My 79 f150 started backfiring & now wont start

Asked by Sep 15, 2015 at 06:38 PM about the Ford F-150

Question type: Maintenance & Repair

I was driving My 79 F150 351M, down the freeway it was running good, had to stop quickly due to traffic, so I down shifted and braked, the truck started running sluggish and backfiring when I tried to accelerate then died, now it wont start and backfires when I do.

6 Answers

69,655

How many miles on her? And that's the 351 M 400?

46,225

It is possible that the timing chain has jumped time or broken. You will need to do a compression test to determine if this is the problem. How many miles on it. Have there been any recent repairs.

69,655

What ever you find you need to access if it is even worth fixing. I had a couple of 351 M 400s and took good care of them. Sorry to say they only go 115,000 miles before needing major repair. They are junk. At the time, any one I knew who had one they had problems at the higher mileage. Now a days 100,000 miles is nothing. But were talking the 351 M 400, Not the 351 Cleveland motor.

It is a 351M that was rebuilt at 300k, now only has maybe 20k on it, the OD isn't working. When it was rebuilt I had a double roller timing chain and gears installed, I am hoping its not that.

69,655

Well then lets get-err going, listen to Bobs input, very knowledgeable, I hope you have it somewhere so you can work on it. I myself seen this once before, and it had to do with timing. Do you know how to work on it? or have a hand. I would look at timing first, #1 TDC on compression stroke, see if rotor is pointing at #1 plug wire. It should be there. If not I have seen where the pin on the distributor gear shears, so would need to pull distributor out and inspect the gear. Let us know from there, and we'll continue to help.

46,225

Well, with a double roller timing chain and gears 20,000 miles ago, that leads me to think something else is causing the problem. Backfiring is usually a symptom of a timing issue, but not always. As Rowefast said maybe something in the distributor. 351M was a great engine that would go many miles if properly serviced. The only thing bad I remember about them was that they used lots of fuel. Keep us posted on what the repair ends up being.

Your Answer

Add photo

Related Questions

  • What's causing my 351 Modified to start backfiring...? 7 answers

    Recently, my '79 F-150 has begun to backfire and it's getting worse. It had been running rough so I replaced the plugs, wires, cap and button(?)... But now, the backfiring...! I know I have the wire...

    1979 Ford F-150

    -

    Maintenance & Repair

  • 99 f150 wont start 2 answers

    99 f150 turns over but wont start. just purchased a couple months ago , so I thought I would change plugs plug wires and coil packs. after that it still wont start. the fuel pump switch is not tripped...

    1999 Ford F-150 Lariat 4WD Stepside SB

    -

    Maintenance & Repair

  • 75 ford f150 wont start at all 2 answers

    My truck wont start when I turn the key

    1975 Ford F-150

    -

    Maintenance & Repair

  • my 90 f150 wont start 2 answers

    will turn over and I have spark at the plugs , I can hear the fuel pump come on before I turn the key over , but wont start

    1990 Ford F-150 XLT Lariat Extended Cab SB

    -

    Maintenance & Repair

  • 79 f150 wont start now 4 answers

    Was driving the truck hit a tree stump which knocked the battery out of its tray and broke a end off the starter solenoid got new starter solenoid but it will not even try to kick over now. Checked ...

    1979 Ford F-150

    -

    General

F-150

Looking for a Used F-150 in your area?

CarGurus has 206,316 nationwide F-150 listings starting at $1,499.

ZIP:

Search Ford F-150 Questions

Ford F-150 Experts

#1 OJ
OJ
Reputation 7,920
#2 dandyoun
dandyoun
Reputation 4,360
#3 tennisshoes
tennisshoes
Reputation 2,750
View All

Related Models For Sale

Used Chevrolet Silverado 1500
1,716 Great Deals out of 175,751 listings starting at $1,250
Used GMC Sierra 1500
825 Great Deals out of 68,199 listings starting at $2,484
Used Dodge Ram 1500
453 Great Deals out of 11,152 listings starting at $700
Used Ford F-250 Super Duty
344 Great Deals out of 46,938 listings starting at $1,895
Used Toyota Tundra
444 Great Deals out of 34,312 listings starting at $2,700
Used Toyota Tacoma
542 Great Deals out of 40,814 listings starting at $2,495
Used Ram 1500
925 Great Deals out of 113,958 listings starting at $6,386
Used Ford Mustang
472 Great Deals out of 45,735 listings starting at $1,999
Used Ford F-250
481 listings starting at $3,475
Used Nissan Titan
170 Great Deals out of 19,555 listings starting at $3,000
Used Chevrolet Colorado
217 Great Deals out of 24,313 listings starting at $2,495
Used Ford Explorer
946 Great Deals out of 72,518 listings starting at $1,000
Used Chevrolet Tahoe
549 Great Deals out of 29,234 listings starting at $1,699
Used Ford Ranger
197 Great Deals out of 5,805 listings starting at $1,650
Used Jeep Wrangler
277 Great Deals out of 18,163 listings starting at $2,950

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.