Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Topic: Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III (Read 32892 times) previous topic - next topic

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #30 – July 20, 2011, 03:10:40 PM

I was wondering why you were talking about EEC-III on a 1984. Good ol' California throwin' in that monkey wrench.

Just a thought: have you changed the camshaft position sensor at all?

Otherwise it's great to see progress and you're definitely getting there. Personally I wouldn't scoff at a 700-800 rpm idle; my '84 V6 hunts at idle sometimes and I've always considered that to be "normal".

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #31 – July 20, 2011, 06:20:06 PM

Quote from: EricCoolCats;363713

I was wondering why you were talking about EEC-III on a 1984. Good ol' California throwin' in that monkey wrench.

Oh yeah, I'm lovin' California right now. Probably something to do with the EEC-IV not being approved yet. I swear CA is the worst place to live for car lovers. (Yet CA is famous for classic car shows, Beach Boys, and Jay Leno. WHAT THE HECK???)

Quote from: EricCoolCats;363713

Otherwise it's great to see progress and you're definitely getting there. Personally I wouldn't scoff at a 700-800 rpm idle; my '84 V6 hunts at idle sometimes and I've always considered that to be "normal".

I'd be fine with it too, if it weren't for the timing being so off, and the high NOx on the smog tests. High NOx is usually just one of three things:

1) EGR system. (My EGR is good.)

2) Exhaust leak before the catalysts. This kind of problem would probably also cause other emissions to be high. (My exhaust is good.)

3) Bad timing, usually firing too early. Fire to late = high HC, you didn't burn all your fuel. Fire to early = high NOx, fire stays in chamber for longer making the combustion temperatures of subsequent burns higher. NOx is created when the combustion temperature reaches something like 2800° F. My timing is ALWAYS 20° BTDC according to my timing light at any RPM while idling and in drive (didn't test high RPM in drive for obvious reasons). This tells me that for whatever reason the computer is not adjusting my timing properly.

Also, I need the idle to be lower than 700-800 RPM because CA smog laws require it to be within +/- 100 of manufacturer spec. which is 550 RPM for this car. So even if I solve the high NOx problem, if my RPM is too high I still fail the test.

Quote from: EricCoolCats;363713

Just a thought: have you changed the camshaft position sensor at all?

This car has a crank position sensor (no cam position sensor) and I've checked it. Mitchell manual says it should measure 100 to 640 Ohms and I read ~400 Ohms. So as far as I can tell it's okay and I'd rather not throw $50 at a new one unless I'm certain it'll do me some good.

Let me describe my crank position sensor and how it relates to the ignition to the best of my knowledge so far:

There is a four lobe ring attached to my crank's balancer. As the crank turns the lobes pass under the inductive CPS. When a lobe passes under it, the CPS's magnetic field discharges, sending the computer a voltage signal. Each lobe is spaced evenly apart and set so that when the crank is at 10° BTDC there is a lobe directly under the CPS. The computer uses the frequency of the pulses to determine engine RPM and knows that for 10° BTDC timing to have the coil send a spark every time a pulse is detected. (The crank turns twice for every turn of the distributor, hence four sparks per turn of the crank for a V8.)

The distributor is a Duraspark III, so it's just a shaft with a gear on one end and a rotor on the other. The computer has no control over which cylinder the spark goes to. It's entirely based on the computer's faith that the wires are in the correct order on the distributor cap and in the alignment of the distributor gear to the crank ... shaft.... because the valves need.... wait.......

HOLY S***!!!! EPIPHANY! I TOTALLY UNDERSTAND THIS IGNITION SYSTEM NOW! And I have something to test!!!! Yay!

BRB. I may have just figured this sucker out.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #32 – July 20, 2011, 11:35:23 PM

My epiphany was to turn the crank to 10° BTDC and adjust the rotor so that it is pointed directly at #1. Makes sense right?

Okay, so new problem.

After making that adjustment I turn the engine over and it starts right up, at 1000 RPM and with a horrifying valve tick (I mean REALLY LOUD...at least to me, I don't know, valve ticks are rare on my cars). My dad was helping me and he managed to quickly check the timing before I shut it off. He read it as 10° BTDC.

Now, this doesn't mean much to me at the moment because as I've reported before, there have been a few times where the timing reads correct and then changes after running for a few minutes. I didn't give this the opportunity to run for a few minutes.

...

Okay it's a little later and I decided to try again. The idle settled at about 700 to 800 RPM and the timing adjusted itself back to 20° BTDC and the valve ticking stopped. I am beginning to think I could point the rotor any way I want and the computer will bring it back to 20° and I'm going to let it do that all it wants...in Hell....because I'm dynamiting this car.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #33 – July 21, 2011, 01:46:36 PM

Quote

This car has a crank position sensor (no cam position sensor)

I knew that...my fingers just didn't type it that way. D'oh.

Your state is messed up.
Couldn't you use something like this to help you?
http://www.amazon.com/CRC-05063-Guaranteed-Emissions-Formula/dp/B000CIPUR8

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #34 – July 21, 2011, 02:34:22 PM

Quote from: EricCoolCats;363756

Your state is messed up.

Tell me about it.

I've thought about using an additive, but I don't know if it would decrease my NOx. I've also heard that some additives can actually increase your HC.

Also, I run Seafoam or Marvel Oil through my cars on a regular basis (something like a six ounces every 3000 miles), so I'm not sure how big of a difference this stuff will make. Yes, I am a nutcase about maintenance. I learned the hard way that you keep a car maintained regularly or suffer the fate of having no car at all.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #35 – July 21, 2011, 05:56:58 PM

Redoing a continuity test of my computer's wiring harness, this time using an ohm-meter instead of a buzzer tester. I already did a test for shorts and breaks (I had none), this test will tell me if any of my wires are acting as resistors. While I was at it I tested to make sure there was no crossover (wires spliced together that shouldn't be). I did this by putting one end of the multimeter into each pin of the computer and then putting the other end of the multimeter in each connector in the engine compartment. Fortunately/unfortunately (because it least then there'd be something to fix) there was no crossover. So my harness is at least routed 100% properly.

Since I don't seem to be able to put tables in my forum post (sadface), I put the table of the resistances on my never updated website:
http://crossalchemist.com/ThunderbirdResistanceValues.aspx

The most anomalous readings are the signal wires for the BMAP, CPS, and ACT sensors, each having resistances of 25 to 30 Ω. Any idea if this is big enough to cause problems for me?

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #36 – July 21, 2011, 11:41:31 PM

Have you looked in the ignition section of volume D of the 84 shop manual?
There is a proceedure for setting the rotor in the EEC III distributor.
The alignment slot should line up with gap between the alighnment ribs at 0° with the #1 piston on TDC of the compression stroke.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #37 – July 22, 2011, 12:05:15 AM

Try this to get a sense of how much slop you have in the timing chain:
With the distributor cap off and the crank at 0° turn the crank backwards until the rotor goes backward. Continue turning backward until you get to an even mark like 20 or 30.
Slowly turn the crank forward (CW) until the rotor starts to move. Check how many degrees of slop you have.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #38 – July 22, 2011, 01:04:37 AM

Quote from: softtouch;363792

Have you looked in the ignition section of volume D of the 84 shop manual?
There is a proceedure for setting the rotor in the EEC III distributor.
The alignment slot should line up with gap between the alighnment ribs at 0° with the #1 piston on TDC of the compression stroke.

I have the 1983 manual, so I have never seen that picture! My manual covers Duraspark III, same exact distributor as the one shown in your picture, so I assumed that it was the same system. But my manual gives a different method for the alignment! My Mitchell manuals (I have the 84 manuals) give the same alignment method as my 83 Ford manual, which I thought confirmed it.

My only problem with aligning it the way you've shown is that the rotor is not pointing at the #1 on the cap at 0° when set like that. It is instead right between #1 and #5. Is the Duraspark III distributor cap different from your typical Ford cap? I know there is a bi-level version of the Duraspark III, but that's not what I have (that was just in trucks with the MCU system I think). Am I supposed to offset the firing order on the cap? Can you send me a scan of that whole page? Or at least post a picture of the cap.

Thank you so much, by the way, that little nugget is probably the most helpful thing I've seen since this ordeal began.

Quote from: softtouch;363793

Try this to get a sense of how much slop you have in the timing chain:
With the distributor cap off and the crank at 0° turn the crank backwards until the rotor goes backward. Continue turning backward until you get to an even mark like 20 or 30.
Slowly turn the crank forward (CW) until the rotor starts to move. Check how many degrees of slop you have.

Yes, I've done this. I have practically no slack in my chain (half a degree at most, not even a discernible amount). I'm considering replacing the timing chain and water pump anyway, just because I don't know this car's history and the hillbillies seem to have done quite the number on everything else. I'm planning for this car's "maiden" voyage to be a trip to Colorado to see my grandmother. Breaking down in the middle of the Utah salt flats with a busted water pump is not my idea of fun. By the time I'm done with this thing I'll probably know every bolt and weld personally and hopefully I can to put enough confidence in it to make the trip.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #39 – July 22, 2011, 05:24:59 PM

The Duraspark II and Duraspark III are interspersed in the shop manual. I have picked out the Duraspark III stuff.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #40 – July 22, 2011, 05:26:47 PM

More
oops The second part is posted first. I selected them in the correct order in the attachment routine. It seems to have a mind of it's own. It also automatically sizes it. hopefully you can make sense of it.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #41 – July 22, 2011, 05:33:39 PM

and more

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #42 – July 22, 2011, 10:19:05 PM

My car hunts for a good idle RPM for awhile. After driving it usually evens out. The problem I have is when I give it any throttle it will bog, spit and sputter at random intervals. It is never the same. Sometimes low RPM, the next time high RPM and in any gear. I've turned down the fuel pressure alittle(I think) using the Gold FPR on the intake. The car will start without giving it any throttle, and will using run by itself. Before I turned that allen head screw it would never start on its own, and would run rough and overfuel extremely bad. Now it's just the very bad bog issue under any type of throttle. My throttle response is poor on the car too. I suspect part of it is due to the C4 transmission which has a rebuilt valve body and whines pretty bad.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #43 – July 23, 2011, 12:17:03 AM

Quote from: softtouch;363835

More
oops The second part is posted first. I selected them in the correct order in the attachment routine. It seems to have a mind of it's own. It also automatically sizes it. hopefully you can make sense of it.

HOLY THANK YOU SO MUCH.

Unfortunately, at the moment I have the whole wiring harness apart replacing the previously mentioned wires with weird resistances. I'll try doing the adjustment like this when I get it back together tomorrow. Like I said though, doing the adjustment like this would make the rotor point BETWEEN the posts on the distributor cap for cylinders 1 and 5 (after 1 and before 5). Now, that seems like it would make the timing WAY too late to me, unless I do not plug the #1 plug wire into the post marked #1 on my cap, like I would for any other distributor.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #44 – July 23, 2011, 01:52:45 AM

You may have to pull the distributor and move it over one gear tooth.