backfire

old man b2 89 · Nov 28, 2015

i have worked on my 89 2.9 for 6 months, now i am calling the big guns, lost a head gasket filled the pan with water, ran it for a day about 50 miles, it ran good, now it idles great but has no power and back fires threw the intake during accelration, checked timing compression new plugs wires dist cap, anything anyone has because i am ready to give up

enjr44 · Nov 30, 2015

Need a lot more info. There is a lot missing between blowing head gasket and backfires.

RonD · Nov 30, 2015

Spark timing needs to be set at 10-12deg BTDC with SPOUT connector removed, this stops computer from advancing spark during base spark timing.

recheck firing order, I know you have checked it 2 or 3 times, but one more time won't hurt and it is free.
And follow each wire to its spark plug, 1 and 2 and 4 and 5 are easy to reverse.

old man b2 89 · Dec 2, 2015

will go check wires again, is it possible i took the cam out with the watered down oil , it dose run exactly like a wire in the wrong place, i put new wires on it but have bought bad ones before, thanks will be back on friday i did set the timing at 10 with spout disconected

mic98xlt · Dec 4, 2015

I chased a no start, sometime start and run, plus an loss of spark and engine shutoff after only 30 minutes run period on my '87 B2 2.9l for quite some time. I tried a variety of shotgun remedies such as new wires, spark plugs, rotor and distributor cap, 2 TFI's and remote mounting the TFI's to eliminate a possible heat related issue along with checking and rewiring the engine harness (solder and clean connections). It sometimes seemed like it was a timing issue also by the way it ran.
The final remedy was replacing the distributor itself as being the real culprit. Somehow after running for a short time the inside magnetic vane would somehow spin out of tune or timing and not produce the proper wavelength to support the TFI ignition system. Maybe this is not your issue but it was something I never imagined with the internal electronics of the distributor going wacky inside the distributor.

old man b2 89 · Dec 5, 2015

my son has his bronco hear i will go grab his dist. an give it a try. at this point i will try any thing, going to buy another new set of plug wires today an try that also, i miss my b2

RonD · Dec 5, 2015

Back firing is either firing order mistakes or if only on acceleration a lean fuel mix or improper computer spark timing advance/retard.

kimcrwbr1 · Dec 5, 2015

Did you check for slop in the timing chain? Pull the distributor cap and put a wrench on the crank and turn the crank clockwise to TDC marks line up then watch the rotor on the distributor and turn the crank counterclockwise until the rotor begins to move. Any more than a few degrees and you need to replace the chain and sprockets. I recommend replacing the water pump while you have it apart, unless its new!

old man b2 89 · Dec 12, 2015

thank you all very much, used all of your stuff but problem is still there, pushing it out back and let the black berries grow over it, done.

old man b2 89 · Jan 16, 2016

ok so i didnt let the berries get it , studied all answers but RonD and the lean fuel got it, exhaust temp on 3 and 5 at and idle were up and down all other ones stayed the same, so went with a new set of injectors at fixed the problem I think what happened was i broke my arm and the motor was apart for a couple of months, an maybe rust or something got to the injectors , but all is good in my world again thanks to all,

RonD · Jan 16, 2016

old man b2 89 said:
ok so i didnt let the berries get it , studied all answers but RonD and the lean fuel got it, exhaust temp on 3 and 5 at and idle were up and down all other ones stayed the same, so went with a new set of injectors at fixed the problem I think what happened was i broke my arm and the motor was apart for a couple of months, an maybe rust or something got to the injectors , but all is good in my world again thanks to all,

Good Work

Thanks for update and posting the fix

backfire

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