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cityrover
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Discussion Starter #1
Hi I'm desperate to get my Son's normally reliable ZT-T 190 to starts we've been trying a number of checks over the last couple of weeks but no success:-

Changed the in-tank petrol filter
Proved fuel pump delivers by direct 12 volts to middle two pins on socket
Replaced the fuse box in the engine compartment
Checked all fuses relays & fuseable links with multi meter or by swopping around

Symptoms, it will crank over but:-
Getting spark at plugs
Hazard lights come on
Driver & front passenger windows are constantly stuck approx 2" open
Engine fault light comes on.
No power at input side of pump relay in passenger foot well so pump doesn't energise

Has anybody had a similar experience & how did they solve it ?
Any suggestion will be VERY WELCOME !!
Thanks
 

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Any water ingress anywhere in the car?
What about the battery? A good recent one?
Did you check all the earth under the bonnet?
The electrics looking erratic I smell an ECU problem... But I may be wrong.
 

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cityrover
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Discussion Starter #3
Hi, Thanks for your thoughts, since my initial post we have by-passed the inertia fuel cut out switch, that made no difference. Then sent a live feed to the petrol pump fuse in the passenger foot well (which had been dead along with the whole right bank). This has woken up the windows & entertainment system but still no pump. We are now looking at the wiring upstream of this fuse box & yes we have a spare ECU system to try.
I will keep you posted on what we discover tomorrow evening.
Regards,
Paul
 

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cityrover
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Discussion Starter #4
We made some progress yesterday we found that a chunky power cable (brown and black) that feeds the fuel pump relay & powers the windows had worn away so it had completed broken from resting on the passenger plastic wing liner.. We repaired this along with a couple of others that had been partially damaged. Once this repair was completed the car did start for 20 seconds. Initially it ran well but then it started to misfire.

We then put the wheel arch liner back in and dropped the car back to the ground. However now it won't start again and we're still not getting fuel to the engine bay. However we are now getting 12v to the right side of the passenger foot well fuse board. We're getting 12v to one of the control terminals but not 12v to either of the load pins. We've also checked the relay's functionality with the battery and this seems to be operating correctly. From looking at circuit diagrams it appears that the fuel pump is fully controlled by The ECU so not so easy to diagnose. We've cancelled the error messages using TOAF (to do with the variable inlet mechanism) and the engine management light is still alight.
We can't try a change of the ECU system at the moment as we need some special 5 point torx tool to undo the immobiliser box in the driver's foot well (RHS)
Any thoughts or suggestions ?
Thanks,
Paul
 

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MG ZT, Rover 25
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You said you’ve already checked the fuel filter is clear and screwed up tightly (best with a clip fitted). Sounds silly, but don’t trust the fuel gauge. I experienced similar with over 1/2 tank of petrol indicated on the gauge, when in reality the tank was empty. Looks like your issue could be electrical, keep checking the earths and wiring...
 

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I quite agree with @gnu. Electrical...
Methinks some other wires may be knackered as well or some bad earth. Keep searching.
 

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cityrover
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Discussion Starter #7
You said you’ve already checked the fuel filter is clear and screwed up tightly (best with a clip fitted). Sounds silly, but don’t trust the fuel gauge. I experienced similar with over 1/2 tank of petrol indicated on the gauge, when in reality the tank was empty. Looks like your issue could be electrical, keep checking the earths and wiring...
Yes we've had the fuel pumps & filter out of the tank which has plenty of petrol, we put in a new filter & it does have the clip on the filter housing to hold it together. Having seen the "flimsy" float arrangement for the fuel level I can imagine the accuracy can be variable !
 

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cityrover
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Discussion Starter #8
More work undertaken today, we found that the inertia switch wasn't conducting reliably so this was bi-passed and provided a reliable 12 volts to the pump relay and the pump is now working when the ignition is turned on so we have fuel as well as sparks. Unfortunately we still have an engine that won’t start an engine warning light on The Dash, TOAF seems to report there are problems with coil packs 1, 4, 5 & 6 yet they are sparking. & there is a fuel pump relay malfunction yet the pump is now running

Further work undertaken today was remove all the sparking plugs they are pretty black, indicating running rich & have a gap of approx 1.3 mm. Wire brushed & gapped to 0.8 mm we spun the engine without plugs to expel any excess fuel. Re assemble still no go.

Checked the Crank Position Sensor with a Fluke Multi-meter got following readings to earth from back of plug:-

Yellow / Green 12.5 volts;

White / Blue 5 volts (dc) static to 2.2 volts (dc) & 175 Hz cranked .

Black 0.002 volts

And same tests on The Cam Position Sensor

Yellow / Green 12.75 volts;(static) dropping to 10.8 Volts cranking.

Blue 0.032 volts (dc) static 1.3 Hz cranked .

Black 0.0024 volts

I guess at it is reading Hz these are working correctly

Now getting seriously confused, how can one broken wire cause so many problems throughout the engine?

Could there be further wiring / earthing problems but if so why have these all become apparent at the same time ?

Is it possible that the fuel injectors are not working, how would we test tham ?

Any ideas please as our only other options now are fitting a 2nd hand ECU (including immobilser) when the special 5 point torx tool arrives.
136231
2021 02 07 TOAF Screenshot 70221.JPG
 

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Ouch! What a job!
You may try now to swap your ECU.
I quite agree: IMHO too many problems, it shouldn't be one only wire malfunction, even your cable is in very poor & miserable condition. That shouldn't do either.
 

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MG ZT, Rover 25
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Has the car been stood for a while? I once had a no start problem on a R214. It had a spark, air (checked the air filter?) and fuel. Turned out to be collapsed baffles in the exhaust blocking it. The back box rattled when shook. Disconnected the back box and the car started fine.
 

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cityrover
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Discussion Starter #11
Update on my last thread, the car had been run regularly until early January when it stopped due to the petrol not passing, this was corrected when the failed feed wire was found. We have now tried the 3 piece substition of the ECU / immobiliser & spun the engine with exhaust disconnected, in case there was a blockage, with no success. We have also had A T4 diagnosis which concluded that the ECU isn't getting a signal from the crank position sensor. So now we are in the process of replacing the position sensor which has fallen apart leaving the sensor body stuck in the bell housing. Heat will not melt the old brittle plastic that has seen 120k miles 17 years of service. The next plan is to remove the radiator to give access to drill the remainder of the crank position sensor, unless anybody here has a better method of removing the failed sensor ?
Thanks, Paul
 

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We made some progress yesterday we found that a chunky power cable (brown and black) that feeds the fuel pump relay & powers the windows had worn away so it had completed broken from resting on the passenger plastic wing liner.. We repaired this along with a couple of others that had been partially damaged. Once this repair was completed the car did start for 20 seconds. Initially it ran well but then it started to misfire.

We then put the wheel arch liner back in and dropped the car back to the ground. However now it won't start again and we're still not getting fuel to the engine bay. However we are now getting 12v to the right side of the passenger foot well fuse board. We're getting 12v to one of the control terminals but not 12v to either of the load pins. We've also checked the relay's functionality with the battery and this seems to be operating correctly. From looking at circuit diagrams it appears that the fuel pump is fully controlled by The ECU so not so easy to diagnose. We've cancelled the error messages using TOAF (to do with the variable inlet mechanism) and the engine management light is still alight.
We can't try a change of the ECU system at the moment as we need some special 5 point torx tool to undo the immobiliser box in the driver's foot well (RHS)
Any thoughts or suggestions ?
Thanks,
Paul
It's still likely to be the wiring at fault here ;)

What fault codes are you pulling from the car?, and if you need to remove the EWS the size you need is a TS30 pentalobe.

Brian
 

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cityrover
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Discussion Starter #13
It's still likely to be the wiring at fault here ;)

What fault codes are you pulling from the car?, and if you need to remove the EWS the size you need is a TS30 pentalobe.

Brian
Thanks for your help in trying to sort out the troublesome ZT-T V6 190.
Since the last post we have achieved an engine start & run but not satisfactory.

To re-cap we've done the following:-
New Engine Fusebox but we replaced the original as it didn't make a difference.
Repair power lead to fuel pump, the cause of original failure.
Taken faulty inertia switch out of circuit
Fuel Pump & Filter inspected pressure tested at injector rail as 53 psi
Tried running with replacement ECU & Immobiliser set, no change so went back to the originals
T4 diagnosis (This was not able to read the engine speed, so a new crank sensor was recommended)
New Crank Sensor
New TMAP
New Coolant Temp sensor
Tested Cam sensor by substitution from 1.8 K-Series
New Thermostat housing & pipes in the engine’s Vee (not the cause of the fault, but it was leaking and needed replacement & at that point we were still optimistic !!!)

Now the engine will start, but when cold it needs Easy Start squirted into the throttle butterfly. Having driven it approx 15 miles The Engine Fault Light flashes continuously & the car is giving perhaps 40 hp so behaving as in some form of limp mode.
There seems to be very little vacuum in the inlet manifold could the VIS / Plenum arrangement be at fault or could a cam belt have jumped & tooth or more ?

Any suggestions on what to do next please ?
(Don’t want it to go spares or repairs after spending all this time & effort on a reasonable looking car).
Thanks Paul
P.happy.T is online now
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cityrover
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Discussion Starter #14

Thanks for your help in trying to sort out the troublesome ZT-T V6 190.
Since the last post we have achieved an engine start & run but not satisfactory.

To re-cap we've done the following:-
New Engine Fusebox but we replaced the original as it didn't make a difference.
Repair power lead to fuel pump, the cause of original failure.
Taken faulty inertia switch out of circuit
Fuel Pump & Filter inspected pressure tested at injector rail as 53 psi
Tried running with replacement ECU & Immobiliser set, no change so went back to the originals
T4 diagnosis (This was not able to read the engine speed, so a new crank sensor was recommended)
New Crank Sensor
New TMAP
New Coolant Temp sensor
Tested Cam sensor by substitution from 1.8 K-Series
New Thermostat housing & pipes in the engine’s Vee (not the cause of the fault, but it was leaking and needed replacement & at that point we were still optimistic !!!)

Now the engine will start, but when cold it needs Easy Start squirted into the throttle butterfly. Having driven it approx 15 miles The Engine Fault Light flashes continuously & the car is giving perhaps 40 hp so behaving as in some form of limp mode.
There seems to be very little vacuum in the inlet manifold could the VIS / Plenum arrangement be at fault or could a cam belt have jumped & tooth or more ?

Any suggestions on what to do next please ?
(Don’t want it to go spares or repairs after spending all this time & effort on a reasonable looking car).
Thanks Paul
P.happy.T is online now
Report Post
Success, The ZT-T 190 runs again !
Thanks to everyone that offered patient advice over the last 3 months.
The final issue was that we found that the plug that feeds the 3 rear injectors had become detached when we changed the coolant pipes so what I thought was limp mode may have been 3 firing cylinders & a 3 cylinder compressor !
For me the lesson learnt is if you're trying to bring a stricken engine back to life give it a sniff of Easy Start before you start swapping out The ECU; Crank Sensors; TMAPS etc, you might save a lot of time & money !
Also TOAF has been a good thing for pointing us in the correct direction for diagnosis & for electrical faults you need more than a Haynes Manual.
Happy Days !
Paul
 

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Happy end! Congrats for your perseverance & open mind. (y)
 
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