fault code power loss under load

[badger]

Hello, I took advice from a fellow member (ray) and obtained a consult lead and software, very good advice.
My Maverick has been ok, done many mods and overhauled, but intermittently got loss of power, which was originally cured with a new MAF.
Similar fault occurred during cold spell, if you creep up on an obstical (hill) all is fine, but try powering up it the load creates a misfire and hesitation that gets worse and stays present until you back off and wait for a short time.
I think it is lack of fuel, as it happens the MOT man advised on corroded fuel lines, I changed these for high pressure hose from tank to halfway down chasis, this gave a brilliant increase in power, when I checked the old pipes the corrosion had collapsed the bore to a minimum, so I assumed all would be ok.
Having been off ill of late I have not been out for a long run, today I had to go to Northampton, and when overtaking the problem returned, so on the way back I hooked up the laptop, unfortunately the battery went flat so no log, but when the fault occurred all appeared ok with mass air input, but the “injection timing c/v” went very low, no fault 100% fault down as low as 50%, this then creeps up to 70,80 and finally 100 and then all is ok, I suspect a fuel blockage in either filter or another pipe, but I am having a job understanding the fault code throw up; Code 21: F/INJ TIMG F/B
Any body ever had this one, I don’t at this stage suspect the pump, mini filter eliminated from return banjo, and fuel filer changed only about 5000 miles ago, I am going to change it again, in case I dislodged something with removing pipe.
But where does the code come from I have read the manual, but must be missing something.

On anther not had anew water pump from Milners, have just changed it again as fan was on all the time, new one isn’t as I would hope, it took 50 miles yesterday for it to stop spinning at full speed, but much better than the first, the viscouse unit looks the same as on some toyota’s, they have different amounts of grease inserted depending on worldwide location, I wonder if current batch are from warmer climes?

Any help with above code appreciated.

 

[centurion]

hi.
I cant advise you about the codes but if you read my thread winter woes/dirty diesel. I sounds similar. The problem on mine has disappeared for now. But it originally kicked off with v/low outside temps -17 and seemed to be worsened after driving over some very rough tracks rutted snow etc

If you get a fix please let me know I will let you know if I resolve mine if it returns.

good luck with it

Regards
Centurion

 

[badger]

i have been doing some more digging on google, and similar fault appears to be common with air leak in diesl lines, which kind of makes sense, i have also rechecked manual and found the following.

P1246
0201
I Injection timing feedback system does not operate
properly. (This system consists essentially of ECM,
injection timing control valve and needle lift sensor.)
I Harness or connectors
[Injection timing control valve, needle lift sensor,
crankshaft position sensor (TDC) circuits]
I Injection timing control valve
I Needle lift sensor
I Crankshaft position sensor (TDC)
I Air in fuel line

so have i got a leak, or did i introduce air when i replaced the fuel line, but i would have thought that would have bled throgh by now.
so i am going to get a new filter in the morning, and check hand priming pump and new pipes for leaks.
had you recently changed filter?
i am hoping it is noticing presure drop in sensor when air is present, dont want to think it is no.1 injector or pump.

 

[badger]

to answer my own question, it was a faulty fuel filter, less than 6 months old, 7,000 miles, top seal decided it didnt like diesel and let go of filter, it had swelled up and was leaking air, did clear pipe test on inlet and outlet, many bubles on outlet, so investigated fuel housing, and found filter was u/s.
filter was a Boshi from Milners, have now fitted a Halfrauds special, and all is well with the world.

 

[Timbo_1975]

When the fuel is aerated the pump case pressure goes abit haywire as you can compress air. Case pressure is maintained somewhere around 70psi by the transfer pump and is needed to enable proper working of the advance/ retard valve.

The ECU monitors timing via the inj.1 lift sensor. When the timing goes crazy from the air, the ecu attempts to correct it via the timing solonoid, but cant enough, so flags the code, then usually goes into limp mode with the MIL lit.

Simples.

 

[badger]

hello timbo,
after some research i came to that conclusion, r20 manual is full of doom and gloom on that, last item is air, not first!
not sure if mine is the only boshi filter to have had such a fault, doesnt look like a neopryne seal, whatever it is, and the bonding agent, they dont like diesel.
all fixed now, much better.

 

[badger]

Bad news as fault came back, so maybe not fuel filter, I decided to find out where problem was happening (air ingress) and set about changing all fuel pipes, whilst carefully checking for bubbles, I bypassed filter head, but no better, then I changed all rubber hoses, this is where my luck changed, I forgot to connect the return pipe from pump inside the wheel arch, when I started car I was hosed down by diesel, I quickly switched off car to remedy, but whilst connecting hose I got to thinking, why would so much diesel be going back to tank?
I then have to go back to a previous post I made, where I assumed I had found a mini filter in the outlet of my pump, others have also reported this, having retrieved what I removed and examined it carefully, it turns out to be a one way pressure relief vale, now when blowing and sucking on it I discovered it fails in the open position, so pressure in pump would lower and with all the fuel being pumped in a loop, the fuel would be well aerated, to lower the flow and increase the pressure I put a reducer in the hose, my goodness on test the drive was so different, power all the way to the red line, fast response the lot, you have to remember I go this car in a very tired and poorly way, so maybe like others I assumed this is or was how it should be, it now seems so much better, it is amazing it was drivable before, add to that the new straight ahead steering and I am looking forward to a long drive.
I have asked our fitter to see if this valve jobby can be obtained from our suppliers, he feels confident it is, he also said it could have been worse in cold weather due to the unit failing open even more when tight through cold.

 

[jace]

ive seen on navara forum ideas of putting electric lift pump inline to boost presure into pump to get more oomphh

 

[badger]

i dont think i want anymore, it keeps spinning wheels now!
amount of fuel being returned to tank was huge, with valve stuck open, or in my case not present:doh

on the rear (return) pump banjo was a screw, i thought to blead or clean, now i am wondering if it was to adjust.
anyway kind man at diesel place is getting part and manual for pump, we will see what it realy is.

 

[badger]

got the info emailed over.
see below, this relates to the boch pump, but part maybe internal, zxel pump part is in banjo on return.

The low-pressure stage of a distributorpump
fuel-injection installation comprises
the fuel tank, fuel lines, fuel filter,
vane-type fuel-supply pump, pressurecontrol
valve, and overflow restriction.
The vane-type fuel-supply pump draws
fuel from the fuel tank. It delivers a
virtually constant flow of fuel per
revolution to the interior of the injection
pump. A pressure-control valve is fitted
to ensure that a defined injection-pump
interior pressure is maintained as a
function of supply-pump speed. Using
this valve, it is possible to set a defined
pressure for a given speed. The pump’s
interior pressure then increases in
proportion to the speed (in other words,
the higher the pump speed the higher
the pump interior pressure). Some of the
fuel flows through the pressureregulating
valve and returns to the
suction side. Some fuel also flows
through the overflow restriction and
back to the fuel tank in order to provide
cooling and self-venting for the
injection pump. An overflow valvecan be fitted instead of the overflow
restriction.

 

[badger]

parts list;

http://www.usfuelinjection.com/reference/zexel/oflowid.htm

 

[badger]

Not sure if this interests anyone, but further to above I have some more information.
The Zexlel pump is a near clone of the Bocsh VP44 as fitted to newer Terrano’s, and on industrial installations the overflow restrictor valve is a known problem, the valve is located within the exit/outflow banjo, and job is to increase or at least keep pressure in the fuel pump at a pre-set level, it would appear many a pump being returned from the motor trade for reconditioning, justs needs a new valve! On the flip side of that, many new pumps which don’t cure original problem, are cured when fitting a new valve.
Having fitted the new one the pressure has been tested and is within spec, I did not do this, but can find out what this is, I have found no google info on this fault for Terranos, but plenty for other makes, again in UK the valve is hard to get, but appears freely on Ebay.us odd, ? our supplier did raise a smile when we ordered it, asked if we wanted pump reconing! Anyway about £50, which seems a lot for a banjo bolt, but seems worth it so far.

Known faults are;

Hard to start

Loss of power

Flat spots and misfires at low RPM

All the low flat spots have now gone, throttle response seems more positive, how much of this is imagined I do not know, but thought this may prove of use to others in the future.

 

[makeitfit]

Sounds remarkably similar to my probs at the mo. is this valve a mechanical device? Can it be modified temporarily?
Pics please, as Zippy will ask later anyway

 

[badger]

it is an internal part of the banjo bolt on the outlet of the pump, the rubber hose that goes from the outlet to the tank, goes to steel pipe on the front chasis, i put a hose clip round this to restrict flow, bent pipe in half and a zip tie, bth worked well, but dont go too mad, you need to let fuel to escape pump, also this escape is the way the pump is cooled, try bending hose in half to start with, see if it improves starting, first start was the same, but after that, bingo.
the change in throtle response is most noticable at low revs, 1500, smooth as anything now, and when i bent hose.

 

[badger]

How To Test Your VP-44 Overflow Valve



Description
The overflow valve is located on the side of the injection pump (Fig. 58). It is also used to connect the fuel return line (banjo fitting) to the fuel injection pump.
Operation
Fuel volume from the fuel transfer (lift) pump will always provide more fuel than the fuel injection pump requires. The overflow valve (a check valve) is used to route excess fuel through the fuel return line and back to the fuel tank. Approximately 70% of supplied fuel is returned to the fuel tank. The valve opens at approximately 97 kPa (14 psi). If the check valve within the assembly is sticking open, fuel drainage of the injection pump could cause hard starting. If a Diagnostic Trouble Code (DTC) has been stored for “decreased engine performance due to high injection pump fuel temperature”, the overflow valve may be stuck in closed position.
Diagnosis And Testing
A rubber tipped blow gun with regulated air line pressure is needed for this test.
1. Clean area around overflow valve and fuel return line at injection pump before removal.
2. Remove valve from pump and banjo fitting.
3. Discard old sealing gaskets.
4. Set regulated air pressure to approximately 97kPa (14–16 psi).
5. Using blow gun, apply pressure to overflow valve inlet end (end that goes into injection pump).
6. Internal check valve should release, and air should pass through valve at 97 kPa (14–16 psi). If not, replace valve.
7. Reduce regulated air pressure to 10 psi and observe valve. Valve should stay shut. If not, replace valve.
8. Install new sealing gaskets to valve.
9. Install valve through banjo fitting and into pump.
10. Tighten to 30 N�m (24 ft. lbs.) torque.
Removal
The overflow valve (pressure relief valve) is located at the outside of fuel injection pump (Fig. 58). It connects the fuel return line (banjo fitting) to the pump. The valve has no internal serviceable parts and must be replaced as an assembly. Two sealing gaskets are used. One gasket is located between pump and banjo fitting. The other is located between the banjo fitting and end of valve.
1. Clean area around overflow valve and fuel return line at injection pump before removal.
2. Remove valve from pump and banjo fitting.
3. Discard old sealing gaskets.
Installation
The overflow valve (pressure relief valve) is located at the outside of fuel injection pump (Fig. 58). It connects the fuel return line (banjo fitting) to the pump. The valve has no internal serviceable parts and must be replaced as an assembly. Two sealing gaskets are used. One gasket is located between pump and banjo fitting. The other is located between the banjo fitting and end of valve.
(1) Install new sealing gaskets to valve.
(2) Install valve through banjo fitting and into pump.
(3) Tighten to 30 N�m (24 ft. lbs.) torque.

 

[Timbo_1975]

Any chance you could get some photo's of the valve and position on the pump uploaded?

Would surely be a help to other forum members.

 

[badger]

trying to upload bocsh picture, but word doc is greater than 70Kb.
i have posted pic of zexel unit before, i will try and repost.
i thought, and others may have also thought, this "thing" was the mini-filter, it does have a gause filter within the bolt.
also info received points to intermittently failing, due to ambient temperature changes.
When viewing ECU-Talk, pump pressure under load varied enormously, with outlet unrestricted, with ne restrictor in, pressure remains constant, or near as makes no difference.
I also note that fuel temp rises with restrictor present, this must be due to cooling nature of return fuel, Bocsh even explain this in manual, so if pump see’s fuel as cold, it will retard timing or fueling as the cold fuel has a greater volume and produces more power, so again this would lead to poor running condition, let alone the loss of pressure on the pump supply to injector.

 

[badger]

http://www.nissan4x4ownersclub.com/forum/showthread.php?t=10688&page=4

wont let me upload same image twice, but this is link to old thread.

 

[badger]

never seen a terrano with a bosch pump, but does it look like this or similar?
is it vp or ve type?

 

[badger]

http://cgi.ebay.com/ebaymotors/DODG...r_Truck_Parts_Accessories&hash=item2ead7f9e11

look at the faults listed, its looking more likely to me that diesel repair centres do not want the uk public to know about this little thing?
why would they?
this may not be in all terranos, it may only be in the zexel ones, but more must have it fitted than just me?
lots appear to have issues as listed here.