Sudden change in behavior: hard start, low-lumpy idle, change in powerband

[UrQuattro]

Yah, it's possible. It wasn't one of the 1.50 relays. It was foe some other usage, but cost 15.00.

It would just be strange that all this happens essentially overnight and out of nowhere.

It almost seems like the new relay was working alright for that first drive, but then it failed again.

What would have been causing it to click repeatedly in sync w/ the backfires. My guess is that there was a temporary short in the circuit. Maybe the o2 sensor itself causing problems. Or it could be the controller couldn't it?

Michael

[UrQuattro]

Also, what are the chances that i have a faulty oxs control unit.

When my car leaked a while ago, it did get a fair amount of standing water on the passenger floor. It's not that there was an inch of water or anything, but because it was covered at the time (supposedly by a waterproof cover - I've learned differently now), once the weather got better, I pulled the cover off, ready to go on a nice ride through my favorite mountain roads, only to discover that my car became a greenhouse for mold.

I got that taken care of really well, and I haven't let more than a drop or two get inside the car since.

But maybe that ended up starting a process that ended up destroying the "ecu".

I hope I'm wrong. Cause I know they are really expensive. Does anyone have one I could buy from them?

What are the symptoms of a failed o2 sensor? But again, why the sudden failure.

Oh, I just thought of something that might be of some potential significance. The weather here in san Francisco has been lousy. It's been very foggy, cold temps, and very misty all the time. So maybe since it's been a few weeks since I drove the car, it isn't that something came out of nowhere, it's that sitting outside over the past three weeks in this kind of weather helped along some corrosion.

I dunno. At this point I'm grasping for straws.

Barring some awesome idea, I think i might just take it to a shop because it really does need some tuning, even before this happened.

In cold weather especially, cold starts have presented performance issues. Similar to the basic issues I've had now, but much more mild.

It would start fine, but anything more than 1/3 throttle would have no additional response as far as power, especially once the car hits about 3500-4000rpms. Once it warmed up after about 3-5 minutes, it ran fine. But Ive been getting HORRIBLE gas mileage ever since I got it back on the road last July after it had been stored for about 4 years after my dad died. I had it resurrected properly, with all new fluids and very carefully cranking the engine over by hand, etc etc. I had that done by the shop that my dad used. They always seemed to do a decent job, but after looking back at the work, there was something that never felt right. They always stood by their work. But I dunno, I wanna give another shop a try.

I dunno if any of this is helpful. But i figure that more information is better.

Michael

[UrQuattro]

Oh, the gas mileage that I've been getting is something like 12mpg city and MAYBE 17mpg highway. Even when I made sure to use a tank by driving conservatively, and I still got 18mpg.

It's sofrustrating to hear about other people getting 20+ mpg regularly in mixed driving.

The tranny was totally rebuilt 55k ago, and the engine was redone 10k after that. That's when they replaced the head studs and piston rings as well as installed the oil fed chain tensioners and the new style alternator.

Thanks again for all the help. Past present and future.

Michael

[UrQuattro]

So, I think I'm going to have it towed to Valhalla Porsche repair in Lafayette, which got a few recommendations when I pinged y'all about shops in the sf bay area.

I have a brand new WUR that I'm going to bring along just in case it needs replacement, and a line on an ecu for an 81 sc.

One question: in the bentley, it says that the ecu for 80 is different, and the one for 81-83 are identical, with more pins and an acceleration enrichment module.

But I don't completely trust the bentley, so does anyone know for sure?

Michael

[Bob Kontak]

+1 on relay connections. Was hunting for vacuum leaks in my 81 last week and pulled the O2 relay and re-installed. On re-start the next day ran like crap. The 200 rpm syndrome. Fine start then an anemic death shortly thereafter. Maybe after 6 starts it would stay running at 200. Forget throttle response.

I said to myself (I swear to God) , "JW said to check the connections at the relay". I fart around for two more days with other household projects - pick up another relay at AutoZone thinking of a world shattering post of how my new-ish PP relay (three months old) just died. Installed the AutoZone one and no change.

So tonight I get my lazy rear end under the passenger seat with my multi-meter at ready and really look at the connections. I had pushed the ground wire connection out of the female harness when I did the unplug / re-install last week. Runs fine now.

[Bob Kontak]

Suspect the addition of the acceleration enrichment caused the boxes to change.

I think your problem is a very simple fix. Don't work it too hard and focus on the O2 system. Once fixed you will be very happy.

Keep us posted.

[UrQuattro]

Ok, so.... Resolution time!

Firstly, to whomever named Valhalla Auto Repair in the sf bay area - THANK YOU SO MUCH!

Anyway, they started working on it today, turns out that the main issue was..... That fracking relay! I guess that the one I got, even though it was spec'd to work in my car was crap and made it seem like the computer went.

BUT that's not all.

I'm glad that I had bought a brand new WUR on the board here for I think 1/3 of retail, because mine wasn't doing it's job properly. So, new WUR is now in the car.

Additionally, the timing was EIGHT degrees off - toward the retarded side.

AND - the mixture was extremely off as well.

he's taking it for the final test drive now, but he thinks it's gonna be ready to go.

Cost: 1.5 hrs labor + a new oxs relay.

So, I guess all of this would explain why my car has been getting, at best, 16-17 mpg.

I imagine that the 8 degrees of retard, along with the hosed mixture has impeeded the power output of the car for the whole time it's been driven by me.

I'm both incredibly excited by this as well as incredibly pissed off at the shop that I had been taking it to up until now. Since my dad got it in2001, upon the recommendation of a coworker of his who had a really nice 912, the car has been taken to the same shop the whole time. And they aren't cheap. That shop is responsible for the horrible state that the car is in. And they would have charged me a TON of money for today, I'm sure.

Anyway, hopefully he won't find anything else on the test drive. Or, if he does, at least I have a feeling I'll be able to afford it.

I just can't wait to drive it now.

Michael

[mca]

Congrats! Let us know how it runs when you get it back.

I experienced similar frustrations during my first 2 years of 911 ownership. Spent nearly $5000 and had nothing to show for it except pressure fed chain tensioners.

Long story short ... I learned how to work on my car. I'm comfortable doing most stuff now. Even did a rebuild 2 years ago with the help of some guys from this forum.

I also finally found a shop that I can trust. They kick ass. I still take my car to them when needed.

[UrQuattro]

So, I have the car back now, and it runs better than I can ever remember the car running in the 10 years that it's been in my family.

What I'm most impressed with is the improvement in throttle response during tip-in and the first, I dunno, 30% of throttle pedal movement.

Before, I'd really have to give it a bunch more throttle in the lower rpms before I was satisfied.

Additionally, the car is significantly quicker than it has been. It pulls so strongly right up to redline.

And, it's hard to tell so far, but my gas mileage seems to have improved noticably as well.

Yesterday I finally bit the bullet and had a set of the Direzza star spec tires installed. I had kumho ecsta spt's on the rear and old bridgestones re730s on the front. The tires are obviously still a bit slick from having only ten miles on them, but I can tell already that there is a HUGE improvement in high speed stability as well as steering feel.

The high speed stability had been an issue for me. I'm very sensitive when it comes to feeling sidewall flex on tires, and though I had never gotten a chance to physically give the spt's a squeeze with my hand to test the sidewalls, I have strongly suspected that they must be very soft. I wasn't wrong. On the new tires, I could barely cause any deflection when I squeezed them to check the sidewalls, but when I did the same to the kumhos, I was able to easily compress them completely. I was blown away at how soft they are. How can a manufacturer claim to have a high performance tire if it has sidewalls that have the ridgidity of jell-o.

Anyway, I'm looking forward to breaking in the new tires, and it is a comfort to know that I finally was able to get those old tires off the front, and get rid of the tires that I really suspected I just did not like on the rear. Plus I know how important it is on a 911 to have matching tires front and rear.

Yup, I love this car.

Michael