DME Relay Re-Flowed - Do This To Other Relays?

[OK-944]

My ‘87NA recently experienced an intermittent no-start issue which eventually got worse - which was solved by my switching out the DME relay. I then took the old relay apart and noticed some cracked solder joints so re-flowed them, then cleaned the internal contacts and reassembled/checked for operation, and all is well.

My question: Are there other relays which I might take apart in similar fashion to check (and possibly re-flow) various solder joints? I ask because I don’t just want to start taking these apart “willy nilly,” unless I know that they might eventually suffer a similar “cracked joint” condition as did my DME relay.

I suppose another approach might be to wait until a specific relay fails...but I'd rather do a bit of preventative maintenance if and when possible.

[944 Ecology]

You certainly are welcome to do so, but the DME relay is quite likely the only one that will leave you stranded.

[Monkey Wrench]

maybe a good question here is what other relays are required for the basic function of starting and driving the car?

in some cases with working with other cars Ill just put masking tape on the relay to label it, then if I return two years later, or if out on the road I dont find myself fussing over things that are not related.

[walfreyydo]

My advice is to go ahead and get a solid state DME relay to eliminate any future possibilities of failure with the analog relays. But if you prefer to keep using (and fixing) the older relays you are free to do so.

https://www.ftech9.com/new-products

There are many other relays that are analog on these cars, another important one is the fan relay (as you can see F9T has a solid state option for that). Other electronic components such as the DME itself, cruise control and even the tachometer, can benefit from having their solder joints reflowed and there are many guides on these and the rennlist forums documenting the process. None are as essential and important (one could argue fan relay is as it controls your fans/keeps the car from overheating when stationary) as the DME relay

[roverbau]

Can someone point to a treatise or three on DMEs? I’m pretty new to this and see lots of posts about them and how they tend to make a car unreliable. But I’ve yet to understand them and what preventive steps can be taken, or even how to diagnose/repair one, especially on the road. My 968 has not had a problem but haunts my brain when considering long drives away from home.

[Jfrahm]

Originally Posted by roverbau

Can someone point to a treatise or three on DMEs?

You probably mean "DME Relay" and not the DME (ECU brain) that the DME relay switches, along with the fuel pump.

This is a relay in the fuse/relay compartment under the hood on the later 944/968, maybe under the dash on the early style.
Plenty of info and pics here:
DME Relay Information and Testing

My opinion: If you have the old part number DME relay, get the newer part with the 993 part number from a good company like Stribel or get the solid-state one.
99361522702

I've had zero problems with the 993 part (over 20 years) but I have had the early version fail. I even reflowed it and hot-glued the internals for support and it failed again, so I lost interest in that.

Carry a jumper (see link above) and/or a spare DME relay to get home in case of failure. Your old relay, if reflowed or working, is probably an acceptable spare.

I personally think the solid-state DME relay is not worth the extra cost vs. a quality relay and I would recommend against the pump-prime option of someone does go for the solid state for various reasons.

The only other relays I have ever had problems with are ABS relays and AC relays. Both of these might be fixed by reflowing but I have not tried.

Cheers,
-Joel.

[roverbau]

Thank you Joel. Yes, I did mean DME Relay and your response and link is exactly what I wanted. My 968 is the newest old car I’ve had and a lot of the electronics baffle me!