How to test fuel pressure on MG ZT 1.8

bitsofbeards · 10th August 2016, 19:02

Hi everyone,

One morning I tried to start my car and found that it turns over but only splutters or doesn't fire at all. It will run fine when spraying easy start into the intake though. So I suspect a fuel problem, although I can hear the pump priming. There are no DTC codes.

I've searched high and low but can't actually find instructions on how to test the pressure on this engine. I can see there is a nipple type thing with a sleeve on the end of the fuel rail. But there is no schrader valve or anything as mentioned for other engines.

Does anyone know the kit I need or steps to take to test this?

Thanks for your help!

(I put the fabled orange clip on the filter a few months ago when the filter came apart. And I can't hear the gurgling that I got before so I'm certain it's not this exact problem)

murphyv310 · 10th August 2016, 19:07

Hi.
Could well be FFS (Fuel filter separation) and the fitment of the orange clip.

I'd recheck it again firstly.

T-Cut · 10th August 2016, 19:11

Quote:

Originally Posted by bitsofbeards

I can't hear the gurgling that I got before so I'm certain it's not this exact problem

Fuel Filter Syndrome doesn't usully cause a gurgling sound, so I wouldn't put too much faith in a lack of it.

If the filter cap seal has failed, the orange clip won't fix it.
Failure of the pump is rather rare. The rail pressure should be at least 50psi as I recall. Maybe the test nipple slackens to allow a reading? If there isn't a V6 type schrader valve, a tyre gauge won't work. You may need to rig up a dial gauge with pressure tubing. It's not something I've done on mine.

Found more info here: http://www.the75andztclub.co.uk/foru...l+gauge&page=2

TC

bitsofbeards · 11th August 2016, 19:00

Thanks for the suggestions.

I checked the fuel filter for separation and it is still together with the clip intact.

I also managed to rig up a compression tester to the fuel line after disconnecting the line from the fuel rail. A bit of hose from home base screwed on perfectly to the gauge and slid over fuel line end.

After priming the pump a few times and attempting to crank I realised that not only was there no pressure, there was no fuel flowing at all. (And to think the AA diagnosed this at the road side as 'over fuelling')

Checking the fuel pump I noticed that there was a grey pipe not connected to anything. Is this the return from the other half of the tank? Or should this be connected to something?

Other than that there was also 12v present at the pump connector when turning on the ignition.

I'm not sure what to do next, but I was planning to empty the fuel filter to see if it re-fills after letting the pump prime a few times. And also check the seals on the filter at the same time. Any ideas?

Thanks

T-Cut · 11th August 2016, 19:59

Quote:

Originally Posted by bitsofbeards

Checking the fuel pump I noticed that there was a grey pipe not connected to anything. Is this the return from the other half of the tank? Or should this be connected to something?

Deja vu: http://www.the75andztclub.co.uk/foru...18#post2342318

bitsofbeards · 12th August 2016, 06:34

Wow thanks! I'll re-attach tonight and let you know what happens.

I must have loosened it when I was doing the filter about 2 months ago and it finally came off on a bumpy road.

bitsofbeards · 12th August 2016, 11:44

I re-clipped the grey pipe into the top of the fuel pump cup. But I doubt that was the source of my starting problems. My tank is about 60%-70% full and the grey pipe only pours fuel from the other side of the tank into the pump cup. The cup was already fully submerged in fuel.

I undid my pressure tester and held the fuel line over a bucket when priming the pump. I got some fuel pouring out. But obviously at no pressure as none was reading on the gauge.

After a few more tries everything stopped working and it turned out that the battery was at 6v when connected.

I'm starting to wonder if it is actually a battery problem preventing the pump from running at a high enough pressure. Although I measured 12v the other day at the pump connector, this was not the under load value as the pump was disconnected.

I'm going to get a new battery as this one is way past its replacement date and the plates inside are completely warped. Lets hope that works...

bitsofbeards · 14th August 2016, 13:31

It's fixed!!

Turns out that the big o-ring that goes on the top cap of the fuel filter had been displaced. I had probably not seated it correctly when doing the orange clip previously. I reseated it and the car started after 10-20 seconds of cranking. It even seems like it has a bit more power now.

Symptoms were:

When putting the filter together previously it was extremely difficult to twist the top back on. I assumed this was normal but after putting the o-ring back on correctly it was much easier to do up the filter by hand.
Fuel level in the passenger side of the tank much higher than the drivers (pump) side.
Some fuel was being pumped into the fuel rail but no pressure could be read.
Engine difficult or impossible to start. When started ran very rough and would die if left to idle.
Loss of power when driving.

I think the grey pipe just came loose when I was removing and twisting the pump. But I think it may be worth checking for anyone installing the orange clip.

Thanks for your help T-Cut and Trevor!

10th August 2016, 19:02	#1
bitsofbeards Newbie MG ZT Join Date: Nov 2015 Location: Leamington Spa Posts: 9 Thanks: 0 Thanked 2 Times in 2 Posts	How to test fuel pressure on MG ZT 1.8 Hi everyone, One morning I tried to start my car and found that it turns over but only splutters or doesn't fire at all. It will run fine when spraying easy start into the intake though. So I suspect a fuel problem, although I can hear the pump priming. There are no DTC codes. I've searched high and low but can't actually find instructions on how to test the pressure on this engine. I can see there is a nipple type thing with a sleeve on the end of the fuel rail. But there is no schrader valve or anything as mentioned for other engines. Does anyone know the kit I need or steps to take to test this? Thanks for your help! (I put the fabled orange clip on the filter a few months ago when the filter came apart. And I can't hear the gurgling that I got before so I'm certain it's not this exact problem)

10th August 2016, 19:07	#2
murphyv310 This is my second home Hyundai i10 998cc Join Date: Mar 2012 Location: Kilmarnock Posts: 6,602 Thanks: 2,088 Thanked 2,298 Times in 1,349 Posts	Hi. Could well be FFS (Fuel filter separation) and the fitment of the orange clip. I'd recheck it again firstly. __________________ Cheers from Trevor MM0KJJ

14th August 2016, 13:31	#8
bitsofbeards Newbie MG ZT Join Date: Nov 2015 Location: Leamington Spa Posts: 9 Thanks: 0 Thanked 2 Times in 2 Posts	It's fixed!! Turns out that the big o-ring that goes on the top cap of the fuel filter had been displaced. I had probably not seated it correctly when doing the orange clip previously. I reseated it and the car started after 10-20 seconds of cranking. It even seems like it has a bit more power now. Symptoms were: When putting the filter together previously it was extremely difficult to twist the top back on. I assumed this was normal but after putting the o-ring back on correctly it was much easier to do up the filter by hand. Fuel level in the passenger side of the tank much higher than the drivers (pump) side. Some fuel was being pumped into the fuel rail but no pressure could be read. Engine difficult or impossible to start. When started ran very rough and would die if left to idle. Loss of power when driving. I think the grey pipe just came loose when I was removing and twisting the pump. But I think it may be worth checking for anyone installing the orange clip. Thanks for your help T-Cut and Trevor! Last edited by bitsofbeards; 14th August 2016 at 13:34..

11th August 2016, 19:00	#4
bitsofbeards Newbie MG ZT Join Date: Nov 2015 Location: Leamington Spa Posts: 9 Thanks: 0 Thanked 2 Times in 2 Posts	Thanks for the suggestions. I checked the fuel filter for separation and it is still together with the clip intact. I also managed to rig up a compression tester to the fuel line after disconnecting the line from the fuel rail. A bit of hose from home base screwed on perfectly to the gauge and slid over fuel line end. After priming the pump a few times and attempting to crank I realised that not only was there no pressure, there was no fuel flowing at all. (And to think the AA diagnosed this at the road side as 'over fuelling') Checking the fuel pump I noticed that there was a grey pipe not connected to anything. Is this the return from the other half of the tank? Or should this be connected to something? Other than that there was also 12v present at the pump connector when turning on the ignition. I'm not sure what to do next, but I was planning to empty the fuel filter to see if it re-fills after letting the pump prime a few times. And also check the seals on the filter at the same time. Any ideas? Thanks

12th August 2016, 06:34	#6
bitsofbeards Newbie MG ZT Join Date: Nov 2015 Location: Leamington Spa Posts: 9 Thanks: 0 Thanked 2 Times in 2 Posts	Wow thanks! I'll re-attach tonight and let you know what happens. I must have loosened it when I was doing the filter about 2 months ago and it finally came off on a bumpy road.

12th August 2016, 11:44	#7
bitsofbeards Newbie MG ZT Join Date: Nov 2015 Location: Leamington Spa Posts: 9 Thanks: 0 Thanked 2 Times in 2 Posts	I re-clipped the grey pipe into the top of the fuel pump cup. But I doubt that was the source of my starting problems. My tank is about 60%-70% full and the grey pipe only pours fuel from the other side of the tank into the pump cup. The cup was already fully submerged in fuel. I undid my pressure tester and held the fuel line over a bucket when priming the pump. I got some fuel pouring out. But obviously at no pressure as none was reading on the gauge. After a few more tries everything stopped working and it turned out that the battery was at 6v when connected. I'm starting to wonder if it is actually a battery problem preventing the pump from running at a high enough pressure. Although I measured 12v the other day at the pump connector, this was not the under load value as the pump was disconnected. I'm going to get a new battery as this one is way past its replacement date and the plates inside are completely warped. Lets hope that works...