Mister Dee
New member
Hi all, new to the forum, and new to the many mysteries of Punto ownership.
My car is a 1996 Punto GT2 with 88,000 miles on the clock. It was very cheap; I think I can see why now
.
A few days after driving the car home with no issues, the Punto all of a sudden decided to run like a dog!
It has been spluttering, popping and farting when the revvs drop below 2000 rpm. The revvs plummet to 500 rpm and it takes a while for the revvs to build back up too.
The little injector symbol sometimes appears on the dashboard. The Punto also misses at low revvs now too.
Not being a mechanic, I thought I'd start with the simple things first. I removed the spark plugs, they were all covered in soot; so I know the engine is running too rich - I suspected it when the car started popping and farting the first time. After cleaning the spark plugs the car ran a little better at first, but as soon as the car became warm the coughing and spluttering started again.
A friend suggested that I try the temperature sensor. I checked the sensor against values quoted by Auto Data and the sensor appears to be working fine.
I checked the throttle body; it was quite clean; but I decided to give it a clean up any way.
I tried unplugging the leads to the throttle position sensor while the engine was running and it made no noticeable difference to the engine.
I have tried cleaning the idle control valve, and I have tried disconnecting the leads to the idle control valve while the engine is running; but it doesn't make a difference to the way the engine runs.
I noticed that the crank sensor wasn't connected; connecting it didn't make a difference; and I'm puzzled as to how the car can start fine without it being connected. I thought the crank sensor and the TDC sensor had to give signals to each other and the ECU for the car to start? But, I'm not a mechanic, so what do I know?
I tried removing the leads for the Lambda sensor while the engine was running, but it didn't make a noticeable difference to the engine.
I then moved on to the after market massive boy racer air filter that the previous owner had added. After cleaning the filter I realised that the MAF sensor was fitted back to front. I reversed the MAF sensor to its intended position and started the car.
I don't know how, but the car doesn't miss on start up any more and it idles fine. Could an incorrectly fitted MAF sensor really cause the engine to miss?
I couldn't believe it! I was just about to open a can of Carlsberg in celebration and then the revvs dropped to 500 rpm and the engine started missing and popping and farting like a 50 year old flat four.
The engine idles fine until it gets to a certain temperature and then it runs like a dog. When the engine starts to run like a dog the dashboard temperature gauge needle is up to about 1/3. I used an infra-red thermometer to check the temperature of the coolant and it was 85 degrees.
The fan works fine on the car. Sometimes the fan will come on twice and the engine is fine, but when the fan comes on for the third time the engine runs badly. Maybe it's just a coincidence?
Can anyone help me with this Punto of mine please? I've tried just about everything I can think of. My last check will be the Lambda sensor. I'm not looking forward to removing it, or paying for a new one!
Regards,
Tony
My car is a 1996 Punto GT2 with 88,000 miles on the clock. It was very cheap; I think I can see why now
.A few days after driving the car home with no issues, the Punto all of a sudden decided to run like a dog!
It has been spluttering, popping and farting when the revvs drop below 2000 rpm. The revvs plummet to 500 rpm and it takes a while for the revvs to build back up too.
The little injector symbol sometimes appears on the dashboard. The Punto also misses at low revvs now too.
Not being a mechanic, I thought I'd start with the simple things first. I removed the spark plugs, they were all covered in soot; so I know the engine is running too rich - I suspected it when the car started popping and farting the first time. After cleaning the spark plugs the car ran a little better at first, but as soon as the car became warm the coughing and spluttering started again.
A friend suggested that I try the temperature sensor. I checked the sensor against values quoted by Auto Data and the sensor appears to be working fine.
I checked the throttle body; it was quite clean; but I decided to give it a clean up any way.
I tried unplugging the leads to the throttle position sensor while the engine was running and it made no noticeable difference to the engine.
I have tried cleaning the idle control valve, and I have tried disconnecting the leads to the idle control valve while the engine is running; but it doesn't make a difference to the way the engine runs.
I noticed that the crank sensor wasn't connected; connecting it didn't make a difference; and I'm puzzled as to how the car can start fine without it being connected. I thought the crank sensor and the TDC sensor had to give signals to each other and the ECU for the car to start? But, I'm not a mechanic, so what do I know?
I tried removing the leads for the Lambda sensor while the engine was running, but it didn't make a noticeable difference to the engine.
I then moved on to the after market massive boy racer air filter that the previous owner had added. After cleaning the filter I realised that the MAF sensor was fitted back to front. I reversed the MAF sensor to its intended position and started the car.
I don't know how, but the car doesn't miss on start up any more and it idles fine. Could an incorrectly fitted MAF sensor really cause the engine to miss?
I couldn't believe it! I was just about to open a can of Carlsberg in celebration and then the revvs dropped to 500 rpm and the engine started missing and popping and farting like a 50 year old flat four.
The engine idles fine until it gets to a certain temperature and then it runs like a dog. When the engine starts to run like a dog the dashboard temperature gauge needle is up to about 1/3. I used an infra-red thermometer to check the temperature of the coolant and it was 85 degrees.
The fan works fine on the car. Sometimes the fan will come on twice and the engine is fine, but when the fan comes on for the third time the engine runs badly. Maybe it's just a coincidence?
Can anyone help me with this Punto of mine please? I've tried just about everything I can think of. My last check will be the Lambda sensor. I'm not looking forward to removing it, or paying for a new one!
Regards,
Tony
