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I'd be inclined just to put in a new relay and see if it ever happens again. What do you gain by waiting? If if dies and you swap it out, and it starts up -- how will you know if it started because of the new relay or just because it's intermittent. You'll have to drive it a while to know -- so might as well start now. Similarly, if you swap it and it still won't start, then it will die with the new relay too and you'll save yourself the trouble of swapping it in traffic. Just say'n...
There's a guy somewhere on the list that was making solid state DME relays . Was it Ftech 9? Seems like they were about 75-80 dollars..might be a good thing to check out and install..he was looking for beta testers. Seems like a better way to go for a one-time purchase. AND eliminate all the guesswork. Or at least part of it..
Yes, it was Ftech9 for the solid state DME relays. Designed by him from the ground up with no moving parts.
I would start with the DME relay, given it controls both the fuel pump and the DME. A lot of current goes though it and over time the contacts of the relay will carbon up and solder joints can go bad from repeated heating and cooling cycles. You can use a jumper, but must remember to remove it when you shut the car off since the fuel pump and DME will be powered all the time. I had one relay go bad and bought a solid state one as soon as they came out.
Been totally happy with my Ftech9 relay and would recommend them to anyone. If memory serves me, URO was working on their own Solid State relay for our cars. Saw a thread someplace, where a rep from URO made regular comments and discussed the new relays.
Anyone price the original relay from Porsche? Just curious. The SS one does sound nice.
Drive to work Day 2 -- so far, all is normal. The only thing I did was fill up the tank; the night of the witchy stalling it was pretty low; I put in 62 litres (the usual for me--unfortunately, I'm in the habit of filling up when it's near empty)
It's about $30 for and OE Suppler, and about $80 for Porsche branded.
If memory serves, the SS relay was around the same price as the Porsche one, maybe a little more. It is worth the extra cost for Solid State. I'm unable to get to Ftech9's website right now, but that may have something to do with my less than stellar internet connection at the moment.
Ok, stalled twice on today's drive in (nothing on the way home). Started up pretty quickly. Good thing; the first time, I was in a construction line--no where to pull over and cars behind me nowhere to go!! New clue....
The second time it stalled, I cranked it three times for about 3 sec. each time. After each cranking, it goes "Bang!" out back. One big backfire right after I stop cranking.
Fourth crank and it fires right up, running perfect after.
Does the backfire indicate fuel is flowing? Would that eliminate the DME relay then?
Last edited by Dan Martinic; 11-16-2018 at 08:16 PM.
No! Put a new DME relay in as soon as possible. You're playing a silly game.
The engine isn't getting fuel. The fact that it happened again, and provided even more annoyance (at least to those blocked by you) - lends even more likelihood that the relay is going bad. Don't make me come over there...
If playing this game gets you to come by, I'm gonna keep at it! Love to have a few pints and talk 944 with company that actually cares LOL
Ok, ok... I'll order the relay. Curious though: how does the post-cranking backfire indicate fuel isn't flowing? I thought pop out the back means unburnt fuel igniting?
If playing this game gets you to come by, I'm gonna keep at it! Love to have a few pints and talk 944 with company that actually cares LOL
Ok, ok... I'll order the relay. Curious though: how does the post-cranking backfire indicate fuel isn't flowing? I thought pop out the back means unburnt fuel igniting?
Originally Posted by Dan Martinic
PS: my intuition is still fuel pump
I would like to come over. As you are welcome here. We met at the Fest this year - not sure if you realize. Not that it matters.
If you have fuel starvation (air) within the fuel lines; reigniting what is left, and what may come back in spurts, can produce backfire. You are over your head in your analysis. You may actually risk engine damage due to fuel cut. I suspect your driving habits make this a remote chance. None the less, you are gambling a lot for something very small.
11-13-2018, 09:02 PM
Similarly, if you swap it and it still won't start, then it will die with the new relay too and you'll save yourself the trouble of swapping it in traffic. Just say'n...
