Excellent.

 

The fuel pump seems pretty unlikely, I have had some old, old ones get sticky and quit, unstick, work for a very short time. Die again, for good. But over a period of a few days. Before then I had some long crank times (rarely) where maybe it was slow to wake up. More likely IMO you have a DME issue. Maybe coil, but coil problems are also pretty rare and heat-related. When it poops out do you have tach bounce? Fuel pump operation? Spark?

It's easy to test for fuel, shoot a little starting fluid into a vacuum line.

 

There is a pressure gauge that can be used to measure the pressure. Screws right into the fuel rail...Not for continued use, but it will tell you what is going on pressure wise. From what I've read in the past, the gauges fail if used continously and spray gas all over the engine bay..NOT cool! There is no hose on this, as it screws right into where the cap goes. Might be worth a shot. All the rental ones will not fit the end of the fuel rail without the unobtainium adapter..I'll have to measure the threads on my rail and post later if you want to make up one. When you mention the fuel filter, did you change out the tank sock filter as well? Might be worthwhile to change out as well if you go the new filter route.

 

Making the adpater should be easy with the extra cap I ordered. Sock? I've never opened up anything in the tank, though time-to-time I have read about various screens etc. This is all accessible through that plate in the trunk, yes?

 

Difficult to diagnose: it stalls while driving then pretty quickly afterwards fires up. Yes, tach bounces. By the time I go under the hood to jumper and listen for fuel pump, it's back anyway. Spark? That would be the same thing I guess, but sometimes on the re-cranks it backfires out the back--I'm not sure if this is lack of fuel or lack of spark.

Another clue is it won't start doing this after cold start; it's almost to the mark on 20km or so on my way in or out. Also more likely as temps increase a bit. And, after one or a couple of episodes, it disappears the rest of the way.

I didn't drive it in today: was running a bit late and couldn't fathom the delays of the now-routine issue on the way in

 

No. Item #28 in the image below. Threads into the fuel tank just upstream from the pump. Would be a good thing to replace, if you're going to be messing around in that area. Don't forget the seal (#27) if it doesn't come with it.

 

Super thanks! I'll order those today

 

Get all the fuel out of the tank as best you can before doing this. You'll still need a catch pan for what you don't get out. Pumping fuel out the end of the rail into a gas can is a good starting point.

 

Thanks for the tip. Sounds like fun. I think I'll drive it down near empty then go from there

 

Not to spend your money, but I'd change that relay anyway. I agree it doesn't sound like today's problem, but a 33 year old relay that's been apart and re-soldered isn't the type of thing reliability is built on. Just say'n. Moving on, if your car is dying abruptly without any warning, then it's more likely electrical than a bad fuel pump. If the pump were to stop pumping, I would expect the fuel pressure to decrease as the injectors spray, causing the motor to quickly go lean, start losing power/smoothness, then die. Is that what is happening? Or is it just humming along and then cutting off like a light switch? If it is just dying abruptly, then I'd suggest you re-read your own post 60. You say this all started after doing something that moved the ignition switch (a known cause of intermittent sudden engine dying) and that the switch is now loose… So why aren't you focused on that -- perhaps a bypass or hotwire to over-ride/test it?

 

By the way, now that you know what a cracked solder joint looks like (see relay pictures), unless you have tried known-good DME/KLR boxes, I'd also open both boxes and look for cracked solder joints where the main connector pins are soldered into the board. Those joints are part of what secures the main connector to the board (unfortunately) so are prone to cracking over the years as the connectors are taken out and reinstalled. If you haven't done that (or tried spares yet) that might be #1 on my list right now, or close to it, assuming you have tach bounce and a good dme relay.

 

Yes, this is exactly what is happening--while driving. It often stutters and hesitates briefly then catches back to normal. There are times it does this and doesn't stall. When this happens, I've been looking ahead and planning where to pull over, as I know the stall will come. Or, if I'm close to where I'm going, I just keep at it and have usually made it. Other times, it just stalls quick. That's when I've been caught in some hairy situation (like the single-lane construction zone with no shoulder!). However, if fires back up pretty quick; that's why I've been driving it still. I haven't had the "idle-stall" as much this week.

My hunch all along has been fuel pump. There is one guy that went through a few bad ones in a short time. I'm ignoring the ignition switch mostly because I don't feel like taking all that brittle dash plastic apart during this cold weather. I don't have an indoor space to work on the car other than my garage "tent". The switch itself isn't loose; what's happening is you can lock the wheel then turn a little on the lock one way or another which causes the entire key area to move accordingly. So, however the lock works, it's got a little play now. I'm assuming that the actual switching connections on the inside aren't affected.

I already ordered the new relay (the Kaehler one noted earlier). It should be here any day now. I think I'll pull the DME tonight and open it up--maybe. It sure gets dark and cold early now

 

PS: In your "quickly go lean" scenario, could that be followed by a single backfire ("pop") out the back right after it stalls? I've heard this a couple times, and one time I had to crank it about two or three times and after each unsuccessful cranking, it backfired once out the back. Interestingly enough, each backfire comes as soon as the cranking stops:

"Crank crank crank crank crank crank.. stop. POP!"

 

Very hard to pinpoint the cause based on those symptoms alone. You need more diagnostic data. Do you have a wideband and, if so, is it going lean or rich when it sputters? Monitoring fuel pressure might save you the trouble of changing the pump (it's a mess). I would think if it died from a bad pump, it would always sputter to death first, and would always take some cranking to get the pressure back up after it dies. Backfiring after cranking just means unburned fuel is blowing up in the exhaust. But that could be caused by lots of things, so doesn't really point to any particular cause or narrow it down much. I'd still check for cracked solder joints. It's fun and free, so why not.

Another possibility is water in the tank...