MG ZT 190 Intermittent loss of pressure in fuel system

[Peter Holt]

Hi all.
I would really appreciate help on this one.
This started 7 days ago when my MG ZT190 lost power for a couple of seconds while climbing a hill after having been driven for about 180 kilometres over the week end I did not experience the fault again (short trips).
On Monday after driving for about 20 Kilometres it started to intermittently duck and dive the nose tried to drive itself into the road and then tried to take off like a plane then stopped completely subsequently I replaced the melted relay.
I then on Tuesday replaced the fuel filter, fuel pump, relay and the crank angle sensor the motor ran like a dream on a short test run.
Wednesday morning on the way to work it started again, I eventually made it to my garage where the mechanic attached a pressure gauge to the fuel rail and we took it for a drive, the pressure initially fluctuated between 2.8 and 3.2 bar then dropped to zero and recovered to 3 bar this continued with the car doing a very good impression of a bucking bronco.
The mechanic hooked the computer up to his analysis equipment and software and tells me that he sees no problems.
We then replaced the dump valve on the fuel rail and the pressure regulating valve on the fuel filter and changed the fuel pump again all to no avail.
I checked the impact cut out switch and it still seems to be ok.
Does any one have any ideas what the problem might be.

[T-Cut]

Originally Posted by Peter Holt

I then on Tuesday replaced the fuel filter - - -

It has the hallmarks of FFS. Did you fit an orange clip?

TC

[Astraeus]

Originally Posted by T-Cut

It has the hallmarks of FFS. Did you fit an orange clip?

TC

Yip, that would be your first port of call. It can be at fault even if it looks OK visually. Make sure the filter is back together firmly and that the seal is in place and not trapped or kinked. Then fit the orange clip to avoid a repeat and hopefully problem cured.
Many a non specialist garage has been fooled by this fault. It only needs to separate a fraction
Chris

[Peter Holt]

Thanks for the suggestion but have had that problem before and am very careful on assembly and insert a self tapping screw between the top and the body to stop the twist that sometimes happens.
I put a test rig with an volt meter in the line and am now waiting for the fault to happen again.
I did remove the excess fuel rail pressure hose connection to the return to the charcoal filter at the back on the throttle body and connected it to the electrical system after clearing some gunk out of it and blew it through both ways and have not had the problem, touch wood, since and have driven about 600km at varying speeds.
I have also rigged up a direct, from the battery, electrical supply to the fuel pump with a switch to test if the problem happens again.

[T-Cut]

Originally Posted by Peter Holt

- - - insert a self tapping screw between the top and the body to stop the twist that sometimes happens.

Hope it hasn't pierced the case.

TC

[T-Cut]

Originally Posted by Peter Holt

- - - insert a self tapping screw between the top and the body to stop the twist that sometimes happens.

Hope it hasn't pierced the case. You'd get pressure loss from that.

TC

[Peter Holt]

Thanks, small screw and I am very careful to guide it between the case and the top cover and not to drive it sideways.
The first seal that slipped was 3 days after the "Agent" had serviced the car, 100,000 km service the service manager then tried to deny that they had touched the filter but quickly backtracked when I pulled out the invoice and started muttering about fraud and putting in a complaint to his boss. That service was a complete failure on their part as the day after the service I checked the oil level and had to add 1.5 litres of oil, the wiper blades fell off within 10 days they had replaced them but not the plastic clips, which broke, they then told me that they had to remove the engine to replace the timing belts at some phenomenal cost.
Needless to say I bought the Haynes Workshop Manual and as I have always serviced my own vehicles started servicing the MG without their interference. These are the people who took 9 months to get a new computer for someone else's Rover. I can get one preprogrammed to my VIN number in 3 days from Rimmer Bros and it gets delivered to my door in South Africa.

[T-Cut]

Originally Posted by Peter Holt

The first seal that slipped was 3 days after the "Agent" had serviced the car, 100,000 km service the service manager then tried to deny that they had touched the filter but quickly backtracked when I pulled out the invoice and - - -

Hmm, if they've been into the fuel filter, I'd say it still has FFS in spite of your self-tapping screw. Probably the worst thing you can do is open up the fuel filter without a very good reason. They were probably just being inquisitive. That's the worst reason.

TC

[Peter Holt]

In Africa the fuel quality varies by supplier and garage so we contend with water in the storage tanks, they make good money on that one. Substandard supplier as a result of garages buying fuel from hi jacked tankers, no one knows where the fuel came from and on the Highveld a very dusty atmosphere with mine dust getting in everywhere including the breather nozzles on the garage tanks. I change the filter every 100,000km and the thing usually looks like the outside of an off road tyre I also scrape the crud out of the filter bowl at the same time.
The joys of living in the 3rd world but the sunshine for 9 months of the year is the upside.

[Sue4960]

What's FFS because I am having sort of the same problems with cutting out on my MGZT CDTI