Rough start

LIZ4RD

MEMBER
2000 PONTIAC BONNEVILLE
3.8L
V6
2WD
AUTOMATIC
212,600 MILES

Hi I have the car listed above series2 motor. I am have a problem with starting. When the motor is cold the car wont start unless I give it gas. I have checked the MAP and, MASS airflow sensors, cleaned the entire throttle body and IAC valve all seems to be working fine. I also have no codes and the fuel pressure good. It has new plugs and wires too. Any suggestions?

Tuesday, January 29th, 2019 AT 8:11 PM

5 Replies

ASEMASTER6371

MECHANIC
52,796 POSTS

Good morning,

What is the exact fuel pressure?

When you say give it gas, do you mean you pour gas into the intake or just push the pedal? If it is push the pedal, that is an indication of the IAC not functioning. It cannot be cleaned or serviced.

The scan tool range is 0 to 255. Displays the commanded position of the idle air control pintle in counts. A larger number of counts means that more air is being commanded through the idle air passage. IAC Position should respond fairly quickly to changes in engine load to maintain desired idle RPM.

Roy

Image (Click to make bigger)

Was this

answer

helpful?

Yes

Wednesday, January 30th, 2019 AT 4:30 AM

LIZ4RD

MEMBER
32 POSTS

That makes a lot of sense because I tested the IAC by taking it out and plugging it in to see if it works and it moved very slowly. I do not have a fuel pressure gauge but I pushed the tire stem on the fuel rail and has strong pressure. The fuel pump and filter was replaced recently like 1,000 miles or so I did not think it would be a fuel issue.

Was this

answer

helpful?

Yes

Wednesday, January 30th, 2019 AT 5:10 AM

ASEMASTER6371

MECHANIC
52,796 POSTS

I would not assume it is not a fuel issue until you can verify it is good. I would test it to be sure.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Roy

Was this

answer

helpful?

Yes

Wednesday, January 30th, 2019 AT 5:30 AM

LIZ4RD