specsalot

Going point to point in the harness - Discovered that the LR-944-Ref harness repair kit was miss wired. On the DME side, the kit wires are carefully marked and color coded. The instructions for the kit are well written. A no brainer to install.

DME Pin 27 is "black" (and numbered) - According to the shop manual schematic this should be RPM Sensor plug pin 1
DME Pin 8 is "clear" (and numbered) - According to the shop manual schematic this should be RPM Sensor plug pin 2

Point to point exam found that the RPM Sensor plug wires for pins 2 and 1 were swapped. Rather than dismantle the RPM Sensor plug I swapped the connections within the DME plug.

Test Point 4 (Reference Mark Sensor) instructions caution that the wave form form must begin with a + slope. Reference Mark Sensor pin outs have been confirmed to be correct between the sensor plug and the DME plug. In contrast to this Test Point 3 (RPM Sensor) instructions do not have the any caution about the initial slope of the output wave form.

The open question is whether a 180 DEG shift in output from the Speed Reference sensor would make a difference to operation? My limited understanding is that two inputs are combined on the digital side of the DME unit and processed digitally. Perhaps someone with deep knowledge of the DME circuit can weigh in on this question?

UPDATE - Completed the full DME/KLR harness check out. No other wiring defects. Harness will not go back in the until I have the battery cables installed (arriving on Saturday).

specsalot

General comment on pulling the DME harness. Its not necessary or recommended if you only need to verify a few connections. It takes 2 people to maneuver the components (plugs / wire) through the firewall penetration. It helps to have a large table to drape it on once out. The table in the picture below is 8 ft long.

The LR kits are decent quality, but for sure they transform the harness into a Medusa head of wires which are a challenge to layer on the engine. If I had it to "do over" I probably would have purchased a new DME harness rather than go the repair kit route. All the harness boots I opened in the original DME harness showed failed insulation and vibration fatigued wires this is why I sprung for the kits.

specsalot

New cables arrived today. I realize there is only a small probability that this is an issue, but at least now it will be off the table. Old cables were a bit ratty and showed internal corrosion. New timing belt / retention BS belts today - Then let the reassembly begin. Distributor parts arrived. TPS delivery was pushed back until Monday most likely due to weather issues.

specsalot

Update - (this is becoming a project)
New Battery Cables Installed
New Timing Belt Installed; Both Belts tensioned
DME Harness Reinstalled
Cleaned and Inspected J-Boot - Found some nice cracks - Parts on order
Tested AFM - found a nice flat spot / open circuit at partial opening - rebuilt exchange AFM enroute

mahoney944

When mine started stalling years ago intermitenly it was the coil. I would start simple, pull the plug wires and the plug itself for each cylinder and plug them into their respect wires, then have a helper crank the motor while you watch the spark plugs and look for a strong arm from each one. dont crank too long this should only take a second. if any or all do not spark, work you way back, typically if all do not the cap and rotor presents the issue, when just one does the wire, or plug way be faulty, the coil is fairly comon to fail. is all spark then you may have an issue with fuel pump or a vac line.

specsalot

Thanks for your advice above. I'm working through the process. The spark looked weak by eye but it was still enough to create a severe bite. The existing cap / rotor had some burning but was not major. When the car stranded me, I found that two of 4 plug wires had issues at the plug (rusty non-functional clips up in the connector). As a result the connection tips on the plugs showed a lot of arc blasting. I think this may have damaged the motronic DME. It was sent off and was found to have defects.

Fuel pump is delivering lots of fuel. TPS was bad. I also think there may have been some vacuum leaks (found some cracks in the Jboot). Also throttle body seals were gone. AFM has a flat spot and had already been reworked by someone in the past (top cover was siliconed on. All these issues should be off the table with the latest cache of parts inbound (arriving early this week).

I've replaced the coil already, but spark still looks weak. The bulk of items being replaced all show lots of age and so the represent a bit of a refresh for the car whether all are root cause related or not is unclear. Arnworx Specialty tools sells a spark jumper that can be inserted in the plug circuit to monitor spark quality / consistency. I will probably order that to support diagnosis. It looks like a pretty handy item for any SI engine.

I expect to be posting great news and doing a wrap up on this thread by the end of the week. Thanks for taking the time to post your comments

mahoney944

i may have over looked it somewhere, but did you change the dme relay? fairly common failure

specsalot

The DME was sent off early on. According to the service report, there were some bad solder joints and some kind of memory module on the digital board had to be changed out. So part of the initial failure appears to have been DME related. Post DME / wire harness kit installation its been a non-starter.

Symptoms, car could be stated, but RPM would not rise above 2K and was unstable, so it was not drivable. Per other comments / advice on these boards that pointed toward TPS and AFM. Found TPS switch contact as bad. AFM also appears to have flat spot. Cracked Jboot. My problem may be a combination of things all contributing to incorrect Air Fuel Ratio for engine to run correctly.

I will update results after this last batch of parts are installed.

specsalot

Sorry about slow updates - Found another cracked up hose (molded elbow on top of oil separator). Parts on order.

mahoney944

what symptoms are you experiencing now that some parts have been changed?

specsalot

Sorry - Slow Replies - spent a couple hours on the car today - No start - NO SPARK. The engine does crank over well. The new cables made a difference. Car had "weak spark" (no start) after putting the rebuilt DME in back in Jan. Now it has NO SPARK. Fuel injection is delivering fuel. I'm waiting for a call back from Specialized ECU for additional feedback guidance.

Operating the ignition coil straight off the battery (intermittent energize primary, grounded spark plug in secondary) doesn't produce a lot of spark.

With everything hooked up I tried to measure current draw through the coil primary today using a Fluke 337 clamp meter. Also separately using a Fluke multimeter in series. Both results showed 0 amps through the coil primary circuit. These symptoms point back at the DME analog circuits which operate the coil.

Ronin-951

The Fluke should be fast enough to measure the Coil draw, so I believe it, but you did jump over a question about the DME Relay, which IS part of the DME Computer input/output.

specsalot

I have validated B+ to terminal 15 of the coil. This means DME relay (and the feeble immobilizer) are out of play for this issue [best I can read in the schematics]. I'm also getting fuel pump operation and fuel injection is taking place. So I think the DME relay is not part of the problem.

I was on the phone with Specialized ECU today. Their recommendation was that I send off the DME and the KLR so that they can be tested together. I got it off late today, so there is a chance I'll have an answer on computer status before the weeks end. The 337 Clamp meter has a fast response "inrush" setting. Even this showed 0 amps. One of those two instruments should have showed something happening in the coil primary circuit. I have validated circuit continuity from B+ to Coil Terminal 15. And also Coil Terminal 1 to DME 1. This unfortunately continues to point at the computers.....

I guess the + spin on this is that I've also refreshed a number of future trouble spots (rotting ground cable, weak DME harness connectors & wiring, vacuum and boost leaks). The car should run better once I get it started

Ronin-951

You're doing an OUTSTANDING job, meticulous and methodical, just the kind of Guy I look/hope to buy a car from.

specsalot

Thanks Ronin-951 - Kind words are always encouraging. This situation has been a bit of a beat down, but I think it's not going to beat me, thanks in no small measure to the help everyone here has provided.

Update - DME & KLR were tested together at Specialized ECU Repair. Per the technician, it turns out that a component failure in the KLR delivered excessive voltage back to the DME which in turn damaged / destroyed components in the ignition circuit. Parts are inbound today arriving later today so I will hopefully be passing along good news. I asked the technician (Wade) if any engine components (sensors) could have triggered this failure. He said, no - the problem originated with component failure in the KLR.

THE LESSON LEARNED IS IF YOU SUSPECT DME ISSUES, SEND OFF YOUR KLR AS WELL.

The failure I situation I had was somewhat unusual. The tech said that this seems to be an emerging situation. Back in January before sending off the DME, in discussions, no one at Specialized suggested sending off the KLR as well. Specialized ECU (of course) honored the 5 year warranty on their work on my DME and repaired it for free. The KLR service was $350, but if this yields a running vehicle, I consider it money well spent.