I have been trying to set the timing for the past week...i have read its suppose to be 10 dbtdc...have tried moving it 1 degree before and after and cant seem to make this thing run decent....i am unplugging the spout to distributor before throwing a light on it....nothing seems to work...truck just bogs and dogs, no snap...also get popping when under load starting out...or riding along at 25 mph. Any help or suggestions would be great.

 

Your 91 should have a TFI-IV ignition and the timing is set by the computer. Your Thick Film ignition module may have crapped out. Accel has an aftermarket, I bet standard does as well.

 

ReAx is right, your TFI module may be starting to puke out on you. Also your timing chain may have stretched a little and jumped a tooth on the timing gear. Bring your #1 piston to TDC on the compression stroke, your rotor button should be pointing to #1 plug boot on the distributor cap, if not you have problems. Also check your plug wires to make sure its in the right order.

 

This is a brand new motor...less then 16,000 miles on it...when i first put the motor in i got it right away....since then i have replaced fuel filter, plugs, rotor,cap and wires again....it was running good, then slowly started to get the popping as if it were carburated and back firing.....i have gone forwards and backwards with the distributor...1 degree at a time...test drive, then adjust , testdive adjust....etc....also i noticed when im looking at the marks with the light and the spout plugged in...there seems to be alot of movement...say its set at 0, it will fluctuate 10 or degrees to the advance.....and also when i set at 10 btdc and then plug the spout in, the computer will advance it way farther then it should be...is this another sign of the TFI going out....Thanks for the help.

 

I just looked up TFI module....on search....come to find out ford had a recall on these....alot of the same things i have been experiencing were listed....Thanks again to you guys for the input....Hopefully happy motoring this wknd now that we have snow and i can get this thing running! Later.

 

not only a recall, but a class action law suit. I got a letter a few years ago saying I was entitled to lots of money because it could go out with out any notice and kill you! You might want to ask about it, or see if your still covered under the recall for a free part.

 

With the spout disconnected it should always return to where you set your timing. With the spout connected, the computor takes over and advances the timing as it sees fit.

 

Have you checked for play in the timing chain? With the SPOUT disconnected, there shouldn't be much movement of the timing at all--maybe a degree or two at most.

 

Thanks Eric for the thought...i have a brand new timing chain on this motor....Im going with Reax's and desert daves theory of the TFI is going bad...am presently contacting Ford here in Wisconsin to see if this is covered under the recall, if not i will change it myself this wknd...Thanks again...

 

From what I've read on the boards, it seems like either the TFI works or it doesn't--there's no in-between, or "going out" phase. I'd be more likely to think that it is the hall effect pickup in the distributor, but without testing any of the system, I don't know for sure. I think some autoparts stores can test the TFI module (and I believe there is a test procedure in most repair manuals) if you want to test it before replacing.

 

Just an update....installed new TFI....re-set timing and still get popping as if backfiring when accelerating.....if i slowly give it gas to accelerate, much less popping....when i kick it down to pass, much more popping but truck accelerates...checked plugs and wires again....wires are 2 months old..no wear and tear...plugs look clean...no odd colors.....im at a loss with this ford.....

 

Clogged fuel filter maybe?

 

I have changed the fuel filter....seems to be getting plenty of gas....and spark...found that out the hard way...lol....got tickled when checking the plugs. I am stumped....thinking possibly throttle position sensor...its worth a shot...just have to nickle and dime it till i get it or someones going to end up with a nice parts truck....lol

 

Briguy, you need to find the absolutes first before buying a bunch of parts you don't really need. You need 3 things for a motor to run; air, gas and spark. But it all has to come together in harmony for it to work.

First thing is to establish where the piston is, in relationship to the cam. Bring your #1 piston (passenger side front piston) to TDC on the compression stroke. Check your timing mark and verify that your pointer is on the "0". If not then you have problems, if yes try the next step.
Second do a compression check. Remove all spark plugs, open throttle fully, disconnect the fuel supply by tripping the fuel cutoff switch under your dash.
Since this is a new motor you should get at minimum 140-150 psi per cylinder.
If these 2 tests come out with positive results then you have a spark issue.
Let us know what you find out.

 

new motor 16,000 later it starts popping

sounds like ignition but it can be valve train.....

pull the valve covers and make sure everything is working like it should. Almost sounds like a real loose rocker or a bent push rod...might even be a bad cam lobe if it's a flat tappet cam.


I had a rocker stud brake on my truck the other day, it was an exaust on #1 and it popped real bad up thru the intake....came on like a switch, but I'm thinking in your case it must have started slowly...did it??? and did you ever or do you hear and ticking noise coming from the valve covers?

most ignitions today or like light bulbs they work or they don't