robrados rado . starting problem solved .

[robrado974 1]

Sorry mods for starting another thread , but even if I change the title it tends to get lost or over looked . Right , I have not as yet tested the bar pressure on the fuel rail , I believe it may be low and that's why it's spluttery on start up .my question is simply this , if you had low fuel pressure , would that not also affect the performance in general ? .So you could have problems starting but if you put your foot down when driving the low pressure would make no difference , or would it be hesitant because of this ? Many thanks again !!

Rob .

Edited September 6, 2013 by robrado974

[Jon_vr6 1]

I would have thought low pressure would mean that you would have crappy performance. Have you checked the fuel pressure regulator on the fuel rail?

[robrado974 1]

No as said Jon , I have not tested it yet . I thought the same , the fuel needs to be sent to the rail at a certain bar , I forget now , how much without looking at the manual .but yeah if it's not right then the car would be running rough?

Rob

[Jon_vr6 1]

What were your symptoms before you changed the fuel pump?

What have you had changed on the car electrical etc?

Had it vagcommed?

[robrado974 1]

It has not connected to vagcom yet Jon . I thought the return valve had gone on the pump , so I put another pump in . Need to find someone with a vagcom . All electrical plugs were cleaned around 1k back . The symptoms are as stated in my non start thread . Basically it will turn over around four times before it begins to start then dies , after another three turns of the key it will splutter and finally run . Sounds to me like not enough fuel ? . The fuel filter has only done 1k if that . I have also changed the relays . Also new are the plugs , dizzy , hall sender and crank sender .

Rob

[Jon_vr6 1]

Youve done the obvious stuff then mate, all you can do is go through each part that is used on start up, ignition switch, ht leads etc

[robrado974 1]

Will have a look at the spark again . The ignition switch is one of the new black ones . Further to testing with a vagcom I am at a compleat loss atm !! Thanks for your replies mate .

[Jon_vr6 1]

No worries we are all here as a team. If you wernt so far away id VAGCOM it for you mate, hopefully it throws up a fault.

 

Have you taken it out for a spin? Whats performance like? Also could it be a dodgy batch of petrol

[Jon_vr6 1]

Just thinking aswell do you have any air leaks from any of the intake parts on the engine worth a look

[robrado974 1]

Once i get her started ,the car runs fine , ticks over fine . I have checked the hoses and found a hole in the large pipe that goes from the throttle body to the maf . Ive sorted this ,as before i spotted it ,when i did get it started the revs were bouncing all over the shop and it would not settle and tick over properly . Now its better . Still have the situation of the car not idleing fast on start up though .Thanks for the vagcom offer mate .

Rob

[robrado974 1]

Well , today I took the fuel pipe off . I then turned on the ignition to prime the system and fuel came out . I then cranked the engine with the pipe of and it came out at a rapid rate . Im doing a pressure test on it tomorrow to see what that throws up . I had left the car for an hour and then went to start it and it fired first time , again in the morning , after standing all night it fired first time and when I got back from work tonight . All we did was remove the pipe from the rail crank it and put it back on . Air in the system maybe ? I don't know ,but it seems to have solved it .

Rob

[robrado974 1]

Then two hours later , I go to start it and its struggling again ! I need a vagcom check !! .

[seanl82 23]

Have you tried it with the isv unplugged Rob? See if it makes a difference between being plugged in then unplugged. I cleaned mine last week and its actually developed an intermittent problem like what your symptoms are. :bad-words:

[robrado974 1]

Hi Sean , just unplugged it and it made no difference . In taking the black cover off to get to it ,two ht leads came out with it ,so they were not put on tight enough . The car started first time , but still no higher warm up revs . The leads being loose were not helping matters but i dont think its the answer im looking for . Will try starting it tomorrow morning . Hope you get yours sorted , i will keep you up to date and swop notes as we may help each other out .

Rob

[seanl82 23]

The ISV is what I'm getting at buddy. If there is no difference between it being unplugged and plugged in, that suggests to me that could be the problem. I thought that I'd left a bit of masking tape over the inner part of the inlet when I painted it, as when I put it all back on it was giving the symptoms your getting. When I revved and it dropped down toward idle it would carry on down to about 500rpm before recovering as well. I cleaned the ISV at the same time too as painting the inlet but it didn't occur to me that this was a problem. I started to take it all back off to make sure there was no masking tape left on, and realised the plug for the isv wasn't pushed home properly. I put it back on and it was fine. I've since been out and started it up and its intermittent as to whether it splutters a bit or not. If I switch off then back on, it usually runs as it should.

[robrado974 1]

I will try it again tomorrow when I'm with the mechanic testing the fuel pressure . Unless I'm unlucky I'm sure it's not the isv as I have cleaned mine , then got one off a mate , cleaned that before refitting and it's still the same , but I could be wrong ! . I can't get it hooked up to the vagcom till next week , so I'm still in the dark with an electrical fault .

Rob

[robrado974 1]

Started the car this morning and the revs are jumping up and down again , I will get to the bottom of this ! .

[Hatton VR6 0]

Hi, Sounds like there is a problem with the residual fuel pressure. If it drops too low the pump has to build pressure back up so engine takes longer to start, once correct pressure is re-established engine runs fine. If stopped and restarted when warm you do not normally notice anything wrong, however if the engine cools down pressure has had time to drop so engine is difficult to start. Do you have the Bentley manual? If you do look at section 24-160 engine code PG or page 24-460 engine code AAA. If you do not have the manual I can email you a PDF of the relevant section. This advises how to check the pressure regulator and possible issues if the regulator is ok. Possible issues listed are line connections are tight, O rings or seals on fuel distributer leak, fuel injectors leak or fuel pump check valve leaks.

 

On my old 1.8 16V when the fuel accumulator failed, resulting in the residual fuel pressure dropping the car had to be cranked to start and initially would be lumpy at idle until fuel pressure had been restored. If restarted when warm I would not notice any issues if left for a while the starting issue returned.

 

Hope this helps.

[robrado974 1]

Thanks Hatton , and to Sean . I thought it was the return valve as I said in previous posts . I've got a vagcom check next week and will check the fuel pressure . I do have a Bentley manual and have looked at the section about the pressure testing . Still concerned about the revs jumping around and the cold start problems with it not reving higher for warm up , weather these are related to the fuel problem I don't know . Hope to solve it soon . Many thanks

Rob

Edit . Forgot to say I have another pump fitted now as I thought the return valve might be not working my old one .

Edited August 23, 2013 by robrado974

[robrado974 1]

Well, thanks to chris langers who came round tonight and plugged in the vagcom . No faults came up at all . I then started the car , it ran higher when warming up as it should do and then dropped to normal idle . I like to put answers to any problems i have on here for future refrence for other people using the search ,but i dont have an answer to what was wrong it just seems to have sorted itself out . Fingers crossed that i when i start it tomorrow it will still be running fine .

[robrado974 1]

Got home tonight and it's struggling to start again ! I really am at a loss now to why this is happening . I can't see how it's the fuel return valve if I had left it for a day and it started first turn of the key ? And it was ideling at 1000 rpm like it used to .I would have thought any fuel that was in the system would have not been present if the valve was not working and it would not start . Yet tonight as said its not starting . Chris Langers put it on the vagcom last night and no faults came up at all .Chris said to change the filter again and mabey the injectors. I have been out again tonight one turn of the key and its spluttering , two minutes later it fires !Any more ideas ??? Thanks

Rob

Edited August 28, 2013 by robrado974

[robrado974 1]

Just thought i would say what was wrong with the vr , as it helps when people are using the search . Firstly, although i had a vagcom check and that was clear , after another check at a local garage it came up with a fault . One of the sensors on the block was in the wrong position so the ecu was reading 70 degrees all the time ,hense no fast idol when starting from cold . Im not sure how this happend as the sensors were all replaced a year or so ago and the problem has only been around for a couple of months ,might be because its been so hot ??. The fuel problem was down to the fuel pressure regulator .

rob

[Jon_vr6 1]

Good stuff you got there in the end

[robrado974 1]

I did Jon , having exhausted all my efforts of taking things apart , checking for leaks etc ,it had to go to a garage in the end .