2008 F150 Starting Issues

155

Asked by Jeffrey Jan 11, 2017 at 01:20 AM about the 2008 Ford F-150 Lariat SuperCrew 4WD

Question type: Maintenance & Repair

My 2008 F150 has been having intermittent no start, no crank when the engine is hot. I've already replaced the battery, starter, digital transmission range switch (neutral safety switch) but still no luck. I checked the cable connections (clean & tight), and tested the fuses and relay (good). Today I tested the continuity of the ignition switch. It appears to be working but I'm not sure about voltage-wise or if it can fail at hot temperatures. I've also read that a relay could fail intermittently?

Here's what I know, when I checked the ignition terminal on the starter, the test light did not come on. This led me towards the ignition switch. I have constant 12 volts at terminal 4 (green wire with purple stripe) but none of the other wires have voltage. Should the other wires get voltage based on the position of the switch? In my Haynes repair manual they only show the terminal 4 wire (green wire with purple stripe) and terminal 7 (red wire with blue stripe). according to the diagram, it seems like terminal 7 should only have voltage when key is turned to start. Is that correct?

I couldn't find information on what terminal 1 is (blue wire with green stripe), terminal 2 is empty,
terminal 3 (solid yellow wire) goes to multi-function switch if I'm correct, terminal 4 (green wire with purple stripe) constant hot,
terminal 5 (black wire with pink stripe) instrument panel (I think??),
terminal 6 (black wire with green stripe) I couldn't find info on,
terminal 7 (red wire with blue stripe) goes to starter when key is in "start"

Could it still be the ignition switch? Is it most likely just a break in the wire somewhere? Could it be an intermittent failing relay or fuse? How can I pinpoint the issue?

2 Answers

189,445

Lets step away form the ignition for a moment and look at a other things that would cause a no start under hot conditions. I would look at the crank position, if heated it could cause the truck not to start. You need to check the fuel pressure when the truck is cold and when the truck is hot. Look at the fuel relay test it when the truck is hot and cold.

4 people found this helpful.

Your Answer:

Own this car?

Share your experience with others.

2008 Ford F-150

Review another car

CarGurus Experts

  • #1
    OJ
    Reputation
    42,510
  • #2
    Gene Arnett
    Reputation
    16,040
  • #3
    Rowefast
    Reputation
    15,860
View All

Know more, shop wisely

Search

Related Models For Sale

Used Chevrolet Silverado 1500
4,160 Great Deals out of 123,229 listings starting at $1,999
Used GMC Sierra 1500
1,891 Great Deals out of 72,257 listings starting at $1,900
Used Ford F-250 Super Duty
1,289 Great Deals out of 51,787 listings starting at $2,905
Used Toyota Tundra
1,044 Great Deals out of 31,840 listings starting at $2,999
Used Toyota Tacoma
2,176 Great Deals out of 55,929 listings starting at $3,995
Used Dodge RAM 1500
76 Great Deals out of 1,407 listings starting at $650
Used Ford Mustang
947 Great Deals out of 19,852 listings starting at $1,950
Used Ford Ranger
656 Great Deals out of 21,674 listings starting at $1,900
Used Chevrolet Silverado 2500HD
1,016 Great Deals out of 40,369 listings starting at $2,495
Used GMC Sierra 2500HD
543 Great Deals out of 24,583 listings starting at $3,995
Used Ford F-350 Super Duty
717 Great Deals out of 28,767 listings starting at $4,984
Used Ford Explorer
2,384 Great Deals out of 56,614 listings starting at $1,950

Used Cars For Sale

2024 Ford F-150 Lariat SuperCrew 4WD For Sale
11 Great Deals out of 7,001 listings starting at $54,995
2023 Ford F-150 Lariat SuperCrew 4WD For Sale
88 Great Deals out of 1,351 listings starting at $34,988
2022 Ford F-150 Lariat SuperCrew 4WD For Sale
114 Great Deals out of 1,300 listings starting at $29,900
2021 Ford F-150 Lariat SuperCrew 4WD For Sale
165 Great Deals out of 1,843 listings starting at $21,999
2020 Ford F-150 Lariat SuperCrew 4WD For Sale
59 Great Deals out of 726 listings starting at $17,995

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.