Fuel starvation and massive detonation - RESOLVED
#21
02-18-2015, 03:16 AM
Veteran Member
Did you clear the ICM codes and those you posted are very recent?
If not, they stay forever and could be as old as the car. Probably caused by any low voltage like bad battery at any time in its existence.
I just ignore codes in ETM unless I know when they were cleared and it's recent.
BTW, you put P1235 & P2135 and I'm guessing you mean the latter in both cases
If not, they stay forever and could be as old as the car. Probably caused by any low voltage like bad battery at any time in its existence.
I just ignore codes in ETM unless I know when they were cleared and it's recent.
BTW, you put P1235 & P2135 and I'm guessing you mean the latter in both cases
#22
02-18-2015, 03:49 AM
Senior Member
Hey Cam Doc here
You just described what happened a few years back to me in my 450SL and it was a bad batch of fuel
We had had heaps of rain up here at the time and the fuel was on the cheap cycle so I figured may as well fill up which I did got 40 litres of water mixed with fuel the car did all the things you described but because the car was driving and vibrating the fuel water mix got stirred up so the car ran albeit really bad
Then after letting it sit for a while at a business meeting the thing started first kick no problems the fuel and water had separated and the pick-up was in the bottom of the tank
By the time I was nearly home it sounded like you described managed to get it to my indie he told me the next day the fuel was putrid and it had blown my distributor cap and melted my rotor button
these newer jags don't have rotor buttons and distributor caps
looking at you other posts might pay to check it out we have had so much rain this year up here and about to get 500 ml tomorrow
I filled my tank this afternoon at a station that is on top of a hill just in case
You just described what happened a few years back to me in my 450SL and it was a bad batch of fuel
We had had heaps of rain up here at the time and the fuel was on the cheap cycle so I figured may as well fill up which I did got 40 litres of water mixed with fuel the car did all the things you described but because the car was driving and vibrating the fuel water mix got stirred up so the car ran albeit really bad
Then after letting it sit for a while at a business meeting the thing started first kick no problems the fuel and water had separated and the pick-up was in the bottom of the tank
By the time I was nearly home it sounded like you described managed to get it to my indie he told me the next day the fuel was putrid and it had blown my distributor cap and melted my rotor button
these newer jags don't have rotor buttons and distributor caps
looking at you other posts might pay to check it out we have had so much rain this year up here and about to get 500 ml tomorrow
I filled my tank this afternoon at a station that is on top of a hill just in case
Hey guys,
I think one or maybe both the fuel pumps in the XJR are failing...
Yesterday afternoon I got the chance to give it a short blast entering the freeway, (full-throttle runs are hard to come by around here) and it was hesitating & felt sluggish.
Rev out in 2nd and at about 5000rpm there was a big hesitation and massive detonation, so loud it sounded like rocks peppering the windscreen.
It's been 15 years since I had a car that pinged, but it was unmistakeable.
Ambient temps were warm, low 30's / 90's, late afternoon. I took it easy on the rest of the trip & got to where I was going, but the car felt sluggish and not as reponsive as it usually is.
After the meeting around 10pm it had cooled down to the low 20's / 60's and I came back onto the freeway & tried again. Again hesitation and down on power, and pinging, but not as bad as earlier in the afternoon when it was hotter...
I don't have my Android phone anymore, so I don't have Torque, couldn't check the fuel pressure or other values at the time. When I got home I plugged in my pocket scanner, no codes.
This morning I hooked up the SDD, no relevant codes (but this car has always had a heap of random "background codes") and I checked out the fuel trims & rail pressure, 55psi at idle, long term trims around zero.
This massive episode of detonation has left no codes or clues, but it reminds me of a couple of old carb-fed vehicles I had, where it was just plain old fuel starvation.
Other info;
Car has now 174'000kms / 108'000mi
Fuel filter was replaced 19'000kms / 12'000mi ago
AFAIK it's on the original pumps
Fuel gauge seems to be working ok, I'd just put in a half-tank of fuel
Intercooler pump is working
I have heard of one or both pumps failing in STR's and X350 XJR's (same twin-pump setup) as well as older models. Pumps don't last forever so at 10 years / 108'000mi, maybe their time is up.
Problem for me is a pair of new pumps will be $1600 in parts alone...
I have searched through the X350 & the S-Type sections. A few mentions of the S/C models with failed pumps, but I could not find anyone who had these sort of symptoms...
I'm reluctant to go out & road test it with the SDD connected to monitor the fuel pressure, that detonation sounded like an engine killer but there has to be some trouble-shooting done.
I am 99% sure its fuel starvation at high demand, just a matter of figuring out what's causing it.
Candidates;
Blocked fuel filter (but it's quite new)
Blocked internal filters in the pumps (possible, age/mileage)
Bad tank of fuel (possible, how do I check this?)
Failing pump or pumps (again, how do I check this?)
What else?
I'll wait for the morning traffic to clear and go for a drive with the SDD hooked up. I guess the thing to look for will be fuel pressure dropping when it's hesitating...
I think one or maybe both the fuel pumps in the XJR are failing...
Yesterday afternoon I got the chance to give it a short blast entering the freeway, (full-throttle runs are hard to come by around here) and it was hesitating & felt sluggish.
Rev out in 2nd and at about 5000rpm there was a big hesitation and massive detonation, so loud it sounded like rocks peppering the windscreen.
It's been 15 years since I had a car that pinged, but it was unmistakeable.
Ambient temps were warm, low 30's / 90's, late afternoon. I took it easy on the rest of the trip & got to where I was going, but the car felt sluggish and not as reponsive as it usually is.
After the meeting around 10pm it had cooled down to the low 20's / 60's and I came back onto the freeway & tried again. Again hesitation and down on power, and pinging, but not as bad as earlier in the afternoon when it was hotter...
I don't have my Android phone anymore, so I don't have Torque, couldn't check the fuel pressure or other values at the time. When I got home I plugged in my pocket scanner, no codes.
This morning I hooked up the SDD, no relevant codes (but this car has always had a heap of random "background codes") and I checked out the fuel trims & rail pressure, 55psi at idle, long term trims around zero.
This massive episode of detonation has left no codes or clues, but it reminds me of a couple of old carb-fed vehicles I had, where it was just plain old fuel starvation.
Other info;
Car has now 174'000kms / 108'000mi
Fuel filter was replaced 19'000kms / 12'000mi ago
AFAIK it's on the original pumps
Fuel gauge seems to be working ok, I'd just put in a half-tank of fuel
Intercooler pump is working
I have heard of one or both pumps failing in STR's and X350 XJR's (same twin-pump setup) as well as older models. Pumps don't last forever so at 10 years / 108'000mi, maybe their time is up.
Problem for me is a pair of new pumps will be $1600 in parts alone...
I have searched through the X350 & the S-Type sections. A few mentions of the S/C models with failed pumps, but I could not find anyone who had these sort of symptoms...
I'm reluctant to go out & road test it with the SDD connected to monitor the fuel pressure, that detonation sounded like an engine killer
but there has to be some trouble-shooting done.I am 99% sure its fuel starvation at high demand, just a matter of figuring out what's causing it.
Candidates;
Blocked fuel filter (but it's quite new)
Blocked internal filters in the pumps (possible, age/mileage)
Bad tank of fuel (possible, how do I check this?)
Failing pump or pumps (again, how do I check this?)
What else?
I'll wait for the morning traffic to clear and go for a drive with the SDD hooked up. I guess the thing to look for will be fuel pressure dropping when it's hesitating...
#23
02-18-2015, 05:45 AM
Veteran Member
#24
02-18-2015, 06:12 AM
Veteran Member
From figure 3.6 and matching text legend of the electrical diagrams ...
the only plausible monitoring output of the modules seems to be CR-26-7 of "fuel pump 2 module"
leading to P11-011 of the ECM.
the definition is PI1–11 FUEL PUMP 2 MODULE MONITOR: 1 Hz FREQUENCY; 50% DUTY CYCLE = OK, 25% OR 75% DUTY CYCLE = FAULT
P1235 says "low", so the ECM is sensing low, which could be the signal itself, or the signal is correct, and the pump or the pump control circuit is truly at fault.
could be something as simple as a loose signal wire or a burned up supply wire. not to mention the ground side as well.
++
the only plausible monitoring output of the modules seems to be CR-26-7 of "fuel pump 2 module"
leading to P11-011 of the ECM.
the definition is PI1–11 FUEL PUMP 2 MODULE MONITOR: 1 Hz FREQUENCY; 50% DUTY CYCLE = OK, 25% OR 75% DUTY CYCLE = FAULT
P1235 says "low", so the ECM is sensing low, which could be the signal itself, or the signal is correct, and the pump or the pump control circuit is truly at fault.
could be something as simple as a loose signal wire or a burned up supply wire. not to mention the ground side as well.
++
#25
02-18-2015, 06:36 AM
Quote:
Originally Posted by JagV8
Did you clear the ICM codes and those you posted are very recent?
If not, they stay forever and could be as old as the car. Probably caused by any low voltage like bad battery at any time in its existence.
I just ignore codes in ETM unless I know when they were cleared and it's recent.
BTW, you put P1235 & P2135 and I'm guessing you mean the latter in both cases
Sorry, it's P1235.
The last time I cleared the codes was in April last year, the car has done about 6000kms / 3700mi since then.
The P1235 was there last April. Since then 6000kms with lots of full throttle runs, including several 1000m runway sprints in ~40deg heat.
Which is why I decided that it had to be the fuel, not the pump.
Quote:
Originally Posted by doc
Hey Cam Doc here...
Thanks Doc, reinforces what I concluded about the fuel.
Quote:
Originally Posted by plums
From figure 3.6 and matching text legend of the electrical diagrams ...
the only plausible monitoring output of the modules seems to be CR-26-7 of "fuel pump 2 module"
leading to P11-011 of the ECM.
the definition is PI1–11 FUEL PUMP 2 MODULE MONITOR: 1 Hz FREQUENCY; 50% DUTY CYCLE = OK, 25% OR 75% DUTY CYCLE = FAULT
P1235 says "low", so the ECM is sensing low, which could be the signal itself, or the signal is correct, and the pump or the pump control circuit is truly at fault.
could be something as simple as a loose signal wire or a burned up supply wire. not to mention the ground side as well.
++
Ah ha!
I checked the fuel pump duty cycle with the SDD, it was showing ~48%, that's close enough to 50% and further enough away from 25% or 75% for me.
Thanks for looking at it, I didn't take it any further once the car was on the flatbed.
As I mentioned above, it occured to me that the P1235 had been there for nearly a year, and i've had no issues, in even tougher conditions than yesterday. It might have been a one-off...
I've gone all-in on the fuel being bad. If i'm right then BP will cover the costs, if i'm wrong....well I don't even want to think about being wrong...
Originally Posted by JagV8
Did you clear the ICM codes and those you posted are very recent?
If not, they stay forever and could be as old as the car. Probably caused by any low voltage like bad battery at any time in its existence.
I just ignore codes in ETM unless I know when they were cleared and it's recent.
BTW, you put P1235 & P2135 and I'm guessing you mean the latter in both cases
Sorry, it's P1235.
The last time I cleared the codes was in April last year, the car has done about 6000kms / 3700mi since then.
The P1235 was there last April. Since then 6000kms with lots of full throttle runs, including several 1000m runway sprints in ~40deg heat.
Which is why I decided that it had to be the fuel, not the pump.
Quote:
Originally Posted by doc
Hey Cam Doc here...
Thanks Doc, reinforces what I concluded about the fuel.
Quote:
Originally Posted by plums
From figure 3.6 and matching text legend of the electrical diagrams ...
the only plausible monitoring output of the modules seems to be CR-26-7 of "fuel pump 2 module"
leading to P11-011 of the ECM.
the definition is PI1–11 FUEL PUMP 2 MODULE MONITOR: 1 Hz FREQUENCY; 50% DUTY CYCLE = OK, 25% OR 75% DUTY CYCLE = FAULT
P1235 says "low", so the ECM is sensing low, which could be the signal itself, or the signal is correct, and the pump or the pump control circuit is truly at fault.
could be something as simple as a loose signal wire or a burned up supply wire. not to mention the ground side as well.
++
Ah ha!
I checked the fuel pump duty cycle with the SDD, it was showing ~48%, that's close enough to 50% and further enough away from 25% or 75% for me.
Thanks for looking at it, I didn't take it any further once the car was on the flatbed.
As I mentioned above, it occured to me that the P1235 had been there for nearly a year, and i've had no issues, in even tougher conditions than yesterday. It might have been a one-off...
I've gone all-in on the fuel being bad. If i'm right then BP will cover the costs, if i'm wrong....well I don't even want to think about being wrong...
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Don B (02-18-2015)
#26
02-18-2015, 11:27 AM
Veteran Member
Fingers crossed that fuel is your culprit.
I checked the fuel pump duty cycle with the SDD, it was showing ~48%, that's close enough to 50% and further enough away from 25% or 75% for me.
Just as a side note, that ~50% doesn't necessarily rule out the fuel system itself. Someone smarter than me will hopefully correct me if I'm wrong, but that 50% duty cycle is more like a binary 1, and 25% and 75% is a 0. In a PWM system, the amount of fuel pumped is determined by how many times that signal is turned on and off over a specific period of time.
Theoretically, you could have a system sending the right signal, but not modulating it frequently enough to meet maximum fuel demand. Or on a S/C car, one fuel pump circuit working correctly and the other out of spec.
Not sure how exactly PWM works in these cars, whether maximum fuel is achieved by turning the signal on and not modulating it, or it is by modulating X times over Y milliseconds.
I checked the fuel pump duty cycle with the SDD, it was showing ~48%, that's close enough to 50% and further enough away from 25% or 75% for me.
Just as a side note, that ~50% doesn't necessarily rule out the fuel system itself. Someone smarter than me will hopefully correct me if I'm wrong, but that 50% duty cycle is more like a binary 1, and 25% and 75% is a 0. In a PWM system, the amount of fuel pumped is determined by how many times that signal is turned on and off over a specific period of time.
Theoretically, you could have a system sending the right signal, but not modulating it frequently enough to meet maximum fuel demand. Or on a S/C car, one fuel pump circuit working correctly and the other out of spec.
Not sure how exactly PWM works in these cars, whether maximum fuel is achieved by turning the signal on and not modulating it, or it is by modulating X times over Y milliseconds.
Last edited by Mac Allan; 02-18-2015 at 11:33 AM.
#27
02-18-2015, 06:06 PM
Senior Member
Cam when you drain the fuel go to super-cheap get a clear drum to put it in then also send some to an independent lab
When that happened to my car I had a hell of a time proving it was the fuel even though I took a 20 litre drum of the stuff siphoned out of the car to the service station and it was only after chucking a tantrum in front of customers that I received any money
Also the money I received was only the amount of the fuel not the repairs something similar happened to my sister in law years earlier on a merc as well killed the engine but she was a women and probably drove it till it died like most women
With my car that time you could see it separating in the clear drum after we let it settle
That's why I am fitting a Separ fuel water separator to my work van
I fill up all over Australia last thing I need is a blown motor in the middle of nowhere
When that happened to my car I had a hell of a time proving it was the fuel even though I took a 20 litre drum of the stuff siphoned out of the car to the service station and it was only after chucking a tantrum in front of customers that I received any money
Also the money I received was only the amount of the fuel not the repairs something similar happened to my sister in law years earlier on a merc as well killed the engine but she was a women and probably drove it till it died like most women
With my car that time you could see it separating in the clear drum after we let it settle
That's why I am fitting a Separ fuel water separator to my work van
I fill up all over Australia last thing I need is a blown motor in the middle of nowhere
#28
02-18-2015, 06:23 PM
This is why it's gone to a Jag dealer Doc. I asked a few people and they all agreed that if you are a little bloke on his own the petrol companies don't give a crap about you.
With a large dealership (i won't say who, but they have Jag, Land Rover, Aston Martin, Bentley, Rolls Royce, McLaren, BMW/Mini, amongst others) you have better results in getting reimbursed on the repair costs.
With a large dealership (i won't say who, but they have Jag, Land Rover, Aston Martin, Bentley, Rolls Royce, McLaren, BMW/Mini, amongst others) you have better results in getting reimbursed on the repair costs.
#29
02-18-2015, 11:28 PM
Oh dear. I just got a phone call from the dealer. They drained fuel from the tank & reckon it looks fine. No water & no dirt/gunk either.
They road tested it & reckon it's running fine. I told them to find a long quiet stretch of road and give it a flogging. It's not going to play up if you are babying it...
Waiting for another call...
They road tested it & reckon it's running fine. I told them to find a long quiet stretch of road and give it a flogging. It's not going to play up if you are babying it...
Waiting for another call...
#30
02-18-2015, 11:43 PM
Join Date: Feb 2014
Location: Crossroads of America
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I hate it when "good" news is so unwelcome.
What are you thinking about your next step?
Last edited by Don B; 02-19-2015 at 06:38 PM.
#31
02-19-2015, 01:28 AM
#33
02-19-2015, 06:09 PM
Veteran Member
#34
02-19-2015, 11:39 PM
Veteran Member
Sorry to hear the fuel wasn't the issue.
Given that the non S/C cars only have one fuel pump, I would suspect that the second pump on S/C cars is solely there to meet peak demand requirements that the supercharger creates. So I would think given your circumstances that the fault might lie with pump 2 or it's circuit.
Given that the dealer you described sounds on the pricey side, if they don't figure it out before they empty your wallet, you might want to get the car back and do some tests yourself.
I'd start a new IDS/SDD session and clear all your codes and clear the Flight Data Recorder. The datalogger function IIRC can be set up to record, so you use to monitor the pertinent signals and record them. Then immediately take it on test drive and attempt to recreate the failure. If it happens again, you'll know which DTCs to focus on, and hopefully the datalogger will yield some insight as well.
You hung in there with me on my recent problem, so I'm happy to try to help any way I can on yours.
Given that the non S/C cars only have one fuel pump, I would suspect that the second pump on S/C cars is solely there to meet peak demand requirements that the supercharger creates. So I would think given your circumstances that the fault might lie with pump 2 or it's circuit.
Given that the dealer you described sounds on the pricey side, if they don't figure it out before they empty your wallet, you might want to get the car back and do some tests yourself.
I'd start a new IDS/SDD session and clear all your codes and clear the Flight Data Recorder. The datalogger function IIRC can be set up to record, so you use to monitor the pertinent signals and record them. Then immediately take it on test drive and attempt to recreate the failure. If it happens again, you'll know which DTCs to focus on, and hopefully the datalogger will yield some insight as well.
You hung in there with me on my recent problem, so I'm happy to try to help any way I can on yours.
#35
02-20-2015, 01:17 AM
I still think it's bad fuel.
Just picked the car up from the dealer, they didn't charge me for their time so i'll drop off a carton of beer for the boys out the back next week.
They reckon the car is FREAKIN AWESOME, running great and is in no way down on power or running rough. I don't think they have much experience with the supercharged cars though...
On the way home I had a bit of clear road, so I gave it a bootful, and it was pinging (a bit) from about ~4700rpm up to ~5500rpm before it short-shifted on it's own. Definitely not as smooth up through the revs as it usually is.
Still have half a tank in there so...what to do?
Before I dump in a bottle of octane booster or buy a can of PowerPlus 110, i'm wondering how feasible it is to have the fuel tested for octane level? Maybe it was a batch of 91 accidently dyed as 98...
More to the point is it even worth pursuing it?
I filled up a 5L fuel can from the exact same pump the day after I filled the car. Poured it into a on glass jar. Fuel was a clean clear yellow (exactly like 98 from BP is supposed to be), couldn't see any water or contaminants... so I do have a "sample" of sorts but it could be argued that it's not the exact same fuel that's in the tank...
If I go & add octane booster or another fuel to the tank, then the "evidence" is gone. But if it stops pinging & starts running properly then I have the answer. If it doesn't, then...back to square one...
Just picked the car up from the dealer, they didn't charge me for their time so i'll drop off a carton of beer for the boys out the back next week.
They reckon the car is FREAKIN AWESOME, running great and is in no way down on power or running rough. I don't think they have much experience with the supercharged cars though...
On the way home I had a bit of clear road, so I gave it a bootful, and it was pinging (a bit) from about ~4700rpm up to ~5500rpm before it short-shifted on it's own. Definitely not as smooth up through the revs as it usually is.
Still have half a tank in there so...what to do?
Before I dump in a bottle of octane booster or buy a can of PowerPlus 110, i'm wondering how feasible it is to have the fuel tested for octane level? Maybe it was a batch of 91 accidently dyed as 98...
More to the point is it even worth pursuing it?
I filled up a 5L fuel can from the exact same pump the day after I filled the car. Poured it into a on glass jar. Fuel was a clean clear yellow (exactly like 98 from BP is supposed to be), couldn't see any water or contaminants... so I do have a "sample" of sorts but it could be argued that it's not the exact same fuel that's in the tank...
If I go & add octane booster or another fuel to the tank, then the "evidence" is gone. But if it stops pinging & starts running properly then I have the answer. If it doesn't, then...back to square one...
#36
02-20-2015, 05:28 AM
Veteran Member
I have been reading this with interest since I have a 2005 XJR.
I have had pinging in other cars where I know the fuel was good and it turned out to be carbon build up in the cylinder head. These cars had over 80,000 miles on the clock.
On one car I used a scope to look inside one cylnder and could see black "crud" on the top of the piston.
If that is the case a compression test should, I would think, read a little higher than it should?
Just a thought.
Just remembered. Waaay back in the UK I used RedX to clean out the cylinder heads in my cars. Lots of smoke!
I have had pinging in other cars where I know the fuel was good and it turned out to be carbon build up in the cylinder head. These cars had over 80,000 miles on the clock.
On one car I used a scope to look inside one cylnder and could see black "crud" on the top of the piston.
If that is the case a compression test should, I would think, read a little higher than it should?
Just a thought.
Just remembered. Waaay back in the UK I used RedX to clean out the cylinder heads in my cars. Lots of smoke!
Last edited by jackra_1; 02-20-2015 at 05:31 AM.
#37
02-20-2015, 09:08 AM
Join Date: Oct 2009
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Be aware that 99.9% of the octane boosters available at car parts stores don't contain enough of anything to be able to boost the octane much more than .1% per bottle per tank.
If you got a tank of 91 instead of the 98 you expected and still have about a half tank, fill up now with known-good 98. That will probably boost the contents of to 95ish which is the level where the engine will render full performance.
If you got a tank of 91 instead of the 98 you expected and still have about a half tank, fill up now with known-good 98. That will probably boost the contents of to 95ish which is the level where the engine will render full performance.
#38
02-20-2015, 09:53 AM
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I would be tempted to buy a couple of cheap plastic 5 gallon (20 litre ?) fuel cans and pump out as much of the existing fuel as you can with a cheap fluid transfer pump, then fill up with 98 at another station and maybe add a bottle of petrol dryer additive (Heet is one of the leading brands in the U.S.). You can always use up the fuel over time by adding a gallon of it when your tank is 3/4 full.
BTW, when you inspected the fuel in your 5L can, did you let it decant and then check again? When agitated, the water molecules disperse in the gasoline so you have to let things sit awhile for the water to separate at the bottom.
#39
02-20-2015, 11:56 AM
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#40
02-20-2015, 01:56 PM
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Heet contains no ethanol. Standard Heet is 99% methanol (CH3OH). ISO-Heet is 99% isopropanol (C3H7OH). Ethanol is C2H5OH. All three dissolve in water and the flammability of the resulting solution depends on the concentration of alcohol, so adding more alcohol has a good chance of improving the flammability of the water/alcohol solution. And since the specific gravity of methanol and isopropanol are both greater than that of ethanol (and gasoline), Heet's claims that their products "sink to the bottom of the tank and mix with the water to help it burn" appear to have scientific validity. Of course, when left to sit for a few days, the ethanol in the gasoline also sinks to the bottom and dissolves in the water (ethanol only suspends in gasoline, it doesn't dissolve).
The one time I used standard Heet in a bad tank of fuel it seemed to help, but then, it could have just been my imagination.
Typical disclaimers: I have no affiliation with Heet, etc.
Cheers!
Don
Last edited by Don B; 02-20-2015 at 02:02 PM.
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AD2014 (02-22-2015)