1989 RENIX 4.7L stroker engine is about 2 years old no major problems until now.
The problem started with what sounded like a cracked header. Pulled the header there were some cracks welded it put it back on no real improvement. Drove it for a couple of days then later when I pulled out in traffic from a stop gave it some gas loud popping cracking noises and zero power. It limped home and could only go about 25mph on level ground and still making the same noises. I open the hood and it’s defiantly backfiring in the intake. So right now it still starts and idles but it sounds terrible and it probably doesn’t have enough power to pull out of my driveway.
Here is what I have tested so far:
Compression is good it’s right around 225 in all cylinders.
It’s running rich air fuel ratio is about 10. something
Pulled the plugs they were all black except for two plugs.
I have an adjustable fuel and map. I don’t remember where I set these originally they may be off. Fuel pressure is right around 30lbs Map sensor is at 4.25v
Then I tested everything else I could think of. TPS is good, coolant and air temperature sensors are within range, O2 heating element is good. The directions I found to test the camshaft sensor was to check the voltage for the blue and gray wires it’s supposed to be 5v but I was getting 7v which would be the supply voltage. I don’t know if I did this wrong.
I need some fresh ideas because I’m running out.
The problem started with what sounded like a cracked header. Pulled the header there were some cracks welded it put it back on no real improvement. Drove it for a couple of days then later when I pulled out in traffic from a stop gave it some gas loud popping cracking noises and zero power. It limped home and could only go about 25mph on level ground and still making the same noises. I open the hood and it’s defiantly backfiring in the intake. So right now it still starts and idles but it sounds terrible and it probably doesn’t have enough power to pull out of my driveway.
Here is what I have tested so far:
Compression is good it’s right around 225 in all cylinders.
It’s running rich air fuel ratio is about 10. something
Pulled the plugs they were all black except for two plugs.
I have an adjustable fuel and map. I don’t remember where I set these originally they may be off. Fuel pressure is right around 30lbs Map sensor is at 4.25v
Then I tested everything else I could think of. TPS is good, coolant and air temperature sensors are within range, O2 heating element is good. The directions I found to test the camshaft sensor was to check the voltage for the blue and gray wires it’s supposed to be 5v but I was getting 7v which would be the supply voltage. I don’t know if I did this wrong.
I need some fresh ideas because I’m running out.