Golf GTI Cabriolet 1988 1.8

Hello
i have a Golf GTI cabriolet 1987 1.8
it starts from cold perfectly, after half hour or so drive,leave it for 10 mins and it takes ages to start??
once it does start it runs fine
please help
thanks
Simon 

Check your in-tank fuel lift pump

Check the fuel accumulator, there's a little screw on the back of it and if fuel comes out when the screw is removed it's shot.

Thank you for your help

how do check the lift pump? I can hear it prime for a few seconds when the ignition is turned on

where abouts is the accumulator? Has anyone got a picture?

i don’t understand why it runs and starts perfectly from cold but when stopped for 5 mins it turns over for ages before starting??

 Thanks again

Simon

If you have the cold start injector, it is adding fuel to the air plenum enriching the air with fuel prior to you injecting fuel in to the head.  So you get a double shot of fuel in to the engine at start, as the WUR gets hot, then when the engine is warm the Cold start injector isn't being used.

On a side note, when starting the car any time turn the key-switch to the first position and wait 4-5 seconds for the fuel system to prime and build up pressures.  This is to aid Hot Starting the car as well as to insure that the system is up to pressure prior to start.

I think of it as similar to a Computer's power supply, sometimes when you turn on a puter with a iffy power supply you are telling the things to start prior to the power supply getting up to speed and it power faults the mother board having sufficient power to operate.  Then if you hit the reset with the power supply already up, it boots.  

This is the same thing as turning your keyswitch from insert directly to start. You aren't allowing the system to get ready to deliver fuel at pressure and quantity, so you have a pressure drop and fuel can't get injected at teh right pressure to Pop the injector and get atomization of the fuel it just may dribble out a wee bit.

Knowing the Fuel pressure after you have run the engine
tells you more than anything.  If your pressure is falling off (residual) then you have an issue.  If you turn the car off, and on restart you don't have 75psi on CIS and 45 or so on Digi, then you have a fuel delivery issue that is a bad pump on Digi, and a plethora of things on a CIS.
The WUR, and accumulator come to mind as well as the pumps.

On 85 and later Cabriolets they have an internal or in-tank boost pump as well as an external fuel pump (primary).  The in-tank pump is rated at 45psi and 33 gallons per hour IIRC.  Where as the CIS main is getting fuel at 45 psi, and boosting it to 75, the DIgi primary pump is getting 45 psi in, and 45 psi out.

my thoughts on these critters….. CIS (Cause it's Satanic).. Where I can understand Digi easier as I have more of a Electrical understanding… and well it can be easier to deal with.

If you are running down the road after getting your car started, and you hear a whine from the Right hand side rear wheel arch or area,,, Can be over heard with the top down and radio volume lowered, or top up and radio down… then you have a main pump that is having delivery issues and it is whining about having to do all the work (digi, as well as CIS).  The noise is that is is having issues with the fuel getting to it from the tank.

Usually on a digi it is the in-tank pump, same on the CIS but you have to also consider the accumulator.

Fuel in the later CIS and Digi is critical to keep the in-tank working.  The Fuel is used as a Heat reducer and keeps it cool as well as a lubricant for the internals of the pump.  operating a car on less than 1/4 of a tank for long periods of time will take out a an in-tank pump quickly.

The in-tank pumps also if still original have issues with the rubber pump to sender rotting out, and fuel pumps falling in to the tank and or holes in it that allows fuel to by-pass and being halfarsed delivered to the accumulator, and shot back into the tank.

A whining main pump usually i have seen over heat, and stop working for about 10 to 20 minutes, then restart and all is good for another 10-20 minutes or so… now you are looking at buying 2 pumps instead of 1.

Update……
i have removed the screw from the accumulator and unfortunately fuel came out arrrrrrrrgggggghhhhhh

where is the best place to get a new one?

 

They are expensive for what they are but a quick search found one here.
They are fitted to lots of 80s/90s cars with fuel injection so maybe have a search around as 1st couple I found.

https://www.classic-vw.co.uk/k-jet-fuel-pump-accumulator-431133441c-8v-16v-mk1-mk2-golf-corrado-scirocco-17137-p.asp

Or same part number
https://www.ebay.co.uk/itm/New-Genuine-BOSCH-Fuel-Supply-Pressure-Accumulator-0-438-170-040-/144030057181?var=0&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338268676&toolid=10044&customid=EAIaIQobChMImMrfxrf38AIV2MLVCh3aJgKLEAQYBCABEgJ5cfD_BwE


Getting the fuel line undone from the accumulator may be your next problem as it lives underneath the car in all weathers so start socking it in Plusgas or similar penetration fluid.  

Thank you all for your help

i”ll get one ordered and fitted and let you know 👌🏻

Fingers crossed it does solve your problem.

Let us know how it all goes and shout if you need advice/help.

So the new accumulator has arrived from amazon Bosch 0 438 170 040
the new one is 140mm long, the existing one is 100mm long - is this right/compatible?
the unions are the same size

also the union on the pipe from the pump to the accumulator is solid even after being squirted with wd40 for a few days so I have removed the pump together with pipe and accumulator so I can have a go at it on the bench but it’s solid! Any idea?

It should not make any difference being a little bit longer.

WD40 is rubbish for freeing up rusty nuts, use Plusgas.

https://www.eurocarparts.com/p/plus-gas-releasing-fluid-aero-400ml-549774741

Keep soaking the fixings, I did mention above getting the lines undone will be the big problem…

Thanks Mark, i’ll Get some tomorrow

if it won’t budge I will need to replace the pipe but I can’t seem to find one anywhere - it’s only about 6 inches long - any idea where I coul get one from?

 Thanks 

Have a look here for the part number as I'm not sure which one you need.

https://volkswagen.7zap.com/en/rdw/golf+cabriolet/goc/1988-44/2/201-69000/

I think I’ve found it ….
https://www.classic-vw.co.uk/mk1-golf-cabrio--scirocco-fuel-pipe-pump-to-accumulator-533201220-14343-p.asp
 

So new accumulator fitted
starts fine from cold and drives perfect

leave it stood for 10 mins after being driven to operating temperature and it takes ages to start - it does start after 45ish seconds

what can i Check next?

 Thanks 

Did you check the in - tank lift pump?


Sent from my iPhone using Tapatalk

How do I check the in tank pump?

Mk1cabsportline said

How do I check the in tank pump?

Lift the back seat should be able to hear it when cranking the engine if no noise use a volt meter  to check the voltage when cranking

Sent from my SM-G955F using Tapatalk

I have removed the in tank fuel pump and tested it on the bench, it spins up.

i dunked it in some water and powered it up and it pumped, I took it out of the water killed the power to it an re-submersed it and it didn't pump so I have ordered a new one.

I”ll let you know 

Hello again,

this morning I replaced the in tank fuel pump - it now starts perfectly from hot and cold - thank you for your help

now I have a new problem……3 of us went out earlier in the car and could hear what I thought was the rear wheels/tyres catching on the arches but it’s not that
it sounds like it’s coming from inside the fuel tank?? Any ideas?
 Thanks
Simon