1985 911 crank no start issue after sitting

[55rag]

Hello All,
I am hoping to get some direction from the experts on a starting issue I'm having. I've been working on my bug for the past 9 months so the 911 got put in storage and hasn't been started since. It did run great when I put it in.

I went over the other day to swap cars out and bring the 911 back home but it wouldn't start. It had a trickle charger on it and cranks over no problem but no start and no fuel smell at the exhaust either. I noticed I didn't hear the fuel pump so I replaced the DME relay with my spare which is new. Nothing changed.

I then came home did a little research and went back to check the fuel pump and all the connections. If I jump the fuel pump fuse to another fuse I do hear the pump run. I also pulled the battery to see if that would reset anything which didn't help.

I'm going to make that 3 prong jumper for the DME harness to eliminate the possibility of a bad spare DME relay. Any other ideas of what I should check on my next visit? I've never had problems with electronics going bad from just sitting but the car is getting old so I guess it's possible.

Oh, I also feel the idle valve vibrate when the ignition is on if that matters.

Regards,
Jason

[Harley Monster]

You might try some fresh fuel, the modern fuels breakdown really fast. Did you add any STA-BIL when you put the Porsche in storage? It really does work well.

[55rag]

No I didn't use any additive before I stored it. I really didn't expect it to sit for so long but one thing leads to another. Old fuel will probably be an issue but at this point the pump isn't pumping anything out anyway. I wish I could get into the car and dump the fuel easily from the tank but it's in a enclosed storage which frowns upon working on cars.

Thanks Harley

[brujo65]

check your reference sensors at the flywheel

[jlex]

It's either electrical or fuel. Try to rule out fuel by giving it a little shot of starting fluid. Had to do that to get a Carrera to go after it sat with bad gas for 10 years. Just don't overdo it as you can harm the engine with too much. If it wants to run on starting fluid, it's time to change out the old gas and flush the system.

[55rag]

So I did read in one of the posts I was researching that tach needle should move while cranking the engine over and mine does not move at all. I don't have the Bentley manual on me but I didn't read anything about a testing procedure for those reference sensors. Do you have any suggestions on how to test?

Also, if the sensors are bad I should still be able to run the car temporarily with the DME 3 prong jumper just to get the car to my garage?

Thanks

[proporsche]

Hi Jason..it points out towards the temperature head sensor which is located on cyl no 3.
i go dig up some tests a give it to you ...
Ivan

also have a look at the engine compartment on the white female plus.Does it have one or two prongs inside.If one it is the old type and replacing the sensor should be done.....

[proporsche]

here is some reading for ya....
3.2 sensor question

one more test you can do

[55rag]

Oh no, it sounds like this could turn into a can of worms. Thanks for the link Proporsche. I do have the white terminal with two prongs in it.

I'm meeting my dad at the car this weekend so i can confirm I'm getting spark and we will bring some starting fluid. I'm hoping that at least I can get it running to get it home where I can work on it.

Thanks for the info.

[proporsche]

do not worry too much..since you 2 prongs that means it is already latest version...do those test it is not hard ..
do you have any alarm in your 911?

Ivan

[55rag]

It originally had an alarm but it's been disconnected for years.

[ClickClickBoom]

If the battery has been sitting that long it might be toast. If the DME doesn’t have enough voltage it won’t work, plenty of cranky, no starty. If the battery spins the motor but no fire, try a jumpstart with heavy gauge jumper cables and a running car. The ECU needs a minimum voltage and a marginal battery might be enough to spin the motor, but not enough to start. Ask me how I know....

[55rag]

Thanks for that. The engine did crank over pretty well but I'll bring cables and give that a try also. My list of things to try and check is growing so I'm sure we'll be able to figure it out this weekend.

[ischmitz]

You have power so it's not the alarm or ignition switch. A couple of quick thing to try:

- squirt starter fluid or brake cleaner into the air filter and try again to crank. If that makes it sputter and try to run you're missing fuel (likely injectors stuck shut, common when 3.2 sit for long times) or the dreaded DME relay not running the pump.

- take an extra spark plug hook it to one of the leads and ground it and confirm you'll see spark when cranking. If not then it's on to more diagnostics and might lead you to one or both of the flywheel sensors (common issue) or something more involved like the DME itself.

Ingo

[Driven97]

I had a similar issue this summer while out of state and it turned out to be one of the two crank sensors. I replaced both (tip I found here was buy the BMW ones, they're the same BOSCH parts but cheaper) and no more issues. Posts #7 & #8 are easy and free checks, assuming you have access to a multimeter.

[GH85Carrera]

Originally Posted by ischmitz

You have power so it's not the alarm or ignition switch. A couple of quick thing to try:

- squirt starter fluid or brake fluid into the air filter and try again to crank. If that makes it sputter and try to run you're missing fuel (likely injectors stuck shut, common when 3.2 sit for long times) or the dreaded DME relay not running the pump.

- take an extra spark plug hook it to one of the leads and ground it and confirm you'll see spark when cranking. If not then it's on to more diagnostics and might lead you to one or both of the flywheel sensors (common issue) or something more involved like the DME itself.

Ingo

I hope you mean brake cleaner. I can't imagine pouring brake fluid into the intake.

[ischmitz]

yep - sorry.. of course brake cleaner

[Flat6pac]

Sounds like you tried everything but this...
Split the hose off the bottom of the idle control valve
Pour a little gas in the manifold and replace the hose, try starting.
If it runs. It your injectors or fuel pump
Bruce

[ClickClickBoom]

Originally Posted by 55rag

Thanks for that. The engine did crank over pretty well but I'll bring cables and give that a try also. My list of things to try and check is growing so I'm sure we'll be able to figure it out this weekend.

The starter will spin at lower voltages just fine, the DME will not work below a set voltage. I had the same symptoms you had. The starter would spin the engine at what seemed enough speed but it wouldn’t fire. When I jumped my car with a motorcycle battery it fired immediately, yeah you heard it right a motorcycle battery. Put a new battery in yesterday. Everything working top notch. It sees that I get about 6 years on batteries, and my car is my daily driver.
Occams Razor....

[55rag]

Thanks everybody for the responses. I worked on the car a bit today and found that I have both no spark and no fuel pump. I get no spark when I plugged in a spare plug and no combustion from spraying starting fluid in the intake. I also test the coil which tested good. I jumped with jumper cables to no affect. The CHT sensor tested within range but I got bad readings on both reference and speed sensors. I am not sure I trust the readings I got because they were totally open between all but pins 1 and 2 on the middle sensor. I'm not sure which is which. So, I find it hard to believe that both sensors went bad from sitting. Is there anyway I can further isolate or is there a way to jumper these sensors so I can start the car? Would these sensors cause both no fuel pump and no spark issue?

Thanks so much,
Jason