Topic: Question On Grounding/Wiring/Ignition woes (Read 16947 times)

patsmx5 · « **on:** April 12, 2009, 12:31:34 AM »

While back I thought I knew what I was doing, and I wired rewired my car for MegaSquirt 2 Extra and Ford EDIS 4 ignition (supposed to be a badass, simple, reliable ignition...). Made an entire new engine harness. This is the schematic of how it's wired, for the most part. Well, this is mainly how I think it should be wired, and for the most part, this is how it is with very little deviation. Yeah the schematic is shitty. I could redo it, and I might. I could clean it up and make it look neater, but whatever...

Questions:
Is there anything fundamentally wrong?
Are there any ground loops?
Why do I have sensor noise on my CLT sensor?
Why does my EDIS 4 ignition system hate me?
What would you change to make the system better and reduce sensor noise?

My damn ignition system is just loosing its mind. Keep in mind it worked great for a couple months boosted. Even ran 15 PSI before and it worked PERFECT. Now I loose spark when it boost. Like I hit anti lag. I'm running 11 PSI and .020" gap on new 5k ohm resistor NGK BKR6E sparkplugs. New tested OEM equivalent Bosch Professional Series wires. Tried two ignition modules, then bought a new one. One used coil, then a new one. One used VR sensor, then a new one. Four sets of plugs. When I put new plugs, it seems to run right for a day (only pattern I've noticed). It even misses at idle and cruise. It just flat out stops igniting the mixture at full boost sometimes, or sometimes at 8 PSI, or 5, or 2. Just whatever it feels like. All wiring has been double and triple checked.

I'm at the point that I don't know what to do next. Perhaps make another new wiring harness for the ignition system is my only idea. I put it the gap to .040" and it wouldn't make but like 2 PSI before spark cuts out. Then .030" and maybe 6 PSI. Now at .020" and it always cuts out a 11 PSI, but varies from 2-11 PSI.

$10.00 to whoever if they figure out why my car misses.

patsmx5 · « **Reply #1 on:** April 12, 2009, 12:51:29 AM »

Gonna test the coil out with a meter tomorrow. I know I've gotten bad coils before. And come to think of it, it usually runs "perfect" for about 20 seconds from a cold start up before the miss at idle/everywhere becomes noticeable.

patsmx5 · « **Reply #2 on:** April 12, 2009, 01:00:20 AM »

Ignition sucking:

patsmx5 · « **Reply #3 on:** April 12, 2009, 11:50:15 AM »

Quote from: c0mpl3x on April 12, 2009, 01:42:50 AM

dont use resistor plugs?

Pretty much all fuel injected engines use resistor plugs. It cuts down on EMI, RFI, and all that. OEM plug is a BKR5E, so this one is just one step cooler from stock.

patsmx5 · « **Reply #4 on:** April 12, 2009, 04:39:38 PM »

Well....... This is weird. Sorta fixed it. I redid the ground for the EDIS 4 module today. Measured the old one a 0.00 ohm resistance, but decided to redo it anyways. It was actually grounded to the body before. I made a new 12 gauge wire for it, crimped a new ring terminal to the wire, cleaned the body area where it bolts to with a dremel to perfectly clean metal, and bolted it down securely. New one measured 0.00 ohm resistance, but should be better/perfect now.

Datalogging, I fired it up and it idles the same for about 2 minutes. Then it got a weeeee bit better. Still misses, but maybe not as bad as before. Now I've had the idle around 1400 RPMs forever, so it makes it harder to detect a misfire. So I put it down in the 600 RPM range it it's much easier to hear it skip a beat now, and now the motor visually torques/jumps over more when it misses. (which it does so 2-3 times every second now, think "dahhh, da, da, dahhhhh, da, dahhhhh, da, dahh, da, dahhhh....").

However, it doesn't completely "cut out" any more at full boost. Made probably 30 boosted pulls :yes: :yes: :yes: :yes: :yes: :yes: :yes: :yes: :yes: :yes: :yes: and it only cut out when I hit fuel cut at 7100 RPMs! Haven't found fuel cut in forever!

But, it's still not 'right'. Datalogs show RPM is always fluctuating 40-50 RPMs, even when boosting. IE- it's still missing, and I can tell cause power ain't what it should be. So, now I'm officially stumped. I did buy some new Motor Craft sparkplugs I figured I'd install just in case this EDIS ignition is partial to a Ford plug. But they're the factory heat range, not cooler, so I'm fixin'a see if I can look up the correct part number for this plug, in a cooler range, since the folks at autozone just work there, and are clueless.

patsmx5 · « **Reply #5 on:** April 12, 2009, 06:31:57 PM »

Quote from: c0mpl3x on April 12, 2009, 06:24:07 PM

try stock plugs if you have them, and id say your ohmmeter is off because wire HAS resistance, albeit very little in short distances

The meter does suck, agreed. It won't even read milli ohm directly. POS from RadioShack. I never would have bought it if I would have known what a piece it is.

Pulled the 1 heatrange cooler NGK BKR6E plugs out after 30 boosted pulls, and the rear most cylinder plug's insulator was a lot cleaner than the other three (IE-it wasn't running ass cool). So I put a new set of NGK BKR7E's, which are two heat ranges cooler than stock. Also gaped them to .040" instead of .020. It's raining, so I couldn't get to full boost to see how it does with the colder plug and larger gap.

From memory, 12 gauge wire is like 2.2e^-4 ohms per foot I think.

patsmx5 · « **Reply #6 on:** April 12, 2009, 07:19:37 PM »

Datlog pics after redoing that ground wire.

As you can see, better, but not fixed. The crazy looking shit at high RPM is fuel cut, so that's normal. But if you look, you can see RPM is still wiggly, where it should be smooth.

patsmx5 · « **Reply #7 on:** April 12, 2009, 07:21:02 PM »

BTW, 75% duty cycle on 550's running 62 PSI fuel pressure in a 2100 pound car = fast.

Joseph Davis · « **Reply #8 on:** April 13, 2009, 11:54:29 AM »

Quote from: patsmx5 on April 12, 2009, 12:31:34 AM

$10.00 to whoever if they figure out why my car misses.

There is no ground in that schematic.

Quote from: patsmx5 on April 12, 2009, 04:39:38 PM

Well....... This is weird. Sorta fixed it. I redid the ground for the EDIS 4 module today. Measured the old one a 0.00 ohm resistance, but decided to redo it anyways. It was actually grounded to the body before. I made a new 12 gauge wire for it, crimped a new ring terminal to the wire, cleaned the body area where it bolts to with a dremel to perfectly clean metal, and bolted it down securely. New one measured 0.00 ohm resistance, but should be better/perfect now.

That is not ground. All you did is alleviate some of the resistance under load in the circuit. Try grounding the system.

My paypal is pgmfielf@gmail.com, and your answer to your engine management problem is in the engine management forum.

patsmx5 · « **Reply #9 on:** April 13, 2009, 01:28:43 PM »

I read this: http://www.realhomemadeturbo.com/forum/index.php?topic=1195 5 times so far. Not sure I understand how it's not grounded.

patsmx5 · « **Reply #10 on:** April 13, 2009, 02:30:06 PM »

Is this any better with regard to AIT and CLT sensors?

Joseph Davis · « **Reply #11 on:** April 13, 2009, 04:31:02 PM »

I'm still not seeing a ground anywhere in that diagram.

patsmx5 · « **Reply #12 on:** April 13, 2009, 04:35:34 PM »

Quote from: Joseph Davis on April 13, 2009, 04:31:02 PM

I'm still not seeing a ground anywhere in that diagram.

Well, I'm confused. The car runs, FWIW.

Joseph Davis · « **Reply #13 on:** April 13, 2009, 04:37:34 PM »

Quote from: patsmx5 on April 13, 2009, 04:35:34 PM

Quote from: Joseph Davis on April 13, 2009, 04:31:02 PM
I'm still not seeing a ground anywhere in that diagram.
Well, I'm confused. The car runs poorly, FWIW.

Yeah, ground problems cause that.

patsmx5 · « **Reply #14 on:** April 13, 2009, 04:48:38 PM »

Grounded now?

Joseph Davis · « **Reply #15 on:** April 13, 2009, 04:59:24 PM »

No change that I can discern, but I'm looking for grounds and not at individual wires.

Maybe you should try questioning your premises, or sending me my ten dollars, or hell here's a crazy thought posting this in the correct forum so the guy who knows the answer to your question quits playing silly games.

patsmx5 · « **Reply #16 on:** April 13, 2009, 05:07:00 PM »

Quote from: Joseph Davis on April 13, 2009, 04:59:24 PM

No change that I can discern, but I'm looking for grounds and not at individual wires.

Maybe you should try questioning your premises, or sending me my ten dollars, or hell here's a crazy thought posting this in the correct forum so the guy who knows the answer to your question quits playing silly games.

Yeah, I realized it's in the wrong forum, my bad. Can't a mod move it? Dunno what premises I should be questioning either. The blocks with wires going to them are grounding bars, like what you see inside a breaker box inside your house.

Joseph Davis · « **Reply #17 on:** April 13, 2009, 05:53:08 PM »

The grounding bars, if hit with dielectric to prevent corrosion, are a good idea. Frankly, I've been pondering something similar. However, they aren't grounded either.

Keep spinning the concept in your head.

patsmx5 · « **Reply #18 on:** April 13, 2009, 06:00:25 PM »

Quote from: Joseph Davis on April 13, 2009, 05:53:08 PM

The grounding bars, if hit with dielectric to prevent corrosion, are a good idea. Frankly, I've been pondering something similar. However, they aren't grounded either.

Keep spinning the concept in your head.

Yeah, they they do corrode. I should have used dielectric on them. How they aren't grounded is beyond me. Wires hook to the ground bar, and a wire connects the ground bar to the "chassis" which is a huge metal frame thingy on the car, which is where the Negative battery cable connects. There is only like 1 wire going from the block to the body though, so I can see that being a problem with grounding shit to body, then it all has to go through that one wire, through the block, back to chassis.

Gonna make a new engine harness this summer again if I can pry out how to ground it properly from you before mid early June.

Joseph Davis · « **Reply #19 on:** April 13, 2009, 06:07:11 PM »

So close. So almost there.

patsmx5 · « **Reply #20 on:** April 13, 2009, 06:17:18 PM »

Run a new wire from chassis to body, or just run a new wire from Chassis right to the ignition system's ground? Hell, perhaps there shouldn't even be a wire going from the block to the body, but that's the OEM ground.

stealthiskey · « **Reply #21 on:** April 13, 2009, 06:24:30 PM »

I think JD's getting at putting a ground on the cylinder head since that's where the spark plugs are grounded, or connecting it with your other grounds.

patsmx5 · « **Reply #22 on:** April 13, 2009, 06:30:20 PM »

So I need to run a big ass wire from the chassis to the head, and hook the ignition systems ground right there to the same lug as the big ass ground to complete the loop when the system fires the plug? Or one heavy wire going from the head right to the negative of the battery? Hell, right now the ignition system is having to ground through some tiny braided factory line that goes from the block to the body.

Joseph Davis · « **Reply #23 on:** April 13, 2009, 10:08:10 PM »

I am deeply saddened by this thread.

Padraig, post pics of your engine bay.

patsmx5 · « **Reply #24 on:** April 13, 2009, 10:09:33 PM »

Quote from: Joseph Davis on April 13, 2009, 10:08:10 PM

I am deeply saddened by this thread.

Padraig, post pics of your engine bay.

patsmx5 · « **Reply #25 on:** April 13, 2009, 11:00:02 PM »

Better?

patsmx5 · « **Reply #26 on:** April 13, 2009, 11:41:04 PM »

This:

Or this?

Joseph Davis · « **Reply #27 on:** April 14, 2009, 10:57:47 AM »

Thanks rawr. I'm glad I pay attention to myself, although I wish I'd let myself continue to play games for a while longer.

There is no such thing as a "body" ground. All a twenty year old unibody is comprised of is a bunch of paint (insulator) and rusted (insulator) spot welds. You throw a ground strap or three to the body in order to keep it from floating and propigating RF interference, but it is in no way shape or for ground. Just because some OEM who cares about 3 years and 36K miles put the battery's negative terminal to the chassis (because six inches of cable is cheaper than two feet) and grounded a bunch of critical systems (fuel pump) to the chassis doesn't mean that it's *correct*.

What you had, between the paint and rusted out spot welds, is a poor "ground" path and a certain amount of capacitance. Between the inductance of the coils and this capacitance you had a big fat tank circuit and at a certain frequency neither capacitor or inductor wanted to pass current so shit just sat there and misfired.

Now go ground your goddamn car.

Joseph Davis · « **Reply #28 on:** April 14, 2009, 10:59:23 AM »

Also, another thought. Avoid your head as ground point. Those cars use a paper headgasket aka insulator, and I've never liked how Al + Fe with current = corrosion.

patsmx5 · « **Reply #29 on:** April 14, 2009, 03:21:26 PM »

Ok, so right now there's a OEM ground wire that goes from the battery to "chassis", which is a big steel beam that connects the tail shaft of the transmission to the rear end (called the Power Plant Frame, PPF). I drilled two holes in the PPF, polished the steel around the holes, and bolted two clean ring terminals down, each with a 10 gauge wire crimped to them. Right now, both heavy wires go to the sensor ground bar.

So would it be correct to remove one of the +10 wires from the sensor ground bar and hook it to another bar that feeds the ignition system and cylinder head ground? Or do these grounds need to come directly from the battery post ground? And I suppose it wouldn't hurt to ground the fans to the PPF as they're currently grounded to the body.

And this car has a MLS headgasket, I know; I've changed it twice.

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Author Topic: Question On Grounding/Wiring/Ignition woes (Read 16947 times)