What do you recommend?

[BIll89]

I have a 89 K5 Blazer with a newly restored 2001 vortex 350 880 block (roller cam) that is running the original OBD1 TBI system with the GM Performance intake manifold. This is the second time I have restored the motor and harness..But this time I can't get the right fuel combination to dialed in... The system keeps switching from rich to lean...

Note: Everything is working no codes ....Just not working right. Fuel pump working, ECM is working.... Timing is correct....I have been using a 90 lbs fuel pump with a 18 psi regulator spring..No fuel pressure regulator and a performance chip from Harris Performance...tbichip.com. Did not have any problem the first time I used this combination.... it ran great.

Now it runs great at cold temperature... it has the complete power band...But when it warms up to operating temperature it will not accelerate at all. but will not stall out either.

Here is a list of the items I have replaced....
* New Distributor
* New control Module
* Rebuild ECM harness---that's working
* New coolant Temperature Sensor
* New Throttle control sensor- reading 0.57 on the Multi- meter
* New TBI injector OEM
*Change the IAC to a shorter shaft
* New fuel filter
* Switch back to OEM regulator spring from a 18 psi aftermarket spring

I believe it is the fuel pump going bad or I received the wrong TBI injectors not sure...

If anyone can think of what I may have missed all input will be helpful...

 

[rampage]

How are the O2 sensors?

 

[BIll89]

OEM working...according to the diagnostic

 

[BIll89]

The system goes to close loop at 110
degree..