$100 Prize for the Guru that solves my Itermittent long cranks problem!

[fintstone]

I have had these symptoms. One was the cold start injector needed an o-ring. The second was one of the wires in the connector to my CDI had backed out a bit and was a bit intermittent. The other time, it was a bad fuel pump.

A bad fuel accumulator or a bad pump will both cause this situation.

[tperazzo]

Originally Posted by ivanuf

91 Octane no ethanol, engine warm or cold.
All days are the same temp.
Car parked flat
Tank full

Hmm, may still want to check fuel pump inlets for restrictions such as filter screens, swollen hoses, pin holes, kinks etc.
This is a tough one to crack right?

[gomezoneill]

It's funny how a 100 dollar reward will get all these responses. got to love it! I have to use that in the future.

[proporsche]

Originally Posted by gomezoneill

It's funny how a 100 dollar reward will get all these responses. got to love it! I have to use that in the future.

[spoke]

Originally Posted by ivanuf

That one is bypassed to feed CDI no shutoff delay.

So with relay 4 bypassed (assuming you mean pin 30 connected to 87a), the fuel pumps should run all the time. You did not mention or I missed it where you said the fuel pumps are running all the time. Do you hear the fuel pumps running when the dead cranking occurs?

Not sure what you mean by "bypassed to feed CDI". On my '86 930, relay 4 is energized by the alarm system or throttle sensor plate. When energized, relay 4 cuts off power to the fuel pump relay coils. A little circuit board on relay 4 delays its turn-on when the IG key is turned from OFF to ON. This turn-on delay is what drives the FPs for 0.5-1 second when the key is turned ON.

[proporsche]

Originally Posted by spoke

So with relay 4 bypassed (assuming you mean pin 30 connected to 87a), the fuel pumps should run all the time. You did not mention or I missed it where you said the fuel pumps are running all the time. Do you hear the fuel pumps running when the dead cranking occurs?

Not sure what you mean by "bypassed to feed CDI". On my '86 930, relay 4 is energized by the alarm system or throttle sensor plate. When energized, relay 4 cuts off power to the fuel pump relay coils. A little circuit board on relay 4 delays its turn-on when the IG key is turned from OFF to ON. This turn-on delay is what drives the FPs for 0.5-1 second when the key is turned ON.

well said --my kinda point in more words;-)

Ivan

[ivanuf]

Originally Posted by spoke

So with relay 4 bypassed (assuming you mean pin 30 connected to 87a), the fuel pumps should run all the time. You did not mention or I missed it where you said the fuel pumps are running all the time. Do you hear the fuel pumps running when the dead cranking occurs?

Not sure what you mean by "bypassed to feed CDI". On my '86 930, relay 4 is energized by the alarm system or throttle sensor plate. When energized, relay 4 cuts off power to the fuel pump relay coils. A little circuit board on relay 4 delays its turn-on when the IG key is turned from OFF to ON. This turn-on delay is what drives the FPs for 0.5-1 second when the key is turned ON.

As I understand relay 4 is a shut-off relay, feeds the CDI after you turn off the ignition to burn excess fuel. Relay 3 is the fuel pressure fuel pump relay that turns the fuel pumps when you start the car.

Originally the car had both relays by-passed and fuel pumps started with ignition switch. I corrected relay 3 to work as it should. Relay 4 is by-passed.

[ivanuf]

Originally Posted by gomezoneill

It's funny how a 100 dollar reward will get all these responses. got to love it! I have to use that in the future.

This might be a new trend.

[ivanuf]

Originally Posted by fintstone

I have had these symptoms. One was the cold start injector needed an o-ring. The second was one of the wires in the connector to my CDI had backed out a bit and was a bit intermittent. The other time, it was a bad fuel pump.

A bad fuel accumulator or a bad pump will both cause this situation.

CSV both “o” rings new and tested with carb cleaner.
Engine wire harness to CDI is new
Both fuel pumps and check valves are new

When I mean new is that they were working but decided to replace them just to see if it will improve to no luck.

[ivanuf]

This has been great so far and thanks to all the interested parties. This has been going on for a couple of years, so I do not expect to solve it overnite. It is annoying but is starts every time so I just let it continue, troubleshoot and use the car. But the car is almost completely sorted out and I only have the difficult details left. From the suggestions I got so far I will:
1. Get the latest fuel pressure readings to post them.
2. Re-do smoke test.

In the mean while please keep asking and I will do my best to provide info on the questions, see attached new video of several stop-starts. You will see that once in a while if it misses that first start attemp, it will need several long cranks to start.

https://youtu.be/5VxvGFu1u-w

[proporsche]

1.what is your sensor plate position physically????
2.what is that white smoke??

[ivanuf]

On a separate note. With all this testing and trouble shooting. I had to hook the battery to the charger. It seems to have improved the start. It seems more consistent. Still not 100% but with battery fully charged engine cranks faster and I have less no-starts when I go to the garage for the random start tests during the day. I guess a new starter to battery cable at some point will not hurt.

[Jonny H]

Whose internals in the CDI box?

[proporsche]

plus check all your ground connections......

[LIRS6]

Just a question - isn’t the consistent starting/stopping as shown on the video a strain on your starter motor? I’d be concerned about it over-heating unnecessarily. Or am I just wrong/they are designed to take that?

Jason

[kach22i]

Originally Posted by proporsche

plus check all your ground connections......

Good idea, typically a classic.

[SchnellSchweitz]

I know you have said you checked your fuel pressure after the fuel filter. Share with us all what your pressure is only after it has been sitting for a while and after a single crank is applied. Keep in mind, when the motor is installed, ignition will route through a relay (key position 1). At key position 1, the fuel line to the motor is primed to the correct pressure. At key position 2, the relay turns the motor over only after the fuel line is primed. With the motor outside of the car, you may be missing this step. Just ideas...

Also... test injectors for leaks: https://www.youtube.com/watch?v=xDxyubTYQew

[HarryD]

I still think it may have to do with your CSV not working on start.

Have you confirmed it is operating as installed. Is there power to the switch when the car is cold? Is the power indeed plugged in?

[boyt911sc]

Originally Posted by SchnellSchweitz

I know you have said you checked your fuel pressure after the fuel filter. Share with us all what your pressure is only after it has been sitting for a while and after a single crank is applied. Keep in mind, when the motor is installed, ignition will route through a relay (key position 1). At key position 1, the fuel line to the motor is primed to the correct pressure. At key position 2, the relay turns the motor over only after the fuel line is primed. With the motor outside of the car, you may be missing this step. Just ideas...

Additional fuel pressure test:
Fuel volume 30 seconds .850 liter from return line from fuel rail.
Pressure Engine off Pump running 2.5 bar (36psi)
Engine running 2.0 bar (29psi)
Engine running vacuum hose removed from pressure regulator 2.3-2.7 bar (33-39psi)
Checking Residual pressure is done by connecting gage to fuel rail port and running pump for one minute. After 20 minutes pressure should be 1 bar (14.5psi)

If all tests above pass, test injectors for leaks: https://www.youtube.com/watch?v=xDxyubTYQew

Schnell,

The information you have posted applies to Carrera 3.2 Motronic system. Ivan has a CIS turbo 3.3 liter engine and a totally different system.

Tony

[SchnellSchweitz]

Fixed... Good catch Tony!