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Author: Subject: Zetec Blacktop dies under load
tims31

posted on 21/7/17 at 03:25 PM Reply With Quote
Zetec Blacktop dies under load

After finally getting my registration paperwork through I was hoping to get the car on the road, unfortunately though as soon as I apply any load/ accelerate the engine dies from fuel starvation and it appears that the fuel pump has stopped running.

Initially I thought it was the fuel lines to the pump restricting flow and the pump dying due to over heating but the pump is very cool to the touch.

If it is the first start it will run about 500 yds before dying after that it won't go more than 50yds if I accelerate. if I just let it gently run along on low power it is fine and will sit and run with no load just fine.

After it has died there is no power to the pump but if I leave for 5mins then it will restart again just fine with no problem until I put it under load again. The LED from the ECU comes on and stays on for 5 secs before going off as I think it should do for the standard Ford ECU so that is not indicating a fault.

What would cause the fuel pump to stop when under load and then restart and run fine 5 mins later until under load???

The fuel tank vent is fine as I have removed the vent valve and the hose from the top of the tank is open.


Any ideas please would be most welcome as this is now doing my head in......

This is the layout of my fuel system

Could the HP filter be causing too much restriction to the fuel rail?

I have the vacuum tube from the bottom of the regulator attached to the GBS Plenum chamber, could this also be a problem?
Sorry for all the questions

[Edited on 21/7/17 by tims31]





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avagolen

posted on 21/7/17 at 04:03 PM Reply With Quote
Hi Martin,

Sounds like a pain. :-(

I know nothing about the ECU etc, but how about bypassing the ECU control for the fuel pump and running a separate (fused)
wire from the ignition switch just to see if it reveals any other symptoms.

You could run a lamp from the ECU Fuel pump wire to see if it switches it on/off while driving.

Could be a bad connection in the pump output from the ECU that shows up when the pump is on full chat.

Len.





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jeffw

posted on 21/7/17 at 04:50 PM Reply With Quote
What fuel pressure are you running ? Are you running an adjustable Fuel Pressure Regulator or a fixed FPR?






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Bigheppy

posted on 21/7/17 at 04:59 PM Reply With Quote
Might sound too simple but does your tank have a vent.
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obfripper

posted on 21/7/17 at 05:52 PM Reply With Quote
Isn't the led you're refering to for the pats immobiliser? If so it will only indicate a fault with the pats system, not with any other aspects of the engine management.

Have you got the obd socket wired up for diagnostic equipment?

I would bridge the 30 and 87 pins in the fuel pump relay base and road test, if it runs correctly you either have a fault with the relay, the wiring, or there is another issue that may be revealed with diagnostic equipment.

On another thought, the fuel pump relay trigger wire hasn't been mixed up with something else? Eg if it was transposed with the lambda sensor heater output the car would run until warm and then cut out as the heater circuit was shut off.

Dave

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big_wasa

posted on 21/7/17 at 06:31 PM Reply With Quote
The above is a good shout.

I would wire the pump direct to the battery with a good gauge of wire and a 20a fuse and go from there.

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tims31

posted on 21/7/17 at 06:38 PM Reply With Quote
The tank vent is clear and theer is no suction from the tank when I take the fuel cap off.

The engine did run fine for a while when I took it for a shake down run but now it dies every time under load.

I have plugged in my OBD reader and the faults it is showing are

P0443 - Evaporative Emmision control system purge control valve circuit - Which I think from what Wasa told me you would expect although I did wire in the resistor that you gave me wasa

P1504 - Which for a Ford states Intake Air Control Circuit Malfunction - But I have no idea what that means.

I just have the fixed pressure regulator attached to the rail but don't know what pressure that is giving...

Do the faults sound realistic, not sure if they were there before tgough so can't say if it was there or not before?

[Edited on 21/7/17 by tims31]





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tims31

posted on 21/7/17 at 06:42 PM Reply With Quote
quote:


P1504 - Which for a Ford states Intake Air Control Circuit Malfunction - But I have no idea what that means.



Just looked this up and I guess that is from the Idle control valve which isn't connected so would throw up a fault so I guess its not that.





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obfripper

posted on 21/7/17 at 07:17 PM Reply With Quote
Neither code indicates a fault which should affect the fuel pump operation (or engine operation). The p1504 is the idle control valve circuit not operating as expected, usually when there is an air leak on the manifold (so measured airflow does not correlate with calculated airflow) , but could be triggered by the different airflow characteristics of the plenum you are using.

How does the pump operate when you put the ignition on?
Is it a 2 secs on then off until you crank to start, on while cranking, and on while running.

If there was a wiring issue on the control side of the relay i would expect p1237 to be stored on the ecu, a fault on the output side of the relay would not log a code as the output is not monitored by the ecu.

It does seem like a dodgy fuel pump from your symptoms until the intermittent power to the pump is considered.
The ecu output is not directly driving the pump? That would cause problems like you have, but tbh i would expect problems within seconds not minutes and other problems to occur.

Dave

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jeffw

posted on 21/7/17 at 07:53 PM Reply With Quote
Clean out your fuel filters....






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tims31

posted on 21/7/17 at 08:01 PM Reply With Quote
quote:
Originally posted by obfripper
Neither code indicates a fault which should affect the fuel pump operation (or engine operation). The p1504 is the idle control valve circuit not operating as expected, usually when there is an air leak on the manifold (so measured airflow does not correlate with calculated airflow) , but could be triggered by the different airflow characteristics of the plenum you are using.

How does the pump operate when you put the ignition on?
Is it a 2 secs on then off until you crank to start, on while cranking, and on while running.

If there was a wiring issue on the control side of the relay i would expect p1237 to be stored on the ecu, a fault on the output side of the relay would not log a code as the output is not monitored by the ecu.

It does seem like a dodgy fuel pump from your symptoms until the intermittent power to the pump is considered.
The ecu output is not directly driving the pump? That would cause problems like you have, but tbh i would expect problems within seconds not minutes and other problems to occur.

Dave


I have changed the pump and the LP filter already and the problem persists.

Yes the pump runs for 2secs when ignition switched on and then stops priming the line. Then runs when cranked and when engine running. It seems that when under load the pump stops and then the engine dies. Straight after there is no power on the terminals of the pump but if left for 5mins with the ignition off it will then start and run again like before.

The two fault codes I think must always be there and so can probably be ignored.

Does the ECU not monitor the running of the fuel pump? I thought there was a feedback to the ECU on one of the wires, i'll have a look at my diagram.

EDIT:- Just looked at my wiring diagram and the Pin 40 from the ecu goes to Pin 87 on the fuel relay so that must be what I thought was the monitor

If there was not enough fuel getting to the injectors would the ECU know this and stop the pump from running.

I may take out the HP fuel filter from the system and try that as another possible.

Does anyone know if the vacuum pipe on the bottom of the regulator should just be left open to atmosphere and blank of the back of the plenum? Does seem strange how it was okay but now isn't.

[Edited on 21/7/17 by tims31]

[Edited on 21/7/17 by tims31]





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chris

posted on 21/7/17 at 09:07 PM Reply With Quote
pipe on bottom of regulator just leave it open
when i first fitted my zetec fitted it all ran fine in the cooler months of the year then when the summer came i started having similar props turned out it was fuel evaporating in the fuel line cos it was getting to hot so the fix was to re route fuel lines away from any heat sources and that cured it

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obfripper

posted on 21/7/17 at 09:35 PM Reply With Quote
I forgot about the monitor line from the fuel pump feed, iirc it will trigger pats related codes if the relay is bypassed and cranked with no transponder present, and p1237 with fuel pump relay present but no output working.
p0232 (not p1237) will be the relay control circuit, but you have no sign of either code, so everything is fine at the ecu control level as far as the ecu's fault detection goes.

Is the pump power actually cutting before the engine dies? It will stop automatically after 2 seconds following a stall (which is likely how the ecu will interpret what is occuring) and should restart straight away once cranking commences again(without cycling the ignition).

The ecu should not cut the fuel pump under normal operation with the engine running, i don't think there is any means for this to happen on either the mondeo or focus ecu. It is a common practice on newer canbus based vehicles where the airbag control unit can request an engine shutdown in the event of a crash instead of using an inertia switch in the fuel pump wiring.

A test drive with the pump relay bypassed will show up if the pump is operating correctly, if there is not enough fuel like this it points to the fuel system or possibly afm as below.

The reading dropping off from a faulty afm could cause the engine to stall out for no apparent reason, an air leak between engine and afm can also cause this.
Has your obd tool got live data?
At idle it should be 2.5-3 g/s (if the units used match) or 0.8v ish on the live data/afm output pin, quickly blipping the engine should jump up to 30-40g/s or 3-4v.(ballpark figures for guidance, i'll post up the corect ones when i've got autodata to hand)

Disconnecting the airflow meter should put the engine into limp mode but improve the running if the afm is faulty (or an air leak is present), the reference voltages and earth want checking as well if an afm fault is indicated.

The vacuum pipe should go from the plenum to the regulator for correct operation, it being disconnected will cause a fuel trim fault code after a running cycle or 2 but will not majorly affect the engine running.

Dave

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Phil_1471

posted on 22/7/17 at 06:40 AM Reply With Quote
Agree with Len and a few others hook up the fuel pump on a separate supply and see what's going on with the supply that's coming from the ecu.
Phil





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tims31

posted on 22/7/17 at 07:46 AM Reply With Quote
Thanks guys, I will get round to trying this all on Monday (busy weekend) and post back what I have tried and the results.

Fingers crossed





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coozer

posted on 22/7/17 at 09:49 AM Reply With Quote
Id also check the fuel pressure reg, is it holding correct 3 bar all the time? A temp fuel pressure gauge should help rule it in or out...





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adithorp

posted on 22/7/17 at 04:51 PM Reply With Quote
Why do you think the pump is stopping under load? Once the engine stops the pump will stop until you crank the engine again. Does it do that or is there no pump until after 5mins? If it doesn't run until 5mins have passed try putting a live to the pump before that and see if it runs. If it doesn't it's in the pump but if it does then you need to look at the wiring... A bad connection/terminal somewhere could be giving a high resistance as it heats up or could be the relay... and check the earth as well as the feed. Try blocking the return and attempt start to check if it's the regulator. If it fires it reg is prob stuffed (though standard ford ones hardly ever fail).

I've a feeling the pump could be a red herring. Valve clearance too tight could give the symptons you describe for instance.

[Edited on 22/7/17 by adithorp]





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gremlin1234

posted on 22/7/17 at 07:50 PM Reply With Quote
quote:
Originally posted by adithorp
I've a feeling the pump could be a red herring. Valve clearance too tight could give the symptons you describe for instance.

as could a slightly misaligned crank position sensor, just getting out of sync as the revs rise.

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tims31

posted on 23/7/17 at 09:01 AM Reply With Quote
quote:
Originally posted by adithorp
Why do you think the pump is stopping under load? Once the engine stops the pump will stop until you crank the engine again. Does it do that or is there no pump until after 5mins? If it doesn't run until 5mins have passed try putting a live to the pump before that and see if it runs. If it doesn't it's in the pump but if it does then you need to look at the wiring... A bad connection/terminal somewhere could be giving a high resistance as it heats up or could be the relay... and check the earth as well as the feed. Try blocking the return and attempt start to check if it's the regulator. If it fires it reg is prob stuffed (though standard ford ones hardly ever fail).

I've a feeling the pump could be a red herring. Valve clearance too tight could give the symptons you describe for instance.

[Edited on 22/7/17 by adithorp]


Once the engine dies the pump has stopped as expected but if it was a stall situation you would expect the pump to run again as soon as the ignition is recyled but it doesn't run until 5 mins (maybe less) after.

I will connect a lamp to the pump terminals and see when the pump stops. After that I will try adding a feed from the ignition to the pump and see what happens. Another option is to remove the HP fuel filter and see if it runs any better.

If I run it on idle or rev on the driveway it runs fine. Driving on low revs, roughly below 2500 then it will drive okay but as soon as I put my foot down is when it dies which is why I suspected the pump/fuel supply route.





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r1_pete

posted on 23/7/17 at 10:36 AM Reply With Quote
Have you checked the throttle position sensor isnt going open circuit when yo plant your foot??
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tims31

posted on 23/7/17 at 11:20 AM Reply With Quote
quote:
Originally posted by r1_pete
Have you checked the throttle position sensor isnt going open circuit when yo plant your foot??


No, haven't checked that but I would expect the same thing to happen when revving on driveway when not in gear but something else to check.





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tims31

posted on 24/7/17 at 12:48 PM Reply With Quote
Ok so an update and a bit of sucess provisionally


I cleared the two faults from the history of the ECU and these came straight back on as soon as the engine started so I don't think they have anythng to do with the fault.

I check the MAF flow and at idle it is 5g/s and when I blip the throttle it rises up to 30-40g/s so that would seem right from Daves post.

I then took out the HP Filter as that was the easiest to do and that made no difference, ran fine on the drive and managed to get about 500yds before the engine died as before.

Then put a lamp onto the terminals of the pump so I could monitor what the pump was doing and as the engine died the lamp went out so the power to the pump had been cut which I am not quite sure happened at exactly the same time but did flicker on briefly again and then went off for good. Tried to restart a few times straight after and the lamp didn't come on and the pump wouldn't run at all. Left it for about 2 mins and then cycled the ignition which lit the lamp, primed the pump again and started ok. The flickering light seems to suggest an electrical fault as if the ECU had cut the power I would have expected the power to be cut and not return for a brief instant.

Next I removed the normal supply to the pump which comes from the relay and did as suggested and wired in a wire from the ignition supply via a 20 amp fuse to the pump and made an earth supply to a point on the chassis. This time the car ran fine and I managed to do three laps around my local street, ok not too far and not over 30 mph but further than it has got since the fault appeared and wasn't dying under acceleration.

With this it would seem to point to the fuel relay which when I removed it did feel quite warm to the touch but not sure if this would be normal???
Also the relay wasn't actually supplying the power to the pump so would you expect it to get warm???

Bypassing the relay does seem to suggest it may be the cause of the fault but I am struggling to understand why it would be more likely to fail when under load on the engine. Does the pump draw more current when the engine accelerates, I would have thought it would just run at a constant speed?

I haven't been able to fully prove its the relay either as my local supplier does not have the type I need in stock. Can anyone recommend a supplier of a good quality relay. Also its been peeing down all day so don't really want to get soaked

Its a 12v 40amp Type A 4 pin




[Edited on 24/7/17 by tims31]

[Edited on 24/7/17 by tims31]





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rusty nuts

posted on 24/7/17 at 05:22 PM Reply With Quote
What actually switches the relay? A lot of ECUs would only Earth the relay to switch it "on" It would be possible to by pass the relay by bridging terminal 30 and 87 using a fused link to test the pump wiring . Check for a good ignition live perhaps by using the light you have already used to test the pump supply , if it still plays up it may? be either a wiring fault or possibly the ECU
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obfripper

posted on 24/7/17 at 09:14 PM Reply With Quote
One thing that i would point out is the relay should be a coil diode type, otherwise it is possible to backfeed into the ecu.
I had this with my megasquirt, resulting in the engine running on when the ignition was switched off. I had accidently swapped the headlamp and fuel pump relays and it took some headscratching to work this out.

The relay you have is a general purpose type that would normally be used in conjunction with a mechanical switch. An oe fuel pump relay would be a good upgrade to your existing one , the other thing is to match the oe pin assignment (12v to pin86 -ve to pin85) so the current flow is correct for the internal diode.
0732014112 is a bosch one that's configured for a fuel pump with an inline diode on pin 86 for landrovers etc, 61361729004 is a bmw fuel pump one that has an inline and a parallel diode. The oe ford one is no good for your existing plug as it is a micro relay.

The other option is to add the diodes to your loom 2x 1n4007 is fine with 1:anode to 85 cathode to 86 2:anode facing 12v supply cathode facing 86.
This should make general purpose relays work as a dedicated fuel pump one.

Your existing relay also may be drawing more current than the oe relay, as the oe ones are micro type that have smaller coil windings. I have no idea what maximum current the ford ecu can provide for this, for reference the megasquirt has approx 1A capacity, a normal relay is approx 0.25A , a micro one is approx 0.1A.

In regards to the relay operating temperature, the relay only requires 12v to bring it to the closed position, it could remain closed down to approx 3v, therefore there is 2.4watts being continuously dissipated by the relay coil.

The pump will draw pretty much the same load regardless of used capacity, as it is either injecting the fuel or pushing it throught the regulator back to the tank with total flow remaining the same, the regulator will increase the pressure under full throttle by 0.7 bar to keep the effective rail pressure at 4 bar, this will increase the load slightly.

Dave

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Phil_1471

posted on 25/7/17 at 05:33 AM Reply With Quote
Second Dave's post, also check the connections on the relay, ECUs don't like a 'dirty' connection, might be upsetting it? more likely just to need a diode relay.
Phil





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