Q – On my 1991 C4 Cab, the intermittent wipers and the “park” function have been inoperative for quite a while. My dash lights have been intermittently inop for a while and now they are completely out as well. So now I can’t drive in the rain and at night, I can’t see my dashboard. Are these problems related? I checked the fuses and they all look good. Electricity mystifies me. Help! Gary
A – You are not alone Gary, electrical problems / gremlins have challenged and annoyed me for over 50 years. One myth that I continue to try and dispel is that you can check a fuse (or a bulb) by looking at it. You might say that is bunk, that you can see a blown fuse or a burnt out bulb my looking at them but I have been fooled dozens of times where I would have been better off walking a few steps over to my box to get my meter.
On the wipers, we begin by checking the fuse for power at both sides of the fuse. Odds are, power is getting to the fuse. (Usually the problem is not on the supply side of the circuit but on the load side.) If the fuse is getting power but the circuit is still dead, remove the fuse and look for signs or heat or burning on the spades of the fuse. Next take a look at the top of the fuse holder in the fuse box to see if it looks charred or melted. (You will need a strong light and a magnifying glass.) If you see evidence of melting, you are onto something. At this point you will want to lift the body of the fuse box up and take a peek under it to see if any other burning or melting is evident underneath where it is hard to see.
The last example of this problem I say involved a melted portion of the fuse panel. The temporary cure is to twist the spades of the fuse so it tensions the loose terminal in the fuse box. The long term cure is to remove the female terminal from the fuse box, replace the terminal, and reinsert it into the box. In a “worst case” you might need to replace the fuse box. There are other more practical, safe and non-factory approved methods of repairing a melted fuse box but if you want to keep it original, this is gonna hurt.
The dash illumination operates through the light switch, fuse box and a computerized relay. One way to check the relay involves twisting it slightly to see if the lights start working. The reason I choose to start at the relay is the intermittent nature of the symptom. When relays start getting flaky, sometimes moving them around will bring them back to life for a while.
In the case of the last failure I was involved in, we popped the cover off the relay, inspected with a magnifying glass and sure enough, found a circuit where the solder had not fully melted into the prong sticking through the circuit board. Odd that it took twenty years to fail. In this situation I recommend a new relay but when you search for one, you discover no one stocks them locally.
So we re-soldered the offending circuit and Bingo! Dash lights!
Intermittent wiper problems and park problems have plagued my own car for years. I have gotten used to parking them manually and frankly, as a short guy, I like them parked on the right side of the windshield rather than the left. I do miss the intermittent feature but you know what they say about “the shoemakers kids going barefoot”. On your Carrera, the intermittent feature (and park) is controlled by another one of those pesky computerized relays and they get flaky with age. Try that twisting trick on the relay and if it works, your choice, replace or fix. – MC
Q – I plan on getting my 944 back on the road after having stored it for 10 years. What should I do to get it ready? Gino
A – Whew! Ten years of storage is tough on a car and the process may be complicated even once you get it running again. First things first, check the oil, coolant, install a fully charged battery, remove the spark plugs, disable the ignition coil, remove the fuel pump relay, oil the cylinders, change the oil and try to crank the car. As you crank it, you will probably notice that initially it cranks slowly then gradually speeds up. Crank it until you see the oil pressure gauge start to move (or the warning light goes out).
Once you get the engine oiled up by cranking you can reinstall the spark plugs and proceed with the fuel system. Drain the fuel tank as best you can and put in about two gallons of fuel, one can of “drygas” and about ½ bottle of Techron additive. It is very likely that you will need to remove the tank to get it clean but you can hope. After you get fresh fuel in it, disconnect the fuel pump and power it up with 12 volts positive and ground. If it actually runs, great! Usually after a number of years, the fuel pump will be seized. If you hear no sound, try reversing polarity of the power and ground on the pump and see it if will run backwards. If you get no fuel pump run at all, you will need to replace it.
So with the original pump functional or a new pump installed, you should have fuel pressure at the rail. You can check this in a number of ways but you are working with fuel and possibly spark so observe safety precautions during this step. The fuel pressure will be in the range of 40 psi plus.
The next step is to reinstall the fuel pump / DME relay and crank the car to see if it fires up. As you crank it, you should notice resistance in all four cylinders that will create what I call “cranking rhythm”. If you get uneven rhythm, you may have a compression or timing belt problem. But even if you “got rhythm”, It probably won’t start.
At this point, you will need to check for spark from the ignition coil. I would assume you will have spark since ignition on 944s is very reliable, even when they are stored for years. Caution: As you check for spark, be very careful that you do not become the ground side of the circuit. It can kill you! Rubber gloves may not be fashionable, but they could save your life.
Let’s say so far, so good; you have spark, but still it won’t fire up:
Now you need to check the injectors for pulse (with a volt-meter) and sound. If the injectors are not getting a pulsed-voltage signal, there is an issue with either the control unit(s) or the wiring. Break out the DIN diagrams, and pack a lunch, ‘cause you’ll be hunting all day! We tend to charge a LOT for electrical diagnosis, because it can be the most difficult thing to do on any given car…searching for a needle in a haystack is easy compared to searching for loose electrons in a wire!
If you ARE getting pulse, but no fire, you probably have clogged or “seized” injectors. As you crank the engine, the injectors should be clicking if they are not frozen due to old fuel residue. You can hear them click with a stethoscope. If you hear the injectors click, they still might be clogged and I would be surprised if they are not. So after a bit of cranking, pull a spark plug and see if it is wet with fuel. If it is not wet, put the plug back in, try a very brief shot of starting fluid into the air filter area and see if the engine tries to start. If it acts like it will start, stop there, that is all you need to know at this point. Do not try to run the engine on ether! This is only to verify that the engine can run with a fuel source.
If you have made it all the way to this point, and you have determined that the injectors will not spray fuel, you will need to remove them and send them out for rebuilding or replace them. A local source for this is Kinsler fuel injection in Troy. Now let’s say you get it to start and run. An engine that has been sitting for a long time will very likely have some collapsed valve lifters that will take a while to pump up. Don’t let a light rattle coming from the cylinder head scare you.
After you have gotten it to start and run, as it warms up, watch out for overheating since it is possible that the thermostat may be stuck. Once you are satisfied that it lives again, replace the fuel filter, fill the tank and add the rest of the Techron. Congratulations on a successful resurrection. But don’t try driving it yet. There is another chapter to this story so stay tuned.
Q – My 92 Carrera 4 blows the fuse for the climate control and then I roast in the summer heat. The circuit calls for a 25 amp fuse and that is what I have installed. Got any ideas? Pete
On a couple of these cars that we have inspected, we have found a 30 amp fuse in that 25 amp position so obviously you are not the only one. The key issue is where is the power going and why. There are two heater fan motors in the cowl area and we have measured the motor load on a number of cars. We get readings of 9.5 to 11 amps and during initial power up of the circuit, the load peaks at about 22 to 24 amps for the circuit. You can see why a 25 amp fuse is marginally adequate for the task. This does not leave much “safety factor” for that fuse.
There are other consumers on the circuit which may explain why we find 30 amp fuses in that position. In addition to the fans, the actuators and climate control head take power from that fuse too. As far as the wisdom of putting a larger fuse, this is a situation where one needs to be very cautious. For instance, if you have a 10 amp circuit and install a 20 amp fuse, you are reducing your protection significantly. This could lead to overheating and burnout on components that cost a LOT, if you can even get them anymore! Since I have no way to monitor your car, be aware of unusual odors or other symptoms related to the climate control and if it blows the 30 amp fuse, stop while you are ahead and get it diagnosed. – MC
Q – I removed the header pipes on my 2000 Carrera to clean out the secondary air injection ports. Four of the bolts broke off. I am scared that we will have to pull the engine and replace the heads to get them out. What do you suggest? Keith
A – Even using the best methods, the most experienced technician with the patience of a saint, will sometimes snap off bolts. Techs hate it since getting the remains out of the head is one of the worst jobs ever; and you are working upside down. If you tried it at home in your garage, without a hoist, an acetylene torch and an air chisel, you are lucky you did not break even more of them. We expect each broken bolt to take about an hour to drill out cleanly while saving the threads in the head. Note the operative word: cleanly. If you are sloppy with your drilling, if you do not meticulously maintain the center, or if you drill too far, the game is over and you lose. You can ruin the head and be left with a very expensive mess on your hands. Experience, finesse, proper tools, luck and prayer usually get it done. Next time I would pay a pro to do it.
I would like to know why Porsche decided to use bolts into the head instead of the tried and true studs. Was it cost? Ease of assembly? With all due respect to Stuttgart, when we remove header pipe bolts, we replace them with studs and for my money, stainless steel nuts and washers. This is Michigan after all. With stainless, the next time the header pipes need to come off, you will have a fighting chance of doing so without breaking anything. MC
Q – I am fit to be tied! I have given my 91 C2 the best of care. It has been running great for years in no small part due to my constant infusions of cash over the years. After 144,000 miles I expect to repair things and I try to plan ahead. I even went so far as to have the distributor belt replaced before it broke. So you can imagine how annoyed I am to find, that only 8 thousand miles after having the distributor serviced by one of the advertisers in the Panorama, the belt broke. Even worse, I am told that one of the coils has shorted out, another one is leaking oil, and the ignition module is burned out as well. The tab is over $2800.00. And if that isn’t enough, it’s my wife’s car! Now I have a rental car on top of the already mounting expense. What did I do to deserve this?! Fred
A – Do you believe in Karma? Remember that old lady that you pulled up next to in the right lane at the stop light and then smoked off the line last year? That could be it. She just got even. But seriously, I can only speculate. Without a post mortem exam on the distributor, it simply does not make sense to me either. One thing I can assure you of however, is that the likelihood of a Bosch remanufactured distributor failing is remote and if it did happen, you would not be singing the blues right now.
As far as the failure of the distributor, naturally you need to contact the company that rebuilt the distributor and see if they will “show you a little love” about your major expense. I expect that any company that wants to maintain their rep will want to make you happy. I know I would.
Although it is a little late, I would have installed a Bosch Remanufactured distributor. The advantage of having the distributor replaced with a Bosch Reman unit is clear when you know how their warranty system works. Bosch will cover the labor to diagnose, remove, and replace the distributor if it should fail within 12 months or 12,000 miles. That’s not really a very long time, or very many miles; but it would have saved you a couple thousand dollars right now.
I have found that Bosch components rarely fail. When they do, even if the damage is outside the time limit or mileage, you will get some help if the parts was installed and diagnosed by an Authorized Service Center. What the fine print won’t cover, the regional service manager often will. I once installed a brand new Bosch fuel pump that would not work, right out of the box. I sent it in, they tested it, and naturally it worked. They replaced it anyway and paid the labor as well. No other company that I have worked with offers a warranty that is this comprehensive, not Porsche certainly. In fact, if the distributor was purchased from Porsche, it is quite likely a Bosch remanufactured unit anyway, sold to Porsche directly. Even in such a case, the warranty would only cover the part, not the labor. If the part was installed by an independent, you could expect a fight to get any satisfaction from Porsche itself. The full warranty is only available through Bosch Authorized Service Centers.
As far as the coil and the module, I can’t say if Bosch would cover those components, but “goodwill” goes a long way. I speculate that the coil and module met their demise when they both overloaded. When the distributor stopped turning, the computer called for spark but it had nowhere to go. The Porsche (Bosch) coils are very robust and were designed to fire a spark that far exceeds the need of any normal engine. When spark is created, the coil is loaded with electrons and when it discharges, they had to go somewhere, probably from the coil tower to the body of the coil, or maybe to the rotor, then to ground. The coil was doomed, as was the module. Fortunately the module took the hit and the DME (Motronic computer) did not.
Fred, there was a well known VW guru named Gene Berg who once said, “buy the best and cry once.”
Disclaimer: Bosch is an original equipment manufacturer of many components used on Porsche and many other German automobiles. This is not an advertisement for the Robert Bosch Corporation, simply my experience. Many of the top shops in the nation that service Porsche cars are authorized by Bosch to sell, service, and warrant their components including many current and former advertisers in the P4.
Q – My 1979 Carrera make terrible crunching noises from the front suspension until I drive it a few miles and frankly I am embarrassed to drive it through the neighborhood. I was told that they were originally rubber and someone changed them to a white plastic then tightened them down to the point that they are squeezing out. Can I go back to the original rubber ones? Larry
A – Considering the age of the car, the rubber ones were probably shot and when the owner of the car found out how much it would cost to replace them, the white ones (made of Delrin) seemed like a good idea. I would bet that just after they were installed, they didn’t even crunch! Whenever you buy these, they give you a tiny tube of assembly lube and that works great…for a few weeks!
If they are not worn out, you could take them apart and grease them (I wouldn’t) or have grease fittings installed in the arms. If you ever do need to replace them, having the ability to grease them makes a lot of sense since rubber replacements are not practical. In addition to the Delrin bushings which are very hard, there are two other grades that you can buy. Red polyurethane and black poly graphite are the ones I am aware of. I am going with the black ones with grease fittings for my own car. For yours, adding fittings and lubricating them will probably do the job and if not, you will need the fittings for the next set anyway. – MC
Q – To add to your comments on the 912, where the engine compartment seal was not doing its job (P 4 July, page 30), an easy way to check the gauge is with one of those temperature guns. Get engine surface temperature readings in degrees and see if the gauge is in a similar zone over time for that reading.
I have 130,000 miles on a 1964 SC. Maintaining the engine compartment sheet metal and the seal to the body is vital to keeping the engine cool, and not much dirt gets in either. I do a reasonableness test with the temperature gun to the gauge a couple of times a year. Harry
A – An excellent comment about a tool we use frequently. Another use for the temperature gun (non-contact pyrometer) is determining which cylinder is not producing equal power. If you can gain access to the exhaust ports and you detect a misfire but can’t be sure which cylinder is causing it, pointing the “ray gun” at the header pipe will quickly show you which cylinder is loafing. We also find the tool useful in verifying the source of brakes that pull to the left or right. After a few hard stops, you can measure the heat on the rotor surface and this helps determine where to look first for the problem. An excellent tool and now that they can be purchased for less than $100.00, any motorhead can afford to own one. – MC
Q – My convertible top boot won’t stay snapped anymore. The little “Tenax” fasteners have no grip and when I look inside them, I noticed that the three little “petals” seem crushed and pulling the knob/release does nothing. Ted
A – Sorry, but you have probably made the same mistake that I and many Cabrio owners have. When you go to snap the boot down, you have to pull that knob and hold it as you place (not push) the fastener onto the ball screw on the body. Then you RELEASE the knob. If you simply push it on, which I agree is the intuitive thing to do, you crush the three little petals inside the fastener and at 20 bucks a pop, that hurts. They are incredibly wimpy. The dealer does not stock them but some top shops do. And I am told by my friends at Paul’s, that Mazda Miata boots or tops use the same fasteners at a lower price. Changing the fasteners is easy if you have access to snap ring pliers to unscrew the spanner nut that secures it to the fabric. – MC
Q – I noticed little bits of foam rubber in the engine compartment of my 1988 Targa and it looks as if the pad above the engine is falling apart. What is the pad for and how hard is it to change it? Jim
A – I call that the sound pad and it insulates the engine from the body and soaks up sound as well as heat. It is not a critical component in my view. It becomes a liability when it starts to shred and gets sucked into the cooling fan where it gets embedded in the cooling fins. I would remove it before it gets worse.
The part is not very expensive so cost would not be a factor in my decision. Labor to change it is a whole other matter. When the car was built, before the powertrain was installed, that pad was glued into the engine compartment and neatly tucked into the corners. With nothing in the way, you can do a very nice job. With the engine installed, I have never seen it done well and I have seen a few feeble and ugly attempts. I won’t do it and I don’t recommend it.
The problem is two fold. 1) It is glued in with contact cement and to get it to stick well, you need to remove all the old glue. That is near impossible if you are working around the engine. And once you get all the old glue off, you have to re-spray the glue while keeping it off your engine (and your body) 2) After you spray the glue onto the engine compartment and the pad, then the trick is sticking the pad on centered, without wrinkles, and even front to back…Good Luck. At least with the engine removed you have a fighting chance.
When you open the engine lid on my Carrera you will notice the pad is missing. I can hear my engine better and I like that. I also like the shiny red paint. Once I got the glue off, I thought it looked pretty. It might be a little hotter inside the car but I know what I am up against. Someday when I pull the engine (and I hope that is a long time from now) I will probably install a new pad while taking my time to do a factory quality job. In your case, get that nasty stuff out of there and listen to the sweet sounds of a flat six at full tilt. You will probably like it too. – MC
Q – I changed the fan belt on my Carrera (1989). After I did it, I noticed a “jingling” sound in the engine near the fan. It wasn’t there before. What do you think? – Patrick
A – That jingling noise was the small change you saved by doing it yourself. That sound will soon change to a loud “grating” noise that foretells the failure of the inner and outer pulley sheave and perhaps the alternator. Shut it off!
Porsche and VW used shims to adjust the working diameter of the alternator/fan pulley. When you change the fan belt, the shim pack also must be adjusted by moving shims from the center to the outside of the outer pulley or vice versa. A new fan belt is a little fatter than the old belt. Without shimming the pulley, if you simply install the belt and tighten the pulley nut until the belt feels “tight”, the inner and outer sheaves may not be properly tightened. This causes the pulley components to wear against one another. In a few hundred miles, the assembly may come apart all by itself and ruin the alternator, the fan, and cause the engine to overheat!
Your best bet is to visit your Porsche specialist and ask if you can watch (and take notes) as the process takes place. Call it tuition. And I sure hope you shut it off in time. – MC