2000 Geo Prism 1.8 driving me crazy

[Raw16057]

Hello, my son cooked his motor by not putting oil in it. I bought another motor took his out and installed new one. changed all the sensors bought new o2 sensor. This engine will not idle, starts good but backfires through the exhaust. the exhaust gets really hot, so much that tailpipe hanger smokes I have eliminated all the codes except RANDOM MISFIRES. I am at a loss on what to do next. I know this is as far away from Rangers as It can be but I have to get this fixed and need help.

 

[srteach]

Check the timing. Random backfires suggest that, as do all the other symptoms you mentioned.

 

[Raw16057]

I thought about that too and pulled the valve cover and all the timing marks lined up on the chain. this motor has no distributor.computer controlled.

 

[cammeddrz]

i have a 2001 prizm and had this same problem after a head gasket job, check and see if you mis-matched the vacuum hose that goes to the fuel pressure regulator, and the return line. it's easy enough to mistake and will pour fuel directly into the intake manifold any time the fuel pump is running

 

[Raw16057]

I hope that will work, but could you give me more info as to what hoses I need to change.I had my bro in law look at it and he said the presssure regulator is on the fuel rail in the middle and there are no hoses but the fuel line. Do you mean hoses coming off the intake? I sent you a PM also.

 

[Raw16057]

i finnaly found the problem. The intake was at one time bent into the motor which caused two small holes. i changed the intake from the old motor and it runs like a charm. Thank you guys for your input.