This car is a 1986 fc3 n/a with pulsation dampener mod,new injectors,cleaned 5th and 6th ports that work,new alt,new plugs and wires,new o2 sensor,most of the factory grounds have been cleaned,3800rpm stumble,no start when hot,Ok today I went to auto zone..I purchased an inductive timing light with advance dial on the back of the gun...I also purchased a dwell/tach/ohm meter. My question,I can get the yellow timing mark to line up with the pickup for the timing light clamped on to the front lower spark plug.But when I try to set the red mark it throws off the yellow? Is there any middle ground with the CAS adjustment? Is there anything I over looked.I am trying to set the timing with the car fully warmed up,rpm as close to 750 as humanly posibble"The car Idles like crap right now" The advance set to zero on the timing light,no jumper wire on ISC.I CAN get either one of the timing marks to hit correct,just not both at the same time?

 

did you read your chiltons

 

yes

 

More importantly, did you read the FSM?

 

just did not much help it said timing should be leading 5 atdc yellow 20 atdc red? so do I adjust my timing lights advance to 5 then 20?

 

Line up the yellow mark with 5deg. The red mark should then be on 20deg. They're not independantly adjustable (the ECU does that).

 

Well......get the yellow mark(first mark) to match the pointer using the timing light. with the timing light clamped on one of the LEAD plugs. If the mark does not align, then rotate the cas til the mark aligns with the pointer.

About the idle. After you get the timing to align, then install a jumper in the Initial Set Coupler, while the car is doing its poor idle (your description). Question: Did the car die when you do that? Or more or less stay about the same??

IF the idle stays the same whether you have the initial set coupler in or out......then I'd suspect the bac is not being controlled by the ECU....or one of the sockets/wires IN THE BAC PLUG is pushed back (a common problem).

A number of things can cause a irregular idle. Some you know about. The common ones are the vac hose leaks. You know, those small vac lines not being on their nipples.

There are some unauthorized air leaks that you probably are not aware of though. One can be the EGR valve on a series four. That would have a busted diaphram causing the problem. You can suck on the vac hose going to the EGR and tell if the diaphram is leaking or not.
A more likely one would be the acv. While the acv on the whole does not supply any air to the intake, there is one small diaphram in it that does feed air to the intake during deceleration only. But this diaphram/valve does wear out over time and can/will cause a small air leak into the intake manifold at idle. That will mess with a smooth idle.

The fix is not to remove and block off the acv. The fix is to get another AFTER you have determined that it is indeed leaking. Usually if you will temporarily remove the airpumps belt and then start the car, you can tell if it was leaking by a change or lack of change in the idle. IF the idle changes noticably, then it was probably leaking and needs replacement. No change? Then it's probably ok and leave it alone.

If the three vac hose on the front of the dynamic chamber are mixed it'll give a irregular idle. Only the two small can be swapped.

Make sure the two small vac hose on the back of the dynamic chamber are connected. They are to the left side of the engine. One above the other.

Or there are a couple of vac hose going to the rear of the throttle body, going to a water thermo valve that might be off/crossed up.

Another item is the Variable Resistor with its Rich/Lean screw. It only rotates about 180 degrees. It has a stop on each end. If it rotates 360 degrees it's busted.

This little jewel is mans best friend at times. A engine that is running too lean at idle will miss a lot. Changing the idle mixture on a series four is as simple as gently turning the screw clockwise Just a little at a time. The idle should respond to just a few degrees of rotation. You should make a mental note of where the screw was prior to adjusting it so you can go back to where you started if not satisfied with the results.

 

I don't think the car is running lean the resistor is set to almost full rich,the car will not idle very well with out it set to rich.the car also dies when I turn on the lights or heater.I put a new transistor in my spare computer for the bac.I also like a fool turned the allen head screw in the bac a few too many times,I can't seem to get it back to where it was? I also still have to ground my ECU I'm searching for the pin out of the ECU grounds.My problem is when I get the yellow mark "which now looks white 20 year old car" to line up,The red is way off=too far forward from the pin.The fsm says after you have set the yellow go and do the red? If you turned the CAS to adjust the yellow,then you go and turn it for to line up the red mark,would that not throw off the adjustment you just made for the yellow? So far what I am getting out of all this is just line up the yellow forget the red am I wrong?

 

When timing clamp the timing gun on either of the LEAD plug wires. With the engine at idle (well below 900 rpm), the first mark on the pulley should align with the fixed pointer. If it does not.....loosen the cas nut/bolt and rotate the cas til the first mark on the pulley aligns with the fixed pointer. You can stop at this point and put the timing light up if you want.

Or you can now put the timing lights clamp on the NUMBER ONE trail sparkplug wire and see if the second mark on the pulley is aligning with the fixed pointer. It should. If you now rotate the cas .....it will throw off the adjustment you made when you were on the Lead sparkplug wire. So there's not really much sense in checking the Trail except to see if there is something fishy going on. Something fishy would be the second mark and the fixed pointer not aligning.

REmember....fully warm up the car OR install the initial set coupler jumper prior to checking the timing.

The large allen scew should not ever be tampered with.

There is no adjustment for the early bacs. No screw to screw with.

 

Did you pull out the CAS and make sure it was lined up with the timing mark before you tried to time the car? If not pull out the Crank Angle Sensor- manually rotate the e-shaft untill the yellow timing mark lines up with the the "timing pin" on the block. Then line the arrow on the cas to the "dimple" on the gear at the bottom of the cas. See if that helps.......

 

I have not fooled with the car for a couple of days now.I have been busy ripping the engine out of my 87fc n/a parts car.Hailers I tell you I have a adjust screw on my BAC it's a allen head bolt blue colored on the front of the bac where the wire harness plugs in.I took it out when I cleaned my BAC a while ago and have not been able to set it right since?

 

first off isnt the timing saposta be -5 on the leed and -20 on the trailing??? just about everything i can find on setting the timing says -5 and -20. second i was told to get the trailing to line up you ajust the first vacume someting (it was a little wile ago when i was told). after you ajust your timing you are saposta ajust your idle speed. i hope that this will help.

now i have a question does anyone know what kind of timing light i can get that will go to negative? iv checked several but none of them do they just go positive or to 0.

 

The marks on the pulley are minus five and minus twenty. In that order. None of my business, but you don't need a timing light that does more than flash at *zero*.

 

ok im no expert but on most cars you have a light that flashes at what evey you want to set your timing at so how do i set it at -5 and -20 when its flashing at 0?

 

You unbolt the nut/bolt that holds the CAS in place, and rotate the CAS while the timing light is flashing, until the mark on the pulley and fixed pin align. Then tighten the bolt/nut down.

The marks ARE at -5 and -20 TDC. The TDC is not marked on the pulley.

 

ok that makes sence then thanks for clearing that up for me man

 

'initial set coupler jumper' is this a piece of wire or what is it?