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88 4A-F distributor problem

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14K views 23 replies 12 participants last post by  Corrolla clone  
#1 ·
My engine which i just rebuilt drove kinda funny and had been pinging horrendously for a long time, and i finally checked out the timing now that i have rebuilt the engine. I found that at idle and the vacum advance disconnected that the base timing was at 38 degrees BTDC!!! The sticker under the hood says that it should be set at 5 degrees BTDC. So I adjusted the timing to retard until i ran out of adjustment in the distributor. It is now set at 15 deg. BTDC.

The car runs great in the low rev range, but now the engine feels winded in the top end. My initial guess is that the centrifugal advance is shot which is why i don't get more necessary advance on the high end anymore and is why the engine feels good on the bottom end now. I haven't paid very close attention to the timing as the was revved when we had the timing light hooked up, but my guess is that it is not advancing as it should.

Is this a common problem with the corolla's? I see in junkyards that 4 out of 5 4A-F/E engines have them already removed. If i remove my distributor, what should I look for?

Thanks!
 
#2 ·
One thing to is check whether you have your timing belt on correctly. The cam gear has both an "assembly" mark (dimple) and a different mark for setting the position of the gear when you put the timing belt on. It's easy to get the mark on the crank shaft pulley right and the mark on the cam wrong when you put the belt on.
 
#8 ·
Ok, I have rebuilt the head on this engine once, and now again rebuilt the entire engine, the distributor is on correctly, the engine RUNS!! It is not off 180 degrees. I do have a fair bit of experience removing and re-installing the distributor, and the after i rebuilt the engine this time, i adjusted the timing to some marks that I made on the distributor before i removed it. The most error there could be from this method is maybe +- 3 degrees or so based on the 4 marks i made, 2 on the rotor, and 2 on the distributor body and I match both sets up. So after i checked with the timing light a few weeks after driving the car again, it read +38 instead of the +5 like its supposed to. I'm 99% sure this is a technical distributor problem and not a simple installation problem. Anybody have any experience with disassembling and inspecting the internal mechanicals of these distributors and checking for the proper functionality of the advance mechanisms. My first thought is that If i opened mine up, i might find the springs on the centrifugal advance are either broken or severely fatigued from all (342,XXX) miles it has been in use.....

Just another point of note here, I have been getting between 35 and 40 miles per gallon on the highway with this car and 28 - 32 mpg city and highway mixed. This is with the dizzy adjusted to +15 degrees, as it is currently. Prior to making this adjustment, i was making between 22 and 35mpg with my old timing of +38 degrees.
 
#9 ·
I used to have an 88 Nova (Toy 4A engine) and had advance problems . I ended up dissasembling the distributor and found rusty centrifugal advance weights and posts they attach to. I cleaned everything up and lubed the posts and it took care of the problem. If you remove cap and turn rotor by hand (clockwise) it should spring back when you release it. If not you need to dig into the centrifugal advance. Can't remember the dissasembly process as it has been awhile but check a good reference manual for the specifics. You may find a broken spring once you get into it.
 
#11 ·
I would take off the timing covers and recheck the timing belt alignment. With the timing mark set to TDC and the #1 piston on the top compression stroke the crank pulley key should be at 12:00 and the cam pulley mark should also be at 12:00. If they are not aligned you need to realign these two with the belt. Also make sure that both the intake and exhaust cam gears are in proper alignment with each other.
 
#12 ·
I haven't done this myself, but this is what the 1989 service manual says about checking the distributor for the 4A-F:

INSPECTION OF IGNITION COIL
1. Remove IIA Cap, rotor and dust cover (I assume "IIA" means distributor)
2. Disconnect IIA wire connector
3. Inspect primary coil resistance with a meter
It should be 1.3 to 1.5 ohnms This is measured across the two terminals
nearest the top (rotor end) of the distributor.
4. Inspect secondary coil resistance.
It should be 10.2 to 13.8 kilo ohms
This is measured from the terminal that is nearest the vaccum diaphram cylinder that sticks out of the side of the distributor to the plate on the top of the distributor, which I assume is just ground.
5. Connect IIA connector

INSPECTION OF IIA
1. Inspect air gap. Gap between signal rotor and tip of sensor should be .008 to .016 inches
2. Inspect signal generator pick-up coil. (Two terminals near the bottom)
It should be 140 to 180 ohms
3. Inspect vacuum advance.
Disconnect the vacuum hoses. Apply vacuum to diaphragms and check that the
vacuum advancer moves.
4. Inspect governor advance. (I assume you reinstall the rotor at this point.) Turn the
rotor counterclockwise, release it and check that the rotor returns quickly clockwise. Check that the rotor is not excessively loose.
 
#18 ·
I haven't done this myself, but this is what the 1989 service manual says about checking the distributor for the 4A-F:

INSPECTION OF IGNITION COIL
1. Remove IIA Cap, rotor and dust cover (I assume "IIA" means distributor)
2. Disconnect IIA wire connector
3. Inspect primary coil resistance with a meter
It should be 1.3 to 1.5 ohnms This is measured across the two terminals
nearest the top (rotor end) of the distributor.
4. Inspect secondary coil resistance.
It should be 10.2 to 13.8 kilo ohms
This is measured from the terminal that is nearest the vaccum diaphram cylinder that sticks out of the side of the distributor to the plate on the top of the distributor, which I assume is just ground.
5. Connect IIA connector

INSPECTION OF IIA
1. Inspect air gap. Gap between signal rotor and tip of sensor should be .008 to .016 inches
2. Inspect signal generator pick-up coil. (Two terminals near the bottom)
It should be 140 to 180 ohms
3. Inspect vacuum advance.
Disconnect the vacuum hoses. Apply vacuum to diaphragms and check that the
vacuum advancer moves.
4. Inspect governor advance. (I assume you reinstall the rotor at this point.) Turn the
rotor counterclockwise, release it and check that the rotor returns quickly clockwise. Check that the rotor is not excessively loose.
I found the resistances of my old coil and the new , just bought, were exactly as given above,HOWEVER when I fitted the new coil the engine started and ran. Any ideas why/ I recon the old was having insulation break down with repeated ccurent changes.:(
 
#13 ·
So i opened it up this weekend and found the centrifugal advance mechanism frozen in the full advance position. A little work with the pliars, some lube, and now the force of the springs brings the assembly back to the retarded position. The timing is corrected and my engine feels GREAT!!! No more pinging, plenty of power down low, and even more up high! Thanks to you for helping me.
 
#14 ·
now i'm starting to wonder if i have a slightly similiar problem although i don't feel as confident just cracking open my distributor they cost like 600 bucks!
 
#17 ·
only has the rotor? we have the same distributor don't we flashmn i've got 4afe and i'll admit i only saw the rotor in the cap but i figured they dis-assembled the whole thing.
 
#19 ·
Old thread (15 years) you are tapping into, Chris pILCHER. But yes, a coil inspection has several checks, of which the service manual has one stated. The coil is also tested under cranking condition to very voltage in on the primary and voltage out on the secondary. This is not stated in the service manual. But in your situation, had to done this check, you would have discovered a difference between your new and your old coils. Do you also have a 4A-F engine?
 
#21 ·
Yes 4 AF from 1987 bought for ÂŁ300 from a scrap yard twenty years back, they said it had come in with a broken windscreen and they had had a spare, I was looking for spares for a dreadfull little Ford so jumped at the chance. Electrically I have only had to overhaul the alternator. Also fit new plug wires and distributer cap - ten thousand miles back these also brought me to a dead stop - or was this the start of problems with the coil ?
 
#20 ·
The resistance measurement with a multimeter is only using a few volts. Under operating conditions the coil is dealing with thousands of volts, so the current is more likely to jump past any break in the insulation.

I believe you may be on to the root cause with the break down of the wire insulation, but it may be more from years of heating and cooling and slight expansions and contractions of the wires slowing rubbing the insulation away from the windings.