Bad Distributor?

[macd7919]

Hey guys, I'm having an issue and hopefully it's something someone else has had so it will be an easy diagnosis. When I'm at low rpm (below 2000) every so often the engine hiccups and the tach will just drop like it's lost it's signal all of a sudden. It usually snaps right back up a second later and keeps driving like nothing happened. Today at a light it was doing it worse than ever, it kept dropping and picking back up but it got to the point where the engine was about to stall. As long as I kept my foot on the gas and kept the rpm's up (2000+) then it seemed to be fine. Once the light turned green I rev'd it out a little bit (took it up to 4k) and it seemed to run perfectly fine.

I know on Honda's when the tach suddenly drops like that it's a sign of the distributor on it's way out. Is it the same on the B2? I recently replaced the ICM (within 2 months) and it has a relatively new cap as well. Any input is appreciated, thanks guys!

 

[adsm08]

Probably a bad pickup module or coil.

Ford says you are supposed to replace all three parts as a set, apparently an old pickup or coil can draw too many amps and cook the new TFI module.

I'm dealing with the same issue right now, but all my stuff is new, so I'm not sure what's going on with mine.

 

[macd7919]

I can replace the coil and pickup but before I do so I was hoping someone might have had the same symptoms and been able to narrow down what it was. Thanks for the suggestions though!

 

[adsm08]

I have an a similar problem, (although I can't speak to the behavior of the tach) and a coil and pickup usually fixed it.

Check your spark quality. If it's poor that may be your entire problem.

 

[kimcrwbr1]

In the tech library under TFI diagnostics it shows you how to test the ignition system coil, TFI and pip coil (hall sensor) like above it could be any combination or just one. Be sure and put it on tdc #1 cylinder and mark the rotor position if you pull the dizzy.

 

[bronco_lou]

Hey guys, I'm having an issue and hopefully it's something someone else has had so it will be an easy diagnosis. When I'm at low rpm (below 2000) every so often the engine hiccups and the tach will just drop like it's lost it's signal all of a sudden. It usually snaps right back up a second later and keeps driving like nothing happened. Today at a light it was doing it worse than ever, it kept dropping and picking back up but it got to the point where the engine was about to stall. As long as I kept my foot on the gas and kept the rpm's up (2000+) then it seemed to be fine. Once the light turned green I rev'd it out a little bit (took it up to 4k) and it seemed to run perfectly fine.

I know on Honda's when the tach suddenly drops like that it's a sign of the distributor on it's way out. Is it the same on the B2? I recently replaced the ICM (within 2 months) and it has a relatively new cap as well. Any input is appreciated, thanks guys!

Have you checked to see if any codes are stored in the computer?
Louis

 

[kimcrwbr1]

Also check all the wires and connectors for cracks breaks or melting it could be an intermittent short or break somewhere just in case you haven`t already done so. Get a tube of dielectric grease to put the connectors back together and make sure all the pins are pushed all the way in and not corroded.

 

[macd7919]

I'll look into all the stuff listed above this weekend. I haven't checked the codes as I've never seen the check engine light come on. Would it still store the codes if the CEL has never flashed?

 

[macd7919]

So I can purchase the pick up for around $40 (I recently replaced the ignition coil and icm) or would i be better off just buying the whole distributor assembly with new icm for $100?

 

[kimcrwbr1]

you can check the coil in the dizzy without pulling it out use the chart to check the resistance in the tech library. Mark the position of the rotor on TDC #1 cylinder before you pull the dizzy. It woud be easier to test the coil and you can inspect the gear and shaft for any defects you will need to pull it to change the coil if you go that route just punch out the roll pin and slide the shaft out. Get a new O-ring for the dizzy if you rebuild it or it might leak when you reinstall it.

 

[kimcrwbr1]

Be careful with the cam gear when you punch out the roll pin they break fairly easy and look for side slop and end play on the shaft first.

 

[macd7919]

Would I be better off just buying a whole new distributor? At this point I would rather pay a few extra dollars for a quick repair than save money by spending time trying to single out one component. I usually wouldn't have a problem spending some time on something but I am moving in a couple weeks and I have another project that HAS to be done.

I replaced the coil today (found the plug had heat damage and appeared that the terminal had a poor connection so they were getting hot), I replaced the ICM about a month ago with a new unit (lifetime warranty) and I checked out the wiring for damage. So what is left that could be bad? Are you guys pretty confident it's the pick up/stator thats bad? If so I'll get one and install it but if it could be other things in the distributor that could cause the problem I will just buy a whole new distributor. I guess I'm just looking for a quick answer as I don't have much freetime for chasing down problems right now. Thanks guys!

 

[kimcrwbr1]

That will work as long as that is the problem from what I have read you still need to isolate the fault and throwing new parts at it will work but can get kinna spendy. especially if it is just a wiring issue at least you will have a new ignition when you get it figured out.

 

[macd7919]

Outside of the things I have replaced (coil and ICM) what else is there left besides the stator/pickup? (Assuming the issue isn't wiring)

 

[kimcrwbr1]

The computer controls the timing so for the ignition you have the ciol the TFI and dizzy coil and the computer. Have you pulled the codes you casn go to any part store and pull the codes or get a code reader. What is the year and model of your truck the tech library has alot of good info on TFI diagnostics and pulling EEC codes sometimes it is better to read all the literature first then you have a better idea how it works and where to start. Intermittent problems can be a bitch double check everything you do if you do a bunch of things it can be hard to tell the cause of the fault for future reference. I stress on using the tech library I always start with the cheapest first that be wiring and grounds check all the wires and connectors sand the grounds use dielectric grease on the connectors and make sure the pins are pushed all the way in look for shorts bare wires cracked insulation anything melted. It can be tedious and time consuming but it pays in dividends in the long term. Every time you fix something test it to see if it fixed the problem. Anything computer related grounds or sensors erase the memory then disconnect the battery for 1/2 an hour to reset the computer then get the engine hot at medium speeds before you pull the codes with the engine at normal temperature.