89 shadow TBI no spark HELP!

[ShadowFromHell]

A buddy of mine bought a 89 shadow tbi 5 spd a few months ago. Has been a good little car for him, he was a truck guy and is now loving his 30mpg car! But today he called me and said he put gas in it and it wouldnt start. I figured it was a fuel issue so I grabbed a few tools and a chain and went to help him tow it home. Here is what I have done.

His story is he drove it to the gas station 4 blocks from his house, filled it up and then it wouldnt start.

Checked for fuel, pump is working and it has FP at the TB. 99.9% sure it is not a fuel issue.

Swapped in a good HEP.

Checked for spark, had none.

Check for broken t-belt, its fine.

Checked for power at the coil. Getting a constant hot on the + side and a flashing power at the - side while cranking.

The wires are old, but using a test light and the cars battery I proved that there is conductive in the main coil wire. The test light was VERY dim though.

I swapped in a random used TM coil that was in the trunk of my car. Still no spark but I have NO idea if it is any good.

If the car was at my house, I would just rob parts off of a running TM until it started, but I dont have that option with this car. Its my buddies car and I dont want to start throwing parts at it. Im thinking the coil is bad but really are not sure. To me that makes the most since, because I seem to be loosing power after the coil. What should be my next step? I think he can get a new coil, wires, and cap for under $50. If he can afford that, we might just do that tomorrow. Ive just never had a problem like this so I am not sure what to do next. As long as I am getting power to the coil, it shouldn't be a ECU or ASD relay problem right?

Thanks!

[ShadowFromHell]

After reading a bunch of other threads I will add that the rotor is spinning during cranking. It was also rather cold today, might have been down to 25 this morning, coldest it has been this year and since he has owned the car. Dont know if that would affect the coil or not.

[turbovanman²]

Check for spark at the coil wire, if no spark, then you have a coil wire/coil or computer issue. If you have spark at the coil wire but not at the plugs, change the wires, cap and rotor. Is the carbon button there in the cap?

Can you see fuel spraying down the TB unit? Any codes? Make sure at TDC, the cam and rotor point correctly, belt could have jumped.

[ShadowFromHell]

Installed a new cap, rotor, and coil. I have spark at the end of the coil wire IF I ground to the head or battery, not if I ground to the post on the distributer. I also hooked it all back up and hooked a spark tester to one of the posts on the distributer and have no spark there. It seems to be loosing spark in between the top of the cap and the spark plug wires. I am at a complete loss here. Anyone have any ideas?

[turbovanman²]

Try another cap and rotor. Is the carbon button intact? Did you push the plug wires all the way in?

Don't use the battery ground to test for spark, you could end up igniting the battery, BOOM.

[ShadowFromHell]

I put a BRAND NEW cap and rotor on this morning. Carbon button is perfect. Wires are all the way in. I am at a complete loss here. Im getting power to the disturber but not out to the plugs. Im not even getting power to the plug WIRES at their base. It seems like it has lost its ground, but I can ground to the head when testing the coil wire and it lights up. At this point I havent touched any of the cam or ign timing. I should be getting spark at the plugs even if it was 180 off shouldnt I?

I will add, that the fan seems to be in-op. It is throwing a code for a bad fan relay. I dont see how that would cause the problem with it not starting, but I thought I would mention it.

[ShadowFromHell]

Was just brain storming with a buddy. Is it possible the car backfired on startup, skipped some teeth on the belt and now during cranking when the ecu sends the spark it is not lined up with the wires and thats why I am getting power to the distributor, but now out of it?

[shackwrrr]

The wires are old, but using a test light and the cars battery I proved that there is conductive in the main coil wire. The test light was VERY dim though.

What do you mean by this, did you put it from batt pos to coil pos and it was dim or from coil pos to batt ground? I am thinkimg you are getting insuffcient current for the coil to saturate. Check the voltage at the coil while cranking and with the key on.

[ShadowFromHell]

I put one end of the spark plug wire onto the negative side of the battery, clipped the alligator clip on the test light to the positive side of the battery, and then touched the probe to the end of wire. The light lite up. I didnt bring my DVOM to test the voltage at the coil. But for as bright as the test light is, I 99% sure it is getting the correct voltage. Everything seems to check out as it goes into the distributor, but the power doesn't come back out of the distributor.

[RoadWarrior222]

Hasn't hammered or carbed the plugs shut has it? Haven't lost the motor ground strap?

[ShadowFromHell]

Grounds are good all there. Added a block ground and body ground using jumper cables and nothing changed. Havent checked to see if the plugs are "hammered shut". Not sure how that would happen, and all 4 would have to be affected. He said it was running fine, he shut it off, and then it wouldnt restart.

[turbovanman²]

Like I suggested earlier, check cam and ignition rotor timing.

[ShadowFromHell]

If the rotor timing is off, will that cause a no spark situation?

[shackwrrr]

Just thought of this, since the rotor is connected to the shutter wheel that tells the hep when to fire and the hep is connected to the cap, the spark can't happen too far from the contact. It can be out of time relative to the crank but you would still have spark at the plugs. I think you have another problem, weak coil, coil saturation, bad rotor, bad cap, funky spark plugs, or something

[ShadowFromHell]

Ive never had a car loose spark due to improper timing, that's why that thought had never entered my head. But now I am grasping at straws. What is coil saturation? Also, is is possible that the coil to dizzy wire has broken down to the point that it will "transfer" enough electricity that it seems to test okay, but not enough to jump the gap between the rotor and plugs?

[turbovanman²]

Did you change the plug wires or try some known good ones?

I find it odd that 2 coils are doing the same thing. What about robbing some known good parts of your car?

[ShadowFromHell]

At this point, the wires are the only thing that hasnt been changed. Im really thinking of ripping everything off of my CSX and taking it to his house and changing parts until it starts. Ive really been thinking about this, and have a new theory. The coil is good. All three coils have shown the same results. The original, the used, and the new. I have power at the top of the distributor. But Im wondering if the coil to dizzy wire is broken down to the point that is is working well enough to light up a test light but not good enough to transfer the power needed to jump the gap inside the dizzy. Does that sound possible? I didn't take my DVOM with me, so I didnt take a ohm reading from it. But if I am not getting power from the rotor to the wires, it almost has to be a lack of power.

[black86glhs]

I'm really surprised you didn't try another coil wire already. Grab the cap, rotor and all 5 wires from your car and swap them. This will get rid of the guessing game.

[ShadowFromHell]

If the car was at, or even near my house I would have already done that. Its about a 1/2 hour away. That will be the next step.

[black86glhs]

Ok, gotcha. That makes sense.:nod:

[turbovanman²]

So sorry, how are you testing for spark? If I am reading correctly, your using a test light?

Grab a spark plug, grind off the ground electrode, now put that on the coil wire and ground the body, if that sparks, then your coil etc is good, try again at the plug wires, if no spark, then you have a cap/rotor/wire issue, simple as that.

[ShadowFromHell]

Had my buddy replace the coil wire when he got off of work. Still wont start, but he didn't check for spark. Im heading down tomorrow to mess with it. What should I be checking? Obviously spark, but any other places to look? Im going to check the voltage at the coil, use TVM's trick and check spark at the end of the coil wire but other then that Im not sure what else to do.

[ShadowFromHell]

Okay, went and messed with the car today, still no start. But, it has spark. Very very weak spark. Holding the coil wire roughly 1/16" or LESS away from the head I was getting a pulsing spark like I should. Today, I replaced the ground terminal on the battery because it was in bad shape. Then I cleaned ALL the connections in the harness that were around the battery and packed them with dielectric grease. I also swapped the ASD relay with another, with no change. I also put 12v to the positive side of the coil and pulsed the ground. When I did this the coil put out a good, normal spark, so the coil is good. I checked the power at the + side of the coil and was seeing between 8-11v. I think the 8v reading was because I have a cheap DVOM that doesn't respond very fast. I checked all the all the fusable links, all those checked out fine. Again I am at a lost, not sure what to do next.

So whats next?

[RoadWarrior222]

take cap off diz, check it's turning when you crank the engine.

[ShadowFromHell]

That was one of the first things I did. Turning just like it should be.

[turbovanman²]

8 volts isn't enough, make sure its getting battery voltage key on, engine off. If not, you've got some wiring issues.

Has he had any work done prior to this? People like to forget and not tell you the whole story.

Did you check belt timing for shitts and giggles?

[ShadowFromHell]

All the work that has been done on this car since he has owned it has been done with me supervising (Im not supposed to be working on cars). The more I think about it, it does seem to be a bad connection somewhere. But I did clean all the harness plugs that are by the battery. Is there any other ones? What about the one that goes into the cabin, does the coil power/ground run through there? All the factory ground are in place, and I have added extra body and engine grounds with no change. At this point it looks like I need to start tracing both the wires that feed/ground the could and see where they go. Does anyone have a FSM in pdf form for a 89 tbi shadow? If I could study that wiring diagram it would help a TON! He has also had a problem with his wipers working intermittently, maybe there is some corrosion in the cabin plug? I wish I would have checked that today!

I meant to check the cam/crank/dizzy timing today but just spaced it. When your pulling your hair out sometimes you forget things. Once I have spark and no start I will check that, right now Im just trying to get spark back.

[black86glhs]

Here's an idea. Unplug the fuel pump and check the voltage at the coil. If the voltage gets better, try spraying Carb cleaner or something flammable like that into the TB and see if it will light off (just don't spray while someone is cranking the engine over). I don't remember if he had just done a pump or not, but I have seen other items on a circuit or bad connections cause a voltage drop and give you a similar situation.

[turbovanman²]

The coil, injector, fuel pump and maybe a few other items are run by one wire per say, which is at the ASD relay, that relay is turned on by the computer, so check the power going to it, if you have battery volts at the relay but not at the coil, then start unplugging things, IE the fuel pump like Bryan mentioned, fuel injector etc, if the voltate doesn't change, then you have bad wiring. If you don't have battery voltage at the relay, you need to check the feed wires.

[turbovanman²]

The coil, injector, fuel pump and maybe a few other items are run by one wire per say, which is at the ASD relay, that relay is turned on by the computer, so check the power going to it, if you have battery volts at the relay but not at the coil, then start unplugging things, IE the fuel pump like Bryan mentioned, fuel injector etc, if the voltate doesn't change, then you have bad wiring. If you don't have battery voltage at the relay, you need to check the feed wires.

[ShadowFromHell]

Now another thing I forgot to add was that if we added a +12 to the coil and then cranked no spark. If we added a ground and pulsed it, no spark. If we added both (not hooked to car wiring at all) we had lots of spark. So it seems to be both a voltage and ground issue...

[turbovanman²]

It really sounds like a HEP/wiring/computer issue. Did you check wiring and voltages like we asked?

[RoadWarrior222]

HEP is definitely something to hold suspect...

Check there's no fuses "glowing" when you're cranking. I've had nasty cheap fuses that would not blow at something over 3x rating... and that would indicate a short somewhere.

Another thought that keeps occurring to me is that there was a bunch of water in the gas he got...

[ShadowFromHell]

I checked the power at the coil like I said, and had a reading between 8-11v but I think the 8v reading may have been a dvom issue. I havent checked the voltage at the ASD yet because I havent had a chance to get back to the car to work on it.

[ShadowFromHell]

So Ive been thinking.... "manually" operating the coil with no factory wiring hooked up, a +12v and a pulsed ground the car puts out good spark. But with the factory wiring hooked up adding a +12v straight from the battery it still has no spark. If you add a pulsing ground, still no spark. Since Ive been thinking about this non-stop the past few days and I think it proves something. If adding the pulsing ground made spark, it would be the ECU or the wiring. If adding the +12v made spark it would be in the wiring or the ASD. But since neither worked, does that prove that maybe the fuel pump got screwed up from bad gas or alot of junk (since after filling the car up this problem started) it is drawing so much power its not letting the coil get enough power to create spark? Because when I added the +12v to the coil straight from the battery the factory +12v was still hooked up, and it is also hooked to the pump. Thoughts?

[turbovanman²]

So Ive been thinking.... "manually" operating the coil with no factory wiring hooked up, a +12v and a pulsed ground the car puts out good spark. But with the factory wiring hooked up adding a +12v straight from the battery it still has no spark. If you add a pulsing ground, still no spark. Since Ive been thinking about this non-stop the past few days and I think it proves something. If adding the pulsing ground made spark, it would be the ECU or the wiring. If adding the +12v made spark it would be in the wiring or the ASD. But since neither worked, does that prove that maybe the fuel pump got screwed up from bad gas or alot of junk (since after filling the car up this problem started) it is drawing so much power its not letting the coil get enough power to create spark? Because when I added the +12v to the coil straight from the battery the factory +12v was still hooked up, and it is also hooked to the pump. Thoughts?

Its possible, but we've already told you to disconnect the fuel pump and see if you get spark, that will eliminate that.

Its also possible that the cold simply "snapped" the computer and she's done, it happens.

[RoadWarrior222]

It's obvious that this problem is going to require a highly disciplined systematic approach, rather than just trying stuff here and there. The computer service industry has long relied on such practices, and it's from knowledge of their methods of analyzing complex systems that I now make this suggestion...


.. change each tire in turn, in case one of them is flat.



j/k, my gut says declare war on the grounds with harsh abrasives...

[ShadowFromHell]

I know guys, my plan right now is to go try the FP thing, and then go over the harness with a fine toothed comb if the FP thing doesn't work. I haven't got a chance to work on it yet, just wanted to bounce ideas off people that know the EFI system in these cars.

[ScottD]

It's obvious that this problem is going to require a highly disciplined systematic approach, rather than just trying stuff here and there.

Yes!

I don't think you've mentioned checking the codes. Have you cycled the ignition key on off on off on in less than 10 seconds and then watched the check engine light? Sometimes (though not all times in my experience) when the HEP is failing it will trigger a HEP specific code. On an 89 should be a code 54.

If no codes, next thing to do would in my opinion would be go over the engine bay wiring harness and check all the grounds. Take them off, clean with a wire brush, reinstall. There should be one by passenger side frame rail, one on the firewall, and one near the battery tray. I think this is all of them, there may be a 4th, if you have an FSM that will show all of them in the wiring diagrams.

Start simple and go from there.

[black86glhs]

There is one more alternative. Pull the drivetrain and sell it. Go find a bottle of the "good stuff" and drink what is needed to make you not care.



:lol::lol::lol:

[raccoon]

that known good HEP you swapped in. how did you come to the conclusion it was ok? did it come off a running driving car?

I once did the exact same thing, thinking it was a "good" one. really wasted a lot of time.

[ShadowFromHell]

The HEP was the spare that was in the glovebox of my CSX. Dont remember where it came from, stuck it in there years ago.

Got to work on the car this saturday. Unplugged the FP, no change. Added a straight 12v with factory wire unhooked, no change. Hooked the factory 12v back up and unhooked the factory coil ground, added a new one and had a buddy pulse it and viola! SPARK! So then I got the pinouts for the ecu and ran a jumper wire straight from the ECU to the - side of the coil. Again, no spark. So now I am thinking ECU, unless there is a reason other then the ecu being bad that the ecu isnt working like it should.

[turbovanman²]

If your 100% the HEP is good, it sounds like the computer.

[shadow88]

Are you trying a turbo hep in a tbi car? I never tried that before.

[turbovanman²]

Are you trying a turbo hep in a tbi car? I never tried that before.

Good catch, that might not work, but I've never tried it.

[ShadowFromHell]

Ive done it before on my 90 sundance. If you look at TBI HEP's the plastic casting is the same as a turbo. Im 95% sure the HEP is good, but like I said I cant remember where it came from, just that I had it in my CSX as a spare. If the HEP was bad the ASD relay wouldn't be turning on and off would it?

[ShadowFromHell]

Wait... the testing I did to prove the ECU was bad was to run a jumper from the negative side of the coil to a wire on the 14pin. Was that correct? It was the one marked coil control or something like that on the 14pin diagram. Was that correct? If it wasnt, would that hurt the ECU?

[turbovanman²]

Ive done it before on my 90 sundance. If you look at TBI HEP's the plastic casting is the same as a turbo. Im 95% sure the HEP is good, but like I said I cant remember where it came from, just that I had it in my CSX as a spare. If the HEP was bad the ASD relay wouldn't be turning on and off would it?

EDIT-if the HEP is bad or not turning, the ASD relay won't cycle, just had a 2.5 towed in, no start, no fuel pressure or spark, timing belt broken.


Wait... the testing I did to prove the ECU was bad was to run a jumper from the negative side of the coil to a wire on the 14pin. Was that correct? It was the one marked coil control or something like that on the 14pin diagram. Was that correct? If it wasnt, would that hurt the ECU?

If you manually jumped the coil and it works, your sure the HEP is ok, then yeah, it sounds like the computer shitt the bed.

[ShadowFromHell]

Well... Put a new computer in today. Pulled it from a wrecked 89 shadow, tbi 2.5/auto. Car still wont start. It seems now it has lost crank signal. The ASD stays on the 3 seconds and then shuts off during cranking. I put the original HEP in the cap, no change. This car has gave me more grey hairs then all my other TM's put together!

[ShadowFromHell]

Fixed!!! When my buddy installed the new JY ecu he put it in the 60 pin crooked and bent a pin. Once that was fixed and the ecu was actually plugged in it started right up!