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View Full Version : Fuel Pump Relay won't close, not CPS, CTS, ICM



hepgot
08-16-2013, 04:10 PM
My 1999 A4 died while driving the other day. I just filled up with gas and got maybe 2 miles from the station when it felt like I lost a coil pack. I continued driving (trying to reach the next exit) and it died. Got it towed home and ran the VAG, no CELs like I normally get for rough idle/misfire or whatever for coil packs, no CELs at all..

Checked for fuel at the rail and had nothing. I took the cover off the FP relay to close it manually to ensure the fuel pump was working, which it is and then I changed out the fuel filter and still no fuel at the rail. The FP relay won't close when I crank the car so I figured (from what I've read) that it might be the Cam Position Sensor so I replaced that and it still won't close. Everything else (wipers, headlights, radio, etc..) is working so I don't think it could be the ignition. Does anyone smarter than me have any bright ideas or has anyone had a similar problem?

I've also check the ignition control module and coolant temp sensor, and both are good.

thanks in advanced for any help

walky_talky20
08-16-2013, 04:24 PM
What engine are we having in this 99 A4?

Are you getting spark or no?

Cam Position Sensor signal has no bearing on Fuel Pump Relay operation, but Crankshaft Position Sensor does.

hepgot
08-16-2013, 05:40 PM
Thanks for the reply. Its a AEB 1.8T. I honestly haven't checked spark. Its not my daily so I havent been in hurry. While I'm checking that is there any way to check the crank sensor?

hepgot
08-16-2013, 05:44 PM
Also, I thought if cps went the car would run until you went to start again. Is that correct or could it cause it to stop while under way?

Seerlah
08-16-2013, 05:51 PM
Replace your fuel pump relay. The coil in it is shot. It closes by the magnetic field created by the coil inside it by the 2 potentials. When the coil goes, there is no magnetic field to close the relay.

hepgot
08-16-2013, 05:53 PM
I did that too. Nothing changed

walky_talky20
08-18-2013, 10:51 AM
Thanks for the reply. Its a AEB 1.8T. I honestly haven't checked spark. Its not my daily so I havent been in hurry. While I'm checking that is there any way to check the crank sensor?

That's good.

Checking the crank sensor (CKP) is easy: check for spark. If you have spark, your crank sensor is fine and we can skip a ton of tests. If you don't have spark, then we have to do more testing.


Also, I thought if cps went the car would run until you went to start again. Is that correct or could it cause it to stop while under way?

I believe you are correct. At least on my 2001 1.8T AWM, even complete failure of the Cam Position Sensor (CPS) will still result in a car that runs. Getting it started is a matter of chance, though. The ECU can no longer tell which stroke it's on, so it only starts and runs when it happens to guess right - which is about 30% success rate or so it seems. But you do get spark and fuel on every cranking attempt. I haven't tested this theory on an AEB, but I believe the behavior would be the same.

hepgot
08-18-2013, 01:41 PM
Okay just checked for spark and got nothing. I also did a check of the icm that i found using a 1.5v battery and it appears fine. So ckp or ignition coils next?

walky_talky20
08-18-2013, 04:01 PM
- Did we check for codes with VCDS?
- Do we have a check engine light on with Key ON?

hepgot
08-18-2013, 04:19 PM
Check for codes with vcds and have nothing other than some security codes because the vacuum pump for my locks is shot. No cel at all. The only thing that ever flashed on was my oil light when my engine failed on the highway... makes me nervous but oil level is fine and timing belt looks okay

Seerlah
08-18-2013, 04:59 PM
Not to be that guy, but where the spark plugs grounded when you checked them?

hepgot
08-18-2013, 05:13 PM
Lol it's okay I know I don't know what I'm doing. I bought a ignition spark checker from autozone, you know the little guy that looks like a spark plug but just jumps a gap. It has an alligator clamp that I put on a ground screw near the connectors of the coil packs on the valve cover. Is that sufficient? Or should I have gone to the block?

Seerlah
08-18-2013, 05:15 PM
No, that was fine.

walky_talky20
08-18-2013, 05:23 PM
Please explain what you mean by "no CEL at all". On a perfectly healthy car, the Check Engine Light should come ON during the "bulb test" when you turn the key to the ON position (with Engine Off). If there are no hard codes, the CEL will shut off a few seconds after the engine is running.

If your CEL is not coming on with the key, then we have to figure out why. Most often this means we aren't getting power the ECU (ie: blown fuse), or the ECU is faulty. When the CEL doesn't come on, I would 100% expect to see things like:

- no trigger to Fuel Pump Relay
- no Fuel Injector pulse
- no spark

hepgot
08-18-2013, 05:29 PM
Had you not said something I would have not noticed... just checked, no CEL with key turned to on position :/

walky_talky20
08-18-2013, 05:36 PM
Alrighty, now we are getting somewhere.

Check the condition of Fuse #32.

If fuse is not blown, check that it has 12V+ on BOTH sides with key in the ON position (use a volt meter or test light).

hepgot
08-18-2013, 05:55 PM
Okay, fuse #32 was blown. I put in a new fuse and ran VCDS and got a whole host of codes:

8 Faults Found:
18010 - Power Supply Terminal 30
P1602 - 35-10 - Voltage too Low - Intermittent
17584 - Bank1: O2 (Lambda) Correction Behind Catalyst
P1176 - 35-10 - Control Limit Reached - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - Intermittent
16688 - Cylinder 4
P0304 - 35-10 - Misfire Detected - Intermittent
18014 - Rough Road/Engine Torque Signal from ABS
P1606 - 35-10 - Electrical Malfunction - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - Intermittent
16688 - Cylinder 4
P0304 - 35-10 - Misfire Detected - Intermittent
16685 - Cylinder 1
P0301 - 35-10 - Misfire Detected - Intermittent
Readiness: 0110 0101

The ABS code is not new. Any suggestions?

walky_talky20
08-18-2013, 08:45 PM
Clear the codes. Nothing critical there.

So the car runs now, yes?

hepgot
08-19-2013, 05:07 PM
Okay, she's finally running. It's a bit rough but it starts. The coil pack on cylinder one was dead and apparently shorting and blowing fuse #32 when I cranked it up. Changed the pack and problem solved. Now over to some rough idle threads. Thanks again for the help!

walky_talky20
08-19-2013, 07:19 PM
Good work. I'm glad my armchair diagnostics were of some help.

hepgot
08-24-2013, 02:24 PM
<a href="http://s1332.photobucket.com/user/brandonhepner/media/20130824_170835_zps37e59bfd.jpg.html" target="_blank"><img src="http://i1332.photobucket.com/albums/w615/brandonhepner/20130824_170835_zps37e59bfd.jpg" border="0" alt="uh oh photo 20130824_170835_zps37e59bfd.jpg"/></a>

http://i1332.photobucket.com/albums/w615/brandonhepner/20130824_170835_zps37e59bfd.jpg

I have no idea how to upload photos...

But upon further inspection, I believe I found the cause of the short that keeps blowing fuse #32... the connector going to cylinder #1 ignition coil is f***ed

1986nate
08-24-2013, 06:17 PM
I was going to suggest checking the wiring to that coil. I've been blowing coils due to hackjobbing my engine harness in previous repairs. Finally snagged a replacement harness.
It kills that coil first before the short continues and kills the one fuse. Repair the wire/connector and you'll be good to go :)

If you need a spare connector with a few inches of wiring, you can have it for the couple doll hairs for an envelope and a few stamps.

hepgot
08-24-2013, 06:20 PM
I have a new connector on order but I'm starting to wonder if I should check the others. Where were you able to pick up a new harness?