Dead Audi S5! Should be an Easy Fix BUT it's NOT!

Now that ladies and gentlemen is what you call Real Mechanic and not a parts changer!!! You guys are far and few in between and that’s a fact! Thanks for your great Wisdom it’s greatly appreciated!!!

David, that is a Lupolen tank, produced under license from DuPont. These were first installed on the Porsche 928 back in 1978, and they have a sterling record. They are very tough and it takes a blow torch to actually cause the plastic to melt. But these tanks can take take a lot of damage from sharp metal in an accident and NOT leak. They are WAY better than a metal tank, since they bend tremendously rather than steel, which just punctures. Porsche used these because they designed the 928 and had it's production line set up. Then during crash testing it was found that this car was VERY susceptible to fuel leaks in a rear impact; This very serious problem literally threatened the whole program. Porsche found that simply changing the tank from steel to this very strong but flexible material solved the problem completely. These tanks are superior and why metal tanks exist anymore is a mystery to me- Great video!

I fix industrial machinery for a living. It's shocking how many times 1 electrical component has failed, causing another component further down the line to fail. I see it FREQUENTLY.

When I worked at BMW for 5 years, when we got a car that had a faulty fuel pump, we would always give the customer an estimate to replace the fuel pump control module in conjunction with the pump. Often times, just like what happened in this video, the pump would draw so much electrical current that it would internally damage the module as well.

I had an 2007 S6 5.2 V10. It was a money pit. Ate coils for breakfast. Engine out for everything but an oil change.

Most repair shops replace the fuel pump relay/module when the pump fails, for the precise reason that you detailed. Probably a good idea.

My sending unit on my old truck went bad and I decided since it’s 28 years old I should check the tank. Opened it up and saw the tank was good, but the fuel lines were bad going to the tank. It has sat for almost 2 weeks because a fuel line got lost in shipping. It isn’t always a simple fix…. I understand the frustration of the client, but I completely understand your end of it also. This video is a good example of what can extend a repair with unforeseen complications.

Fuel pump control modules are known to give out on vw/audi models that year. VW issued multiple revisions and even added heat sinks to help with the cooling.

setting expectations and communication with clients is the absolute best way to retain them.

Years ago I read a report on Cadillac's, I think, that had stalling problems once the engine was warmed up. Ends up an owners survey was taken and they found out the majority of owners drove their cars almost to that gas empty mark. The in tank fuel pumps are cooled by the gas around the pumps and with little gas the fuel pumps run hotter which caused the pumps to fail earlier the report summarized. Because of that survey I hardly ever let my fuel tank get below 1/2 empty. I buy high mileage luxury cars, keep them for about 3 years or so and sell them for about 1/2 of what I paid. I've been doing this for over 30 years until obama started the cash for clunkers scheme. No more high mileage luxury cars now. I also had an 82 Lincoln Town car (beautiful) and it would stop in traffic, on the side of the road, in driveways - anywhere. After about $800 in towing bills and $500 or so of service to the Lincoln dealer with no resolve I eventually called up the Lincoln service manager and told him they could have the car after I told him the one year story of engine shutting down problems. He said "Did you change the power up relay to the fuel pump" in which I had not. He says $11.47 for for each relay which is mounted on top of the drivers side wheel well with his advice to also change the exact type relay which runs the main computer too. I got them, paid, installed and never had a problem while I had the car. Heat kills electrical and electronic things.

Anytime I see/hear of a fuse blowing after something else has failed, I always suspect the wiring loom. In this case, the control module for the fuel pump got hot, as did the connector in the old fuel pump. I would check every inch of wiring you can; there may be melted wire insulation that could create an intermittent fault. Rainman Ray’s Repairs (YT Channel) recently featured a repair video where an O2 sensor heater shorted, and kept blowing a 15A fuse, but only intermittently. Once Ray traced it back to a connector, he removed the old tape and - sure enough - there was melted wire insulation and you could see the bare, copper wire. Tapping on it just right would cause the short and blow the fuse…. and one of his meter test leads! That sucker was pulling north of 24 amps! HTH! 😊

We usually replace the Module along with the pump and also the wiring. Many an Audi tech has been burned just selling a pump. I’m so happy you made this video because it’s common across the line. Good repair Wizard!! Side note: I need that S5 as a donor for my V8 Q5 swap!! Tell the customer I want it! 😂

Just shows that having an analytical mind is required when dealing with these seemingly simple strait forward problems.

I have an '11 S5 with some sort of electrical gremlin. I bought it and it wouldn't start the next day. Took it to a local VW/Audi shop in Wichita. They had it a month, replaced the ECU and fixed some wires on the harness. Car started fine for a couple weeks, then no more communication with ECU again.. It's back at the same shop.. hopefully they can figure out the issue.. OR I might need to bring it to see you!

Like I've always said, you can buy a car from anywhere but finding an honest mechanic to work on it is the key to a happy motorist!

I appreciate how you diagnosed the problem fully. Like you said, sometimes a problem is simple: replace the bad part. But other times there's a sequence of issues that needs to be looked at.

The fact that it didn't throw an error code indicating faulty fuel pressure sensor is a clear sign that the programmers who set thresholds and logic triggers for fuel system faults were on holiday when they should have been programming. If the engine is running ok based on oxygen sensor, manifold pressure, engine speed, ignition timing, fuel injector timing, and engine load data - then a low voltage reading from the fuel pressure sensor should immediately result in a faulty pressure sensor error code. If it doesn't, the programmers who mapped out the engine operating data statistics and error code triggers were clearly asleep at the switch. This is really substandard for a car that cost as much as this did when it was new and boasted advanced "German" technology.

Brilliant deductions! And that last item, the power pin pushed out of the socket, I made that very mistake with one of my Mercedes. I was replacing front shocks on a CLK55, and had to remove some electrical modules out of the way. Somehow when replacing one of the plugs, this very thing happened. I could NOT figure out why the car wouldn't start and had to have it towed to my mechanic. I was embarrassed as all get out when he told me what the problem was!

Great video! Explaining how we techs think and know there can be more than the one obvious thing to fix AND explain it to the customer. Wonderful way to do business!! I wish I could bring my fleet of two to your shop. Just like going to the Dr for a check-up. Good Job both of you!!

Having worked in electronic repairs for over 50 years these sort of issues where you fear that you are never going to fix it are all to common. And as in this case.all it takes is one damaged connector to drive you insane. Now that todays cars are stuffed full of connectors and modules a lot of cars will be scrapped as to expensive to repair in a reasonable time.