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When I took the car out of hibernation, the old front fuel pump was iffy. Replaced with a new one. I supposed its possible an electrical issue is causing the pumps not to get juice.

Any quick way to check this when the car dies? Remember, it restarts within 2-3 minutes. I guess I could try to jump the relay in that time. I need to find the yellow relay everyone keeps talking about too.

I will keep everyone posted. Thanks.

Old 07-29-2014, 04:53 AM
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Updates...

Went to start the car today, and it tuned over but no go. Checked with a strobe light, no spark.

Checked for 12 volts at the Cdi pin 4, that was fine. Checked all of the ohm recommendations to the other pins as listed on permatunes website. All looked fine, except 1 to 5, and I don't know if my meter was reading right. It's supposed to be faraday, my meter read volts.

Checked grounds front and back, read good on the meter.

Put everything back, started right up.

Went to hook up the the afr leads directly to the battery. The 3 small leads to the positive terminal were hot!!! The wire covering was turning black. What the heck?! Figured perhaps a loose connection, so cleaned them off. Still got hot to the touch. Looked at all of the relays. All cool except the rearward one, which was barely warm.

Did get some afr readings though...these were just with the oxygen sensor up the tail pipe about a foot. Tomorrow it gets installed in the bung.

At idle, cold start starts at 14, then in 5 seconds or so it's at 15.7. Then it slowly gets richer, and after a minute plateaus at 12.7 or so. And it stays there. Will drive it tomorrow.

So it seems like an electrical issue, right?

What are the 3 smaller wires off the positive battery lead? Will clean the battery terminal, and check amperage at those leads next. I would think if something were overdrawing juice I should be blowing fuses... Bit I'm not...

As always, thought appreciated.

Bo
Old 08-01-2014, 10:21 AM
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If your car has a front AC condenser and fan Porsche never fused that fan. I guess the AC wiring was an after thought.
In hot climates where people run the AC most of the time those fan motors are known for seizing up after a while because the electric motors inside them are nothing great and very few people take them apart to clean and oil the armature bushings in the motors.
Making things worse that fan is right next to the gas tank so when it burns out and melts down it's plastic blower fan casing they can light the gas tank and burn down the car.

Anyway, it's easy to put an inline blade fuse in the power wire going to the fan. Radioshack has them.
I don't know where the other factory red wires on the battery positive terminal go. You could trace them or look at a wiring diagram if they are original. Sometimes someone posts a jpeg of the wiring diagram but you have to find one for the year of your car to have everything.

The interior lights, glove box, and front trunk lights can be a steady drain on the battery because they are hot all the time and the little button switches in the door jams ground them to turn them on when you open the door.
The glove box light and front trunk light are on a shared circuit and work the same way off their button switches.
Old 08-02-2014, 11:22 AM
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Quick update...

Installed the afr gauge. Found the perfect spot for it, with pics to come.

Just to the right of the steering wheel is a small quarter sized vent hole. Looks like it was for some kind of option? Pulled out the plug filling the hole, and epoxied it to the back of the plx afr gauge. Now, I just push the gauge into the hole, and can easily remove it. Looks and works awesome. Also it's a very high visibility spot.

So, after several minutes of running, afr was 13 or so. Gunning the motor, went down to 10.8 or so while parked. Tweaked the idle mixture and got it to 14.7. Car didn't like it. Gunning it to 4000 rpm the car sounded fine, but back burbled like crazy on deceleration. The burbling was like the deceleration valve was disconnected... But it wasn't.

Then... It died again, no juice to the sparks. Big backfire when it died. i assume thats because the fuel pumps worked, but the spark didnt. Sigh.

What are you guys running at idle? The car seems way happier at 13-13.5, then at 14.7. I assume the afr will change while driving, and when the turbo kicks in...

Any other tips and tricks to differentiate between the Cdi, coil, and other stuff?

Thank

Bo
Old 08-03-2014, 04:35 PM
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Quote:
What are you guys running at idle?
Around the 14 area, 13.5 like you have is fine i just like to pretend i'm getting decent gas mileage so i keep it in the low 14 range.
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Old 08-03-2014, 06:09 PM
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Bpu did you replace both fuel pumps or just the front one? If so then sounds like either your coil,cdi box or relay may be the culprit. I had a similar issue when I had cis...turned out it was a bad coil which damaged my MSD.
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Old 08-03-2014, 06:44 PM
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I replaced the forward pump. It doesn't seem to be a fuel issue (I think), as clearly there is no spark when this happens. I also bought an inlime amperage tester, so I can see what the pumps are drwaing in terms of juice. $15 at harbor freight.

I thought about replacing the coil, but wish there were a way to tell for sure. If I replace the coil, and its not at fault, then I still have to buy a new CDI such as the MSD and that requires its own coil...

I bought an inline spark tester light, and plan to install it inline with the lead that goes to the coil. Seems to me if there is juice there, but none at the spark, then the coil is bad. Otherwise, its the CDI.

If this works, then folks on this board will have an easy way to test this in the future . The inline tester was only 5$ at harbor freight...

Bo
Old 08-04-2014, 06:36 AM
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Ok. I think I fixed it, though I am not sure how.

My battery cables were getting hot. The 3 smaller wires to the positive terminal were hot after a couple minutes. Looking a bit, it looked like the large of the three was the culprit, and was turning black.

I was getting ready to do some major electrical searching, when a buddy asked if I had tried just changing the crimp on the end.

I couldn't see how that would fix anything. But I went to take the end lug off, and under the heat shrink it was severely frayed at the crimp. I cut it off, and put on a new connector, solidly crimped.

All of a sudden, everything worked. Idle was perfect. Wire was cool to the touch. Went for a ten mile ride, no issues.

Honestly, I am shocked something so stupid could be the issue, but seems to be. Perhaps as the wire got hot, the voltage to the ignition system dropped, and it all went to crap...

Guys, go check these 3 red wires on your positive battery post. If they are hot, change the crimped ends...

The Afr is now 14-14.7 at idle. 13.8 at cruise. And drops to 10-11 at full boost. Runs like a bat out of hell... Again.

Thank you for your help.

Bo
Old 08-17-2014, 03:07 PM
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Good going, we missed a basic one there.
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Old 08-17-2014, 06:19 PM
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Sigh...problems back. Cuts out intermittently. The restarts. No more running rich... Just goes out. No spark.

I guess the permatune gets replaced next. I see they do a free diagnostic on it if you send it in. Any value in that before going msd?

I would buy a new coil, but if that's not the issue its a waste of money. And from what I understand, the msd needs its own coil...

Any other checks before spending the 300-400$ to go msd?

Thanks all...

Bo
Old 09-08-2014, 03:44 PM
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Your previous post sounds like near perfect tune - more or less - ie no major issues with WUR/airleaks etc. The crimp terminal deal was never going to fix things. The hot wire means you are drawing lots of juice. The poor crimp wouldn't let you do that. It suggests you may have an intermittent short somewhere. A ***** to detect. But you need to measure the amperage on that wire when it is hot, and you need to find where it goes to.
Alan
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Old 09-08-2014, 11:45 PM
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Originally Posted by Alan L View Post
Your previous post sounds like near perfect tune - more or less - ie no major issues with WUR/airleaks etc. The crimp terminal deal was never going to fix things. The hot wire means you are drawing lots of juice. The poor crimp wouldn't let you do that. It suggests you may have an intermittent short somewhere. A ***** to detect. But you need to measure the amperage on that wire when it is hot, and you need to find where it goes to.
Alan
Thats a good idea, I should go back to that. The wire wasn't getting hot any more, so I figured the issue was gone.

Next time it starts up, I will let it run and see if it gets hot again...
Old 09-09-2014, 05:00 AM
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Hihihihi my car

https://www.youtube.com/watch?v=PKN714u8YJY&list=UUyuiCJvo4ttVZxw498kjVVQ
Old 09-09-2014, 05:45 AM
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What's going on there???
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Old 09-09-2014, 06:08 AM
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Drivin' ms.Daisy
Then after a little (ab)use last year, I got a little knock in my engine, that led me to an overhaul...
Old 09-09-2014, 10:10 PM
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Updates .

Installed the MSD 6 AL.

Putting that thing in was a pain in the rear, due to its size. I mounted it on the firewall as other have. This gives me access to the fuel filters/etc if needed in the future.

Mounting it was some work though. The firewall is not flat. I had to make a template, drill some holes, then tap the holes so the screws and rubber mounts would hold. The finished product looks good, but my body is killing me .

The good news is, the car idles better than it ever has. Rock solid at 600 RPM. No black smoke. Previously at idle it sounded like it was dieseling or lumpy, Thats now gone. Starts quicker too. I haven't regapped the plugs, as that was a pain last time due to access. That will have to wait.

I did order the NAPA rotor EP 407, and did recieve the correct non-resistor type (beige). That was the cheapest porsche part ever, at $4.07 plus tax .

I love this car, but I am getting a bit tired of fixing something every weekend. Lots of this is doing upgrades/beautification though...

For folks looking to get the MSD, the 6AL works great. If I had to do it over though, I would get the 6AL-2 which is the much smaller programable model, as its only $30 more. I didn't see this until after I already recieved the 6AL. The smaller model would fit where the previous CDI was. The 6AL won't, unless you are willing to leave the watersheild off the rear fuse box...

Bo
Old 10-07-2014, 12:26 PM
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Itssss baaackkk...

Just once, I would love to fix something and have it stayed fixed....

Car starts fine with the new msd Cdi. Runs great, driven for a month with no issues.

Started it today, and noticed that the afr meter said it was really rich at less than 10 at idle. Odd.

I slowly add throttle. Stays at less than 10. Then at 3200 rpm goes to 14.7. Driving it, it's 13-14. Let off the throttle, at idle, and the afr slowly drops back to 10.

Seems like a lambda issue. I disconnected the 02 sensor, and it fixed the issue. Afr goes to 13.5. Reconnect, and it slowly gets richer and richer. Disconnect, and its fixed.

Odd. Is there some intermittent fault in the lamba system? I should note that's its cold today. 40 degrees or so. Prior to this, it's been in the 70-80s...

Prior to this, the lambda system kept the afr at exactly 14.7 at idle...

I posted another thread about me fuel pumps, as they also now seem louder.

What the heck is causing this?

Bo
Old 11-01-2014, 06:39 PM
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Gave this some more thought. Whatever my original problem ,it's still there.

I suspect that before when it happened, the permatune couldn't overcome the severely rich condition, so the car had black smoke and was dying. Occasionally backfiring as it died.

The msd can overcome it, so it doesn't die. It just runs rich.

The po must have had the same problem, as he had the o2 sensor disconnected to compensate.

Yet, at some point I connected it back, and it worked. For a month.

So far, new fuel pump, new cdi... Same issue.


What else can cause an intermittent rich condition at low rpm?

Wur? Wur heating element? Cold start valve sticking?

One other thing I am really confused about. If the car is running rich, afr of ten, shouldn't the lambda system pick that up and lean the car out??? Why would unplugging the o2 sensor lean the car out to 13.5? That just doesn't make sense to me. I would think that unplugging it signals to the computer that there is no voltage and that it's lean, so this would make it run richer, not leaner. I see folks on here unplugging their o2 to drop their afr, not raise it? Does this isolate the issue to the lambda system? Or am I understanding this wrong???

All help appreciated.

Bo

Last edited by bpu699; 11-02-2014 at 07:07 AM..
Old 11-02-2014, 06:01 AM
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When the oxygen sensor is disconnected on a working Lambda system that will make the car go lean not rich. That's how my car responds when I disconnect the oxygen sensor.
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Old 11-02-2014, 05:48 PM
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When the oxygen sensor is disconnected on a working Lambda system that will make the car go lean not rich. That's how my car responds when I disconnect the oxygen sensor.
OK, then what mine is doing is correct.

I don't understand the following, and hope someone can help me understand.

Lets say you have an AFR of 10, and its supposed to be 14.7.

Disconnecting the o2 sensor gets it back to 14 or so.

Clearly, the car has a mechansim by which it leans the mixture out, and that mechanism is working. Right?

So, why wouldnt the connected 02 sensor "see" that the car is rich, and raise the afr to 14 without being disconnected???

Do you understand what I am trying to ask?

The o2 sensor is working (its new). The same o2 sensor also feeds the PLX AFR METER. So, if it weren't working, the meter wouldn't work either, right? The PLX unit reads the wide band AFR o2 sensor, and converts to a simulated narrow band output to feed the computer.

I suppose I can postulate that the PLX AFR meter is not working, but the same issue existed before I put it in. The PO had the same issue also, as he had the 02 sensor disconnected.

Again, its intermittent. I am just trying to figure out where to look. Does it sound like the lambda system is the problem???

Bo

Old 11-03-2014, 04:44 AM
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