Still No Spark

[tooldude]

Are you trying to get an analog voltmeter to test for trouble codes? I believe you could do it with a test light.

[Zanzer]

^^ The Haynes manual has a procedure for doing it with an analog meter, but you can actually just ground the STI plug and count the CEL flashes.


Also, I agree with tooldude, this job is much easier with the proper schematics. I've been chasing an electrical problem in a 89 auto for a couple of days now. No injector pulse, no +12v at the injector plugs. I traced back through the wiring using the [proper] schematics, a test light, and a DVM. As I looked at the drawing and followed everything back I found that the problem HAD to be something with the 15A engine fuse! It seemed odd because the fuse checked out good on both legs with a test light and DVM set for Ohm's. I said "screw it! It has to be there!" and I dropped out the fuse panel. Well it seems that someone had gotten creative with the wiring at some point in the past and where the wire should have been terminated now hung a nice blue crimp connector with nothing going to it. I pulled the connector from the fuse block, did as good of a patch job as I could with what I had left, and now the car runs once again. Although it could use a harness swap due to the PO's wiring debacle.

[getnpsi]

I would turn the key on and start yanking on that positive battery cable. No one bolts down their batteries admit it...4 used festivas, none of them had sun visors, and none of them had secure batteries...anyway...so all of that area shakes around and is generally loose. Overheat the engine and it vomits rust water on top of the relay box. 10 bucks all the shaking will make a connection and you'll hear the relay energize. The outer fuse links are the ones to check, not the center one. In the thread he admitted he still hasn't ruled it out!

[Zanzer]

Hey Toast....who's your buddy? :mrgreen:

Page 1


Page 2


Page 3


Page 4



Send me a PM with your email addy and I'll send you an electronic copy of a 1991 service manual. I know it isn't the exact year but I'm willing to wager there is little to no difference.

[burnt_toast]

Wow, lots to respond to. Here we go:

Rhodestiva: I accidentally tested it I think, by sending 12V down the ICM pulse wire. It tripped the main relay I assume. It's the only electrical do-dad I saw in that area and it was definitely a relay "clunk" sound. I have not actually checked to see if it's tripping while cranking though.

1chrisapple:
it sounds like you are describing a problem someone was talking about earlier in this thread about getting spark and then it suddenly losing it. May have some hints if you read back through it. I am def not as the "sell point" as there are several things to rule out and I still have several possibilities. I will never sell this thing. I will drive it until parts can't be bought or fabricated and then I will gut it and make a flower pot out of it. It's the best car I've ever had.

Tooldude:
I know the test light was a jackass move; I'm just working with what I have. Once I probed the wrong thing and (I think) tripped the main relay I was given sufficient fear to have more respect for the electrical system in general. I primarily do electric trouble shooting on old motorcycles (hard to make a mistake) or aircraft (the book tells you specifically what pins to check and you always have the right tool available). I want an analog multimeter simply to verify there is an injection pulse signal or not. The digital mutlimeter may not be seeing it (that's my fear). Watching it read the CKP pulse as a very steady .30-.32 volts had me really wonder what this $3.99 multimeter is capable of.

Also, for injectors, I only removed the #4 wire and checked between the 2 connectors for volts DC while "ON" and while cranking. I will pull all 4 and check. I expect not to see pulse. I pulled the #1 spark plug and cranked to check for spark once and saw no fuel mist/smell expelled from the spark plug hole. While it of course could be a bad injector, I'm expecting to find no signal going to them. I'll check and report back

As for the tests described in your last main post, I'll be on that Monday morning and report back. I think tomorrow (Sunday) night I will have enough time to at least check the injector pulse properly. If I have no injector pulse, no spark, and no CEL I'm going right at the ECA and it's grounds. There have been some good offers on my Parts Wanted thread that are far less painful than the prices on ebay.

Getnpsi:

I've had the battery out to charge it so I not their connections are good. The fuse block is quite corroded so I've not ruled it out. If I could find the damn thing in the wiring diagram I could look at the items running through each block and easily verify if all of them are working or not. However, usually with blocks like that you'll have a bunch of stuff not working. I have no idea how to test them other than to verify each thing they are controlling is not working. I tried swapping the outer links but nothing changed. The links have continuity so I have to assume they work. The fuse block itself is corroded but I'm not sharp enough to devise a proper test to verify. I was surprised though that when I checked for continuity I got none (between the black wire coming off the fuse block and the engine block). Still, if that entire block was bad, the main link would also not work and how would I have power to anything? I haven't ruled it out, but I'm keepin' my eyes on the prize; the ECA or ICM.

Zanzer:

Heck yeah! That is much more detailed than the wiring diagram in the Haynes manual. I still don't see the fusible links in there but I only scanned through the img you posted for a quick second. I'll shoot you a PM.

Everyone:

Thanks for all the help and support. Just sitting here typing what I'm doing actually has given me 2-3 "oh shit" moments where I realized I was missing things or doing tests wrong. It's been a big help just forcing myself to explain what I'm doing. It makes my scattered thoughts seem a bit more organized, and it also reminds me that I'm in over my head and need to slow down and figure out what I'm doing before I do it. It's so easy to start testing this and that, but if you don't remember what you're checking and why (and what the result was) you are just running in circles.

Cheers,
-toast

[tooldude]

The first diagram has aview of the one fusible link that you have to deal with. It's the one immediately after the battery. The other fusible links don't show in this view because they are not in these circuits.

[tooldude]

To further clarify this a little bit for you, the first picture goes to the left of the second (middle) picture and the third one is on the right. These are the ones I was telling you about but I don't know how to post pictures yet, and I'm not sure how they would come out on my phone camera. I was wanting to post them for you.

[Zanzer]

Email sent, should hit your inbox soon.


PS: Just hit my 2k post milestone. Woo hoo! :mrgreen:

[tooldude]

Well I see something went wrong on my edit, it's supposed to read: To further clarify this a little bit for you, the pictures lay out from left to right. The fusible link you want is the one at the top of the 1st picture, right after the battery, under "main fuse link panel" (doesn't show it's 15A). Only one link is shown because it's the only one in this circuit. Notice that the B/W wires at the top of Pic.4 [A] connect back to the B/W wires at the top of pic.1 [A]. Regarding your earlier question on fusible links- they are only wires engineered to burn out at a rated amperage. They have a special insulation designed to not catch on fire from the heat. They are not designed to arc to ground, just melt through.You can test for B+ getting through that link if you connect to battery negative and probe for B+ on the W/BL wire where it comes out or at the relay. I don't know if you know this: the only good way to test that circuit for bad connections is by a voltage-drop test. This can only be done once you have power restored through that circuit. You have to have current flowing (circuit on) to register voltage drops. Of course, right now you still need to check for static voltage to be there so that you HAVE a circuit. If you are not knowledgeable about voltage-drop testing I'll be glad to get with you on that.

[burnt_toast]

All great info. Heading out to the car to check the injectors, then will come back in and re-read on fusible links. I'm pretty weak in electrical trouble shooting so it takes several reads to understand. The military training I have is always "check pin 1 here and pin 19 here and see xxx ohms or volts" so you don't get any theory, just how to test a part like a monkey. My hands-on is from vintage motorcycles, and you don't even need a wiring diagram 90% of the time on a bike from the 70's; there are so few wires you can trace them all by hand and the problem is always one of 2-3 things.

Anyway,l lemmie verify the injector pulse isn't happening before it gets any hotter outside, then seek some shelter and read up on the fusible links post. I'm familiar with voltage drop tests though I don't consider myself an expert. I totally get how to do it, but usually don't know what I'm really seeing. Of course, I don't usually have a schematic either, and diagrams in service manuals don't usually show a logical flow to me, so that might be the source of my confusion. For any lurkers following along, this is the video I used to learn what a voltage drop test is/does:

-toast

[burnt_toast]

Question on the fusible links:
I just saw in a video that if something is corroded green (oxide) there is not way to clean it, as the oxide starts from within and works it's way out. I don't particularly believe it, but the fisuble links were all pretty corroded. I cleaned the crap out of them but here is a shot of one before I cleaned it:

http://johnnykillmore.smugmug.com/Ot...3jC86&lb=1&s=O

Not the worst in the world, but not bad either. They cleaned up pretty well I thought, and I did the blades in the fuse block with a small file as well. Just tryin' to rule everything out.
-toast

[Zanzer]

Yikes! Those are pretty nasty. May be time to swap to the cartridge type. You can probe across the link and see if it's getting 12v through it after you cleaned and reinstall them. Or you can set your meter for Ohm's and check them for continuity, but it would be best to do this on the backside of the block so you aren't just testing the link itself.

[burnt_toast]

Okay I am totally baffled at the fusible links, particularly the fuse block. Lemmie just run through what I did though, then end with that.

• Pulled all four connectors from the fuel injectors (hey, that rhymes)
• Starting at injector #1, I probe the 2 wires, key ON and get 0.1 volt DC
• I verify I am on the 20VDC setting and not on a higher setting. I am on the correct setting.
• I crank the engine and see the reading jumping around. It almost entirely is reading negative voltage, but I still assume I'm get getting a pulse cuz, hey, it's jumping around.
• I repeat the same with injector #4's connector and get the same result.
• Plugging in #1 I check #4 and get nothing with key ON or START.
• I unplug #1 and plug in #4, then test #1. Still nothing. I then plug in #2 and get nothing ON or START.
• Not believing all of the injectors are bad, I check resistance across the pins of the injectors themselves. I can't reach #2, but #1,#3, and #4 all read 15.1 ohms.

Okay, now I go to the fuse block because I think I'm getting injector pulse. I re-verify the 10amp fuse in the dashboard fuse box has continuity and that 12V are coming to it with key ON by probing the slots the fuse goes in. I get 12.5VDC.

The battery shows 12.6VDC across it's posts. so I move to the fusible links and the block they go in. Here's where I get way confused.

• There is continuity on all 3 fusible links. The one I was told to focus in is the inboard-most one (marked EGI on the fuse block).
• I get no continuity between the 2 blades the EGI fusible link goes in. I check down where the black wire connects instead of at the blade and still get nothing.
• Not understanding how all 3 fusible links go to a single black wire after exiting the fuse block I start wondering about that side. I go from the screw holding that wire to the block and check for continuity to the negative post of the battery. Nothing. I'm obviously not getting this.
• Screw it, I'll start looking for volts DC. Key ON and I try probing the EGI fusible link itself and get nothing. I back probe into the fuse block, taking the EGI wire and the screw holding the black wire to the fuse block. That HAS to work... I get 0.01VDC. Wtf?!!!
• I flip the meter to 2000m setting and get 009. WTF?!! I got to the 200m setting and see 8.4. "This can't be real" I say to myself.
• I take the negative lead to the meter off the fuse block, set it again to 20VDC and go to the negative terminal on the battery. -12.5V. Thinking that odd, I flip the meter leads so the negative is back-probing the white/blue wire of the fuse block and the positive lead is on the negative battery post. +12.5V.

Oh and also-- since I was right there-- I hold the main relay to feel it "click" when the key goes ON and also back to OFF (EDIT: the schematic shows the main relay having different color wires than the relay I grabbed)


So, I'm getting milivolts through the fuse block but 12.5 if I use the battery instead of the fuse block's ground. It appears I'm not getting 12V to the injector wires but it still seems to be pulsing when I crank the engine. I'd like to know how that's possible. I also no longer think I have a clue how the fuse block works. I always thought fuses were inline and power just ran right through the fuse. How can all 3 of those fusible links cross over to the exact same plate and same black wire? This system is different than the fusible link on my van, although the concept is similar. It's a single heavy gauge wire that a bunch of hot wires meet at one end, and then the other end runs down to the positive battery terminal.

-toast

[Zanzer]

Your injectors plugs are dead. That tiny little reading you're getting is just noise.

All 3 fusible links pull 12 volts from the single wire that feeds one side of the block and distributes it to 3 wires on the opposite side. That's why there's only 1 wire on the outer facing side of the block (incoming), those 3 hots are strapped together to feed single wires on the inner facing side (outgoing).

Check to see if you have 12V at the purge canister solenoid plug and IAC plug (the blue plug just to the right of the exit of intake runner #4). If those are dead as well sounds like you still have a fusible link issue or either there's a wire broken after the 10 amp engine fuse or in that part of the circuit feeding the injector plugs and the 2 other plugs I listed.

[FestYboy]

toast, your testing the injector harness incorrectly. with the key on, you should see battery voltage at the injector plugs (all of them). the injectors are HOT all the time with the key on. what changes is the ECU controled ground. so to clarify, if you want to make sure that your injectors have power, the negative probe of your DVOM should be attached to the BATTERY ground (not the plug), and the positive probe should touch the (green/yellow?) wire of the injector plug. then turn the key on, you should see battery voltage.

i still think you should be focused on the lack of spark issue.