GM Service Manual Online
For 1990-2009 cars only

CNG Pressure vs Percent Full

kPa (psi)¹

-50°C (-18°F)²

-30°C (3°F)²

-9°C (23°F)²

11°C (43°F)²

32°C (54°F)²

53°C (84°F)²

73°C (105°F)²

93°C (125°F)²

114°C (146°F)²

134°C (166°F)²

156°C (187°F)²

2825 (410)

17%

15%

13%

12%

11%

11%

10%

9%

9%

8%

8%

5650 (819)

40%

34%

29%

26%

24%

22%

20%

19%

18%

17%

16%

8474 (1229)

79%

59%

49%

41%

38%

34%

31%

29%

27%

25%

24%

11299 (1638)

115%

87%

70%

56%

50%

45%

41%

38%

36%

33%

31%

14124 (2048)

122%

109%

85%

73%

65%

60%

53%

48%

45%

42%

39%

16949 (2458)

122%

122%

101%

88%

79%

71%

65%

58%

54%

50%

47%

19774 (2867)

122%

122%

116%

100%

90%

81%

75%

67%

63%

59%

55%

22599 (3277)

122%

122%

122%

112%

100%

92%

83%

76%

70%

66%

62%

25453 (3686)

122%

122%

122%

122%

109%

100%

90%

84%

78%

74%

70%

28248 (4096)

122%

122%

122%

122%

111%

103%

96%

90%

84%

80%

76%

¹This indicates the fuel pressure inside the CNG fuel tank.

²This indicates the temperature of the fuel inside the CNG fuel tank.

Use the table in order to determine the amount of fuel vs fuel tank capacity.