v6 s15 no spark

[loftyc92757]

1987 s-15 have replaced all major componants related to fuel delivery. problem is elec in nature . cannot get spark to plugs . have replaced coil , dist. , checked fuse links , replaced all fuses in box . problem started when i replaced water pump . after repair was made I tried to start engine and the starter wouldn't disengage so I replaced it . truck kicks but won't start ( no spark ) . cannot find voltage in wires leading into top of coil .I NEED HELP !!!

[busa_4]

first! double check your wires to make sure you didnt leave anything unplug or loose when you replaced the water pump. check your ignition module. your coil should have a 12v wire going to the primary side of the coil (i think on an hei system it is the big red wire). check it and make sure you are receiving 12v with the ignition on (not running).

[loftyc92757]

Originally Posted by busa_4

first! double check your wires to make sure you didnt leave anything unplug or loose when you replaced the water pump. check your ignition module. your coil should have a 12v wire going to the primary side of the coil (i think on an hei system it is the big red wire). check it and make sure you are receiving 12v with the ignition on (not running).

thanks for reply . I double checked as you asked all connections seem ok . I didn't find voltage on primary wire , so I guess my next question is where does that wire lead back to and is there a fuse or possibly a fuse link that is hidden ? I have jumpered the trouble code system as described in a haynes manual and the only code I get is one ,one two ,one . the computer doesn't offer any other codes . I really appreciate your help as I feel this is a small but critical problem . I have reasonably good mechanical skills as I am an HVAC tech however I am sometimes guilty of thinking too hard . Thank you Lofty C.

[Mikado14]

It has been awhile but when you changed your starter, there should have one or two fusible links attached at the hot from the battery. Did you reconnect them? Are they good? Are there any other circuits dead?

[loftyc92757]

Originally Posted by Mikado14

It has been awhile but when you changed your starter, there should have one or two fusible links attached at the hot from the battery. Did you reconnect them? Are they good? Are there any other circuits dead?

mikado thanks for your reply but I've checked this area several times and found nothing else wrong . all other circuts are fine . obviously there is no electrical circut when changing a water pump but let me explain the starter problem a little more . after the water pump changeout I tried to start the truck and the starter would not stop trying to start it was so fast and high pitched that I thought it was going to spin apart . Turning the key off didn't do it so I had to disconnect the battery cable . So you can see my dillema . The truck was fine as far as all functions until this water pump / starter problem . I'm wondering if the computer has something to do with it .

[BlazerLT]

Did you replace the rotor? I see you replaced something in the dist are but I wanted to know exactly what.

Also, have you checked your fuel pressure?

Does the truck try to start if you spray stating fluid right into the TB?

Did you check the timing with the timing wire removed from the PCM?

[busa_4]

you say your starter kept turning even with the key off and out of the ignition? if that is the case, i would start looking at the ignition switch. its the only thing i can think of that would be sending poewr to the coil. i am assuming since it is an 1987 truck it doesnt have an factory alarm system. does it have a aftermarket alarm system?

[loftyc92757]

Originally Posted by BlazerLT

Did you replace the rotor? I see you replaced something in the dist are but I wanted to know exactly what.

Also, have you checked your fuel pressure?

Does the truck try to start if you spray stating fluid right into the TB?

Did you check the timing with the timing wire removed from the PCM?

Thanks these are things I need to hear . I had a previous rotorcap and rotor replacment approx. 2mos prior and did second rotor change 12/17/04 when I replaced entire dist . Fuel pump is brand new and is delivering to throttle body . 2 new injectors and throttle body assy. at this point I would ask if injectors should be delivering fuel even though there is no spark present . I am getting 12v readings at injectors but not seeing or smelling fuel .starting fuid in TB had zero effect . you're helping me a lot , thanks lofty .

[loftyc92757]

Originally Posted by busa_4

you say your starter kept turning even with the key off and out of the ignition? if that is the case, i would start looking at the ignition switch. its the only thing i can think of that would be sending poewr to the coil. i am assuming since it is an 1987 truck it doesnt have an factory alarm system. does it have a aftermarket alarm system?

Here's a potential solution !! I had lost a set of keys while fishing and had to change the ign. switch about two years ago . This would explain the starter not being able to stop in the first place . I didn't consider this because I had been driving this truck just fine until the water pump job and that just didn't have anything to do with this circut . I will check it tomorrow . Thanks a bunch ! Lofty .

[BlazerLT]

You sure you aren't getting any spark?

If it kicks then you are getting some spark.

Sounds like it is severly out of time.

Use a timing gun and time the engine with the timing wire disonnected from the PCM.

Check for spark in the plugs wires by inserting a screwdriver into the plug wire end and see if spark will arc to a brace or a piece of metal on the engine.

[loftyc92757]

Originally Posted by BlazerLT

You sure you aren't getting any spark?

If it kicks then you are getting some spark.

Sounds like it is severly out of time.

Use a timing gun and time the engine with the timing wire disonnected from the PCM.

Check for spark in the plugs wires by inserting a screwdriver into the plug wire end and see if spark will arc to a brace or a piece of metal on the engine.

My bad ! I meant it turns over . also to clear up the key was in the ign. it just had no effect in stopping the starter . I'm at lunch now but right after work I'm going to change the ign. switch again as that seems a more logical area to look at and it's not very expensive . I've put too much money into this vehicle as it is but I want it to be reliable . as far as timing I never had a problem . as to spark I'm positive I'm not getting spark . What about the lack of fuel delivery when I try to start the engine doesn't that also point to the ign. switch ? I'll talk to you later and as always thanks for the help . Lofty

[BlazerLT]

Originally Posted by loftyc92757

My bad ! I meant it turns over . also to clear up the key was in the ign. it just had no effect in stopping the starter . I'm at lunch now but right after work I'm going to change the ign. switch again as that seems a more logical area to look at and it's not very expensive . I've put too much money into this vehicle as it is but I want it to be reliable . as far as timing I never had a problem . as to spark I'm positive I'm not getting spark . What about the lack of fuel delivery when I try to start the engine doesn't that also point to the ign. switch ? I'll talk to you later and as always thanks for the help . Lofty

Check the timing, just because you have never had a problem with it doesn't mean it is not the cause of the problem. It is a common occurence and costs nothing to adjust.

[loftyc92757]

Originally Posted by BlazerLT

Check the timing, just because you have never had a problem with it doesn't mean it is not the cause of the problem. It is a common occurence and costs nothing to adjust.

Will do BlazerLT . I will bring number one to TDC and go from there . thanks . when you say if it kicks I have spark do you mean just turns over / I have a plug with wire attached pulled out of cylinder and placed where I could observe spark but I see nothing . Even if the timing was bad wouldn't I still see a spark at some point in the rotation ? Lofty

[BlazerLT]

Yes, you would see some spark. Check the coil wireing for improper connections and reseat the wire going from the coil to the distributor cap.