928 1988 S4 Idle, Stall, Stalls, Dies - help needed
01-26-2012, 11:14 PM
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928 1988 S4 Idle, Stall, Stalls, Dies - help needed
When I bought my S4, the seller mentioned it sometimes had an issue when it idles. I didn't experience it much in the beginning, it'd only happen maybe once a week. I'm driving it every day and now it's happening multiple times a day. I will come up to a stop sign or stop light, or be sitting in a parking lot and it will just die. I put it in park, turn it off and back on, and it starts up like a champ. I've figured out that if I keep the break pressed in and my foot on the gas, I can get through without it completely stalling. It's working but hardly what I want to be doing as a long term solution.
I searched the 928 forum and found a few threads that reference replacing the 53B relay. It sounds like a good place to start, and surprisingly inexpensive. I've ordered a few 53B relays and will install one when it arrives. I believe in having spares, so I picked up a few.
I'm wondering if anyone has any other thoughts or ideas, or perhaps a different path I may consider if the relay doesn't resolve the issue.
Any help would be appreciated. And by the way, this site rocks
Laurie
1988 928 S4 Granite Green
I searched the 928 forum and found a few threads that reference replacing the 53B relay. It sounds like a good place to start, and surprisingly inexpensive. I've ordered a few 53B relays and will install one when it arrives. I believe in having spares, so I picked up a few.
I'm wondering if anyone has any other thoughts or ideas, or perhaps a different path I may consider if the relay doesn't resolve the issue.
Any help would be appreciated. And by the way, this site rocks
Laurie
1988 928 S4 Granite Green
For a new owner with a new car and unknown history, it's probably a good PM task to replace all the critical engine relays. Premium relays can be a bit more than $5, worth getting with one of our sponsor/vendors to make sure you don't end up with something less that totally reliable.
The short list:
Fuel Pump relay in position XX
LH (fuel injection brain and injectors) in position XXV
EZK (ignition brain) in position XVI
All of these can use the common 53B relay. The EZK relay installed from the factory has a fuse tester built in, but otherwise is a 53B.
The ignition X-bus relay in position IV is also a candidate.
The car has/had a nice fuse and relay chart attached to the door on the central electrics panel, under the forward carpet in the passenger's footwell. 928 Specialists has a copy available on their website www.928GT.com, with handy links to make it easy to buy replacements.
All the relay stuff aside, there are more than a few things that will cause the poor idle/stumble/hard to start symptoms, too many to just say that there are one or two fixes that cover everything. First thing's first, and that first list should include catching up on all the normal maintenance stuff. New plugs, caps, rotors, and wires make that list if there isn't documentation showing that they have been replaced in the last 50k miles or so. New oxygen sensor too. New plugs regardless, since they are cheap and it's an easy way to see how the cylinders are firing.
Poor idle is often the result of partially-fouled injector nozzles, and/or a tired mass airflow sensor. These aren't cheap enough to just replace them without a little confirmation. But if the originals are still in there and the car is over 100k, it's probably due.
Vacuum leaks from tired or split hoses will cause the car to idle poorly. There are a bunch of hoses and connections that gather under the intake manifold. A bit of false air leaking into the engine confuses the controllers.
The idle air control valve under the intake is sometimes a problem, and function is tied to the throttle position switch. Both would be checked and usually replaced as part of a full intake refresh effort.
Lots of things to think about. Relays are relatively cheap and easy place to start.
The short list:
Fuel Pump relay in position XX
LH (fuel injection brain and injectors) in position XXV
EZK (ignition brain) in position XVI
All of these can use the common 53B relay. The EZK relay installed from the factory has a fuse tester built in, but otherwise is a 53B.
The ignition X-bus relay in position IV is also a candidate.
The car has/had a nice fuse and relay chart attached to the door on the central electrics panel, under the forward carpet in the passenger's footwell. 928 Specialists has a copy available on their website www.928GT.com, with handy links to make it easy to buy replacements.
All the relay stuff aside, there are more than a few things that will cause the poor idle/stumble/hard to start symptoms, too many to just say that there are one or two fixes that cover everything. First thing's first, and that first list should include catching up on all the normal maintenance stuff. New plugs, caps, rotors, and wires make that list if there isn't documentation showing that they have been replaced in the last 50k miles or so. New oxygen sensor too. New plugs regardless, since they are cheap and it's an easy way to see how the cylinders are firing.
Poor idle is often the result of partially-fouled injector nozzles, and/or a tired mass airflow sensor. These aren't cheap enough to just replace them without a little confirmation. But if the originals are still in there and the car is over 100k, it's probably due.
Vacuum leaks from tired or split hoses will cause the car to idle poorly. There are a bunch of hoses and connections that gather under the intake manifold. A bit of false air leaking into the engine confuses the controllers.
The idle air control valve under the intake is sometimes a problem, and function is tied to the throttle position switch. Both would be checked and usually replaced as part of a full intake refresh effort.
Lots of things to think about. Relays are relatively cheap and easy place to start.
Last edited by thelaurie; 01-26-2012 at 11:16 PM. Reason: add signature
01-26-2012, 11:18 PM
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When I bought my S4, the seller mentioned it sometimes had an issue when it idles.... now it's happening multiple times a day... and dies. I put it in park, turn it off and back on, and it starts up like a champ.
I'm wondering if anyone has any other thoughts or ideas, or perhaps a different path I may consider if the relay doesn't resolve the issue.
Any help would be appreciated. And by the way, this site rocks
I'm wondering if anyone has any other thoughts or ideas, or perhaps a different path I may consider if the relay doesn't resolve the issue.
Any help would be appreciated. And by the way, this site rocks
could be the MAF, but that does not makes sense for the way its driving and dying.
Good to see you around
01-26-2012, 11:39 PM
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Fraggle, I looked under the hood and found the throttle but I don't see anything that looks damaged or disconnected in any way. Can you clarify for me? Would it be visible if something were broken?
To be honest, I am very new to working on cars, so please bare with me. I appreciate the help and if you want to dig at me a bit for being a newbie, I can take it. Let'er rip.
Emerald, nice to be back. Haven't posted in awhile but I'm trying to be better. There's so much knowledge here how can I stay away?
To be honest, I am very new to working on cars, so please bare with me. I appreciate the help and if you want to dig at me a bit for being a newbie, I can take it. Let'er rip.
Emerald, nice to be back. Haven't posted in awhile but I'm trying to be better. There's so much knowledge here how can I stay away?
01-27-2012, 12:01 AM
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Nah no issues mate!!
You won't be able to see what's broke, it's buried under the intake. You'll need a volt meter to test it - or someone with a bosch hammer, or the 928 diagnostics software and plug in.
First order if you don't have a dvm (digital volt meter) is to move the throttle by hand with eveything turned off. You should hear a soft click when you move off the idle position. That's the microswitch actuating in the throttle position setup that tells the lh to go into idle mode.
If you can't hear a click, somethingks wrong. If you can, you still need to test it electrically to make sure it's doing its job. If you search someone's probably wrote a guide. If youy can't find anything I'll wait until Speak or Coreman jumps in, they'll have the pin-outs memorized on what to test. Alternatively, post your location and someone probably local may be able to help. If it's in your signature or avatar I apologize, that stuff doesn't show up on mobile.
You won't be able to see what's broke, it's buried under the intake. You'll need a volt meter to test it - or someone with a bosch hammer, or the 928 diagnostics software and plug in.
First order if you don't have a dvm (digital volt meter) is to move the throttle by hand with eveything turned off. You should hear a soft click when you move off the idle position. That's the microswitch actuating in the throttle position setup that tells the lh to go into idle mode.
If you can't hear a click, somethingks wrong. If you can, you still need to test it electrically to make sure it's doing its job. If you search someone's probably wrote a guide. If youy can't find anything I'll wait until Speak or Coreman jumps in, they'll have the pin-outs memorized on what to test. Alternatively, post your location and someone probably local may be able to help. If it's in your signature or avatar I apologize, that stuff doesn't show up on mobile.
01-27-2012, 12:24 AM
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Great information, thank you. I don't have a meter but I think I know someone that does. My relays should be here next week. I am going to start there. If it doesn't fix it, I'll move find a meter and hopefully the other two gurus you spoke of will chime in. If not, I'll send them a PM.
I'll also try and listen for a click when I move the throttle. Perhaps that'll give me some information too. And I'll search for a guide. That can't hurt.
Thanks for replying while mobile, I appreciate it. My avitar has my location, I'm in northern CA. And I know there's some great helop around here.
Have a great evening - cheers!
Laurie
1988 928 S4 Granite Green Metallic
I'll also try and listen for a click when I move the throttle. Perhaps that'll give me some information too. And I'll search for a guide. That can't hurt.
Thanks for replying while mobile, I appreciate it. My avitar has my location, I'm in northern CA. And I know there's some great helop around here.
Have a great evening - cheers!
Laurie
1988 928 S4 Granite Green Metallic
01-27-2012, 11:50 AM
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Laurie:
Well, OK, but I haven't don't this since first grade. You first. Hint bare = uncover; bear = put up with.
Multi-meter or Digital Voltage Meter (DVM), is a must if you are going to work on this car. You can get a cheap one for $10 at Radio Shack or you can buy a Fluke for $100.
HTML Code:
so please bare with me.
Multi-meter or Digital Voltage Meter (DVM), is a must if you are going to work on this car. You can get a cheap one for $10 at Radio Shack or you can buy a Fluke for $100.
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01-27-2012, 06:08 PM
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02-05-2012, 01:22 PM
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Steve, thanks for calling me on this one (blush)...
02-05-2012, 01:24 PM
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Laurie:
Well, OK, but I haven't don't this since first grade. You first. Hint bare = uncover; bear = put up with.
Now I'm embar-assed lol
Multi-meter or Digital Voltage Meter (DVM), is a must if you are going to work on this car. You can get a cheap one for $10 at Radio Shack or you can buy a Fluke for $100.
HTML Code:
so please bare with me.
Now I'm embar-assed lol
Multi-meter or Digital Voltage Meter (DVM), is a must if you are going to work on this car. You can get a cheap one for $10 at Radio Shack or you can buy a Fluke for $100.
02-05-2012, 04:03 PM
#12
You may want to read about thrust bearing failure, the really bad TBF.
You need to check the crankshaft endplay. With an automatic S-4 that is far too common a problem. Once that is ruled out you can chase the other possible causes of stalling at idle.
You need to check the crankshaft endplay. With an automatic S-4 that is far too common a problem. Once that is ruled out you can chase the other possible causes of stalling at idle.
02-05-2012, 06:34 PM
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The relay was installed today, but sadly my alternator went out yesterday and I had to have my S4 towed home from the bay area. I ordered a new alternator this morning and it should arrive Monday. Once I've got that installed, I'll be able to see if the relay worked.
In the mean time, any knowledge you would care to share would be greatly appreciated.
Thank you for your reply. Happy Superbowl Sunday
02-05-2012, 06:50 PM
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I'm not sure exactly what this means, I'm still very new to working on my car. Would you consider educating me?
The relay was installed today, but sadly my alternator went out yesterday and I had to have my S4 towed home from the bay area. I ordered a new alternator this morning and it should arrive Monday. Once I've got that installed, I'll be able to see if the relay worked.
In the mean time, any knowledge you would care to share would be greatly appreciated.
Thank you for your reply. Happy Superbowl Sunday
The relay was installed today, but sadly my alternator went out yesterday and I had to have my S4 towed home from the bay area. I ordered a new alternator this morning and it should arrive Monday. Once I've got that installed, I'll be able to see if the relay worked.
In the mean time, any knowledge you would care to share would be greatly appreciated.
Thank you for your reply. Happy Superbowl Sunday