Datalogging, ignition/electrical bugs

I think I've spotted the gremlins in action.

I took some data logs using the venerable WinALDL during my test drives (on 2013-05-04 and today, 2013-05-08), but I only bothered to analyze them now. The graphing software I used for these pics is called ALDLView.

Logs from 2013-05-04

This time I had the crappy ignition coil in.

The battery voltage drops intermittently and often. I suspect these are the same incidents when I've seen the SES light flash and/or the tachometer jump wildly.

If we add more variables and zoom in, we'll see that all values drop to zero simultaneously. Here are Speed (VSS), MAP, RPM and O2 readings in addition to Battery Voltage.

In the second incident, the VSS jumps to 180, but in most of these it drops to zero as well. This matches what I've seen the speedometer do: most of the time it shows a realistic value, but a couple of times it's jumped up randomly.

Here's a sample of the "DRP Occurred" signal (Distributor Reference Pulse). I find it odd that it DRP frequency doesn't correlate with engine RPM.

Logs from 2013-05-08

I made another 16 km (10 mi) test drive today. This is after putting the original ignition coil back in & replacing the vac hoses.

There were only 2 voltage drops, and they happened while the car was still idling on the lot (pic below, speed zero, CTS rising). All in all performance felt "normal", there were some random tachometer jerks still.

2nd part of the test drive. The battery voltage didn't drop at all (according to the ECM), so ALDLView scales the white line differently.

I saw one SES flash, though. This happened on WOT (wide open throttle) acceleration in the middle of the graph.

Here's a closeup of the WOT part, i.e. where TPS (throttle position sensor) jumps to 100%. The speedometer also jumped almost 45 degrees upwards and the tach was acting up. The car accelerated nevertheless (yay). Right before flooring the pedal, I saw the tach jump a couple of times, this might match the two minor voltage drops just before the WOT part.

Maybe the acceleration itself shook some contacts loose and this caused the ECM to reset for a short moment?

Also, here's another graph of the DRP flag:

Odometer: 225 974 miles.

Ignition Coil Trouble

Lesson for today: don't bother with "closeout", "white label" etc. products.

After replacing the ignition coil, I found out the terminals on the part I received from RockAuto are simply too small for the primary coil connectors that are supposed to plug into the coil, even though it's a supposed to be a compatible part. I ordered a Standard Motor Products DR-37, but what they sent was labeled "ProFire UltraPower DR-37".

The difference is down to a 0.4-0.6 mm, but it's enough that the connectors simply won't stay in place. 

Also, the openings for the actual contacts are 1,5 mm wider and shaped differently.

It was a bit of an effort to convince RockAuto that the part really was incorrect. Eventually they agreed to refund the $23 I had paid, even though the part had only a 30 day warranty. So, I have no complaints about their customer service.

Action taken
* Put the original ignition coil back.

Results

* The engine runs much better. I was able to complete a 30+ km test drive without any stalling or choking -- when you're cruising at < 50 mph everything seems mostly fine, but during WOT acceleration there were still a couple of SES flashes and back/misfires.
* Towards the end of the test drive, I had cruise control set to ~55 mph adn there was some weird, repetitive jamming / halting action going on. Is the TCC trying to engage and failing? Or Highway Lean Mode failing?

Distributor & ign. connector replaced, timing reset; better but not good

So.

Action taken
1) I've replaced the whole distributor with a Cardone Select 841830.

2) Also, the gray connector on the ignition coil needed replacement, since the holding clip on the old one was broken. Apparently this connector is responsible for carrying current from the ignition key (pink lead) and supplying a signal to the tachometer (white lead). I used a Standard S562 i.e. this thing...

... only to find out that the bloody connector will not stay on the ignition coil it was meant for.  The plastic clip is too loose and simply won't hold the connector in place, and the white styrofoam cushion/seal inside the connector is too thick, so it pushes the connector out of the socket. WTF? Both the connector and ignition coil are stock replacement parts from Standard Motor Products. It got a bit better after replacing the styrofoam piece with the flattened-out piece from the old connector, but it's still loose and you can detach it just by pulling. So I used electric tape to keep it in place. --> update: the coil was faulty, not the connector - see the next post.

3) I readjusted the timing to what might be the factory default. I haven't found reliable documentation on what values the timing  marks stand for, but now it's set like this:

Results
The same symptoms persist as before, but now my tachometer is dead most of the time. Apparently white lead, or the tachometer connector it attaches to, is even more unreliable now.

The symptoms are less frequent though, I was able to complete a 25 km (15,5 mile) test drive without the engine dying at all.

Also, I noticed some stutters / surges while driving at about 100 km/h (60 mph). Another halfhearted guess, is the TCC trying to engage and failing?

Pick-up coil replaced, no help

Action taken

Replaced the pick-up coil inside the distributor

Results

No changes; symptoms remain.

Other

Since changing the coil involves taking most of the distributor apart, I got a chance to clean it more thoroughly. Looks like the magnet has fractured in  at least three locations. 

Also, this clip was quite helpful - http://www.youtube.com/watch?v=K5QRK9VZwcM

Spare part lottery II

Action taken (Apr 12 - 20, 2013)

• Distributor cleaned, pulled out and cleaned some more
• A lot of dust, rust etc under the distributor cap
• Also, there were some mysterious black flakes on the distributor shaft, but they didn't seem metallic. They don't react to a magnet, and break when you crush them with your fingernail.
• Ignition Control Module (ICM) in the distributor replaced (Standard Motor Products LX340)
• Ignition Coil replaced (Standard Motor Products DR37)
• ECM & its PROM chip replaced (original part, ordered from an eBay merchant in California, pulled from a 1992 Camaro, )
• PROM version is "AXKT", while the original was ANTT. As far as I know, AXKT is just a compatible upgrade.
• Battery negative terminal connector replaced
• The threads attaching the cables to the old connector were gone, so this might have caused some contact issues
• Grounding cable between battery and chassis replaced, contact point in chassis cleaned
• Grounding cable between battery and engine block was left in place, looks "ok"
• Battery terminals and connectors cleaned
• Wires to the Heater / AC blower motor disconnected
• Wires to the AC compressor disconnected
• I don't know what condition the AC is in, at best it's very low on refridgerant

Results
I had hoped that blindly replacing most of the ignition-related parts would take care of this problem, but the same symptoms that I had last fall are still there. I think things got a bit more reliable after I fixed the battery contacts and disconnected the heater/AC blower motor, so bad grounding and that worn-out motor were probably at least part of the problem. Still, this only lowered the frequency at which the symptoms occur.

I made a test drive of about 9 km today (5.5 miles), and the car died / SES'd maybe half a dozen times.

Other
Next up, I'm looking at

• Replacing the distributor Pick-up Coil (since I already have a new spare part)
• Replacing vacuum hoses
• Replacing the whole distributor (at about the same cost as all those distributor parts above....)
• Replacing the grounding cable between battery and engine block
• Checking / replacing the cable for the VSS (Vehicle Speed Sensor) 
• Replacing that 8th plug...

And possibly

• Checking the fuel pump wiring
• Replacing the TBI injectors

If none of this helps, it looks like I'll have to switch my brain on, do a bit of homework and actually try to diagnose the problem in a structured way.

Running trouble, Spare part lottery

[backdated for chronological order]

Recoup of the mysterious running issues that started last fall.

Symptoms

• "Service Engine Soon" light flashes randomly when driving
• This happens very often when you hit a bump, but it also does it randomly on an even road
• "Security" light flashes less randomly when driving 
• (referring to the VATS chip in the ignition key)
• Tachometer jerks up and down randomly, maybe +/- 500-1000 RPMs
• Speedometer jerks less randomly
• Engine dies semi-randomly when driving or taking off
• After the engine has died, the SES light sometimes stays lit, other times it's off
• No error codes given by the ECM, ever, despite the SES light

Steps taken last autumn (Oct 2012):

• Switched from E85 (Ethanol) back to E95 (Regular Gasoline)
• Injector cleaner stuff added to gasoline
• PCV Vent replaced (Standard Motor V178)
• old one was making a rattling noise, although it was less than 6 months old
• TBI injectors and their filters taken out and cleaned with a carburetor cleaning spray 
• Stream from the injectors looks clean, stable and has a conical shape like it's supposed to.
• Spark Plugs 1-7 replaced (AC Delco R45TS) 
• Plug no. 8 was impossible to reach in the freezing weather....
• Spark Plug Wires replaced (Standard Motor Products 7850)
• Distributor Cap replaced (Standard Motor Products DR468)
• Distributor Rotor replaced (Standard Motor Products DR326)
• Battery replaced (62 Ah)