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CO is not to spec. Could not find a shop to do it, and don't want to drive this anywhere while it is exhibiting this random ignition cut & heating up in traffic. Looking around for info on the throttle switch. May dig into Bentley manual later to see if there is a testing procedure. |
Hi Mike.
You have two separate issues without taking into consideration the CO setting. Overheating.- Check you trombone cooler in the front fender? Is it hot after the engine is warm? Lean running could cause the overheating too. Intermittent shutting off. Most likely electrical. Again clean all connections, paying attention to the fuel pump relay and ground on the CDI box. I would send the CDI and ECU to Systems Consultating in La. for testing- if the stalling continues. Going over a bump could cause a loose connection. Look at #20 & 21 in this thread about throttle switch (s) operation. http://forums.pelicanparts.com/porsche-911-technical-forum/956477-cold-start-issue-my-newly-refreshed-cis.html Hang in there. PS- How about a picture |
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What's the history of the car and engine ? |
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http://forums.pelicanparts.com/uploa...1606078813.jpg Running a bit hot in town, according to the gauge. Trombone reading about 210F which seems high. Running a tiny bit cooler with the condensor and a/c pump removed from the engine bay (belt was already off compressor). I'm going to take a look at the electrical connections at the CDI, and the microswitch and report back. Quote:
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What are the component numbers ?
"3. WUR model number: 0438140" All WURs start with those, you need the 3 digits following which identifies the model in your engine. Fuel distributor has the component numbers on a plaque 0438100xxx. Post the model of the lambda controller under the passenger seat 0280800xxx. Hopefully you have a matching system. |
Sounds stupid but I saw an SC with the pop off valve installed backwards, at first glance I didn't notice but then it was like WHAT'S GOING ON!
Surely you've checked the airbox. |
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0438 100 077 on the fuel distributor. I'll grab the ECU number in a bit. |
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Bosch ID numbers......
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The FD is -077. The number for the WUR is to the right of 086 or to the left of 980. You could see the numbers from your picture but hard to read. Tony |
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1 checked my Spec Book (Dempesy) It simply says 19-25 degrees BTDC at 6000 rpm with vacuum lines disconnected then let the idle ignition timing fall where it falls with vacuum lines connected. (I believe I plugged my retard vacuum line.) So, check and see where your timing is at 5-6000 rpm? Let us know. |
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Today, I : -when pulled on throttle linkage slightly, i can hear an audible "click" from microswitch. -Cleaned microswitch spade connectors -checked the ecu connection and relay. (cleaned them before, theyre looking alright.) -Cleaned both ends of the ground strap for the CDI box. -Cleaned CDI Box connector (looked pretty good) -Cleaned main harness connector at the engine bay fuse box -Listened to my car idle nice and happy before its test drive Took the car out for a test drive around town and on off the highway. Still running warm in traffic. Trombone still around 200. Hoses in the rear wheel arch test around 175-160 ea. Cut out on me on the highway while cruising again. Still seems like ignition is getting dropped. |
OK.
What coil are you running? Get a voltage meter that plugs into the cigarette lighter plug to monitor running voltage. Maybe their is a correlation of the shut downs. |
With advance Vacuum line connected to ignition distributor total should be around 30*. Right? We are checking that the advance is working on the distributor. At 250K who knows.
Just thinking out loud from far away. |
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Multiple failures at this mileage are no surprise - feel like Ive made progress though! |
<iframe width="560" height="315" src="https://www.youtube.com/embed/NqnR0JlO6Ko" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
Quick clip of a startup after idling the car a few minutes. |
WUR identification numbers.......
Mike,
“481” is not the WUR ID # (0-438-140-481). That is probably the serial number. Take a picture and post it. The numbers should read like 0 438 140 xyz. XYZ would be the last digits. Tony |
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EDIT: Also mentioning I pulled the vac line off for the photo! Reads 090. Also including the number from my ECU, requested earlier http://forums.pelicanparts.com/uploa...1606111204.jpg http://forums.pelicanparts.com/uploa...1606111204.jpg |
CIS troubleshooting............
Mike,
If you want to find out the culprit of your cold idle problem, take a short video after sitting over night. Show how the engine does its warm up cycle for the first 3 mins. Attach the pressure gauge and monitor the control pressures versus time. Based from the information in post #1, the engine will experience a cold erratic idle specially at this time of the year when it is colder. Once the engine has warmed up, everything would be normal. And that’s what your video showed up. Thanks. Tony |
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This represents an improvement versus when the FV wasn't working. No more backfires into the intake. Its also 50-70* in SF pretty consistently. <iframe width="560" height="315" src="https://www.youtube.com/embed/iTiaU0FUVVE" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> |
Unassisted warm up........
Mike,
The video of the warm up is of no value because you were helping the engine by pressing the gas pedal. What I like to see and watch is how the cold engine performs during its warm up stage. Repeat the test and put the car in neutral and hand brake on. Open the driver side window and reach for the ignition switch. Do not get inside the car. Start the motor and video the start up. I like to see the cold engine RPM for the initial 3 mins. unassisted. Meaning you stay out of the car and let the engine run unassisted. If you install a CIS pressure gauge during the test, you will have an idea how the cold control pressure transition to warm control pressure in a couple of mins. or less. If your engine will not idle without further assistance, you got a big problem. Thanks. Tony |
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I'll see if I can get you another clip of it idling before I send the CDI out to our hosts for a check and rebuild. Aware there are multiple issues in play and I'm hopeful with the improvement of cold idle at this point. Will be pulling injectors in a future test. I know the FD will also need work due to the low residual pressure at the unit causing an intermittent hard warm start. |
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Here's 10 mins of starting from cold, gauges on, until the idle fully settles down. |
Mike,
I think you need to set the mixture before doing anything else. Here is a link to setting the mixture without any special tools. https://www.youtube.com/watch?v=8TcAzqKxWgY Pay attention to the way he sets the mixture- not the stuck plunger. |
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cis
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When he turns the CO adjustment screw he moves it WAY too much , the screw is very sensitive and makes large changes for small adjustments . Turn the screw with reference to minutes not hours , rich in , lean out , idle at 925 , make sure ignish timing is set to spec . mix is correct when surging is gone and no rpm bounce after a rev up. Just my thoughts . PS Tony is the master , do what he says and you will be successful. HAPPY THANKSGIVING |
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From another post (not me). "I found that every CIS engine has its particular 'happy place' where it likes to run. No two are exactly the same but CO% usually falls between 2-3.5%. This can be set by ear and its very acurate for best performance. If tuning CIS w/ lambda, disconnect the O2 sensor first. The trick to find your engines happy CO is to get the engine at least running and with the airbox cover and filter off, SLIGHTLY lift the air sensor plate via the exposed elbow with a finger, knuckle or whatever. All is needed is very slight pressure to notice any change in RPM. If the engine RPM increases it wants to be richened. This is also true if you were to pull down on the sensor plate. If RPM's increase, then it wants to be leaned out. Make very small adjustments with the 3mm allen as necessary. The trick is to get the engine at a max RPM so when you either push or pull on the sensor plate, the RPM's will drop (from either being too lean or rich)." ______________ |
Quick update here:
Adjusted mixture with o2 disconnected, appeared to be running ok until reconnecting. I also had an epiphany, realizing while I was debugging and running around, I was doing so with the heater duct disconnected. This was introducing more heat into my engine bay. Car is running a little cooler now. I expect that once I replace the inop heater blower fan, this will improve further. Haven't gotten the car hot enough to stall it on the highway lately. One last thing that may have related to my "CDI problem": cleaned up several electrical connections under/around the rear fuse box. I'll post results once i have the new blower fan in place, but I still think the CDI may benefit from a refresh. We'll see. |
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Wrapping this up for now.
Cold start fixed by cleaning the harness connection on the shock tower area. Corrosion was causing the FV to be inop or intermittent. Prior to this thread, my car got new plugs, wires, cap and rotor and battery ground. Highway stall condition seemed related to excessive engine compartment temps. Mitigated this by: 1. Cleaning out the mouse nests in the fan shroud. 2. I was driving around troubleshooting with my heater pipe sending super hot air into the engine bay (blower was off). Replaced the bad heater pipe, inop blower motor, and cleaned up connections at the rear fuse box that were corroded. 3. Fixed a loose connection on the sensor on the right timing cover. 4. Coil resistance was out of spec, replaced with MSD HV 8222 The car has since not gotten hot enough for the ignition drop /highway stall to happen. If this behavior resurfaces in warmer weather, I will send the CDI unit for rebuild with Pelican. I plan to address the low residual pressure/hot start by replacing the pressure valve o rings at the CIS, since tests showed the issue was not in the WUR part of the circuit. Will test again before those parts are bought. I still need to fine tune the mixture more and will reach out to a local pelican for help once this pandemic subsides some. Thanks again everyone here for help. Took the car out on a few joyrides and I'm feeling good. |
Mike That's great news. Glad it was something stupid and (cheap) like corroded wires.
Thanks for reporting back. |
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Revisiting this thread. A lot has happened since the end of 2020.
Fixing the electrical connections got the car running well enough to drive on weekends and fun highway jaunts. I continued to experience overheating issues and random stalls, but less frequent. CIS testing got me to change the fuel accumulator too. Much improved. Eventually, the oil leaks became so severe that I was unable to drive the car safely any longer. I did have the CDI rebuilt by Pelican but my stalling issues remained. I (mostly) parked the 911 in the summer of 2021 and pulled the engine out two months ago. Contributing to my running issues I found:
I'm replacing all vacuum hoses, fuel lines, chain tensioners (Carrera), drain tubes, triangle of death, CIS hoses, fuel dist rebuild, injectors, front and rear crank seals, and topping it off with a new clutch mating to the rebuilt 915 transmission. Had the oil tank and cooler cleaned and refurbed at Pacific cooler. Oh and some new pedal bushings and shocks as these were way worn... |
Post #1 Item #5 (WUR).........
Mike,
Have you done anything to the WUR? The problem would not be noticeable with the heat wave going on now, but once the weather gets cooler in the fall an erratic cold idle problem would appear. Item #5 (Post #1): Says that the WUR heater resistance with the engine cold was 9.5 Ohms. This was a clear indication that the WUR needed some work. Tony |
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