Someone shoot the designer of this ignition system...

Falcon4 · Post by **Falcon4** » Sun Oct 21, 2007 7:45 pm

Ignition problems have been haunting my poor Fiero for months now. I guess if it's not fuel problems, cooling problems, or interior problems, it's something else, and this time it chose the ignition system.

For the past few months, I'd had intermittent problems with the pickup coil coming somehow "unconnected" to the ignition module - that is, it's plugged in, but not delivering a signal, resulting in a "0" tach while cranking. It happened about once a month, where I'd get a stuck tach while cranking, and I had come to learn a surefire way to fix that problem - go in the back, unscrew the distributor cap, wiggle the wire, put it back together, and hit the road. It worked every time, but was still annoying to have that problem occur at totally random times.

Now, I come upon a different problem. Now, for some reason, the ignition seems to be "skipping" beats. The engine runs "rough" in a weird way - where it just seems to miss random cylinders, causing a "bump" each time it happens, in no rhythm whatsoever. The tach also reflects those bumps rather distinctly.

Tried replacing the ignition module (from the original one to a cheapie BrandX one I hadn't yet installed for any length of time), then tried replacing the coil (from a BrandX one to the original one), and all I get is still the same behavior. The pickup coil is also "new" (less than 10,000 miles, I'd say) and I haven't bothered tearing the whole distributor apart to try replacing it. The only ignition items I can think of that I haven't replaced are the ECM (yeah, right!), and the tach filter with fraying, shorting, really-fucked-up wires. Only reason I haven't replaced THAT is because I haven't found one that includes the plug (which I need, badly), and because if I understand correctly, it only affects the tach gauge. ...Right?

I took a video of what the tach does as I drive and idle. It might be of some help. It was taken with my PPC, so the picture is clear but has a lot of motion blur... =\
(Will have video in a moment, having trouble getting the FLV converter to cooperate and there's no way I'm posting this publicly on YouTube...)

And at this point I'm really not sure what the hell the problem is, so I'm open to suggestions. So long as they're not "replace your headlights, lol"... :salute:

Xanth · Post by **Xanth** » Sun Oct 21, 2007 7:49 pm

Don't rule out the ECM yet, I had the same problem for months and replaced nearly EVERYTHING, hundreds of dollars at that damn hiccup, coil, plugs, wires, module, pick-up, grounds, cap, rotor, etc.

It was a stumble that occured at all RPMs, though I didn't really notice it when flooring it. My tach also clearly showed the bumps.

I bought the ECM as a "why the hell not" , turned out the entire time the rebuilt ECM that was in the car was no good. :cussing: You can get a used one cheap on Old Europe, maybe someone here has one too.

Also you can bypass the tach filter if you're concerned about it, just unplug it and jumper the two wires it was connected to.

Falcon4 · Post by **Falcon4** » Sun Oct 21, 2007 8:21 pm

... Hmm. Well, I haven't seen a SES light in a very, very long time, I wonder if it's still counting?

I should have a look at that. Tuesday's my day off (today and tomorrow I still have to deliver pizza with my poor car, GAH!), so I'll have a look at the ECM then. Just out of sheer curiosity, is the ECM a sealed box, or is it "user" serviceable (e.g. by someone with mediocre electronics skills)?

p8ntman442 · Post by **p8ntman442** » Sun Oct 21, 2007 8:31 pm

sounds like a coil on its way out.

Falcon4 · Post by **Falcon4** » Sun Oct 21, 2007 8:33 pm

Well, I finally got that damn video converted and uploaded... =\

http://hostfile.org/viewfile.php?file=V ... 20x240.flv

Guess it wasn't as useful as I thought... can't really hear the engine noise but you can see the back/forth shaking.

Oh, and I should mention... it does seem to be getting noticeably worse as I continue to use the car. So whatever I fix, it'd better be soon =o

edit:

p8ntman442 wrote:sounds like a coil on its way out.

Falcon4 wrote:...then tried replacing the coil (from a BrandX one to the original one), and all I get is still the same behavior.

<.<

Xanth · Post by **Xanth** » Sun Oct 21, 2007 8:35 pm

Falcon4 wrote:... Hmm. Well, I haven't seen a SES light in a very, very long time, I wonder if it's still counting?

I should have a look at that. Tuesday's my day off (today and tomorrow I still have to deliver pizza with my poor car, GAH!), so I'll have a look at the ECM then. Just out of sheer curiosity, is the ECM a sealed box, or is it "user" serviceable (e.g. by someone with mediocre electronics skills)?

You can open up the ECM, nothing in there makes any sense to me though. I would have no way of identifiying a problem area unless it was something as obvious as a blown cap. I think it is mostly low-tech besides the PROM chip, you may be able to make some sense of it.

Even though my ECM was bad, the SES light still functioned, and I was able to hook up my laptop with a ALDL cable with no obvious signs of failure. I got my used ECM for $15 with the prom chip.

As an added note, I suppose it may be possible the PROM chip itself was bad. I don't fully know its function, but I used the one in the new ECM rather than swap in mine, so I suppose my chip could have been the issue.

Falcon4 · Post by **Falcon4** » Sun Oct 21, 2007 8:40 pm

Well, the PROM (Programmable ROM) chip should only contain car-specific information like the VIN (maybe), engine-specific information, and maybe a program the system runs... Hell, I'd love to open up the ECM just to see what chips make the car tick

15 bucks, you say? That's a steal considering the Fiero Store wants 100 bucks for one! =o

The Dark Side of Will · Sun Oct 21, 2007 9:23 pm

ECM does not contain a VIN... at least ones that old don't.

What condition are your plugwires in? I've experienced similar "hiccuping" signs from a generally shitty $20 set of plug wires. Problems vanished when I dropped $50 on a set of Accel universal wires and built them for the V6.

Has your pickup coil been replaced? I have seen a problem with the conformal coat on GP Sorensen pickup coils that allows stray strands from the coil to module wires to ground to the distributor body intermittently. It sounds like that's a possibility with your pickup coil problem, as my car again had similar signs. AC Delco coils are identical except that they have superior conformal coating that eliminates the potential problem (but they cost twice what the GPS coils cost...).

Falcon4 · Post by **Falcon4** » Mon Oct 22, 2007 1:32 am

Ah, fuck. Wild goose chase again? =P On a Pizza Hut budget (which, granted, is better than what I had with previous repairs)... geh!

Well, I'm starting with a new tach filter, because I can see with my own eyes that it's on its very last leg, and has caused problems in the past by shorting one of the frayed wires to ground. Wasn't TOO expensive anyway, only 30 bucks for a new one from TFS.

But I can say the problem definitely seems to be getting worse by the mile. It seems to be missing 1 fire a second now, making for a very rough ride - and sometimes those statistics get mashed together for missing two or three fires in a row, almost stalling at idle. Oddly, it doesn't translate up to higher RPMs, it actually misses at the same frequency, not per engine revolution, if that makes any sense.

Plug wires? Quite likely, especially those ones on the back (front, I guess), by the firewall. I did replace the original ones when I first gt it, too.

Eh, ramble ramble. I'm at a hockey game on my PPC. I wub my ppc. O don,t blame ne if I missed a letter or two above. Stupid thumb keyboard...

Ah, and yeah, the pickup coil is, uh, replaced new and cheap (from a Niehoff-branded box...). Shrug...

Starlite528 · Post by **Starlite528** » Mon Oct 22, 2007 1:57 am

My car failed smog the first time I did it this year. It was making missing cylinder noises and it wasn't until I got jolted real good by the plug wires.

It failed with two hundred something on hydrocarbons, but CO was in the clear. Replaced the plug wires and it passed well in the clear.

YMMV

Falcon4 · Post by **Falcon4** » Mon Oct 22, 2007 2:24 am

Well, that does it for me. Next stop, plug wires. Cheaper and more readily available than a new damn ECM anyway.

So, without getting racing or show car profssional, what do you think I should ge, or rather, where should I get it? We're talking less than thirty bucks, right? I need something that'll get me through the next few months, not particularly concerned about lasting a Really Long Time. The damn wires get cooked under that hood anyway

I was thinking of going to Pep Poys and getting a set of wires, and depending on my plugs' condition, maybe a new set of plugs too. Still the same plugs since before I replaced the head gaskets. Gah. Objections? Better ideas? Long as I can buy it locally in this big city, I'm all ears

And thanks for the help! I would never have suspected the wires...

Starlite528 · Post by **Starlite528** » Mon Oct 22, 2007 3:16 am

I just got the regular plug wires from CQ auto parts for like 20 bux. The reason mine failed before was mainly because they were bent at a wrong angle, and one got pushed up against the exhaust manifold the last day of their lives (after which I got a shocking awakening)

Falcon4 · Post by **Falcon4** » Mon Oct 22, 2007 3:48 am

Oh, let me tell you how many times I've had an unpleasant brush with sparks. Come anywhere near the tower boot, with the engine running, even if I'm leaning from a mile away from the car, I get a blast of awakening magic. Fun times. =o

p8ntman442 · Post by **p8ntman442** » Mon Oct 22, 2007 5:36 am

if your getting shocked, your wires are fucked, replace them. I went through several sets of $20 wires until I ponied up for $100 magnecores but the magnecores come with 2 stickers!

The Dark Side of Will · Mon Oct 22, 2007 9:35 am

A $20 set of plug wires will last about 6 months, even if you don't let them touch your exhaust manifolds.

Pay $20 three times over the next year and a half, or pay $50-100 now and not need to plug wires for years.

Starlite528 · Post by **Starlite528** » Tue Oct 23, 2007 12:14 am

The 20 dollar wires are going to have to do for now. I can't afford to get the 'spensive wires in one shot with the pay I'm making, not yet anyways. The one wire in the front was failing, but the wire in the back failed after the bologna with the fuel pump wire, because I somehow let it rest on the manifold. It wasn't until the next day when it ran like total puke that I started poking around and got it good. :rotflmao:

This spark wire was one of the highest voltage shocks I've had that really hurt. In second place, I brushed a 220volt prong as I was unplugging something when I was deployed in Egypt. In first place was the nine volt battery incident; 50 used 9volts from wireless mics in a big string. Made a nice inch long arc with some RG-6, then I brushed my hand on it by mistake. (8x50=400)(8 because they're slightly used).

Falcon4 · Post by **Falcon4** » Tue Oct 23, 2007 4:10 am

Well, seems to have reached the peak of its shit-running-ness... still drivable, but definitely not a "comfortable" ride (is a Fiero ever a "comfy" ride?). Couldn't get the new wires today, since I was working (bleh) from 4 to way-past-bedtime tonight and I wake up at like, noon. Tomorrow and Wednesday I have off though (yippee!).

And yeah, come to think of it, for a (visible) spark to choose my finger as a path-of-least-resistance over the fucking spark plugs, is a rather obvious note of "no shit sherlock, there's your problem". I take it that touching the tower wire boot on the distributor cap SHOULDN'T result in an awakening jolt?

The Dark Side of Will · Tue Oct 23, 2007 7:34 am

Right. That's what the boot's for...

Mach10 · Post by **Mach10** » Tue Oct 23, 2007 10:03 am

3 things:

1) You never mentioned if you'd fixed that sloppy connection in the distributor. A bad connection to the pickup coil can cause spark scatter. This will make it run rough at the best of times. spark Scatter doesn't mean it' earths to ground through your wrist-watch, just that the timing gets all screwed up. Pull the bizzatch apart, take the connector apart and either crimp on a new one, or see if you can't clean out the contacts and tighten them.

2) You should be able to grab the block with one hand, the distributor with the other, and never have a single hair on your arm stand up. Your wires is fuck-ed.

3) You also never mentioned if you re-timed the car correctly last time you had the distro apart... And if you did, make sure the distributor hold-down is tight... A distributor that's walking around will also make things progressively worse.

Suggestion:

1) Line up the motor to #1 TDC/Compression (keep turning until you get compression, then line the front pulley to 0Âº
2) Scribe the distributor base and the block together so that you have a reference.
3) Pull the cap off, and mark the rotor position so you have a reference.
4) Yank the distributor OUT
5) Dissassemble, clean like nobody's fucking business. Scour the contacts until they gleam, test the operation of the pickup coil (multimeter, 2000kOhm, resistance should spike every time the reluctor ring lines up with the points on the shaft)
6) Rob some random junky for a syringe (or buy one from the pharmacy) and use it to pack every damn connector full of dielectric grease (AKA spark boot grease)
7) Pull off the module, and use fine sandpaper or scotchbrite to polish the base AND where it sits on the distributor to a shine. Then coat with dielectric grease and reinstall (makes sure the ground is solid--and that it's not overheating)

Replace the rotor
9) Replace the cap
10) Use brake-cleaner to clean out the wiring harness connections, toothpick and steel wool if the contacts look particularly bad.
11) Put everything back together so that everything lines up to the marks you made earlier. Take this opportunity to install your brand new spark plug wires
12) Start the car, let it get up to temperature.
13) Jam a paperclip into the AB ports of the ALDL connector--ignore any change in engine idle/whatever
14) Pull out your trusty timing light (or rob the Junky again, steal his heroine, sell it, and buy one) and set to 8Âº Advance
15) Come back and tell me how much I rule, or else come back and bitch about how that solved nothing and wasted your afternoon--either way, I'm happy

Falcon4 · Post by **Falcon4** » Tue Oct 23, 2007 4:55 pm

I kinda stopped reading seriously after step #1, the whole "rotate" part. You know, like people think car engines have this huge propeller on the end of them that you can just grab, and "turn" to any desired position. I take it you haven't seen a 2.hate in a while? Er, like, how impossible it is to turn those fuckers? Didn't we go over that on Old Europe with the whole head gasket, valve lash, whatever crap? I just tapped the starter because that shaft was going nowhere fast.

Oh - and yeah, I already did all the whole distributor-rebuilding thing a few thousand miles ago. And I timed it, and screwed it down tight (because I went through so much hell getting it timed right the last time). It's also got a "new" block (it seems), so it doesn't run THAT bad, or need "wood blocks holding up the engine" ghettorigging QUITE yet

But I did get the new wires, I'm now just waiting for the damn engine to cool off first. Gonna head out in a sec and put a little battery powered fan on it to speed up the process by a few minutes

As for mileage? I check each time I fill up... 15 MPG. :puke: