engine turns over...but won't start.
#1
Three Wheelin'
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Well...for the first time in 12 years of ownership...my car won't start. So I'm looking for help in the best place I know of...Rennlist. My car is a '97 narrowbody with 50K miles and no history of starting problems. I will mention, that my battery is like 10 years old and the car stays on a battery tender all the time....I really dont' think the battery is related to my problem.
Here's the situation. My car sits without being driven for weeks at a time...so about 2 weeks ago, I decided to put some Stabil in the gas. So at the gas station, I added the proper amount of Stabil to an empty tank, then filled it up with Chevron 93 octane, drove it around for about 30 minutes and then parked it, and put it on the tender. The Stabil is the only thing out of the ordinary that I did...so I wanted to mention it.
So today, I try to start it, and it turns over fine...but failed to start after about 2 or 3 turns...it's never done that. Tried it several more times...but it will not start.
I haven't done any troubleshooting at all, so I don't know if I'm missing spark or fuel or both. I'm looking to you guys to point me to any simple things first. A quick search showed the DME (is that a relay?) is a common cuprit. I know a bad fuel pump would cause this. Is there any kind of fuse that could kill the fuel or spark? Thanks in advance for the input.
Here's the situation. My car sits without being driven for weeks at a time...so about 2 weeks ago, I decided to put some Stabil in the gas. So at the gas station, I added the proper amount of Stabil to an empty tank, then filled it up with Chevron 93 octane, drove it around for about 30 minutes and then parked it, and put it on the tender. The Stabil is the only thing out of the ordinary that I did...so I wanted to mention it.
So today, I try to start it, and it turns over fine...but failed to start after about 2 or 3 turns...it's never done that. Tried it several more times...but it will not start.
I haven't done any troubleshooting at all, so I don't know if I'm missing spark or fuel or both. I'm looking to you guys to point me to any simple things first. A quick search showed the DME (is that a relay?) is a common cuprit. I know a bad fuel pump would cause this. Is there any kind of fuse that could kill the fuel or spark? Thanks in advance for the input.
#3
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The DME relay powers the fuel pump. If it is defective, the engine may still crank over, but won't start because there is no fuel pressure.
These cars need a good strong battery to power the fuel pump, fuel injection system, fire the ignition, and crank the engine over at the required speed for ignition. I would replace the 10-year-old battery--you've more than gotten your money out of it.
If it still won't start, hook up an inductive timing light and crank the engine over to see if the light flashes--no flash means no spark. In that case, you may have a bad Ignition Control Unit, part #993 602-706-00, located under the driver seat.
These cars need a good strong battery to power the fuel pump, fuel injection system, fire the ignition, and crank the engine over at the required speed for ignition. I would replace the 10-year-old battery--you've more than gotten your money out of it.
If it still won't start, hook up an inductive timing light and crank the engine over to see if the light flashes--no flash means no spark. In that case, you may have a bad Ignition Control Unit, part #993 602-706-00, located under the driver seat.
#4
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This happened to my 95 today for the first time also - car has never failed to start in 16 years.........had a spare DME relay that I kept in the fuse box and it did the trick in my case.......back on the road in minutes.......ordered a new spare DME relay.................$ 25.00 from Automotion catalog.......You can potentially fix the old one with soldering connections, but new one is affordable........
All 993 owners should have a spare in the glovebox, etc........very inexpensive insurance to keep you on the road..........
All 993 owners should have a spare in the glovebox, etc........very inexpensive insurance to keep you on the road..........
#5
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Lets keep it simple and start with it.
This is where it is...its the one at the lower left with "DME-Relais" molded into the top of the case...
![](http://edelweiss.smugmug.com/Cars/Porsche-Technical-Stuff/Temporary-Pics/Fuse-Panel/1123571677_teH88-X2.jpg)
They can be repaired in most cases...or at least you can have a look at its condition.
DME Relay - Failure & Repair
This is where it is...its the one at the lower left with "DME-Relais" molded into the top of the case...
![](http://edelweiss.smugmug.com/Cars/Porsche-Technical-Stuff/Temporary-Pics/Fuse-Panel/1123571677_teH88-X2.jpg)
They can be repaired in most cases...or at least you can have a look at its condition.
DME Relay - Failure & Repair
#6
Three Wheelin'
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I just checked the fuel pump fuse...ok. I located the DME relay. Doesn't seem to be another relay in there that I can swap it with for a check. Is there a to check the relay or should I just order a new one?
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#8
Three Wheelin'
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Good news....the DME was the problem. I removed the relay, cleaned both sets of contacts, re-soldered the (2) joints that Alex showed...and a few of the other joints, put relay back in...and it started right up.
Many thanks to you guys for the quick responses...especially Alex for that write up and pictures.
My next course of action. First...remove the DME relay and touch up ALL the solder joints. Second...order a new relay as a spare...probably install new one in car use existing one as spare. Last...get a new battery...lol.
Many thanks to you guys for the quick responses...especially Alex for that write up and pictures.
My next course of action. First...remove the DME relay and touch up ALL the solder joints. Second...order a new relay as a spare...probably install new one in car use existing one as spare. Last...get a new battery...lol.
#10
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I'd at least load test it, but then your starter sort of does that and you stated that it turns over well. The capacity aspect of the battery might get you home if your alternator belt fails if you are less than about 120 minutes away (Reserve Capacity specification).
If you do, here is a list of batteries. You can either choose a group 48 or 91. The 48 is the so-called Porsche replacement battery, but its a bit taller than the 91 (see dimensions in chart) and interferes with the plastic trim, but fits.
I also opted for a traditional FLA battery over a VRLA battery for many good reasons (I work with batteries).
![](http://edelweiss.smugmug.com/Cars/Porsche-Technical-Stuff/Battery/Battery-List/1053997922_88VSU-O.jpg)
I went for an East Penn Pow-R-Surge 7000, 648MF battery. Other than case colour, this battery is 100% identical to the Porsche Moll-Kamina that was previously installed.
If you do, here is a list of batteries. You can either choose a group 48 or 91. The 48 is the so-called Porsche replacement battery, but its a bit taller than the 91 (see dimensions in chart) and interferes with the plastic trim, but fits.
I also opted for a traditional FLA battery over a VRLA battery for many good reasons (I work with batteries).
![](http://edelweiss.smugmug.com/Cars/Porsche-Technical-Stuff/Battery/Battery-List/1053997922_88VSU-O.jpg)
I went for an East Penn Pow-R-Surge 7000, 648MF battery. Other than case colour, this battery is 100% identical to the Porsche Moll-Kamina that was previously installed.
![](http://edelweiss.smugmug.com/Cars/Porsche-Technical-Stuff/Battery/East-Penn-648MF-Battery-Front/828769524_cMjx5-M-1.jpg)
#12
Three Wheelin'
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The current battery is the Sears Diehard International. It's been flawless for 10 years...so I'm gonna get another one just like it.
Yes...simple fixes are my favorite. Thanks again for everyones help.
Yes...simple fixes are my favorite. Thanks again for everyones help.
#13
Race Director
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Always a good idea to have a spare DME relay on hand, cheap roadside insurance (about $25). IIRC the original DME relays had 944. part numbers and the new ones have 993. (?) part numbers.
Personally, I would buy a new relay, install the new relay and leave your old one as the spare.
Personally, I would buy a new relay, install the new relay and leave your old one as the spare.