Another 1984 911 that won't start.

[nixomose]

I've looked up other posts here and I think I need a little more beginner help. I've had my 84 911 since 2005. I garage it, keep it charged over the winter, and it has never failed to start right up even after sitting for 6 months.

I've been driving it a bunch lately, and the only interesting thing I did was wash it and wax it, and now it cranks and cranks, but never turns over. It's only been sitting a week.

I replaced the DME relay this morning, same results, no VROOM. All the gauges read fine while cranking. What are some other simple things I can check before I give up and have it towed somewhere?

Alas it's just me so I can't crank the engine and hold the fuel pump (where is it?, by the way) at the same time. I'm not a mechanical genius, but I can do bolt-on type work. Engine work scares me.

Could I have gotten something wet when washing it? There was one regrettable time I took it to a car wash and it stalled while being washed, but it started right up after that. So that's why I'm thinking the water might be an issue. Taking off the distributor cap looking for water? Any other suggestions?

Thanks.

[KNS]

Try a search here, many with similar problems. Your engine is cranking, that's a good start. It's either fuel or spark - do you have a Bentley manual? It has a trouble shooting section.

[rusnak]

spray some starting fluid into the airbox BEFORE the air cleaner, then immediately turn the key. If it starts, then you have a fuel issue or a vacuum leak. If it doesn't then you have no spark. Make sure that the battery is fully charged, and that the relay clicks twice, the second time while cranking.

[ned447]

check the hose that sits between the oil tank and the air box, might be dry-ed out or loose / torn. That looses you vacuum in the intake preventing it from starting as well. (same effect if you remove the oil cap without having the restrictor fitted). Good luck

[Joe Bob]

Does the DME relay click when you turn on the igntion? If not you have a power input issue. The kwik start will tell you if you have a fuel issue. Grounding a spark plug looking for spark is something that should check as well.

Air, fuel, power, spark...

[Laneco]

Pop the cap off the distributor, check for moisture. If you see any at all (tends to condense in the top of the cap) - wipe and dry the cap, use a blow dryer to get it COMPLETELY dry - use the dryer in the distributor bottom to make sure everything down there is dry too. If you have compressed air - that will do the same trick uber-quick.

It should not have gotten wet - but the fact that it decided to quit after a wash makes a wet ignition system a likely suspect.

angela

[Bill in OKC]

My '84 had one of the flywheel sensors go bad. I don't know if water getting in the connector is possible or if that would keep one of them from working. The bracket holds them up where a spray would get to the connectors if you washed the engine compartment.

[kidrock]

if you washed your car, you've probably got water inside the distributor cap. Dry the inside of the cap and, if necessary, carefully pull one wire at a time from the cap and dry the inside of each connector.

[gtc]

I had a no start a while back. I thought at first that it was a reference sender, but eventually I narrowed it down to a fried DME. I had Ingo here repair it, and it turned out to be a bad power transistor, or something like that.
Replacing 3.2 reference senders with engine in car?

[nixomose]

As the porsche is a hobby, it tends to fall lower on the list of things to get to than tending baby and mowing the lawn, but I finally had some time to look at it this weekend.

I did the spray in the intake thing and cranked, no firing, no vroom.

I took the distributor cap off, it's all dry and spinning.
I pulled a spark plug out (quite the feat without a spark plug puller for this size plug) and grounded and crank, and there's definitely spark.

So I tried the spray in the intake thing being more liberal, still no go.

I checked all the fuses, none burned out, I had a spare DME relay, replaced it, no change.
I didn't try listening for a click, I'll have to do that next time I have a chance.

But thanks for all the advice, I'll check out the other suggestions mentioned here.

One thing I'm a little confused about. Based on reading lots of similar articles, it sounds like the relays in the front storage compartment of the car (trunk?) on the drivers side wall were rewired for different things every year. One says the leftmost one is the fuel pump relay, but the writing on the inside of the cover on mine says it's for a/c or something like that.

Is there a separate relay for the fuel pump or is it part of the DME relay under the driver's seat?

[nixomose]

Spraying starter fluid after taking off the air filter didn't do anything, but when I took the hose off to the throttle body, opened the butterfly and sprayed in there, and cranked the engine then it fired up for about a second or two then sputtered and stalled.

So I have a fuel problem. Thoughts on where to look next? Where exactly is the fuel pump on this car. I've looked around and I see various answers in various places. It's raining or I'd go hunt for it myself. Suggestions on how to test the fuel pump?

Should I take off the fuel filter (I know where that is) and see if it sprays when cranked? Not the safest thing in the world, other suggestions welcome.

[robhamster]

Don't forget, if all else fails, the proverbial bad solders within the DME. A search should yield many threads on this.

[rusnak]

The fuel pressure is checked on the fuel rail. The left side rail has a cap, with a sealing ball under it (don't drop it, and whatever you do, don't overtighten the cap). If you don't already have one, a Bentley service manual is your friend. It has a procedure to jumper the DME socket to check fuel pressure, and also to make sure the fuel pump is running. I'm sure you can find the procedure mentioned here, as well. Try tapping on the injectors a few times to see if one or more are stuck.

[Bill in OKC]

A relatively easy check is with a noid light. It plugs into the injector plug and will light up if there is a signal to the injector.

[Richard Paris]

Same prob on my '89.
DME was ok so they started the search - finally came down to the Alarm Module had failed and cut power to the DME.
Did a factory bypass and everything is back to normal - except of course, now the alarm is dismantled which I don't care about anyway.

[rusnak]

A noid light wont tell you if you have a stuck injector, only if there should be a signal to them.

If the DME was dead, it would not cough or sputter. There would be nothing. I would check the fuel pump next by jumpering it at the dme socket. Check for two clicks at the dme relay, which indicates that there is a signal from the ref sensor to the dme, and that the dme sees it. Ohm out the sensors (ref, speed, and temp).

[nixomose]

Had a few minutes today, found the fuel pump, held a meter to the pump leads while my wife cranked the engine 12v while cranking and I felt the pump vibrating and heard the sound of whooshing fluid in a pump.
I guess I check pressure next.

[RufusMadore]

It plugs into the injector plug and will light up if there is a signal to the injector

[nixomose]

So after much rain, I had some more time today. I spent the past week trying to find either a fuel pressure gauge, or a set of adapters to connect the fuel rail plug to my pressure gauge with no luck.
So today I did the simpler volume test and the pump is definitely pumping a lot of gas, according to bently about a quart in 30 seconds and that's about what I got. I did notice that while it was pumping there were a lot of air bubbles coming through my plastic tube. Anything to worry about?

So now I'm thinking the flywheel speed and position sensors. Is there a way to test these for malfunction? I'm trying to avoid throwing $150 each at a pump, pressure regulator, 2 sensors, whatever else in trying to guess what's wrong. So I could be sure it was the sensors I'd just go and replace them.

[darrin]

Originally Posted by Woodyhfd

Check for spark with an old plug or one of these. It's cheap and easy.

per the above "I pulled a spark plug out (quite the feat without a spark plug puller for this size plug) and grounded and crank, and there's definitely spark" he has spark -- one thing I haven't seen mentioned on this thread is the head temp sensor -- Has the OP checked the head temp sensor -- the '84 would have shipped with the older single wire unit, which would cause this behavior if it had gone bad. Easy to check its resistance per bently to rule it out. At a minimum, very easy to check at the plug (same series of plugs as the reference sensor) to confirm that the old single wire head temp sensor's been replaced with the newer 2 wire version.