964 3.6 valve timing and injection timing

[daleint]

Wondered if anyone can help with a small problem I have with the valve and injection timing on this 92 964 I have?. I thought I had set the timing all good with no1 cylinder at TDC with the Z1 mark on the pulley all ligned up then when rotating the crank 360 degrees No 4 cylinder comes up to its TDC with Z1valves closed as if on compression stroke. I used the DTI (drop clock) to check the valve timing and did this several times to get the correct reading as specified by my local Porsche dealer. Placed the engine back in the car and fired the old girl up. Well not quite. The engine only runs on 1,2 and 3 cylinders. Checked the exhausts on that side and they were warm. on side 4,5,and 6 stone cold. I have a great spark at the plugs and good compression but the car does not run on that side. I pulled out the injectors to see if fuel is squirting and yes it is. It is as if I have the timing out somewhere could anyone help.
cheers
David

[daleint]

Well I had another couple of hours looking at the engine and used strobe light on Ignition also checked leads and all is ok. engine still not running on 4,5 and 6 cylinders. any help would be great as I will have another play with the engine Wednesday this week all going well. cheers

[DW SD]

Is the second (4,5,6) cam timing out by 180 degrees?

fuel and injection timing comes from the computer, which is timed from the crank position sensor.

You can try posting in the engine rebuilding section for my detailed responses.

Doug

[Fast951]

The DME sends the ignition signal to all cylinders on 1 wire. The signal goes to 2 ignition amplifiers, which in turn fire each of the coils. The coils signal is then distributed to the various cylinders by the distributors.

Start by checking the output from the ignition amplifiers and proceed to the next component.

[daleint]

Thanks for your reply Doug and I have placed in the Engine re building section as well for 911's
I am about to take the engine apart again and have a look at the timing of the CAM on cylinders 4,5 and 6 I will let you know what the outcome is. First I will check the amplifiers.
On another matter when I first purchased the car I had trouble with the engine trying to drop down gears and stalling and even cutting out. The car spent almost two months with a Porsche specialist in Christchurch and they said they did not find the fault. Near the back of the engine there is a sensor that picks up on the flywheel this has a few marks on it similar to those made with vice grips. could this sensor cause the problems?
David

[DW SD]

If you are getting spark at 4,5,6 it seems to me that you are already confirming amplifier, DME, distributor, wires, etc. Do you have a fuel injection test light, which would confirm signal to the injectors?

I cannot remember: are the injectors batch fired in groups of three?

Did the engine ever run properly? What prompted this troubleshooting? Maybe more history would help with the diagnosis.

I would venture to guess that the crank position sensor either works or does not, but wouldn't cause the symptoms you describe. Can you check the signal?

Christchurch is a beautiful spot! I spent a month in New Zealand at the millenium changeover - unforgettable!!

Doug

[daleint]

Doug
Yes NZ is wonderful and getting better with age. Right last night I removed the rocker cover from the inlets on 4,5 and 6 set the engine to TDC on No1 and Distributer in the correct place as if it were to fire on No1 all looked good. moved the crank 120 degrees and No6 looked good then 120 degrees and No 2 looked good then another 120 degrees and No 4 piston was on compression stroke and Distributor was in correct firing position. so unless I have missed the plot the CAM timing looks good. I do not have a tester for the fuel injection at this stage. I have noticed the battery is a bit suspect so will get a new one today and re try tomorrow. Cheers David