The V8 Owners Forum -

HELP PLEASE!!!!!
I have stupidly booked my 3.5EFI Capri in for its MOT on Thursday after being laid up for 12 months. I have now discovered it will not start when hot, starts great from cold, will idle and rev great but once stopped it does not want to start again.
Whilst i had it running, i checked the timing and it is approx 30 degrees out? There is not enough swing on the dizzy to get it anywhere near and even if it would the engine will stall. My RR manual shows that No1 plug should be at approx the 4 oclock position on the dizzy when viewed from the front of the car, whereas mine is more in between 12 and 1?
I guess, what i am asking is, have i put the dizzy in wrong when i converted from carb to EFI about 3 days before laying the car up, although i do not remember having issues before with the hot starting.
I have about 4 hours garage time left before the MOT so i am up against it a bit.
Any ideas from the cr**py description i have given

I'm assuming your system still has a rotor arm in the distributor.

As long as it does - DON'T PANIC - You just need to ensure that your rotor arm is pointing to Number 1 lead which can be connected to any one of the eight holes in the cap. Whilst you're doing this, check the leads to ensure the firing order is correct

Were you checking the timing at idle? If so, did you disconnect the vacuum advance from the dizzy? If you were using a timing (strobe) light, did you have it connected to No 1 lead?

Hi,
Yes it is still running a rotor arm which does line up to No1 cylinder and the firing order is correct.
I was checking the timing with a strobe at idle although i did not disconnect the vacuum advance from the dizzy although in my RR manual it states +-1degreeTDC and makes no reference to the vacuum advance (although for the later models it does say to remove the pipe)
Would having the advance pipe connected alter the timing by this much though? or is it possible the crank pulley or pointer have been installed wrong.
Also, what figures should i be timing to, as it is an SD1 carb engine fitted with RR 3.5 flapper EFI system and dizzy?

The only data I have is for SD1 but I can't see that there would be that much difference - in which case the vacuum advance should not make any difference below 600/800 rpm (depending on the unit). at full stretch, the vacuum advance will affect timing by less than 10%.

If it helps, the SD1 Vanden Plas EFI (1984 on) should be timed at 8 BTDC @ 600 rpm with vacuum disconnected (DM8 dizzy)

Seems to me that your engine would have a big problem running at all if the timing were 30 degrees out. you may be right that the pointer/pulley may have been put back incorrectly.

Given that your engine starts fine from cold and runs well, it may be that your hot start problem is due to, Eg, plugs simply due to the time it has been standing or some problem with the electronic side which i'm afraid is beyond my limited scope. I know there are people on her far more knowledgable about the flapper system than me

Goughie wrote:Hi,
Yes it is still running a rotor arm which does line up to No1 cylinder and the firing order is correct.
I was checking the timing with a strobe at idle although i did not disconnect the vacuum advance from the dizzy although in my RR manual it states +-1degreeTDC and makes no reference to the vacuum advance (although for the later models it does say to remove the pipe)
Would having the advance pipe connected alter the timing by this much though? or is it possible the crank pulley or pointer have been installed wrong.
Also, what figures should i be timing to, as it is an SD1 carb engine fitted with RR 3.5 flapper EFI system and dizzy?

You must disconnect and plug the vac advance, when checking the timing, as it'll easy give you an extra 20 degrees advance at idle.

However, as mentioned above, it sounds like thre is more to the problem than timing.

Thanks for the responses, i have had to postpone the MOT until next thursday
Last night, i checked the plugs and they were black, i cleaned and regapped and as normal she started fine, i let her get up to temperature and rechecked the timing with the advance plugged, it is 8 degrees BTDC so everything looks fine.
I stopped the engine, waited 30 secs and tried to restart and this time it would barely turn over almost as if the engine is fighting against the starter? I rechecked a plug and it was still clean, I tried swinging the dizzy either way but no good. The battery is new and fully charged, can heat affect the starter motor? or does any one have any suggestions.
Thanks again in advance,
Paul

It sounds like a bad earth problem to me

Check the cables
Battery to earth and earth to engine block

While you are at it make sure positive feeds are also well done / connected.

With a bad earth the current draw goes really high and hence not enough to get a fat spark and spin the motor.

I bet when she's hot she would start instantly with a push!

Ian

Goughie wrote:Thanks for the responses, i have had to postpone the MOT until next thursday
Last night, i checked the plugs and they were black, i cleaned and regapped and as normal she started fine, i let her get up to temperature and rechecked the timing with the advance plugged, it is 8 degrees BTDC so everything looks fine.
I stopped the engine, waited 30 secs and tried to restart and this time it would barely turn over almost as if the engine is fighting against the starter? I rechecked a plug and it was still clean, I tried swinging the dizzy either way but no good. The battery is new and fully charged, can heat affect the starter motor? or does any one have any suggestions.
Thanks again in advance,
Paul

Check your leads, especially earth to the block, chassis etc.
Check your battery, see if it is just about knackered.
And then check your starter, see if that is about knackered too.

You were both spot on, the earths were c**p and the starter just about knackered.
I had a local welding supplies company make me up two new leads for the starter and earth and swopped the starter for another untested one i had lying around, and it turns over quicker than my 4 cylinder engines! I left it running and grabbed a beer in celebration
After a few minutes, i turned her off to bask in the glory when she fired up again
You guessed it, zilch! Turns over great but will not fire, i have tried it at none/half/full throttle and with or without the 9th injector plugged in and also with a spare AFM i have.
Is there any sensors that could be knackered? I have a spare complete engine i could rob bits off to test.
I could really do with it fixed this weekend cus if i have to cancel another MOT the chap will think i am a right idiot! (although possibly correct )

Just nipped back down the shed and tried it again, it fired a couple of times but still would not run, i know if i tried it in the morning it will start and run no problems until warm/hot?

Goughie wrote: Is there any sensors that could be knackered?

Coolant Temp Sensor.

First check circuit connections and the earth at the rear of the block behind and below the LH rocker cover.

It should read approx 200 ohms @ 90C. If it reads high or is open cct then the ECU will supply a rich mixture when the engine is hot resulting in heavy carbon deposits and difficult/impossible starting when hot.

It can be tested with an ohm meter in a pan of water being brought to the boil, readings should be approx

TEMP----OHMS
-10°C----9100 to 9300
0°C------5700 to 5900
20°C-----2400 to 2600
40°C-----1100 to 1300
60°C-----500 to 700
80°C-----300 to 400
100°C----150 to 200

First off, when hot stick a spare plug in a lead and see if you ahve a spark, if so start looking elsewhere, if no spark then you have to start on your electrical system.

Thanks to you both, i swopped the temp sensor for another one i had and ran it up from cold and it does exactly the same. I then checked to see if it was sparking and it is. I have also tried a spare thermotime switch.
I have pan checked the original sensor and it is within the specified figures so i will replace that.
I have also checked the connections and have spliced in some better plugs from another loom, can these plugs be bought seperately as they seem to be very brittle.
I am getting really desperate now, any other ideas?

Just had another go, if you leave it for 5-10 mins and try again, it will fire up an run for 1-2 seconds then die and no matter how much you turn it over it will not go again until left for a bit.
The plugs are dry, slightly sooty now but probably from not being run at temperature.
Out of interest, the plugs, leads, rotar arm, dizzy cap, coil were all new just before i laid the car up.

Had another go, fitted new coil and managed to get it started then did not touch it, evenually it stalled when the electric fan cut in, rechecked with spare plug and still a spark, so decided it must be fuel related, i wound the AFM idle mixture screw in and it restarted, again it stalled but restarted immediately so i adjusted idle speed and everything seems to be okay.
I would say it is still not running properley but at least i will be able to work on it, although, knowing my luck, it probably wont start from cold now
Anyway, are the sensor plugs available seperately (see above post) and for all you Capri owners, what does your oil pressure gauge read when hot? mine is way down in the red and just about clears it when revved.
I will let you know what happens tomorrow as i am off to the pub now

plugs available here http://www.vehicle-wiring-products.eu/V ... usings.php