1991 No Spark .....
Thread Starter
5th Gear
Joined: Jun 2012
Posts: 5
Likes: 0
From: Norfolk VA
1991 No Spark .....
I have a 1991, Turns over , but does not start... if I let it sit a day, it will start, run fine, then when I shut her off , she won't start. i have no sensor lights on inside ....
So far I have replaced ; Fuel pump, filter, Relay switch, Ignition module, Coil... I also checked the Temperature sensor... Not sure where else to look! Any help would be appreciated!
Thanks
Lucy
So far I have replaced ; Fuel pump, filter, Relay switch, Ignition module, Coil... I also checked the Temperature sensor... Not sure where else to look! Any help would be appreciated!
Thanks
Lucy
Last edited by LucyC4Lucy; Jun 12, 2012 at 12:10 PM.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
I have a 1991, Turns over , but does not start... if I let it sit a day, it will start, run fine, then when I shut her off , she won't start. i have no sensor lights on inside ....
So far I have replaced ; Fuel pump, filter, Relay switch, Ignition module, Coil... I also checked the Temperature sensor... Not sure where else to look! Any help would be appreciated!
Thanks
Lucy
So far I have replaced ; Fuel pump, filter, Relay switch, Ignition module, Coil... I also checked the Temperature sensor... Not sure where else to look! Any help would be appreciated!
Thanks
Lucy
If ecm is setting a code it may not be storing it. have you checked for fault codes? per the FSM, 6e 3 b 3, to check that codes are setting, disconnect tps, idle engine until SES comes on. check codes, and 22 should be set, and kept in memory when key is off. if not ecm is faulty.
(not likely, but possible.)
I have a 91. would check with a test light, screwdriver to ground, whatever, to see if you have spark. IF you have the FSM, page 6e3 a 18.
ck MAP sensor by disconnecting it, see if it starts. ecm uses a default code for the sensor. if it starts, replace sensor.
try opening throttle to floor while cranking to see if the engine is flooded, or if the ecm thinks it is.
you will have to verify injectors are working. if you have fsm, I can direct you through it. sounds more like fuel than spark, but a bad pickup coil can cause it, many other things. this section of the manual is quite large.
I'm jumping around here, but watch the tach while cranking to verify the needle is jumping slightly, indicating ref pulses sent to ecm, so that injectors "should be" firing.
joe
Instructor
Joined: Aug 2011
Posts: 114
Likes: 0
Hi guys.. I'm trying to help Lucy here... I was guessing the pickup coil too... it will not start... there is no spark at the plug wires.... intermittent but now it totally dead... advanced tested the ignition module.. it was ok.... explain the tach bouncing
.. are you saying if it bounces the pick up coil is ok?
.. are you saying if it bounces the pick up coil is ok?
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
Have the harness grounds been checked/cleaned?
ECM codes...showing a 12 as it should?
prom pins? connectors?
Is there a FSM involved or are we tossing parts at it hoping to get lucky?
fuel? whats the pressure?
whats the leakdown time?
noid lite?
ohms the inj? where are they? hot? cold?
Lots to do with the proper diagnostic technique
ECM codes...showing a 12 as it should?
prom pins? connectors?
Is there a FSM involved or are we tossing parts at it hoping to get lucky?
fuel? whats the pressure?
whats the leakdown time?
noid lite?
ohms the inj? where are they? hot? cold?
Lots to do with the proper diagnostic technique
Last edited by leesvet; Jun 12, 2012 at 07:29 PM.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Hi guys.. I'm trying to help Lucy here... I was guessing the pickup coil too... it will not start... there is no spark at the plug wires.... intermittent but now it totally dead... advanced tested the ignition module.. it was ok.... explain the tach bouncing
.. are you saying if it bounces the pick up coil is ok?
.. are you saying if it bounces the pick up coil is ok?
if you have tested for spark and find none, per fsm, un hook the "est" plug, the tan wire that comes from the ecm 4 wire connector at rr of dist. then test for spark. if you now have spark, pickup is defective.
you can also ck resistence on the pu coil, after it is disconnected from module, may be 900 to 1300 ohms. flex the two wires while reading the ohms. if any change in reading, the coil is defective.
I would be sure the tests point to the pu coil since the dist has to be taken apart totally to replace it.
Thread Starter
5th Gear
Joined: Jun 2012
Posts: 5
Likes: 0
From: Norfolk VA
Still no Luck..
So far this is what I have checked/replaced..
Fuel pump, Filter, Relay switch, Ignition Module, Coil, and tested the Pick up coil reads 600-800 ohms....( not sure what the normal reading is)...Checked every fuse,
tested plugs with screw driver, Still no spark to the plugs, fuel coming thru fine.
So far this is what I have checked/replaced..
Fuel pump, Filter, Relay switch, Ignition Module, Coil, and tested the Pick up coil reads 600-800 ohms....( not sure what the normal reading is)...Checked every fuse,
tested plugs with screw driver, Still no spark to the plugs, fuel coming thru fine.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Still no Luck..
So far this is what I have checked/replaced..
Fuel pump, Filter, Relay switch, Ignition Module, Coil, and tested the Pick up coil reads 600-800 ohms....( not sure what the normal reading is)...Checked every fuse,
tested plugs with screw driver, Still no spark to the plugs, fuel coming thru fine.
So far this is what I have checked/replaced..
Fuel pump, Filter, Relay switch, Ignition Module, Coil, and tested the Pick up coil reads 600-800 ohms....( not sure what the normal reading is)...Checked every fuse,
tested plugs with screw driver, Still no spark to the plugs, fuel coming thru fine.
some fundamentals, lucy: check volts at BAT terminal on dist, key on, then cranking. should be 7 min.
disconnect the EST wire from dist -it has a plastic plug connection, the tan wire. now test for spark. if spark is present, pu coil is defective.
when testing pu coil with ommeter, leads have to be off the ICM. connect ommeter to each terminal, one then the other of pu coil and ground to dist base. reading should be infinite. if not coil is defective.
connect between each terminal, and flex the wires. reading -500-1500-should not vary. if it does coil is defective.
the coil is only $20 or so. the problem is in replacing it but I have done it many times. if you have a Haynes it will show you exaclty how to do it.
Thread Starter
5th Gear
Joined: Jun 2012
Posts: 5
Likes: 0
From: Norfolk VA
don't recall if you have a manual or not...
some fundamentals, lucy: check volts at BAT terminal on dist, key on, then cranking. should be 7 min.
disconnect the EST wire from dist -it has a plastic plug connection, the tan wire. now test for spark. if spark is present, pu coil is defective.
when testing pu coil with ommeter, leads have to be off the ICM. connect ommeter to each terminal, one then the other of pu coil and ground to dist base. reading should be infinite. if not coil is defective.
connect between each terminal, and flex the wires. reading -500-1500-should not vary. if it does coil is defective.
the coil is only $20 or so. the problem is in replacing it but I have done it many times. if you have a Haynes it will show you exaclty how to do it.
some fundamentals, lucy: check volts at BAT terminal on dist, key on, then cranking. should be 7 min.
disconnect the EST wire from dist -it has a plastic plug connection, the tan wire. now test for spark. if spark is present, pu coil is defective.
when testing pu coil with ommeter, leads have to be off the ICM. connect ommeter to each terminal, one then the other of pu coil and ground to dist base. reading should be infinite. if not coil is defective.
connect between each terminal, and flex the wires. reading -500-1500-should not vary. if it does coil is defective.
the coil is only $20 or so. the problem is in replacing it but I have done it many times. if you have a Haynes it will show you exaclty how to do it.
I do have a Haynes... I figure if I have to replace the PU Coil, and pull up the distributor, I might as well just put in a whole new Distributor...I hope that doesnt have to be done, but if so Im ready. I just wish this was an easier fix!.. Now even after sitting a day or so , it wont start up like it did before...Hooked it up yesterday to a computer, didnt throw any codes....., just 12 which from what I understand means nothing. ERRRRR Frustrating!!
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Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
I do have a Haynes... I figure if I have to replace the PU Coil, and pull up the distributor, I might as well just put in a whole new Distributor...I hope that doesnt have to be done, but if so Im ready. I just wish this was an easier fix!.. Now even after sitting a day or so , it wont start up like it did before...Hooked it up yesterday to a computer, didnt throw any codes....., just 12 which from what I understand means nothing. ERRRRR Frustrating!!
"easy" and c4 don't go together, generally.
the coil is $140 less than the distributor, and it won't be any better except for the new pu coil. once you replace one you will wonder what the fuss was about. as they say, 'every song was once new.' if you can drive out a roll pin with a .180 punch, and remove the cat whisker snap ring on top, the rest is easy.just be sure to read up on removing dist from engine BEFORE you do it, not after.
verify the coil is defective -which is from the FSM and the Haynes. if you have voltage in at the bat terminal, it is going to be the pu coil.
joe
Burning Brakes
Joined: Aug 2003
Posts: 944
Likes: 0
From: Mesa Az
the distributor when you remove before you mark the distributor is a pain in the @ss and will make you paranoid to put it back in and trying to make sure your engine is at top dead center and your distributor is on correctly.
mark it with a white out marker.
if you go the route of a new distributor you can pick one up fairly cheaply at a corvette junk yard.
mark it with a white out marker.
if you go the route of a new distributor you can pick one up fairly cheaply at a corvette junk yard.