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

71,415

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

47,805

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.

71,415

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.

71,415

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.

47,805

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

  • My 79 f150 started backfiring & now wont start 6 answers

    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...

    Ford F-150

    -

    Maintenance & Repair

  • My 2006 f150 wont start 1 answer

    I changed the batterie on my truck, and the starter and truck wont start. Wen i changed the starter it started and i drove it and after i parked it it wont start. When i turn the key to start it i ...

    2006 Ford F-150 Lariat SuperCab 4WD

    -

    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

  • My 2006 f150 wont start 2 answers

    What is a saver tool? I went through 4 batterys at auto zone last week trying to figure out what was wrong with my truck. I really have tried everything to fix my truck i wish that somebody could ...

    2006 Ford F-150 Lariat SuperCab 4WD

    -

    Maintenance & Repair

  • My 2006 f150 wont start 1 answer

    Ok well i have changed my battery, my starter, and starter relay and truck still wont start. I had a guy hook up a amp to my factory radio befor this all started and wondering if he screwed my truck...

    2006 Ford F-150 Lariat SuperCab 4WD

    -

    Maintenance & Repair

F-150

Looking for a Used F-150 in your area?

CarGurus has 207,340 nationwide F-150 listings starting at $1,499.

ZIP:

Search Ford F-150 Questions

Ford F-150 Experts

#1 OJ
OJ
Reputation 8,210
#2 dandyoun
dandyoun
Reputation 4,390
#3 tennisshoes
tennisshoes
Reputation 2,880
View All

Related Models For Sale

Used Chevrolet Silverado 1500
1,764 Great Deals out of 181,202 listings starting at $250
Used GMC Sierra 1500
760 Great Deals out of 69,126 listings starting at $1,850
Used Dodge Ram 1500
411 Great Deals out of 10,833 listings starting at $1,400
Used Ford F-250 Super Duty
328 Great Deals out of 46,262 listings starting at $1,450
Used Toyota Tundra
437 Great Deals out of 34,678 listings starting at $2,990
Used Toyota Tacoma
473 Great Deals out of 41,591 listings starting at $1,995
Used Ram 1500
909 Great Deals out of 112,641 listings starting at $6,386
Used Ford Mustang
543 Great Deals out of 45,845 listings starting at $1,999
Used Ford F-250
469 listings starting at $2,000
Used Nissan Titan
177 Great Deals out of 19,078 listings starting at $3,000
Used Chevrolet Colorado
240 Great Deals out of 24,818 listings starting at $2,499
Used Ford Explorer
928 Great Deals out of 70,253 listings starting at $997
Used Chevrolet Tahoe
559 Great Deals out of 31,371 listings starting at $1,500
Used Ford Ranger
176 Great Deals out of 5,676 listings starting at $950
Used Ford F-350 Super Duty
373 Great Deals out of 25,769 listings starting at $1,995

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.