Weird Injector Issue when Remapping 110 HDI with DV6-C 8V Engine & EGR Delete

[Captain Nick]

Hi All,

I had a weird issue this morning when I took my DS3 into SP Tuning at Hinckley and as such it was decided to err on the side of caution and not to apply the remap until I'd got it fixed. Makes sense to me!

Backstory:

I've had the car from new and there has been no changes to the Injectors at all.
Car was working relatively ok and I serviced it in August when I noticed a couple of Fault Codes on the ECU such as P1162 and P12B4 which are EGR Valve getting stuck error messages. So once I'd located the bleeding thing, after much hammering, swearing and achy calves, I removed it, cleaned up as much coking/claggy stuff as I could and refitted it. Reset the DTC Fault Codes and lo and behold, it was still throwing up fault messages. I was getting rafts of obvious EGR messages but alongside that and somewhat weirdly it also started throwing up C1390, C1391 & U1208 DTC Codes which are ABS/ESR Engine Torque error messages and with those the car puts itself into "Limp Mode". This means significantly reduced power and max 3000rpm. After some Google-Fu, just for useful info, apparently this is not unusual with Citroen's and the EGR faults can mess up the ABS even though it's got nothing to do with it and there is no fault at all with the ABS systems! To make the car useable again my workaround was to disconnect the multiplug from the EGR Valve and make sure it is closed firmly, which once all the codes have been reset, only throws up P0405 & P0490 thus allowing the car to be driven normally (or so I thought). We drove the car around like this for a week with the "Check Engine" light on but perfectly useable and then took it to SP Tuning for an EGR Delete and Remap.

In For the Remap:

At SP Tuning it was quickly established by the chaps that the Dyno curves were not normal with the Torque being 80Nm too low! They applied just an EGR Delete map (just those 2 codes) to see if the issue was related and indeed once the "Check Engine" light went out the Dyno run looked like a normal DS3 110 HDI with 116PS & 300Nm measured. We weren't aware that there are different levels of "Limp Mode" but this proves that there is a reduced power mode when the light is on that isn't as restrictive as when the ABS thinks it is faulty.

With a decent baseline, they did a normal Remap and before the power run on the Dyno they gave it a gentle revving and a knocking sound was heard on gentle throttle at the bottom of the rev range which appeared to disappear when revved a little. It wasn't present when idling either. The chaps at SP Tuning were brilliant and straight away thought it may be an Injector. They put it on the diagnostics and it appeared that the No.3 Injector was giving very different readings to the other 3 cylinders although there were no DTC's. I needed to drive it away and get the Injector replaced but they didn't want to leave the remap on and potentially hole a piston so put the EGR Delete only map back on for the meantime. When listened to at gentle throttle it was still knocking though so we believe the extra fuel pressure of the remap probably pushed the injector over the edge and it now needed replacing. I would just take the car away and repair it an bring it back to be remapped once sorted.

The Issue doesn't seem so obvious now:

At SP Tuning -
At tickover, Injector Flow Correction Factor No.3 = Approx 1.57 (all others were 0.6-0.9 ish)
Just a little throttle, Injector Flow Correction Factor No.3 = Approx 1.55 (all others were 1.0-1.1 ish I think)
Number of complete programming cycles of diesel injector 3 = 0 (all others read 162)
Obvious knocking sound and some wrong sounds when revved

I drove home very gently so not to damage it, from Burbage to M69 it sounded a bit horrible. M69, revved a little to get up to 70mph ish and still not good! Constant 70-80 from M69 to M1 and only to Loughborough J23 (25 miles total) came off the motorway and noticed it sounded normal. Stopped to pickup the missus in L'bro and as she was in the car she could read out the numbers from the OBD2 tool whilst I drove (still gently) -
At tickover, Injector Flow Correction Factor No.3 = Approx 1.30 (all others were 0.9 ish)
Just a little throttle, Injector Flow Correction Factor No.3 = Approx 1.30 ish (all others were 1.0 ish)
Over 1100rpm, Injector Flow Correction Factor = 1.02 on all cylinders 
Number of complete programming cycles of diesel injector 3 = 0 (all others read 162)
No knocking sound and completely normal when revved

Got it home (10 miles from L'bro) driving normally (not overly gentle) and all still sounds and feels normal -
At tickover, Injector Flow Correction Factor No.3 = 1.11 (No.1 = 1.12, No.2 & 4 = 0.93)
Just a little throttle, Injector Flow Correction Factor No.3 = same as above
Over 1100rpm, Injector Flow Correction Factor = 1.02 on all cylinders 
Number of complete programming cycles of diesel injector 3 = 0 (all others read 162)
No knocking sound and completely normal when revved

So I thought I'd do my best to replicate a Dyno run on the road (took it for a thrash on the bypass) by revving it to over 4,500rpm in each gear a couple of times then parked up and then checked the values -
At tickover, Injector Flow Correction Factor No.3 = 1.18 (No.1 = 1.05, No.2 = 0.97, No.4 = 0.89)
Just a little throttle, Injector Flow Correction Factor No.3 = almost same as above
Over 1100rpm, Injector Flow Correction Factor = 1.02 on all cylinders 
Number of complete programming cycles of diesel injector 3 = 0 (all others read 162)
No knocking sound and completely normal when revved

So interestingly, when thrashed a bit, the No.1 and No.3 injectors values seem to diverge a bit so I'm wondering if the No.3 is just a bit weaker than it should be or if indeed it is fine as when driven normally all seems ok? Should it be replaced? If everything is normal and ok now, why has No.3  never completed a programming cycle? If it's never completed a cycle, has it always been bust?

Is there anyone with knowledge/experience of these things that can understand what is going on as I don't see the point in replacing the No.3 Injector if it sounds and drives completely normally.

Sorry for the life story here, but not sure what kind of info may be needed to give the right person a Eureka moment!

Thanks in advance for any help,

Nick

 

[Captain Nick]

Just an update, after speaking to Jamie at SP Tuning with regards to all the above info, it was determined that the injector was possibly reset and was re-learning. This is consistent with my check on Friday that showed:

Number of complete programming cycles of diesel injector 3 = 3 (all others read 165)

This indicates that Injector 3 has programmed itself 3 times since last weekend which is the same as the other 3 injectors and the car has driven perfectly all week thereby implying that the injector is fine and simply lost its values. So I went back to SP Tuning on Saturday and they applied the Remap and here are the results:


So about 45Nm and 31BHP peak improvement but overall the area under the curves show a great improvement which is reflected in driving the car. It pulls much better overall but is noticeably smoother at the low end before the turbo comes in meaning you can pootle about in a higher gear so we're hoping to see an increase in MPG too, although only time will tell.

Oh and it drives perfectly since the remap, none of the weird gremlins that affected us last week. Very odd that it just reset one injector and no idea why but this time it was all fine!

[Captain Nick]

Does anyone know why there are weird characters all over my posts? I also can't go back and edit them! Kinda makes it hard to read.

[Chris_Blue]

Does anyone know why there are weird characters all over my posts? I also can't go back and edit them! Kinda makes it hard to read.

No, short answer. Ive seen those symbols on other posts- obviously the forum software doesnt like/ recognise some stuff
Glad ure DS3 is good now
Remap for mine soon

[Funky]

That's a great increase in torque and bhp from SP Tuning. Another top job from Jamie. Is it very noticeable when driving?

[Captain Nick]

It's night and day from before although it was in a semi-limp home mode and was 80Nm below the usual torque until the EGR Delete was applied last week! The driveability from very low revs is much better before the turbo comes in and then the mid-range pull for overtaking is greatly improved leading to a good chunk of torque-steer when booted. It's the missus daily driver and she drives 26 miles each way to work on single carriage A roads so she is very pleased with the grunt for getting past the 40mph lot.

As the EGR valve was getting stuck open/closed (codes popped up on check during service), I took it out (b*$tard of a job) and de-coked it but the valve solenoid was obviously faulty as the issues continued. I looked at replacing which was £160 for the part only so having the EGR Delete and Remap for £250 from SP Tuning was a no-brainer really and I shouldn't get any future aggro from the EGR either! When you realise what the EGR's are for and how they function, it is obvious they are a fudge to help keep the emissions down when new for gov't testing but in actual fact compromise the fuel system and lead to worse MPG/problems in older cars. Definitely better without the EGR even before the Remap!

[Captain Nick]

Just an update for future reference regarding the Remap. The EGR code delete is still working fine and have had no problems with the car, i.e. no Check Engine lights or other codes pooped up and the car is still performing well.

Regarding the fuel consumption after the Remap we now have 2 consistent months of data to compare with the previous driving before the Remap which is generally the same routes as it is used daily to drive to work.

Before Remap = 57 MPG Ave
After Remap = 54 MPG Ave

This is calculated and not according to the on board computer as it is not truthful! 3 MPG loss for those gains is to me, worthwhile, but it may be of use to some people in their decision making.