Helpp......Starting problems 911sc

[black 911sc]

Hi,

I am new here, come from holland (far away) and have a 1983 black 911sc.

Problem 1, is that the starter is not cranking.
One time is does crank, the other time (2 min later) it doesn't crank.
You can hear the solenoid cams in (12v on the yellow wire is good)
Battery ok, Ground/chassis ok

Problem 2, When the starter does crank, the engine fire up but dies after 1 second.....

Checks:

The FPR, when lifting the air plate senor the pump runs.
Ignition turn to start, i hear the pump running, 12v measure on #87 from FPR.
Solenoid does click, but the engine not turning over??

Question's

Ther are 2 yellow wires on the starter, one goes to the ignition (50 on wiring diagram) the other goes to startvalve and thermoswitch for cold start.

If the solenoid doesn't work fine, couldn't it be that the startvalve and thermoswitch not working and the engine fire up for 1 second???

There are 2 grounds, one from the gearbox to chassis, the other is a brown wire, where is that locked??


It all happens when I put my (overhauled) engine back in for the second time.
(The first time the engine runs fine, but had to pull it out because one head gasket wasn't good)


please help....... my in this little wet country

[Alan L]

I am having trouble understanding your question.
Is your starter motor not firing (cranking) or the engine not firing.
If you have a bad contact inside the starter, it may be intermittent. If you have a bad contact in solenoid relay it may also be intermittent. You could try jacking car up and putting jump leads direct onto solenoid and see if cranks.
If engine is only running for a second and dies, suggests fuel supply.
Have you hooked the fuel lines up right. I dont think you can get them wrong.
Is your battery OK?
Alan

[black 911sc]

mayby because i am from holland


problem 1:

The starter motor sometimes doesn't crank up, 2 min later it does crank up


problem 2:

If the startermotor is cranking, the engine fired up than dies after 1 second.


my question's


Why does the startermotor crank sometimes en somtimes not??
Thos the solenoid have anything to do with not firing the engine??

(The 2 yellow wires on the starter, one goes to the ignition (50 on wiring diagram) the other goes to startvalve and thermoswitch for cold start.)

I have 2 battery's, both does the same thing.
Fuel lines are hooked up in the right way.

[Alan L]

My guess is you have a bad contact (burnt) in the solenoid.
From memory you can pull it apart.
Next time it does this you could try bypassing the solenoid with jump leads from a battery - direct on to the starter terminals.
Alan

[black 911sc]

I jump from the red wire on the starter (battery) to the fat yellow.
Starter does the same click.

I did not try a new fat wire form the battery direct to the + starter.

[Alan L]

You need to bypass the solenoid to isolate the problem.
The solenoid has a trigger that pull an arm in to make a contact on a large copper terminal, internally. They get burnt over time, and can be cleaned up.
Or, it may be stiff,and not pulling in properly.
You need to feed the batter power direct to the starter - briefly and see if kicks over, when key start won't.
Alan

[black 911sc]

ok, I am going to try this next friday.

(my car is stalled 40km away in a garage)


nothing else I can try, because it runs only for 1 sec???????

[Alan L]

The starter one will be the easiest to fix. Get that sorted, and then see what problems there are.
Thinking again, you can just jump the solenoid - with a sturdy piece of wire - from power input to solenoid, to solenoid output to battery.
This bypasses the solenoid function.
If motor cranks each time you jump these terminals, then solenoid is problem.
The 1 sec running could be a looong list of things. But sounds like fuel.
Alan

[Mothy]

I had the exact same problems that you describe - put not at the same time.

Problem 1 - intermittent working of the starter. In my case it turned out to be buildup of dust etc in the solenoid - got the starter reconditioned and it went away. Up till then, a whack with a lump of wood would sometimes fix it (dislodged the dust)


Problem 2 - start for 1 second then die. Turned out to be more complex than a single item but was a combination of Fuel pump relay, pump circuit being on all the time rather than only when engine running and warm up regulator having rust in it!

Tim

[black 911sc]

I fix first the startmotor problem, then see what problems there are with the engine.

The FP and FPR are new.

It is wird, I have no troubles before with the engine.
Most be some ground or wire problem.

The are two things i have done before i stall the engine back in.
I clean the engine room with water, and paint it with body sealer.
The ground (gearbox/chassis are clean)

I hope the give me al lot off things too look for on this forum, before i drive another 40 km, and try one thing and go back home again.......

[T77911S]

alan, the problem with bypassing the solenoid is that it will not pull the starter into the flywheel, it will just run the motor. you are correct about the contacts.
pull the starter, remove the solenoid. there are 2 wires on the end of the solenoid that need to be de-soldered. remove the screws and pull the end of the solenoid off. remove the big nuts on the 2 lugs. pull the lugs out and clean. if you rotate the lugs 180 degrees from where they originally were, there will be fresh metal there. also clean the big contact on the solenoid itself. = new solenoid!

[Formerly Steve Wilkinson]

It can be very baffling when two different problems occur simultaneously and seem to be related--i.e. your bad starter solenoid (probably) and the engine's fuel or ignition problem. I would guess they have absolutely nothing to do with each other and have simply, coincidentally occurred simultaneously.

Happened to me recently when I had the very same starting problem that you are having, and simultaneously had a situation where the engine would briefly die, then pick again, as I was driving along. I wasted a whole lot of time trying to figure out what single thing could cause them both when it was in fact two entirely different things.

[Alan L]

I would think jumping across the soleoid should fire the starter. The ring gear engagemant is centrifugally driven I think - not solenoid driven.
But my money is on the solenoid - and probably the copper contact.
The 1 sec run could be anything. You will have to check a list of basics.
It could be it is only running on the CSV shot of fuel. Check the injectors load up with fuel when you lift the airplate (whine).
Check the fuel delivery at an injector end if you have to - ie pull the injector and watch.
You are just going to have to work backwards thru the basics.
Alan

[T77911S]

you are correct in that it is the solenoid, as long as he is getting a good 12v for the start signal, which he said he had checked.
the solenoid pulls the starter into the flywheel, the contacts mate and the starter turns.

the 1 sec run, sounds like it runs off the start valve, once it turns off, the car dies. seems to a common problem. he may want to search and see what he finds.
could be a dirty screen to the warm up regulator (WUR). bad pressures, air leak just to name a few.

[Alan L]

You are correct on 2nd thoughts, there is a lever arm for the starter to engage.
So, jumping it may not help.
Some systems have the solenoid independant,and the starter engages on rotation.
But he needs to pull the solenoid.
This bit is easy.
The next problem will take a bit longer.
Check basics.
Check you have fuel going to injectors.
Once starter is fixed, check you have spark at plugs.
Check anything else that you can think of.
Washed engine bay out. Water in fuel?
Alan

[black 911sc]

Tomorrow i am going to pull the startmotor out.
Then I jump it with starting kabels, and look of it cranks.

[T77911S]

the ones that engage on rotation have a seperate solenoid, like you find mounted on the fender wall of most american cars. but your right, this is the easy fix.

if you take the starter out to test it, PUT IT IN A VISE. if it spins the torrque will send right off the bench.
its kind of tricky to test out of the car. you need to attach ground to the chasis of the starter. then attach the positive to the big post on the solenoid. then you need to jumper the 12v over to the spade terminal on the solenoid. that will pull in the solenoid,then the motor should run.

if you just want to run the motor to test it, attach the positive to the short big lug on the solenoid, the one with the braided cable attached to, the hang on.

[Gunter]

Originally Posted by black 911sc

Tomorrow i am going to pull the startmotor out.
Then I jump it with starting kabels, and look of it cranks.

Before you remove the starter, why no test it on the car?
This test will also show if the yellow wire from the Solenoid to the ignition switch is not working correctly. Or if the ignition switch (Starter position) itself is not working.
Lift the car securely, gears in neutral, disconnect front battery, ignition OFF.
Take a charged battery close to the starter, connect a ground lead from negative terminal to the starter body, pull the 2 yellow wires off.
Connect a wire from the positive terminal of the battery to the Solenoid spade.
If the Solenoid works, it'll pull the starter in. (But not crank)

If you want the engine to crank, leave the front battery connected (Ignition OFF) and repeat the procedure.
This time, the Solenoid pulls the starter into the flywheel ring gear and the engine will crank but not start because the ignition is OFF.

If the Solenoid doesn't work with this process, remove the starter for cleaning and testing as suggested by T77911S.
Make sure you disconnect the front battery before removing the wires on the Solenoid!

Removing the starter can be tricky; you'll have to hug the transmission to reach the top nut.
Many SC's have a barrel nut on top and you'll need a 10mm Allen socket plus a short extension.
There is very little room and you have to manipulate the tools to open the barrel nut.
Gloves and safety glasses are recommended because of the dirt falling down.

[black 911sc]

Today the startmotor removed. (5min)
I Jump the starter with starting kabels, and it works fine.....
Put the starter back in, and it cranks......

So thats ok,

Now the engine is still fire up for 1 sec

Measure 12v on te WUR.

The funny things is, wen I start the engine, the air-plate(CIS) goes up and down.
When I healed the plate study the car runs, but not good and (back)fire's a little bit.

Anyone

[Gunter]

Originally Posted by black 911sc

Today the startmotor removed. (5min)
I Jump the starter with starting kabels, and it works fine.....
Put the starter back in, and it cranks......

So thats ok,

Now the engine is still fire up for 1 sec

Measure 12v on te WUR.

The funny things is, wen I start the engine, the air-plate(CIS) goes up and down.
When I healed the plate study the car runs, but not good and (back)fire's a little bit.

Anyone

Sounds like it is "hunting" for the right mixture.
Try adjusting it leaner with a long 3mm Allen wrench (Lean is counter clock wise, ccw) Just a little maybe 1/4 turn.
If no improvement, go cw for richer.
Also, open the big fast-idle screw on the left side of the TB a little more.

If you don't know where the mix-adjust screw, and fast-idle screw is, do a search here or look in the Bentley SC Repair Manual.