S4 will not run
12-24-2007, 02:21 PM
#16
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One other thought: It is probably a given that the body shop ran the battery dead (with the help of the 928 normal drain when off for two months) and then used a "booster charger" to quick charge and start the car. I have heard that over 16 volts will fry an LH. These "booster chargers can put out way over 16 volts.
12-24-2007, 04:43 PM
#17
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If you hear hoof beats in the street, don't look for a zebra. It pertains to diagnostics of all sorts.
12-24-2007, 07:01 PM
#18
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Disconnecting the MAF throws the LH into a limp home mode, so you can't always draw simple conclusions from that test.
Try the O2 sensor disconnect test:
1) disconnect battery ground
2) unplug O2 sensor at 3way conenctor in footwell.
3) reconnect battery and start the car.
Does car run better from a cold start than when hot ?
Try the O2 sensor disconnect test:
1) disconnect battery ground
2) unplug O2 sensor at 3way conenctor in footwell.
3) reconnect battery and start the car.
Does car run better from a cold start than when hot ?
The car is None O2 type (no cats either, sorry I should have mentioned that earlier). It has a potentiometer next to the brains. The car starts/runs the same cold or hot.
Last edited by touay001; 12-24-2007 at 07:10 PM. Reason: More info
12-24-2007, 07:14 PM
#19
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Odd......it is likely that the battery went dead at the shop & they jumped it with one of those high voltage jumpers that fry LH's....or partially fry them....take yours out and test it in a known well running 928....this is what I did when my fuel pump failed (slowly)...which of course eliminated the LH as the problem?
The problem I had was the pump would warm up and its internal resistance would get too high and it would fail....a good pump should measure about 1.5 ohms....mine would spike to 15 ohms when it died....but you did say your pump is running.....but is enough flow coming out of it??
Another thought is fuel pressure regulator is shot....but it doesn't really sound like it...
The problem I had was the pump would warm up and its internal resistance would get too high and it would fail....a good pump should measure about 1.5 ohms....mine would spike to 15 ohms when it died....but you did say your pump is running.....but is enough flow coming out of it??
Another thought is fuel pressure regulator is shot....but it doesn't really sound like it...
12-28-2007, 10:50 PM
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The later cars - 89 and up had a relay and sensors to keep the injection from feeding gas to the non operating cyclinders. So if a body man bumped one of the coil wires or the amplifiers on the front of the car - those things under the plastic cover on the front cross member driver's side. Before starting the car remove the plastic cover and disconnect each plug to the amplifier. You are best removing the metal spring clip on the connectors and then plugging them back in. Start the car and let it idle. Go to the front of the car and one at a time remove and replace one of the plugs. If there is a change in the idle for each plug then the ignition is working. If the car dies when you pull one of the plugs then the opposite of the ignition system is dead.
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Last edited by touay001; 12-29-2007 at 06:46 AM.
12-29-2007, 05:52 AM
#24
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Is that with or without the MAF connected? Can you test to see if you have spark either one of the spark plugs connected to the the drivers side coil? BTW convention says left and right are from back looking forward (as if you were sitting inside), so it would be the left coil in this case.
12-29-2007, 06:51 AM
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Is that with or without the MAF connected? Can you test to see if you have spark either one of the spark plugs connected to the the drivers side coil? BTW convention says left and right are from back looking forward (as if you were sitting inside), so it would be the left coil in this case.
We drive here on the wrong side of the road (right hand drive). That's why I opted to use front of the car to avoid any confusion
.I will test the car on Monday. I hop it is a coil or something simple
12-29-2007, 08:13 AM
#26
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It's more likely to be an amplifier than the coil.
You can confirm by swapping the connector from the non working ampfier to the presently working one.
You can confirm by swapping the connector from the non working ampfier to the presently working one.
12-29-2007, 05:29 PM
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I have a stack of these amplifiers. I am sure Jim does too. I have yet to see one fail. I suppose they can, but I have not seen it.
Good now you have figured out your problem. The car is running on four cylinders as I suggested from the start. Too bad you spent money on a new MAF but they do degrade over time.
The car has been in a body shop. The last time I was in a body shop there was lots of dust every where. Things may be different today with all the new regulations, but there is still dust and it will get every where. Some of this dust is corrosive. Getting into electrical componets it can raise havoc. This is one of the reasons I suggest using dielectic grease to seal the electrical connections on the 928, but that is a different story.
Coils like MAFs and LHs do not generally go bad from sitting around. Anything is possible, but being the car has been in a corrosive environment I would begin looking at the things causing the car to run on four cylinders.
There are two places to look. The first is the coil wires. Mounted upside down on the distributor car the boot acts as a perfect trap for water. Water under the boot combined with copper turns things green. Carefully inspect both coil wires. If they show any discoloration replace them. The coil itself can be cleaned.
Next look at the two distributor caps. They could have junk inside or have been cracked when work was done on the car. Even a small crack will cause huge problems. If you want to do in someone take a graphie pencil and scribble inside their distributor cap. They will never find the problem.
Then the next thing to locate is the grounds for the two coils. the ground points are up in the front of the car and can be located from the manual. Cleaning grounds should be a five year maintenance item anyway. Finally look at the ground strap on the underside of the engine. A broken or dirty engine to chassis ground causes all kinds of weid problems.
If you want to trouble shoot the coils take the one from the bad side and put it on the good side. If the car runs the same way then the coil is good. The coils are pain to change out - other stuff in the way. However, by swapping your coil you may clean up the problem.
Good luck. You are close ane the car is all but back on the road.
Dan the Pod Guy
Good now you have figured out your problem. The car is running on four cylinders as I suggested from the start. Too bad you spent money on a new MAF but they do degrade over time.
The car has been in a body shop. The last time I was in a body shop there was lots of dust every where. Things may be different today with all the new regulations, but there is still dust and it will get every where. Some of this dust is corrosive. Getting into electrical componets it can raise havoc. This is one of the reasons I suggest using dielectic grease to seal the electrical connections on the 928, but that is a different story.
Coils like MAFs and LHs do not generally go bad from sitting around. Anything is possible, but being the car has been in a corrosive environment I would begin looking at the things causing the car to run on four cylinders.
There are two places to look. The first is the coil wires. Mounted upside down on the distributor car the boot acts as a perfect trap for water. Water under the boot combined with copper turns things green. Carefully inspect both coil wires. If they show any discoloration replace them. The coil itself can be cleaned.
Next look at the two distributor caps. They could have junk inside or have been cracked when work was done on the car. Even a small crack will cause huge problems. If you want to do in someone take a graphie pencil and scribble inside their distributor cap. They will never find the problem.
Then the next thing to locate is the grounds for the two coils. the ground points are up in the front of the car and can be located from the manual. Cleaning grounds should be a five year maintenance item anyway. Finally look at the ground strap on the underside of the engine. A broken or dirty engine to chassis ground causes all kinds of weid problems.
If you want to trouble shoot the coils take the one from the bad side and put it on the good side. If the car runs the same way then the coil is good. The coils are pain to change out - other stuff in the way. However, by swapping your coil you may clean up the problem.
Good luck. You are close ane the car is all but back on the road.
Dan the Pod Guy
12-29-2007, 06:14 PM
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Thanks guys for your help. I have sourced out two coils, an amplifier and an ignition ECU. Monday I will go to the shop fully armed . I hope I'll get it up and running again and enjoy the rest of my holidays.
. I hope I'll get it up and running again and enjoy the rest of my holidays.
12-31-2007, 10:59 PM
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Happy new year All.
I got my car from the shop yesterday. It was the LH. I got a rebuild LH from John Speake and the car started and will rev up and down. The problem is that the car is running too rich and will not idle without my foot on the accelerator. The car doesn't have O2 sensor (it has a pot). Is there any difference between the LH with closed loop (O2 sensor) and the one with the pot. I thought there is no difference. Now we know that it is the LH, why it is running so rich with the new one?
Summary for the testing I made yesterday:
All sensors are new (< 1000 KM).
I got my car from the shop yesterday. It was the LH. I got a rebuild LH from John Speake and the car started and will rev up and down. The problem is that the car is running too rich and will not idle without my foot on the accelerator. The car doesn't have O2 sensor (it has a pot). Is there any difference between the LH with closed loop (O2 sensor) and the one with the pot. I thought there is no difference. Now we know that it is the LH, why it is running so rich with the new one?
Summary for the testing I made yesterday:
- Replace ignition amplifiers --> no difference
- Replaced EZK --> no difference
- Replaced coils --> no difference
- Replaced with another MAF --> no difference
- Replaced LH --> started and ran too rich
All sensors are new (< 1000 KM).
01-01-2008, 01:06 AM
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I've just read that I might have to adjust the MAF or use the pot to get CO level to 1%. I don't have CO meter so I might just turn the pot 10 turns anti clock wise and see what happens.