2015 tucson
 

Currently have a 2015 tucson that runs poorly on cold start. Vehicle has recently had new short block installed due to oil consumption issues. Due to parts availability, vehicle sat for nearly 4 months waiting on all the additional parts to make a complete engine. Customer received vehicle back after engine install and unit ran fine for 2 days then returning with the runs poor on cold start, runs rough. After a few test drives and data streams, system finally showed rich fuel codes. Removed high pressure fuel system pump, found fuel leaking from seal around pump piston. New high prssure pump installed. Ran great first day but after set outside cold and restart in the morning, again runs poorly on cold start, idle erratic and rough. Data stream not indicating anything out of specs.

What are some things we should be looking at that we might be missing. We are a chevrolet store so some of our data stream infor will be limited. Closest hyundai dealer 2 hours away and does not want to look at it or even assist.

Any thoughts or ideas would be greatly appreciated!

Can you you post some of the data stream info ?
We sometimes overlook the simple basic things and that leads me to ask if we know if the ECT sensor is accurate. How does it run when warmed up?

once warmed up the unit runs perfect.

I'll try to get some fresh data stream information and post as soon as i can.

thanks for the response.