3.6 Issues - I'm really scratching my head Options

[RiqueMar]

Hi There World!

Messaging the community here, as I'm thoroughly 'stuck' and I'm hoping someone has had a previous experience or perhaps point me in the right direction.

My car had been performing incredibly well. I probably put 1,600-1,800 miles on it driving back from Oregon. Yesterday, in the span of about 10-15 minutes it went from running and driving great to awful. I coasted down a long hill, and the engine starting dying and then immediately surging, like an on/off switch.

I eventually shut it down, but being only about 1-2 miles from my parents house made it back at a bit higher than normal revs. I believe a small bracket holding the Mass-airflow gave out and as a result, the air-intake lines / boots came disconnected. This made sense to me, as the engine was acting as if it might have had inconsistent air-intake / fuel mixture.

After fixing it - Over the course of the next hour, it went from bad to worse. I disconnected the battery, understanding this was a way to allow the ECU to reset, however now I cannot get the engine to 'hold' any level of RPMs.

Example, if I put my foot on the accelerator, it will rev-up-and-down about 400-600 RPMs. Likewise, I can hear and 'feel' the DME-relay 'cycling' on and off as I try to hold the accelerator / RPM level - I think this is very wrong as I think that one of it's responsibilities is the injectors. I've spent the last day to figure it out. Checked all my vacuum and air-connections as well as electrical. Tomorrow perhaps the fuel-pump. It's strange as for the last few weeks, it was incredibly reliable, 1-2 'stalls' under cold-start, but otherwise excellent.

I already missed 'having the car for my birthday' and hope to make it available for the 'Air and Water' event this weekend, so messaging other owners and the community is my last-shot before going to a shop. Any and all direction or previous experience anyone might have is greatly appreciated.

For communication purposes, I've done the following:
- Replaced the DME-relay - maybe slightly better, no change
- Made sure there's fuel - at least 3/4 tank
- Secured the Mass Air-flow sensor - no change
- Disconnected the battery, reconnected at different intervals (30-min, 60-min, overnight) - no change
- Checked all my air-lines / vacuum lines - no change
- (Earlier today) Added 1-qt of oil (why not?) - no change
- Checked the Flywheel position sensor - shook it, seems secure
- Checked the camshaft sensor - shook it, seems secure

[Cairo94507]

Congratulations Enrique. (IMG:style_emoticons/default/beerchug.gif)

[RiqueMar]

Oh man, what a couple of days! I spent this last-week troubleshooting various items on the car - only for my Father to come in last minute and solve the issue. After the ordeal of this 'incident' and all the 'noise' of this post, leaving my notes should anyone find this thread in the future. It's my opinion that, often, issue like this will come up and once resolved, the original Author fails to tell the World 'what happened, what fixed it?'.

I originally took the car out as stated on Saturday, and headed to my parents ranch that evening. The next day was my birthday, being new and part of a 'car family', I asked my family to grab a car and take a Drive on Easter Sunday. We started out well enough, taking photos but from the beginning, the car kept loosing power and immediately regaining. I pulled over and thought we were done.

I was able to get it started with little effort, and making it back to my parents house realized a bracket on the AFM had given up. This made sense to me, as now the rubber boots and likes were disconnected and my knee-jerk thought was that the engine couldn't figure out a variety of items. We made a temp solution and tried again - but still weird.

Working on the car later, I checked all my connections, secured everything and still running rough, read various articles that I should disconnect the battery to 'reset' the ECU and then it could reacclimatize. Thats when the trouble REALLY started. Rough running and starting, a 'cycling' DME relay that would shut on and off, and so on.

The engine would start, but the RPMs were erratic. I could 'kinda' hold an RPM range, but the engine speed would fluctuation 200-400 RPMs up and down and would need somewhere between 2500-3500 to stay running. I spent the next few days 'digging in' and troubleshooting - each time with the same result. To summarize, here's the items I tackled that had no-effect.

- Checked Idle Control Valve (ICV) - this is often the culprit, but unfortunately not in my case.
- Tried to scan through Diag-port and I couldn't get connectivity. Need to research this, perhaps I'm not using the right tool or I don't have 'power' to the plug.
- Replaced DME relay (same result, new v. old)
- New fuel pump (at one point I thought I had low fuel-pressure)
- Checked Fuel-pressure regulator, fuel filter, injectors, lines for 'kinks'
- Back-up ECU (Thanks to Steve Wong 911chips.com)
- Checked / cleaned Air Flow meter internals and sensor
- Found inconsistent resistance on AFM, and corrected (loose terminals)
- Checked oil level / flow, reinstalled 'oil tube' restrictor (Thanks to Clay for the reminder)
- New Speed sensor (This was Bens 'Martin Mid Engine' suggestion) and it made sense, but no result
- Charged / Swapped battery
- Checked dual-distributor belt (This is a known issue, Porsche recommends replacement every 5-years / 50k miles). I misdiagnosed this as broken, but easy enough to correct. Extract, cleaned, Set engine TDC, Reinstall, Reconnect leads, etc. For the record, while not fun, I did this with the engine mounted - took about 2-3 hours - add another 2-3 if one truly replaces the belt.
- Re-placed distributor caps and rotors and 'tested' swapping coil leads.
- This was CLOSE to my actual problem, more on that.
- Checked, re-checked, triple-checked, quadruple-checked all electrical and vacuum lines for anything loose, air leaks, etc.

There's probably more, but on with the story....

This whole thing had me thoroughly stumped and, with a Saturday 'deadline', I thought I would be going to Air and Water sans car. Bummed, I started packing and setting-up for the show load in Friday morning. My Father had just returned from a 3-day Performance Driving Course and I had been using his workshop and crew to work through the issue. Walking in, we were gathered around he car recapping the last few days when he asked, 'Have the checked the coils'? I replied that I did, and had tried 'swapping' the leads from the distributor to each (One coil and dist. controls the top-spark plugs, the other the bottom). Thats when he replied, 'Yeah... But from the top-connector', as there are two-leads from the control unit to the distributor.

I swear, the man had 1-hand in his pocket. Leaned over the car. Unplugged both coils. Swapped them. Reconnected. Immediate 'start up'. My jaw was on the floor. I was 'close' and had spent hours, often until 2-3 in the morning, but he hit it dead on after coming off the racetrack.

- - - -

Solution: While I need to dig in further, it looks like the car was running on 1-set of the twin-plug (which it should be able to), though with the issue of the AFM and probably some sort of leak from the bracket giving way, was just too much to overcome. When we secured everything and switched to running off the 'top end' of the ignition, it was able to run and drive, even though underpowered.

For me, this was incredible news. I was lucky enough that the guys I had worked with over the previous days where familiar with the car to get it back up to presentation-level for Air and Water as myself and the 914Seis team setup. I returned home late, my Father helped me load the car in one of his small race-trailers, and early morning, we set off for the show where it made its first-appearance!

Shout out to my Father as well as his shop-crew, Ben Martin, Bruce Stone, Steve Wong could have done it without them. Same here - I'm so happy and proud to be part of this online-community of 914World, Rennlist, and individual-builders and drivers and very grateful to EVERYONE who chimed in on this massive 'headscratcher'.

Sharing a snapshots to give you all my perspective over the last week and photos of the ordeal - Thanks everyone! (IMG:style_emoticons/default/bye1.gif)