Solid state DME Relay conversion ?

[uwanna]

Originally Posted by DanielDudley

So I got mine, and installed it Saturday. It has the pre prime option, and I LOVE that. You can actually hear the fuel pump running, and this is a great thing, IMO. Very reassuring. Confirms the DME relay and the fuel pump are working every time you start the car.

It comes in a static free bag, and you have to ground yourself to the car before you install it, but I am super happy with this product.

DITTO to your remarks! Installed mine yesterday. Just hearing the fuel pump pressurizing the system for 3 seconds instills confidence and the engine starts without any delay. Another benefit, in case of a "no start" you don't have to wonder if the fuel pump is operational! What a great product and the price delta vs the old style relay is minimal!

[jlex]

I ordered the non-priming model. Was a bit afraid of hydro-lock or flooding if the fuel pump was running each time the key was turned in a no-start situation. I suppose the designer figured out how to deal with that but I just wanted to be on the safe side if I had to crank the engine multiple times due to a no-start situation. I guess I'm just paranoid...

[winders]

Originally Posted by jlex

I ordered the non-priming model. Was a bit afraid of hydro-lock or flooding if the fuel pump was running each time the key was turned in a no-start situation. I suppose the designer figured out how to deal with that but I just wanted to be on the safe side if I had to crank the engine multiple times due to a no-start situation. I guess I'm just paranoid...

Irrationally paranoid!

That's not how the fuel system works. Excess fuel flows back to the fuel tank and the fuel pressure regulator controls the fuel pressure. The fuel injectors have to get power to inject fuel into the cylinders. There is no downside to the fuel pump running for 3 seconds when the ignition is turned to the on position.

[OffCamber00]

Got mine as well on Saturday. Car started right up and ran flawlessly.

Great product and customer service.

[scarceller]

I gutted an old stock relay, removed the circuit board but kept the pins. I then wired up 2 40AMP heavy duty relay's to that gutted relay, I now have a super duty 40AMP relay solution for both the FP and the DME power. Added bonus is these are 40AMP standard style relays, super cheap upgrade.
I used relays like these:
10 PACK HARNESS + RELAY BOSCH STYLE 5-PIN SPDT 30/40 AMP 12V DC + 2 YR WARRANTY

If I get some time I'll take a picture.

[azhodge]

speaking only of my baby 88 911, I thought the system stayed under pressure when turned off?? second question when can I get one and why does Pelican not sell them???

[DRACO A5OG]

^^^, you are correct, it does stay under pressure.

[wrxnofx]

Originally Posted by azhodge

speaking only of my baby 88 911, I thought the system stayed under pressure when turned off?? second question when can I get one and why does Pelican not sell them???

The fuel systems of most fuel injected cars, especially newer ones, stay pressurized when you shut the car off. But over the course of a day or so that pressure slowly drops back down to near atmospheric. Newer cars have a Schrader valve on the fuel rail to relieve the pressure if necessary.

[Lyle O]

I just ordered one with the pre-prime feature as well.
I also noticed on the Rennlist blog that he (Focus 9 Technology, LLC) will offer 911 DMEs soon. Curious as to what he will do to update the components or layout, etc.
Pretty cool that there are options out there...

[DanielDudley]

Originally Posted by scarceller

I gutted an old stock relay, removed the circuit board but kept the pins. I then wired up 2 40AMP heavy duty relay's to that gutted relay, I now have a super duty 40AMP relay solution for both the FP and the DME power. Added bonus is these are 40AMP standard style relays, super cheap upgrade.
I used relays like these:
10 PACK HARNESS + RELAY BOSCH STYLE 5-PIN SPDT 30/40 AMP 12V DC + 2 YR WARRANTY

If I get some time I'll take a picture.

Makes perfect sense that you would figure that one out. I'm going to shoot you a PM about your other electronic talents...

[uwanna]

Originally Posted by Lyle O

I just ordered one with the pre-prime feature as well.
I also noticed on the Rennlist blog that he (Focus 9 Technology, LLC) will offer 911 DMEs soon. Curious as to what he will do to update the components or layout, etc.
Pretty cool that there are options out there...

If you look at his pics of his 944 DME's you will see just how much he has changed the layout and reduced the component size. The vintage Bosch DMEs (BMW, Porsche,etc) are very similar in design and I suppose his redo would look very similar to the 944 ones. I would buy one in a heartbeat for my 3.6 964 motor if he offered one!

[DRACO A5OG]

Just plugged in my SS DME Relay, I ordered the non-Pump Prime but F9T sent me the Pump Prime version by mistake.

I did not know the error and was like "WTF" after my engine reinstall, what they heck is that noise to discover it was my fuel pump, NICE I did not have to prime her for the initial start.

No complaints, car started right up, Thanks F9T.

[dan88911]

I was thinking about the purchase of the non-prime unit as well.
I don't get the need of a fuel pump prime feature.

[DRACO A5OG]

It will do no harm as I found out.

[DanielDudley]

There is no need for a pre prime feature, it is simply a choice. It can be a band aid for some problems, but I bought it because I like to hear my fuel pump. I went through an entire go round with my car and running issues, intermittent no start and rough running. Having the fuel pump fire up for three seconds tells me something about the health of my relay and the operation of my fuel pump. I like that.

I also have other cars that activate the fuel pump at initial start. I am used to hearing them. As others have stated, no one needs a solid state relay. I wanted one, so I opted for the one with an extra feature. I still carry a known good spare in the glove box. Given the trouble people have had with new, out of the box DME relays over the years, I actively sought out the solid state unit. In the end, I replaced three sensors, a DME, and found two bad wiring connections. Only one of the sensors needed replacing, but it absolutely needed replacing. Finding the bad wiring connection was problematic, simply because it was intermittent, and that made it hard to trace. Now if I have a fuel pump related issue, I do not have to test anything to find out if I am getting fuel. My ear tells me every time I start the car.

To be honest, a good mechanic might have found my issue right away. But being that it was intermittent, it might not have been so easy for him either. I think in the end, even with spending a few bucks extra, it was still cost effective to do the work myself. Plus I made some new friends on this board, and learned a few more things about my car. And you know it feels good when you finally solve a problem. I don't feel good owning a hobby car that I can't fix.

The DME relay was simply a present I bought myself. I also bought a spare here from Pelican.

[scarceller]

Priming the fuel pressure actually is important for cold start. At initial startup the DME sends a cold start injection pulse width that's carefully calibrated based on ambient temps. This is a pre startup shot of fuel and typically lasts about 2milliseconds. But for this to work correctly the DME assumes fuel pressure is ample at the fuel rails. This is also why most modern day OEM fuel injection also has a fuel pump prime prior to startup.

All my DME offerings have this feature, my chips via software turn the pump on for 3 seconds even with the stock relay. I found that it really helps cold start especially on very cold days, motor catches faster.

The relay offered here does have value in this feature and it seems like a decent alternative to getting the fuel pressure primed in an all stock DME.

[GH85Carrera]

Originally Posted by DanielDudley

There is no need for a pre prime feature, it is simply a choice. It can be a band aid for some problems, but I bought it because I like to hear my fuel pump. I went through an entire go round with my car and running issues, intermittent no start and rough running. Having the fuel pump fire up for three seconds tells me something about the health of my relay and the operation of my fuel pump. I like that.

I also have other cars that activate the fuel pump at initial start. I am used to hearing them. As others have stated, no one needs a solid state relay. I wanted one, so I opted for the one with an extra feature. I still carry a known good spare in the glove box. Given the trouble people have had with new, out of the box DME relays over the years, I actively sought out the solid state unit. In the end, I replaced three sensors, a DME, and found two bad wiring connections. Only one of the sensors needed replacing, but it absolutely needed replacing. Finding the bad wiring connection was problematic, simply because it was intermittent, and that made it hard to trace. Now if I have a fuel pump related issue, I do not have to test anything to find out if I am getting fuel. My ear tells me every time I start the car.

To be honest, a good mechanic might have found my issue right away. But being that it was intermittent, it might not have been so easy for him either. I think in the end, even with spending a few bucks extra, it was still cost effective to do the work myself. Plus I made some new friends on this board, and learned a few more things about my car. And you know it feels good when you finally solve a problem. I don't feel good owning a hobby car that I can't fix.

The DME relay was simply a present I bought myself. I also bought a spare here from Pelican.

Dang, you are reading my mind! That is spooky.

I feel the exact same way. My running problem was ultimately a combination of issues and the intermittent part is the killer to find. I am happy to have a neat toy like the SSR DME relay. I will feel a bit more confident when I hear that fuel pump buzz. I actually enjoyed the learning process and solving the issue with the help of this board and some parts from Pelican Parts.

[mysocal911]

Many seem to forget that the probability of failure of the SSR has increased over the simple
two mechanical relays of the original DME relay, given the increase in the number
of components of the SSR. A properly re-soldered original DME relay rarely if ever fails.

Remember, most all OEMs, e.g. Porsche Cayenne, still use a mechanical relay in critical
areas such as activating the FP.

Bottom line: One still needs to carry a spare FP relay to have a little security!

[DRACO A5OG]

^^^+1 Oh yes, I have the pulled Proper non URO relay and placed it in the anti-electro static bag that the SS relay came in

[DanielDudley]

Originally Posted by mysocal911

Many seem to forget that the probability of failure of the SSR has increased over the simple
two mechanical relays of the original DME relay, given the increase in the number
of components of the SSR. A properly re-soldered original DME relay rarely if ever fails.

Remember, most all OEMs, e.g. Porsche Cayenne, still use a mechanical relay in critical
areas such as activating the FP.

Bottom line: One still needs to carry a spare FP relay to have a little security!

I seem to recall that these units are pre tested at a higher draw than they will experience in operation, and that the electronics are all heavy duty. My gut told me to buy this before I even knew if they made one for the Carrera.

You too should listen to your gut. I just put the word out for people who might be interested. I am in no way a salesman for this product, just a happy consumer. And I am happy that people are still making new parts for our cars, and providing technical support and upgrades. I want to support these people, and encourage their efforts.