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[wvengr]

So I am on a business trip, several hours from home, driving my Capri again after finally getting it back from the head gasket getting replaced.  Well it was fine in the few days leading up to the trip, so i had no second thoughts driving it.  Now, though, if the car is hot enough to make the fans run, and i shut it off, it doesn't want to start, and I have to let it cool off before i can go again. Also if i am sitting in traffic and the radiator fan kicks on it drops the idle so low it almost stalls, like 3 or 400 RPM, but usually recovers in a second or two.  it is very frustrating and i am afraid that it is either not going to start some day even after i let it cool down, or it is going to stall in traffic and I am going to be sitting in the middle of the highway trying to fix it.  Anyone got any advice?   It is a 1994 NA. Also it dosen't almost die for headlights, power windows, horn, radio or anything else, just the radiator fan.

[rcdraco]

This sounds like a dumb suggestion, check the belt deflection on the alternator belt.  You should only be able to push it down about 1/2 - 1 inch.  If it's overly tight it can be damaging the alternator.  And if it's loose it can slip and cause the alternator to not make enough power, and incidentally cause the water pump to slip as well.

Otherwise sounds like you might have a short somewhere, but the low idle seems like you might have another problem.

[Rocketman]

After the head gasket did you re-time your engine? Where does it normally idle at?

[wvengr]

It normally idles a little below 1000 when its warm. I would say 800.  I had the timing belt replaced athan the same time. I assumed that they set the ignition timing right because it seems to run fine once it starts.

[itsmeisatu]

Could be two problems.
1. The fan motor has bad bearings and draws a heavy load trying to start and when it does spin, probably not spinning fast enough for good cooling.
2. An ignitor that is going bad.

[wvengr]

I forgot to mention that it got a new distributor at the same time as the head gasket because the shop broke my old one somehow

[Rocketman]

I'd rent a timing light somewhere and set it in the parking low, if the timing is off that will cause hot start problems. Should be 2° BTDC with the vac lines plugged on the NA. Could also help with the idle dip issue with the fan coming on. I agree though it sounds like the fan is sucking down a little too much current

[wvengr]

ok, i have a timing light at home, but as I am not home i will try to rent one.  anyone know a way to test the fan, as in how much amps or power it is supposed to pull.  was thinking i could just attach a multimeter to it but I have no idea what it is supposed to be.  Also anyone know what the values are for our coil for testing?  I have one i picked up with some other parts in my trunk, so i figured i could test mine and that one and see if either are bad.

[Rocketman]

Clean your battery terminals. Remembering now I had some issues like that when mine were loose & corroded.

[wvengr]

My coil is 12.9 k ohm across the secondary and 1.2 ohm across the primary.  is this high.  i tested one while I was at the junkyard today and it was only 9.8 k ohm, but i don't know if higher is better or worse...

[Rocketman]

FSM states acceptable resistances:

Primary: 0.8 to 1.6ohms
Secondary: 6k to 30kohms

you're fine in that aspect

[wvengr]

from my days in electrical engineering class 6 to 30 k ohms is a hell of a tolerance, i don't really trust that.  my general idea is that if anything is over 20% out of spec it is junk.  just managed to track down the specs on exact replacement coils.

Ballast Resistor Included:   No
Coil Wire Included:   No
Input Voltage:   14 v
Mounting Bracket(s) Included:   No
OE Replacement:   Yes
Peak Current:   6 amps
Primary Ohm Resistance:   0.95 ohms
Primary Voltage:   14 v
Secondary Output Voltage:   34000 v
Secondary Resistance:   9600 ohm

It would seem as if my secondary is out of spec by 3300 ohm.  Going to try replacing that next.

[Rocketman]

Note that it's 6kohmn to 30kohm, not 6ohm to 30kohm. I do agree it's a fairly wide range though.

It's a high voltage step-up transformer. It will have ~100 windings of thicker copper wire as a primary and many thousand windings of hair-thin copper wire on the secondary. The secondary will have much higher resistance because of this. I believe the ratio is somewhere along the lines of 1:2000

Our ignition coils don't usually fail intermittently. You can get a break in the secondary because of how thin the wire is, that would check out zero on the ohm meter. You can get carbon tracking in the cast resin insulation, but this usually becomes progressively quickly, resulting in misfiring usually under heavy load. I don't believe that matches your conditions.

I can't find my multimeter, else I'd check one of the several coils I have here on hand for you.

[wvengr]

Well it's worth a shot to me anyway.  I have the money to throw at it, I have sunk $1500 into it already this month, whats another $60?

[Rocketman]

Fair enough, I wish ya the best of luck!