the gas a little long enough it settles down  but stall as soon a i put it in gear any ideas?
87 GMC V1500 305 700R4 NP208 and 10 bolts front and rear

Offline Captkaos

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Re: est timing issue looking for shorts
« Reply #1 on: November 15, 2012, 06:15:40 PM »
Did you set the timing to 0 with the wire disconnected?

Offline rusty but trusty

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Re: est timing issue looking for shorts
« Reply #2 on: November 16, 2012, 05:56:35 PM »
yes i set the timing exactly to 0 and i have replaced ignition module
87 GMC V1500 305 700R4 NP208 and 10 bolts front and rear

Online bd

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Re: est timing issue looking for shorts
« Reply #3 on: November 16, 2012, 08:12:31 PM »
Did the problem exist before you set the timing?  Was the timing very far off when you set it? 

Edit:  Was anything else changed or repaired?
« Last Edit: November 16, 2012, 08:14:29 PM by bd »
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline rusty but trusty

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Re: est timing issue looking for shorts
« Reply #4 on: November 16, 2012, 08:54:17 PM »
the problem has exsisted since i bought the truck but i found a intresing crimp in the wiring conecting the injectors to the eletronic spark module
87 GMC V1500 305 700R4 NP208 and 10 bolts front and rear

Online bd

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Re: est timing issue looking for shorts
« Reply #5 on: November 16, 2012, 09:51:56 PM »
That IS interesting, since the EST module should only have ground, ignition, ECM and Knock Sensor connections on a TBI engine.  However, the pink/black wire connecting to the EST module splices with the red wire and white wire connecting to the two injectors, as well as other pink/black wires; and then collectively they connect to 12-volt ignition power.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)