slow staring except when sitting overnight

[spugeddy]

As the title states, my car will start almost immediately if it has sat overnight. or after about 8 or so hours of sitting. If I run errands for example, it will take 3-4 seconds to start. Battery and starter are great. I just did the dist cap, plugs, fuel filter, and cleaned battery cables at the battery,

Once running it is pretty solid with occasional lopes, or reductions in rpm at idle only maybe once minor one every 30 seconds at idle. It is very responsive and smooth with a hard acceleration run.

Does this sound like the fuel check valve at the fuel pump, since once running it is really a non issue. I guess the only other issue may be at the fuel rail, although I am really have no issues once it starts.

[walfreyydo]

Troubleshooting - Engine

#1 fuel pump/DME relay

Most have upgraded to a solid-state relay, you may want to do the same just for preventative measure. All 944 owners should do this.

[spugeddy]

Interesting... thank you.

So is it just a matter of buying a replacement relay, solid state version, and plug and play?

[Jfrahm]

If you are still running the old version of the DME relay (944 part number) it should at least be put in the glove box with a note that it might not work 100%. The newer ones, 993 part number, have been reliable for me over 4 cars and 20 years but if I were in the market I'd probably get the solid state version now.

DME Relay Information and Testing

The Focus 9 Solid State relay seems pretty bulletproof but but keep a spare relay and/or a jumper wire on board. My choice would be without pump priming as a few cranks to build oil pressure when cold seems like a good idea.

Not sure if the DME relay is your problem but a problem like you have is a lot harder to track down if you have the old DME relay. You can try the jumper wire in the meantime to see if the problem goes away.

-Joel.

[Fast Freddy 944]

Take it to a shop, don't monkey around with computer, it will only make it worse...

[walfreyydo]

To be clear, you should not need to take it to a shop to replace the DME relay - this is as basic as basic gets. Its as simple as replacing a fuse (and its located in the under hood fuse panel).

You should buy a solid state relay and install it yourself. Its a good preventative and necessary upgrade for these cars due to the age and the advancement of technology since the original relays were manufactured.

You will not be touching or "monkeying" around with your computer by changing this relay, and you would be wasting your money taking it to a shop to change out the relay.

In addition, if you wanted to test your old, possibly faulty relay, see the article that Jfrahm posted above "DME Relay Information and Testing". I will provide all the information you need to diagnose and fix yourself.

Here is the upgraded Solid State relay:
http://www.ftech9.com/new-products/993-ssr-pp

[Jfrahm]

Looks like Pelican sells the Stribel DME relay for $32 and an OEM Supplier version for a bit less. The URO version is like $16 and a URO rep has claimed that the trouble prone early version of their relay has been updated.

I'd probably go with the Stribel, $30 is $30 and I have not had problems with that part.

[UROParts]

Originally Posted by Jfrahm

The URO version is like $16 and a URO rep has claimed that the trouble prone early version of their relay has been updated.

Thanks Jfrahm, that's correct, here's the post regarding updated URO Parts DME Relay 993 615 227 01 / 99361522701:

Originally Posted by UROParts

Hi everyone, quick FYI: as of March 2018, URO discontinued its second-generation DME relay and released a completely-redesigned third-gen unit. The new relay utilizes strong through-hole component mounting using Surface Mount Technology (SMT) "pick-and-place" robotics in a clean room environment for consistent assembly quality, along with modern modular-design mechanical relays for long-term reliability.

Here's what Rennlist forum member "steeley90" posted about our new relay on 3/13/2018, after not having much luck with other relays:

"The {URO} parts arrived at my work and I swiftly made my way to the car park to try one out. I wish I had a dash cam that had captured my face when the car started first time with the new relay installed. I'm absolutely ecstatic. I cannot value these new relays high enough. I've tried every other option of relay including Porsche OEM and none worked. It's still a luxury for me to get in the car and not have to pop the bonnet. One I'm sure I won't get tired of for a long time. Thanks ever so much to the guys at URO, you've made this 944 owner the happiest guy!"

Pelican hasn't updated their product photo, but they offer the new relay here: https://www.pelicanparts.com/More_Info/99361522701M253.htm?pn=993-615-227-01-M253&bt=Y&fs=0&SVSVSI=

[spugeddy]

yep, i bought and installed the 3rd Gen URO. still having issues, although it is slightly better.

[UROParts]

Not familiar with this engine, but speaking generally the cold start system can be the culprit when experiencing "warm-start" issues. In a nutshell, the cold start system works properly when the engine is cold, but falters if the engine is cool enough to need a bit of extra fuel, but the system thinks the engine is hot enough (due to a failing temp sensor, etc) to not need any extra fuel, so the system doesn't add any.

Again, don't know enough about this engine to say this could be the issue, but something to consider.

[spugeddy]

That makes sense.

[jjeffries]

Spug, what year is your car? There are more things possible than mentioned. The clearer you can be in terms of exactly what happens, and when, the better advice you’ll receive here. “Still having issues”, can you expand on that? With the starting, or the idle quality?
I have an excellent Bosch document describing how this early generation of Motronic works, and how to troubleshoot, kindly sent by one of the other guys here, which I’ll happily forward to you if you PM me your email address.

John

[Fast Freddy 944]

I might replace my dme relay just for kicks, what do those upraded dme's cost these days?

[spugeddy]

it was like $30 shipped,

What happens to mine is it struggles to start (4-5 seconds) starter is spinng great, it just isn't firing off, then once running, it chokes down but only for 3 or so seconds, sometimes it dies right away if I don't help it with gas pedal. after about 10 seconds its fine and runs great from this point on.

[Jfrahm]

Maybe a leaking injector or blown FPR/Damper diaphram. Crank it a bit when it struggles but not too much, then stop and whip out the plugs. See if any are wet with fuel. Check for fuel leaks from the FPR and damper int the vacuum system.

-Joel.

[spugeddy]

cool. thanks. that could be the area of the problem.

[spugeddy]

It was...... the fuel pump.

I changed the fuel tank screen as well, and the check valve I suppose was replaced as part of the Bosch Fuel Pump assembly.

Man, I should have got a fuel pressure gauge and it may have saved me some time and money.

[Monkey Wrench]

That DME relay has two contactors, As far as I understand it , one supplies power to the fuel pump , the other supplies power to the DME solid state is OK , they maybe more reliable but they can still fail. One advantage the mechanical device has is that it can be more easily observed, or heard.

it really simple to pick up these two hot wires ( provided they are not actually switching the ground) ,, in which case it's just reference to hot rather than chassis ground..

Run them also to a couple of small watt bulbs. I think this takes a lot of they mystery out of these starting issues. then you can tell at a glance if both of these relays are latched or not.

In this case it would have proven that the DME was latched ,o was the fuel pump relay, and that would have simplified things .

a defective / stuck fuel pump could draw a lot of amps so maybe it's o to change the relay anyway, the hight motor draw may have caused more amps thus wear to the contact points, more amps, bigger spark, more burning of the contacts....

When I get into working on mine I think I will just put them in the glove box or somewhere easy to access and not really noticeable. inside the console maybe.. or even just up near the fuses.

if you see the indicator lamp is on but the fuel isn't being delivered, or the pump makes no sound, then it would point you straight to the pump or tank or filter issues the relay would already be proven to be functioning.

this should not in any way affect how the car works, it just helps troubleshoot if you have a no start issue or similar. I feel it will give me a bit of peace of mind, not needing to be puzzled about if it's latched or not. the amp load of a tiny 12V indicator bulb is miniscule. I got some tiny ones from a model shop they use them for electric train displays, but any tiny 12 V low watt indicator bulb should be fine.

You can get to the same point in troubleshooting using a meter, I just feel it's a worthwhile mod to add this, mainly for convenience but it may be nice to see when it latches or see if there is an intermittent, things like that.

question ?
did you find any goop in the fuel tank? or was it clean on the bottom? I seem to be learning that as cars sit , if they are unused for a period of time, they can make this thick tar like goo and that may take out the pump and filter and cause issues. maybe with the old style of carb with a clear in line fuel filter, it becomes obvious but with FI you never really see the issue until it creates a problem.

I learned in previous post that the filter is after the pump , so the fuel in it is under pressure but maybe a run of the mill inline fuel filter could be added between the spout on the tank and the rest, then you could simply see if it's dirty or has a water slug. maybe that could also prevent garbage being sucked into the pump and stalling it. I dont know if that is wise, just thinking out loud.

[spugeddy]

There wasn't much sediment at the fuel screen port when i removed it. the screen didn't look terrible either. but i replaced it anyway and cleaned up the bottom of the tank while i had the fuel drained. Car was being driven, so it wasn't sitting. Fuel pump was an aftermarket one, and so someone had previously replaced it before me.

[944 Ecology]

Is this the car that you are trying to sell for $8K?