its been 3 months I'm working on it..(although the problem is older)

here is the info..

the car start nearly fine when cold and outside cold..

outside hot , engine cold still not bad but cranking gets longer

outside hot , engine hot, cranks 6,7,8 depending on the period I let the car alone..approx 30-60 minutes gives the longest cranking.. if I press the accelerator it starts immediately..(may be its carburetted and I dont know :-?)

if  I disconnect the ICV hose and disconnect MAF plug it starts immediately even its very hot and outside hot..

me and mechanics observed that when it starts black smoke comes from the exhaust.. so I think its flooding..

tried parts..

* new fuel pump (GM) (also another brand new tested) (installed)

* new crank sensor (GM) (also another new tested) installed

* new fuel relay-main relay (original) installed

* new fuel pressure regulator (original) installed (gm package) (also another tested)

* engine heads rebuilt, gaskets changed , valves changed..(lifters no they were good)

* new ECU programmed and tested, no change and given back..

* new Idle control valve tested , no change and given back

* SAI plugged , unplugged no change..

* Injectors cleaned (sound cleaning) tested at 6 bar no drops no leak..

* all earth points checked..

* battery new..

* sparks new (also sparks observed when starting)

* voltage at the fuel pump checked and measured..

* throtttles very shiny and closes tight..

* throttle potentiometer 4 years old but in good condition (I think)

as I need to wait for parts trials take time.. :(

* no EML

now whats interesting, it takes 6, 7 cranks to start when really hot and let for 40-50 minutes .. but after you start it  starts at the first crank..

also I added a check valve above the fuel pump (inside tank for fuel feed)


I read lots of tests and info on it.. but no way..

so my question is, can we take the injectors outside (connected) and put in a jar  and try to start the car and check they inject on time or not ?

and any idea , info appreciated :y

ps: before check valve the fuel pressure was dropping to 0 in nearly 40-50 minutes..

pps: CTS changed (original) added,  as Abiton reminded me :y

purge valve changed (for the canister) , as Abiton reminded me :y

It would be very useful to know whether the coolant temperature sensor is telling the truth to the ECU.

Abiton wrote on 23. Aug 2011 at 20:47:

It would be very useful to know whether the coolant temperature sensor is telling the truth to the ECU.

sorry my mistake , its already changed twice ..

but your analysis bang on :y :y :y :y

thanks for your help :y :y

its checked also via tech 2 ..

we didnt changed maf ..
as it will also create problems when starting on hot for second time but it didnt ..

and the mechanis start to tell me that these cars start late when hot :-? :( :'(

and no one could answer why it works at the first crank if I start second time :'( :'( :'( :'(

could it be a fractured solder under relay box :-/

Hmmm.

What about a sticking-open purge valve?  Never heard of it happening; but if that was letting fuel vapours go direct from tank/carbon cannister to inlet, uncontrolled, maybe that would fit with the symptoms?  :-/   

Abiton wrote on 23. Aug 2011 at 20:59:

Hmmm. What about a sticking-open purge valve?  Never heard of it happening; but if that was letting fuel vapours go direct from tank/carbon cannister to inlet, uncontrolled, maybe that would fit with the symptoms?  :-/

another bang on .. also changed :-[ :-[

I didint know the exact name of it :y :y :y :y :y

this valve was wide open, the new one is close if no electric applied.. now the fuel tank doesnt make whoosh sound when opened..

however starter was serviced one year ago and the problems increased, but mechanics and electricians say that it wont do that :-/

Did you try to swap coil pack with some known working one? Could be it, it has happened on my former bmw
325 :-/

It sounds like it might be flooding, to me. Weeping injectors would be a thought, but you've hopefully eliminated that.

Voltage dropping too low for reliable ECU operation during cranking? If you connect jump leads from another car, negative to the engine lifting bracket, positive to the battery terminal, does this help?

If you disconnect the MAF sensor before a "troublesome" start, does it make any difference? I doubt the MAF makes any odds until it's at least reached idle speed, but you never know.

Does intake air temperature look plausible on a Tech 2 before starting? Doesn't make a lot of odds in normal running but might affect cranking fuelling quite a bit more.

Throttle position sensor might be another suspect. If it's erroneously registering a slightly open throttle before you attempt to start, it might cause more fuel to be injected during cranking, causing a flood. Second attempt, the ECU would probably back off the fuelling anyway to avoid flooding, so maybe that's an explanation?

No reason why you can't fire the injectors into jam jars when cranking. Obviously bear in mind that this will get fuel vapour everywhere, so disconnect the coil pack and make sure there is no chance of it catching fire. Another trick is to make up a lead with an injector connector on one end and an LED with series resistor at the other. Remove the fuel pump relay and crank with this connected to each injector plug in turn when cranking. You will see a short flash each time the injector signal goes live. This will only prove that the injectors are being fired, of course, but might eliminate the possibility that the ECU doesn't see cranking the first time (no idea why it wouldn't, though).

Lots of "mights" and clutching at straws here, but you've covered all the obvious things.  :-/

danzigfan wrote on 24. Aug 2011 at 11:04:

Did you try to swap coil pack with some known working one? Could be it, it has happened on my former bmw 325 :-/

nope.. didnt tested.. but will give it a try .. thanks :y :y

Kevin Wood wrote on 24. Aug 2011 at 11:22:

It sounds like it might be flooding, to me. Weeping injectors would be a thought, but you've hopefully eliminated that. Voltage dropping too low for reliable ECU operation during cranking? If you connect jump leads from another car, negative to the engine lifting bracket, positive to the battery terminal, does this help? sounds like a good plan.. and easy to test.. #1 on the list :y If you disconnect the MAF sensor before a "troublesome" start, does it make any difference? I doubt the MAF makes any odds until it's at least reached idle speed, but you never know. didnt try.. also will be tested.. :y Does intake air temperature look plausible on a Tech 2 before starting? Doesn't make a lot of odds in normal running but might affect cranking fuelling quite a bit more. checked with tech 2.. showed around 55-60 celcius temp.. which seemed normal.. tried to change , but the replacement part needed a new style of socket :-/ Throttle position sensor might be another suspect. If it's erroneously registering a slightly open throttle before you attempt to start, it might cause more fuel to be injected during cranking, causing a flood. Second attempt, the ECU would probably back off the fuelling anyway to avoid flooding, so maybe that's an explanation? very logical.. opel service didnt have that part during tests , so couldnt try.. on the test list with high priority  :y :y No reason why you can't fire the injectors into jam jars when cranking. Obviously bear in mind that this will get fuel vapour everywhere, so disconnect the coil pack and make sure there is no chance of it catching fire. Another trick is to make up a lead with an injector connector on one end and an LED with series resistor at the other. Remove the fuel pump relay and crank with this connected to each injector plug in turn when cranking. You will see a short flash each time the injector signal goes live. This will only prove that the injectors are being fired, of course, but might eliminate the possibility that the ECU doesn't see cranking the first time (no idea why it wouldn't, though). yep.. and really important to see..so we will decide on the direction of tests :y :y Lots of "mights" and clutching at straws here, but you've covered all the obvious things.  :-/

thanks for your interest Kevin.. Your notes are all on the todo list :y :y :y

will report the results as soon as we finish them :y