Ok. I've decided to do a thread on my TD4 SE, dedicated to its misfire and what I've done and what I am doing to track down the cause.
Things I've done up to this point are as follows.
First off, about 2 months or so ago, I disabled the EGR valve. After this, I noticed a slight misfire at around 2K Rpm on a trailing throttle.
Reactivating the EGR seemed to cure the problem. However I also decided to start using a fuel additive to help clean the fuel system.
All was well for a few weeks, until 2 weeks ago, I half filled the tank with fuel from my normal budget station but neglected to put in my additive.
Within a few miles, the engine started missing and generally mess about, mostly on light and training throttle.
So I added a dose of my normal additive and half filled the tank with V Power.
This made little difference so I decided to investigate further.
I had already serviced the engine in January, with the exception of a fuel filter as it looked very recent. I filled the engine with quality 5w30 semi, fitting a genuine oil filter and CV filter. At the same time I cleaned out the black goo from the intake system.
Last weekend I changed 3 glow plugs and I fitted a budget £25 MAF off Ebay, which I would normally avoid tbh. At the same time I checked all the injector plugs and did a resistance check on the injector loom. I also blanked the EGR pipes again and took it for a good run. The engine initially ran well, giving more low down torque and losing that delay in power when pressing the throttle.
However once the engine was warmed, it started missing at all throttles except full throttle. So I checked the live values of various sensors to see if I could find a cause.
MAF showed 540 Grams Per Cylinder Per Stroke at idle to around 1500 GPCPS at full throttle @ 3.5K Rpm.
The MAP was 100 KPa at idle to 190 Kpa at 3.5K Rpm.
Low fuel pressure was 360 KPa at idle, dropping to 320 KPa at full throttle.
High pressure fuel rail was 25,000 KPa at idle climbing to around 100,000 KPa @ 3.5K Rpm.
So nothing obviously wrong there.
So last Monday I decided to reactivate the EGR valve for my journey home. Well that was one interesting drive. The engine misfire was very obvious, the instant I drove out of my carpark. Only this time, the missing was accompanied by plumes of black smoke. I drove home, mostly at full throttle, because that was the only time the smoke cleared.
I had other more pressing things going on the rest of the week, I used the wife's Kuga parking the Freelander up until today's fun.
Today I swapped out the Ebay MAF for the original. I also noticed that the oil level appeared high. However that could be me overfilling the engine when I changed it. It didn't smell of diesel but I'll keep an eye on it.
I also decided to go "old school" and use my trusty stethoscope to listen to the injectors running. It was quite interesting to hear them in operation. More interestingly injectors 1 and 2 sounded different to injectors 3 and 4.
1 and 2 clicked with a very hard metallic clack.
3 and 4 made a softer tick, 3 was the quieter than 4.
I listened the injectors at idle and at 2,000 Rpm.
I also checked the injector loom and connectors again.
I also blanked the EGR pipes again. I had also noticed that the engine never goes above 75°C. I assume that the thermostat has stuck open. So I fitted a Renault 5 stat in the top rad hose. That was fun, but it was worth the effort as the engine now gets to 86°C.
That's where I'm at to this point. The car ran fine on the short test drive. I'll see how it goes this week.
If anyone has any ideas on this, then post them up.
I'm suspecting that an injector or two will ultimately fix this, but I want to exhaust all other possibilities first.
Things I've done up to this point are as follows.
First off, about 2 months or so ago, I disabled the EGR valve. After this, I noticed a slight misfire at around 2K Rpm on a trailing throttle.
Reactivating the EGR seemed to cure the problem. However I also decided to start using a fuel additive to help clean the fuel system.
All was well for a few weeks, until 2 weeks ago, I half filled the tank with fuel from my normal budget station but neglected to put in my additive.
Within a few miles, the engine started missing and generally mess about, mostly on light and training throttle.
So I added a dose of my normal additive and half filled the tank with V Power.
This made little difference so I decided to investigate further.
I had already serviced the engine in January, with the exception of a fuel filter as it looked very recent. I filled the engine with quality 5w30 semi, fitting a genuine oil filter and CV filter. At the same time I cleaned out the black goo from the intake system.
Last weekend I changed 3 glow plugs and I fitted a budget £25 MAF off Ebay, which I would normally avoid tbh. At the same time I checked all the injector plugs and did a resistance check on the injector loom. I also blanked the EGR pipes again and took it for a good run. The engine initially ran well, giving more low down torque and losing that delay in power when pressing the throttle.
However once the engine was warmed, it started missing at all throttles except full throttle. So I checked the live values of various sensors to see if I could find a cause.
MAF showed 540 Grams Per Cylinder Per Stroke at idle to around 1500 GPCPS at full throttle @ 3.5K Rpm.
The MAP was 100 KPa at idle to 190 Kpa at 3.5K Rpm.
Low fuel pressure was 360 KPa at idle, dropping to 320 KPa at full throttle.
High pressure fuel rail was 25,000 KPa at idle climbing to around 100,000 KPa @ 3.5K Rpm.
So nothing obviously wrong there.
So last Monday I decided to reactivate the EGR valve for my journey home. Well that was one interesting drive. The engine misfire was very obvious, the instant I drove out of my carpark. Only this time, the missing was accompanied by plumes of black smoke. I drove home, mostly at full throttle, because that was the only time the smoke cleared.
I had other more pressing things going on the rest of the week, I used the wife's Kuga parking the Freelander up until today's fun.
Today I swapped out the Ebay MAF for the original. I also noticed that the oil level appeared high. However that could be me overfilling the engine when I changed it. It didn't smell of diesel but I'll keep an eye on it.
I also decided to go "old school" and use my trusty stethoscope to listen to the injectors running. It was quite interesting to hear them in operation. More interestingly injectors 1 and 2 sounded different to injectors 3 and 4.
1 and 2 clicked with a very hard metallic clack.
3 and 4 made a softer tick, 3 was the quieter than 4.
I listened the injectors at idle and at 2,000 Rpm.
I also checked the injector loom and connectors again.
I also blanked the EGR pipes again. I had also noticed that the engine never goes above 75°C. I assume that the thermostat has stuck open. So I fitted a Renault 5 stat in the top rad hose. That was fun, but it was worth the effort as the engine now gets to 86°C.
That's where I'm at to this point. The car ran fine on the short test drive. I'll see how it goes this week.
If anyone has any ideas on this, then post them up.
I'm suspecting that an injector or two will ultimately fix this, but I want to exhaust all other possibilities first.
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