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Discussion Starter #1
I need help on my 1999 Mercedes S500!

The engine cranks fine when starting but does not catch for about 10 seconds (seems like and eternity). After starting it seems to run fine, and if I shut it off and restart the problem disappears…until left for a while and I try to restart again.

I read the codes:

P1519 – right adj camshaft timing solenoid
P0300 – random multiple misfire
P0308 – Cylinder 8 misfire

In the past, I have had the solenoid code when a coil failed and replacing the coil took care of the problem.

My first guess was the number 8 coil, so I switched with the number 7 coil to see if it would throw a number 7 misfire code. No codes where thrown, although the problem persisted.

I took a shot at replacing the number 8 coil and spark plug – still no change – and still no codes being thrown. The plug was only 2 years old with little miles on it and did not look fouled.

I am not sure where to go from here. Should I wait a week or so to see whether new codes appear? The CEL has never lit.

Anything else I can do to troubleshoot? I hope someone can help me – this has turned into a frustrating saga!
 

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1995 S500 coupe, 1990 Mazda Miata
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I would hook up a fuel pressure gage and see if it holds good pressure after shut off. Mine holds a steady 50-52 lbs idling and then holds it for at least an hour after shutoff. If I remember correctly the fuel pump has a built in check valve that is supposed to maintain fuel pressure when the engine is off.
 

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Discussion Starter #3
Thanks for the tip!

Thanks for the quick response - I am a novice, but I would imagine the guage would be placed at some point between the gas line in the engine compartment? Any suggestions of which part to uncouple? Also, if my pressure does not hold, does that mean bad fuel pump?
 

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1995 S500 coupe, 1990 Mazda Miata
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The fitting to check fuel pressure is on the front of the fuel rail, just below the front edge of the cover which is right in front of the air cleaner assembly. It's a big brass cap which you unscrew and the gage will screw on there. You might check pressure while idling and then watch the gage upon shutoff. It will raise a little just as you turn the engine off and then settle down to about 45-50 lbs. it should stay there for at least an hour. If any readings are lower than that, the pump is suspect.
 

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Discussion Starter #6
Thanks guys. Rented a unit and tested the pressure. The first try it read 15PSI and jumped to around 18 PSI when I disconnected the regulator vacuum hose. Shut the car off and restarted - it read at 10 and jumped to 13 when the vacuum hose was disconnected. After these readings I didn't bother leaving it on to check if it held any pressure. My question is, can the car even run at such a low PSI or could the guage be faulty? Thanks in advance.
 

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98 S500
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Camshaft position sensor?
Happened to one of my prev cars. 03 Altima with v6. It stalled near parking lot for no reason. Then it was taking forever to start it(sometimes about 20 sec), and it went to limp mode couple of times. Otherwise-perfect running car.
One of your codes can indicate that problem(solenoid in your case). I swapped both sensors at same time, and problem was solved. Be careful, those sensors are very sensitive to magnetic fields.
 

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Discussion Starter #8
Thanks - part of the maddenning problem is that no codes are being thrown since I cleared them the first time - I checked again yesterday and nothing.

:(
 

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1997 S600 (sold)
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I could see the camshaft sensor causing a problem with starting. The computer needs input from the cam sensor to find top-dead-center for cylinder #1. But, I can't say definitively whether you should replace it.

Your fuel pressures are really low. Are there 2 scales on the gauge? Did you read the correct psi scale? Did you hook up the gauge properly?

Brett
 

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Discussion Starter #10
Thanks Brett - Yes I made sure I was reading the PSI side - I did a double take in reading it and thought that was my error, but it was PSI. I will say the steady flow of gas out the weep tube surprised me - is that normal? A few other things - if I start the car after it has sat, I get the cranking and cranking before it fires up. If I turn it off and start it again immediatley, it fires up fine. Also noticing a strong gas smell yet can find no leaks.....I read somewhere else on the site that could be low fuel pressure/bad atomization of gas as a result?
 

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1995 S500 coupe, 1990 Mazda Miata
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When you pulled the vacuum hose off of the pressure regulator, did you notice any wetness? Fuel getting through the regulator into the hose would indicate bad regulator. The pressure readings are really low and maybe somebody on this forum might know if the car would even run at those pressures. I would still pursue checking whether pressure holds after shut off.
 

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1997 S600 (sold)
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No, you should not get a flow of fuel out of the fuel pressure gauge when in operation. Take the gauge back if it is leaking like that. 95Scoupe is right about the fuel pressure regulator. If the diaphragm is compromised, raw fuel can feed directly into the intake through the vacuum hose causing starting problems. For the low cost of the fuel pressure regulator, it's probably worth just replacing it.

I would tend to believe if the car runs perfectly fine when started, then the fuel pressures must not be really that low. On the other hand, I've never tested what effect an artificially low fuel pressure has.

Brett
 

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2006 S500 AMG Wifes Rig Hillbilly Girl 02 ML320
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When was the fuel filter changed ?? Fuel pressure does sound low!

Smokie
 

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Discussion Starter #14
Great advice on the pressure regulator - I checked the hose after starting today and it was dry. Drove 10 miles - parked it - and checked it again and found it dry. While holding the hose I gave it a squeeze a few times and ah ha - - fuel poured out!!!! Found a great price on a Bosch replacement via Rock Auto also thanks to this site. I'll keep you posted but I am hopeful this was it. Thanks a million to all!!
 

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1995 S500 coupe, 1990 Mazda Miata
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I checked the hose after starting today and it was dry. Drove 10 miles - parked it - and checked it again and found it dry. While holding the hose I gave it a squeeze a few times and ah ha - - fuel poured out!!!!
That's great info for somebody checking this. The vacuum hose is sucking the fluel so it makes sense that the fuel would be further down the hose and the wetness at the end will evaporate quickly.
 

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Discussion Starter #16
Well, the FPR arrived Saturday and was installed about ten minutes after it was delivered. Thanks to all who helped - the hard starting has totally disappeared!

Only one problem left - the very slight engine miss/stumble while idling has not disappeared. This miss began in the middle of the hard starting saga and I thought it would go away with the new FPR and some highway driving. Unfortunately it did not. It is at idle only - same whether in park or drive - and occurs on average once every 6 to 10 seconds.

Will have the codes read (if any - the CE light is not on) - in the meantime I am wondering if anyone thinks this was caused by the bad FPR or am I looking at a totally unrelated issue?
 

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1997 S600 (sold)
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I think it's probably a coil issue. Hard to tell which one if the computer doesn't give you a fault code. Must be "too intermittent" to throw a code. If you're up to it, just replace all of them now, and you'll be good for many more years. Or wait for a code... or buy one new coil and plug connector and work cylinder by cylinder until the miss goes away.

Brett
 

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Discussion Starter #18
Finally - a code!!! P1519 RH adjustable crankshaft timing solinoid. I've searched the forums and the internet - but can't find where this is located on my vehicle. Any direction would be appreciated - and at the risk of sounding like a moron, what is RH an abbreviation for?
 

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Discussion Starter #19
I think I found it - round plate bolted onto each side of the front of engine? Does RH mean right side and is that the passenger side?

Lastly, anyone know of an aftermarket source for these?
 

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1997 SL600 Brilliant Silver Sport with grey/dark metal interior, 234K miles
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If it's on the front of the engine, I think you mean adjustable camshaft timing solenoid.
 
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