Turns over won't start?

[Kurt Koseck]

My son pulls the A4 out of the garage, and parks it. I go to put it back in the garage later that day, and it won't start. It turns over just like normal, I even press the gas pedal, and not even a single hint of any firing. I think that I should look at fuel first. Is the fuse for the fuel pump blown? Other than that, I don't know where to begin? I don't have any way of checking fuel pressure. I had the timing belt replaced about 500 miles ago.
Any other thoughts as to what I might check?

Thanks,

[seanj130]

Put jumper cables on and go from there.. Even if the fuel pump is shot it will start for a second then die. Clean the terminals on the battery and battery cable. Maybe it just doesn't have enough juice to turn over.

[Kurt Koseck]

It turns over perfect, battery is very strong. Maybe it is flooded, I could press & hold the accelerator all the way down and eliminate flooding as a potential problem. Plugs are new, so this shouldn't be it. I'll also try to see if I can hear the fuel pump running.

[qo0v]

I had the same problem a while back, but my car died when it was at idle and then it would turn over but wouldn't start. It ended up being "relay 30" in the ecu box, might want to check that.

[walky_talky20]

- Make sure the fuel pump is pumping while cranking (should be easy to hear if you put you fold down the passenger rear seat and put your ear near the tank).
- Check for spark. That really checks lots of systems at once (ECU, crank sensor, ICM, etc) and it is really easy to do.
- Check for codes if possible

I've seen this a few times where it is just the coolant temp sensor that has failed. If it reads hot (in error) the car will fail to perform a "cold start". Which is basically like trying to start your lawn mower without the choke on = not going to happen. That's kind of an outside case, so I'd check the basic stuff first. Good Luck.

[Kurt Koseck]

I don't hear the fuel pump. However, I removed the fuel filter and it seemed to be under pressure. How can that be? I turned the ignition on with the filter removed, and expected to see gas pumping out of the line, but got nothing. Fuse looks like it is ok. Shop manual says there is a relay, but not sure where this is.

[Kurt Koseck]

Pulled the cover off, the one in the trunk that allows access to the fuel pump. Pretty dirty in there. Cleaned it all up, looks brand new. Shop manual says to multimeter lead 1 (green/yellow) and 4 (brown). With the ignition on, I am reading 4 volts. This seems odd. Shop manual says to "Press remote control switch continously while reading Voltage. * Specified value: approx. Battery Voltage."
Not sure what they mean by 'remote control switch', is this the key FOB? Does that initiate something different than turning the ignition on? Maybe when you turn the engine over it should jump up to 12 volts?
So far, I think that it is the fuel pump itself. The next step (per the shop manual) says to remove the cover flange and sealing ring. This would allow you to check for continuity of the wiring. If the wiring is OK, then you have to assume that the fuel pump is faulty.
If everything were operating properly, would having the fuel filter out stop the pump from running (safety feature)? Doesn't seem likely, everytime you changed the fuel filter out you would have the same situation.

[JoBuNY]

May be a dumb suggestion but it happend to me so I'll throw it out there.

I have a sloped driveway, and one day I drove home and parked like normal. Came out later to start it and no go...it wanted to start but never fully fired. Ended up being that because I was low on gas and the car was on the slope the fuel pump could not reach any of the gas in the tank so it wouldn't start. After I rolled the car down to the flat part of the driveway and waited about 10 minutes it fired right up.

[walky_talky20]

Depending on temperature (I think), just turning the key on may not make the fuel pump prime. And it certainly won't run continuously that way. Blip the starter (ie: engage the starter for just a moment). This will make the fuel pump run for just a few seconds. The fuel pump should run continuously while the starter motor is engaged and stop a second or two after you let off the key (assuming the engine start was not successful).

The "remote control" is a diagnostic tool used to close the fuel pump relay on command. This is not a tool that you have.

[ECS Tuning-Audi]

Is this a 2.8 or a 1.8T?

Jason

[Kurt Koseck]

This is a 98 A4 2.8 Q. Spark plugs and fuel filter are new. Gas tank is almost full, it seems like this will be another issue if I have to replace the pump. Shop Manual says that the tank should be 1/3 or less full. Not sure why this is. Can't everything just be pulled out from above?

[walky_talky20]

Yes, you will be elbow deep in gas is the issue, lol.

[seanj130]

can you post a video of you trying to start the car so we can hear please

[Justin@FCP]

No CEL on?

[builditup]

Just my two cents...... i had a 98 A4 2.8 and i took it to a shop to get the radiator fixed. Went to go pick it up and it cranked and cranked and would never even try to hit on one cylinder. went in the shop and the guy was like " i just drove it out there about 5 min ago, let me check." so he did the same. all in all we ended up taking the spark plugs out to check for spark.....nothing......what it was was the cam position sensor. on the back of the driver side valve cover. i put a used one in it and fired right up! i hope this helps and it was very easy to check if you ask me.... pull the plug and check it out....good luck

[Gdlaszako]

One of the A4's that I used to get rides in had the same problem. it was a 2001 it ended up being the coil pack that were the problem.

[mRestrepo]

Fuel pump relay..was having the same problem on my 1.8t, the relay should be labeled 372. I actually didn't even have to replace mine, I pulled it, cleaned off the contacts put it back in and no CEL, and start ups are back to normal.

Oh..and this was the culprit after having numerous people telling me to buy new fuel injectors. It's definitely always good to do some research first, good luck.

[Kurt Koseck]

Car is running. Fuel pumps has 4 volts to it with the ingnition on. When I go to start, voltage increases to almost 12. It also pumped gas out of the open fuel filter. Next, checked and found good spark. Took my trukery baster, and sprayed some gas into the intake (past the MAF). Turned car over, and it reluctantly started, and then started running smooth. No CEL or codes. With 245,000 miles on the original fuel pump, my guess is that it is starting to get weak. Now I can run the tank low and change out the pump. Thanks for all of the advice. Sometimes, it is dificult to know where to start trouble shooting. I still can't "hear" the fuel pump running, this also makes me think that this is where the problem is.

[Justin@FCP]

Glad to hear it's running again, hopefully changing out the fuel pump will solve your problem. Keep us updated on how you make out with it!

[builditup]

good to hear its running again......245k! i hope mine makes it to that!..... probably walnt letting my girl drive it all the time. haha

[Gdlaszako]

nice to here that it started again. you could probably find a fuel pump cheap at a junk yard though.

[walky_talky20]

Personally, I don't think the fuel pump is the problem. It has the *easiest* job when the motor isn't running because it has to deliver hardly no fuel. Once it starts to run, the demand on the pump only goes up. So that doesn't really explain your issue. If it really was starting to die, it wouldn't deliver fuel at all, or the pressure would drop at high demand times, like WOT at the top of 3rd gear.

What does explain your issue is that it wasn't going rich enough during cold start. I'd put a new CTS in it and then see if you have any more problems after that. I wouldn't go dumping money into a fuel pump just yet. With such high miles (245k, for realz?) changing out the pump isn't an altogether bad idea, just for reliability sake (they don't last forever) - but I don't think that was at all causing your issue here. The fact the pump runs quietly during operation reinforces this (junk pumps will often run *loud*).

^Above is just IMHO. You can take that for what you will. Good Luck!

[Crispy222]

Your idea on the demand of the pump while no running and running is a little off. All B5s (1.8t/2.8) utilize a return system. So when the pump is running, its pressurizing the system til the regulator opens and returns the fuel. At idle there less fuel pressure in the rail/system due to the design of the regulator. With vacuum pressure, it decreases the regulated pressure. I can't be 100% certain that this is true for 2.8, but I think it is. I would agree that a weak pump would make more noise and cut out once demand for fuel into the motor increases at higher rpm under load. Most pumps either work or don't work, but is one of those components you can tap on to bring back to life for a few more miles. There isn't much middle ground from my experience. I would recommend to do the CTS to eliminate that as they go bad often and can lead to a lot of chasing around problems. Age on the fuel filter is another issue to look at. Maybe when you remove it, it back flushed out some silt and flows enough fuel again.

[walky_talky20]

^I agree, most often the thing just quits completely. Sometimes you can get a clogged pre-filter (in tank) which can cause weird issues, but yeah. The OP certainly had fuel delivery (he disconnected at the filter) when cranking, so she was definitely pumping. If the car ran good once it actually started, I can hardly believe it was a system pressure issue. If it is so choked up that it will barely start, the thing is going to run like absolute poo regardless. I'm much more inclined to believe it was just a problem getting cold start enrichment.

[B5RiceEater]

buy ecstuning.com v checker pro 100 buck scan tool, set aside from that buy a 25 dollars inline spark tester kit with noid lights from eppys.com or pull each coil pack and have some1 crank the engine while u gap the coil pack to an engine ground to see spark, disconnect fuel line and have some1 turn the key on for a second to see if fuel squirts out to see if your getting fuel to the injectors if no fuel, have some1 crank the car and take a rubber hammer and bang underneath the gas tank if car starts its youur fuel pump, if not check fuel pump main relay ..case closed back to boosting lets go!!!

[ECS Tuning-Audi]

buy ecstuning.com v checker pro 100 buck scan tool, set aside from that buy a 25 dollars inline spark tester kit with noid lights from eppys.com or pull each coil pack and have some1 crank the engine while u gap the coil pack to an engine ground to see spark, disconnect fuel line and have some1 turn the key on for a second to see if fuel squirts out to see if your getting fuel to the injectors if no fuel, have some1 crank the car and take a rubber hammer and bang underneath the gas tank if car starts its youur fuel pump, if not check fuel pump main relay ..case closed back to boosting lets go!!!

Thanks for the support!!

Jason

[GCSheffield]

I have a 2008 84. Had the same problems that you guys did. At first I thought it was the EVAP purge valve. I also had the problem that my car would not start every time I got gas. We ended up changing the low-pressure fuel sensor which seem to work or fix the problem for a few minutes, but then had the same issues. Later found out there was too much variation from the low-pressure fuel pump that is either in or attached to the fuel tank. This has finally fixed the issue. There are 1 million posts out there of what it can be, but this is what fixed mine after about a week of searching and trying different things. Some places will claim that it is the high-pressure fuel pump. And my research and testing though, the only time I would really consider that as the problem is if you lose acceleration while driving at higher speeds. If it is just an issue in the car sits idle I would think that it would be the low-pressure fuel pump and sensor. While they're in there I also had them change the fuel filter as well. This seems to have solved everything. Hope this helps!

[Rickystewart]

I have a 2001a4 1.8t it started right up an then shut off now it wont start ive hook ed it up to jumpers checked my relay I do not here the fuel pump wine when I turn the key but a small click any ideas guys or gals

[Crispy222]

I have a 2001a4 1.8t it started right up an then shut off now it wont start ive hook ed it up to jumpers checked my relay I do not here the fuel pump wine when I turn the key but a small click any ideas guys or gals

Bad pump

[euroclass]

That's kind of an outside case, so I'd check the basic stuff first. Good Luck.

Im having the exact same issue except in a cold climate condition, typically under 10celcius. starts perfect in the warm or when warmed up.
any idea on that if it was an outside case?

[walky_talky20]

^That can be caused by a faulty coolant temp sensor, yes. Easy to check with VCDS or a scan tool.

It can also be some component that is failing to operate properly in very cold temps. Failing Ignition coils can have dramatically lower output voltage when cold vs warm, for example.

[euroclass]

Failing Ignition coils can have dramatically lower output voltage when cold vs warm, for example.

Thanks for the reply, Ive replaced the cts already and still to no avail crankshaft sensor also replaced so i was suspecting potentially my cam sensor had gone out and ordered one today. That makes sense with the ignition coils though they do have a fair bit of rust buildup on the top plates. appreciate it

[dgunn69]

Thanks for the reply, Ive replaced the cts already and still to no avail crankshaft sensor also replaced so i was suspecting potentially my cam sensor had gone out and ordered one today. That makes sense with the ignition coils though they do have a fair bit of rust buildup on the top plates. appreciate it

Did you resolve this problem, my car is having the same issue.

[CRAIG COURTNEY]

Did you resolve this problem, my car is having the same issue.

2007 A 4 WONT START CRANKS OKAY HAS NEW FUEL PUMPS FUEL PRESSURE SENSORS AND TURBO...SHOWS ABOUT 100 TO150 RPMS ON CRANKS

[CRAIG COURTNEY]

NO I AM INSTALLING CAM AND CRANK SESNORS AT THE MOMENT ..IF NO START THEN A GUESS ECM ..DOES ECM NEED TO BE REPROGRAMMED

[CRAIG COURTNEY]

ANY ONE WITH ANY IMPUT DONT HAVE MUCH HAIR LEFT TO PULL OUT

[hightime80]

🤔🤔

[B5BRIXS4]

Thread bump, 07 a4 2.0t, new apr HPFP, had shop install new JHM LPFP, then was told my rs4 controller was shot, so ordered Torqbyte PM4, controller, car shut off on me while driving(dangerous) it cranks cranks cranks but does not start, everything in the fuel system is new, replaced crank sensor as well, only thing I have not done was the fuel pump relay,m in the ECU box,any ideas? I’m baffled.

[B5carl]

Thread bump, 07 a4 2.0t, new apr HPFP, had shop install new JHM LPFP, then was told my rs4 controller was shot, so ordered Torqbyte PM4, controller, car shut off on me while driving(dangerous) it cranks cranks cranks but does not start, everything in the fuel system is new, replaced crank sensor as well, only thing I have not done was the fuel pump relay,m in the ECU box,any ideas? I’m baffled.

You went from a HPFP to a LPFP? Anyways You posted this in the wrong section btw this is the B5 1.8t, 3.0L forum not the 2.0T. our cars don't have HPFP's. You need to go to the B7 or newer forums with that work on that engine.