Hello everyone, I have been having troubles with my throttle response on my 2008 Grande Punto 1.3mjet 55kw for 2 months now.
Here is my diagnosis.
First things first, my throttle is so random that I can't go anywhere without it being unresponsive. At first, I had to press the throttle 2 or 3 times slowly for it to get into revs and go. Then, it was due for me to do the clutch. My clutch was very bad and it had to go. But thought that would maybe solve it.
Keep in mind that there is no check engine and diagnostics says that P0101 code for MAF Sensor which I cleaned.
MAF was very expensive for me at the time but I replaced my MAP sensor (Manifold Apsolute Pressure), thought that it would fix it. Old MAP was very dirty, couldn't see any signs of shiny metal in there. At the same time, I cleaned my old MAF with brake cleaner and it somewhat sorted my issue. At that time, I also removed half of my EGR, the actuator thingy to see if it was maybe stuck or something. Had a peak through MAP Sensor hole and other holes, intake didn't have that much of carbon buildup - yes, there was some of it but it was a very thin layer.
It seemed to me that the issue was fixed until I got stuck in traffic and had to go in reverse a few times to park. Then my throttle response in reverse gear was very weird, car was stalling like 3 times in 5 meters if I go into reverse. I had to go into 3000 rpms and relase the clutch slowly like a noob driver to go.
Then, after I did my clutch all issues were still present, still had issues with going in reverse. P.S. Crankshaft position sensor was cleaned when clutch was replaced.
Then, with diagnostics we found out that 2nd injector was almost dead and was spreading too much fuel and other 3 were trying to compensate that. After changing the 2nd injector, all 4 were great. Pressure in common rail was spot on and fuel pressure regulator was 100% working.
Then car went like crazy for about 2 hours, when I parked it and wanted to start it tomorrow morning it kept stalling itself. I turn on the engine, works for about 2 seconds on 900 rpms normally, for 2 seconds goes to 500 rpms and just stalls itself. No throttle response at all. Then bought a brand new MAF Sensor and same happened tomorrow morning when I wanted to start the car.
My mechanic told me to disconnect the MAF Sensor and I drove to him, (car went like crazy without the MAF) we connected it to diagnostics and watched Intake Air Temperature and Amount of air. Now this is where it gets interesting, when MAF is connected it says correct Intake Air Temp which was about 12 to 15 degrees celsius this morning. But Amount of air doesn't make any sense, sometimes it's 200mg, sometimes is 11mg and starts to stall, when throttle randomly works it goes up to 350, 600 and so on up to 1000mg at 5000rpms. But when you relase the throttle it can't adjust itself at idle. Basically goes from 5mg to 350mg at idle. When MAF is disconnected it shows 40 for air temperature and that's firm, doesn't change. Which makes sense because it's disconnected. But amount of air keeps changing when I press throttle. I have my throttle response like before and there are so low imperfections in amount of air at idle that it goes so smooth in reverse. It's like 220mg to 235mg.
Another fun fact, if I disconnect the MAF Sensor it doesn't turn on the check engine lamp.
My question is now what can be the issue? MAF is brand new, fuel pressure regulator seems to be working when MAF shows 5mg of air or 0mg, it stalls the car. Injectors are all in range. My glowplugs are brand new also.
P.S. My DPF was removed by previous owner, I have no idea if it's diagnostically turned off or if the car had different remap done.
My only logic is that whoever removed the DPF left the lambda sensor before the DPF. It sends some idiotic readings to ECU and then I think it ruined my ECU. My other logic is that there is an issue with wiring but I'm not that smart to check that.
Any help would be great, thanks
Here is my diagnosis.
First things first, my throttle is so random that I can't go anywhere without it being unresponsive. At first, I had to press the throttle 2 or 3 times slowly for it to get into revs and go. Then, it was due for me to do the clutch. My clutch was very bad and it had to go. But thought that would maybe solve it.
Keep in mind that there is no check engine and diagnostics says that P0101 code for MAF Sensor which I cleaned.
MAF was very expensive for me at the time but I replaced my MAP sensor (Manifold Apsolute Pressure), thought that it would fix it. Old MAP was very dirty, couldn't see any signs of shiny metal in there. At the same time, I cleaned my old MAF with brake cleaner and it somewhat sorted my issue. At that time, I also removed half of my EGR, the actuator thingy to see if it was maybe stuck or something. Had a peak through MAP Sensor hole and other holes, intake didn't have that much of carbon buildup - yes, there was some of it but it was a very thin layer.
It seemed to me that the issue was fixed until I got stuck in traffic and had to go in reverse a few times to park. Then my throttle response in reverse gear was very weird, car was stalling like 3 times in 5 meters if I go into reverse. I had to go into 3000 rpms and relase the clutch slowly like a noob driver to go.
Then, after I did my clutch all issues were still present, still had issues with going in reverse. P.S. Crankshaft position sensor was cleaned when clutch was replaced.
Then, with diagnostics we found out that 2nd injector was almost dead and was spreading too much fuel and other 3 were trying to compensate that. After changing the 2nd injector, all 4 were great. Pressure in common rail was spot on and fuel pressure regulator was 100% working.
Then car went like crazy for about 2 hours, when I parked it and wanted to start it tomorrow morning it kept stalling itself. I turn on the engine, works for about 2 seconds on 900 rpms normally, for 2 seconds goes to 500 rpms and just stalls itself. No throttle response at all. Then bought a brand new MAF Sensor and same happened tomorrow morning when I wanted to start the car.
My mechanic told me to disconnect the MAF Sensor and I drove to him, (car went like crazy without the MAF) we connected it to diagnostics and watched Intake Air Temperature and Amount of air. Now this is where it gets interesting, when MAF is connected it says correct Intake Air Temp which was about 12 to 15 degrees celsius this morning. But Amount of air doesn't make any sense, sometimes it's 200mg, sometimes is 11mg and starts to stall, when throttle randomly works it goes up to 350, 600 and so on up to 1000mg at 5000rpms. But when you relase the throttle it can't adjust itself at idle. Basically goes from 5mg to 350mg at idle. When MAF is disconnected it shows 40 for air temperature and that's firm, doesn't change. Which makes sense because it's disconnected. But amount of air keeps changing when I press throttle. I have my throttle response like before and there are so low imperfections in amount of air at idle that it goes so smooth in reverse. It's like 220mg to 235mg.
Another fun fact, if I disconnect the MAF Sensor it doesn't turn on the check engine lamp.
My question is now what can be the issue? MAF is brand new, fuel pressure regulator seems to be working when MAF shows 5mg of air or 0mg, it stalls the car. Injectors are all in range. My glowplugs are brand new also.
P.S. My DPF was removed by previous owner, I have no idea if it's diagnostically turned off or if the car had different remap done.
My only logic is that whoever removed the DPF left the lambda sensor before the DPF. It sends some idiotic readings to ECU and then I think it ruined my ECU. My other logic is that there is an issue with wiring but I'm not that smart to check that.
Any help would be great, thanks
- Model
- Grande Punto
- Year
- 2008
