Starting Problem

[dmabud]

I have a 1984 930 turbo with an intermitant starting problem

Always starts from cold ( with a slight puff of smoke that clears ) sems to run a little rich , but once its warm , there is a risk at if it does not fire first time - it will not start for until it is completely cool

turns on key , no attempt of the engine starting - leave for 24 hours and starts again

Know it is running rich - any ideas please

 

[vic cohen]

When u find out please let me know !
I have an '86 , low mileage, factory 330 bhp model ................starts hot 90 % on the button, but after 12 hrs when cold churns over for ever .....always starts in the end and blows out all the excess fuel when it does

Recently changed both fuel pumps,cold start , metering unit,.............

its totally unpredictable ........................the Indie i use says they re all like it and he has loads of experience with them ....................way back had a 3.0 for abt 10 years ....never occurred !

 

[p27549]

dmabud,

I have the opposite, takes a while to start from cold with smoke, starts okay when hot. My cold start AFR's were too rich. In your instance you may have a fuel accumalator issue. Its not holding pressure for the initial start until the fuel pump cuts in. On the back of the fuel head there is an electrical connector. When this is removed it switches the fuel pumps on. It maybe worth while getting the engine hot, leave it for an hour , disonnect the plug, let the pumps run and then try to start the engine, if it start straight away then a possible accumalator issue. The other thing is to listen to ensure your pumps are running. Mine is an 88 and have two pumps.

Let us know what you find

 

[p27549]

Vic,

My specialist checked my fuel pressures for cold start etc and identified as them per book values.
I have a LM1 AFR reader. When i started my car from cold start it registered 9.9 AFR and leaned to 10.5. Too rich for my liking.
i adjusted the cold start AFR to 11.6 AFR. When hot ensured the warm idle AFR was 13.4 , it now starts fine.
If your independent is only using the fuel pressures as a guide then you maybe running too rich at cold start as mine was.
I even changed my fuel injectors because of it. Wish i had checked the AFR's first as it would have saved me a load of money.

Tim

 

[bernard tester]

If it starts ok when cold and not hot the chances are it's the speed or reffrence sensor I always change both, they are on the bell housing on the lhs you can see them if you take the nsr wheel off but better to do on a lift, they plug in at the rear of the engine bay on the left you have to take the bracket off take care not to break it you may have to cut or drill the old ones out or one of them, take your time! and set the clearance when fitting the new ones . Berny.

 

[chas3.2]

Bernard

I think you will find a 930 Turbo dose not have Speed or reffrence sensors. Dont they have a spark box.

Charles

 

[bernard tester]

Your right Charles I think it's the same as the sc 6 pin spark box Berny.

 

[vic cohen]

Sorry have nt replied sooner..............have to get this in........ 2 days at Spa , best of all one was dry , not in the flattie though!

Thks for advice will go back and check what Steve at Jaz has set things at ...............just went out after 4days flattie sitting outside and it started on the button !

 

[p27549]

Vic,
Hope its somthing simple, mine would start well intermiittently, actuallybacame more of an issue as it got warmer, cold days not too bad.

Cheers

Tim