my manifold is cracked right before the O2 sensor

im just wondering can a cracked manifold (if it has a decent crack) cause the o2 to give a bad reading and give starting issues? (flooding easy, long cranks, etc)

we just tried to crank it and held the throttle wide open and it started.

my truck seems to have a starting issue even after i have changed the following:

- all main grounds + new battery to body
- TPS
- Coil
- Plugs, wires, cap/rotor
- fuel pump
- injector seals
- new battery
- starter

 

21 views and no reply??? BUMP

 

i know the crack can throw off the 02 censor and ruin your mpg's but my 89 was cracked pretty bad and didnt affect the starting at all it started fine just sounded like a diesel

 

Is the TPS adjusted properly? Hows the fuel filter? Power wire to coil broken or grounding out anywhere?

 

yes tps is adjusted.

wires are fine

 

bump....

 

If air is leaking into the exhaust pipe, it will cause the O2 sensor to read lean. That will make the computer add fuel so the engine will run too rich when it thinks it's lean...

 

While Renix are retarded, they're pretty strong little guys, and they'll try to run in any condition.

I can't precive an 02 sensor giving a hard starting condition, seeing as how the motors basically running on injector pulse. If, while giving it throttle, it cranks better, I'd focus on the TPS first.

 

the TPS is brand new and adjusted

 

did you check crank position sensor? does renix have one
serious cracks before o2 sensors effects everything. small ones may not.