Requesting Help with Diagnosing Engine Problem

[Hallque]

Hello all,

I inherited a FF Roadster build by my father and grandfather. I posted here once before when I had an issue and the help I got was overwhelming. In the end, I was able to fix that problem and have been enjoying the car very much ever since. Thought I would try again with the latest issue I am having. As I mentioned in my last post, I am a bit of an automotive novice. However I am committed to getting to know this car, and so I enjoy the opportunity to work on it myself and learn in the process.

I was driving the car few days ago. I was on the road for maybe 10 minutes before I stopped to fill her up, and to that point in the trip (and the day before), she was running great. I fill her up with 91 octane (I have the receipt, so I certain that is what I put in) and started to drive out of the gas station. Not 20 seconds out of the parking lot, the car begins to run very rough. Several seconds after that I notice black smoke coming from the exhaust. I took my foot off the accelerator and the engine shut of and I coasted into a parking lot. I attempted to restart it once, but the engine would not turn. I had the car towed home.

My first guess was that I had somehow put diesel in the tank, but like I said, the receipt confirms that I put in premium. Moreover, the filler nozzle smells like gas, not diesel. With the car home, I disconnected the cables from the spark plugs (plugs were still in) and tried to turn the engine with the key - no luck. I took the spark plugs out to examine them and the look fine. Then I tried to turn the engine manually with a breaker bar - it does turn. I took the bowls off the carb to check and see if there was a busted float, but everything looked normal (although, granted, I am only really guessing about what "normal" looks like). I put the carb back together, put the spark plugs back in, and then tried to start the car again. This time in turned for maybe 2 seconds before stopping. When I tried a second time it wouldn't turn at all. They battery reads at 12 - 13 volts.

If anyone has any theories about what could cause the issue described above, I would love to hear them. If you need more info please let me know. Thanks in advance for your help!

-Nick

[Bob Cowan]

Will the starter spin the motor with the plugs out?

[jrcuz]

Nick, I would first go back where you gassed up and ask if anyone else had an issue that day. I gassed up my 1972 Corvette one day and ended up getting towed home, turned out the gas had water in it. Ended up draining the tank and putting in fresh gas.
JR

[edwardb]

It seems unlikely (to me anyway) that bad gas would prevent it from at least turning over. It may run poorly or not at all with bad gas, but it still should crank normally. Sounds like maybe you had something fail that was around the time of refueling. But maybe not related. Assuming that it's really gasoline and not diesel as you already described. You said the plugs looked OK when removed. Dry, not wet? Didn't smell strongly of wet gasoline? Agree with Bob's question. Does it turn over normally without the plugs installed? Should be fast and real easy to turn over with the starter and no plugs. If it was running OK, not sure I would have torn into the carb. Are the floats set properly? Do you see the fuel level roughly in the middle of the sight windows? The starter itself is something to consider, assuming the battery is OK. Having the battery actually tested would be another recommendation.

[Norm B]

As Bob and Edward have said, bad gasoline should not stop the engine from turning over. Your problem sounds electrical to me. When you started the car at the gas station did it crank over normally? If it started normally at the station then check for a broken/disconnected engine ground. Clean your battery terminals and charge the battery for awhile. Check your voltages at the ignition switch and look for any loose connections. It could even be a bad ignition switch! Try starting it again and report back with the results.
Hope This Helps
Norm

[michael everson]

Its not the gas. Everyone that fueled up that day would be in the same parking lot as you. the lack of starting and running rough almost seem unrelated, but that's unlikely. My guess is you have a bad alternator. Your car was running off the battery alone. Once you restarted it, there wasn't enough left to keep it running. Just a theory. I would put it on a charger or try jump starting it from a known good battery. Leave it hooked up and see how it runs.
Mike

[CraigS]

"I attempted to restart it once, but the engine would not turn. I had the car towed home."
"This time in turned for maybe 2 seconds before stopping. When I tried a second time it wouldn't turn at all. They battery reads at 12 - 13 volts."
Can you clarify what you mean by the word "turn"? Do you mean the engine is rotating? Or do you mean it is actually running? One reason I ask is the last quote where you have a 12-13V battery reading but it won't rotate(?) the engine. That is unusual.

[seagull81]

The battery could read 12-13 volts and still have a bad cell. Once you load it there isn't enough power to do anything. Have it checked at the auto parts house. That happened on one of my vehicles.

[Corsair]

I recently had a similar problem with a 2001 ford falcon, and with a CBR600RR motorcycle a few years ago but no black smoke. To check for the bad engine ground, you need a Multimeter set to Ohms, touch one probe to a clean section of the engine block, not the rocker covers (alcohol wipes clean a patch off pretty well) and the other probe to the negative terminal of the battery, it should read below 50 Ohms, (Roughly, it will prob read between 5 and 10 ohms due to the resistance of copper wire), if it reads higher than that, give the earth lead (the thick black cable that connects the engine to either the battery or the frame) a scrub with either a fine sandpaper or a scotchbrite pad till shiny and where it attaches the same treatment, you can also check the cable itself by disconnecting it and touching the multimeter to both ends, I had a 4wd that wouldn't turn over or run because the resistance for the earth line was a few giga ohms and this was fixed by tightening the crimps for the terminals in a vice (bush mechanic style and not recommended).
Before doing this i would attempt to charge the battery, if not fixed, borrow a battery out of another car and try that, if it runs on the borrowed battery, check the voltage over the battery terminals, if it is below 14 volts, replace/rebush/overhaul the alternator, including the voltage reg for the alternator. the battery can still produce 12-13 volts and not produce enough Amperage to turn the engine over. voltage is how far the lightning can jump, amperage is how big the lightning bolt is and ohms is how hard it is to make the jump.
apologies if the numbers are incorrect, it has been a while since i had to do this and can't remember the exact numbers for the ohms, hope this helps and hope you get the car running again soon.

[Mesa Mike]

You say you tried to turn the engine over by using a breaker bar and it wouldn't turn over? If that's true it sounds like a hydraulic issue. Lately a friend drove his Cobra home from the track and it was running a little rough. Next day it would not turn over with starter or breaker bar. Removed the plugs and turned over the engine and watched "old faithful" come out of a couple of cylinders. Blown intake gasket.

[rich grsc]

You say you tried to turn the engine over by using a breaker bar and it wouldn't turn over? If that's true it sounds like a hydraulic issue. Lately a friend drove his Cobra home from the track and it was running a little rough. Next day it would not turn over with starter or breaker bar. Removed the plugs and turned over the engine and watched "old faithful" come out of a couple of cylinders. Blown intake gasket.

He said it 'did' turn over with a breaker bar

[Hallque]

Hello All,

Thanks for all of the suggestions. The first thing to figure out seemed to be "is it an electrical/starter related issue or something else." To that end, as suggested, I took the spark plugs back out and tried the key again. It turned fine under battery power. I put the spark plugs back in and tried again and, as before, it turned for (but didn't start) for maybe 1 to 2 seconds before stopping again. Subsequent attempts to turn the engine via key/starter were fruitless. Thus, it does not seem like this is a starter/electrical problem.

The spark plugs come out perhaps slightly damp, but not soaked. The first time I took them out they smelled strongly of fuel, but not this last time. I currently see no fuel in the carb window, but I did before I took the carb bowls off.

I am totally stumped (although that isn't saying much). Any additional suggestions based on the new info will be greatly appreciated!

[Norm B]

Have you tried charging the battery or jumping it with another good battery to see if it starts. Still think it's an electrical problem of some kind. Leaning more towards Mike's suggestion of a bad alternator, causing the battery to drain until everything quits working.

Norm

[edwardb]

Agree with Norm this is an electrical problem. Not sure why you think the test you did ruled out the starter or electrical problem. The current required to crank a motor with no plugs versus with plugs is significantly different. I would start with having the battery tested. Then the alternator as several have suggested. Starter motor itself could be suspect as well. If all those parts are good, do you have a firewall solenoid? Ignition switch itself could be a possibility, but it doesn't see all that much current. So with it spinning with no plugs, I doubt that's the problem.

[PaulW]

Agree with Norm this is an electrical problem. Not sure why you think the test you did ruled out the starter or electrical problem. The current required to crank a motor with no plugs versus with plugs is significantly different. I would start with having the battery tested. Then the alternator as several have suggested. Starter motor itself could be suspect as well. If all those parts are good, do you have a firewall solenoid? Ignition switch itself could be a possibility, but it doesn't see all that much current. So with it spinning with no plugs, I doubt that's the problem.

I agree completely. Right now it seems that the battery is the problem that is keeping it from starting. Voltage is good but it needs to be load tested. Once that is determined then the question shifts to why the battery is bad. This could be the alternator or could be that the battery is just old and tired. If it were me I would take both the battery and the alternator in for testing.

[Corsair]

First, change out the battery with one from another car that you know works, sounds like the battery you have doesn't produce enough amps to drive the fuel pump or the spark plugs, hence no start and no fuel on the spark plugs. can you hear a clicking noise from the starter?

[Hallque]

Hello All,

Thanks again for all of the suggestions. Here is a quick update.

I charged the battery for quite a while and tried starting the engine again with no success. The noise that the engine makes is a bit strange. It is not the typical clicking sound that you get when the battery isn't producing enough amps. Its as if the starter is trying to turn the engine but something is stuck, preventing the engine from turning.

Next I took the spark plugs out one by one to see if I could isolate the problem to a single piston. As I mentioned before, when I take all the plugs out the engine turns fine, but when I put them all back in it will no longer turn via starter. Well, one by one the plugs came out and the engine wouldn't turn. Finally after removing and replacing 7 plugs, I found that the engine will turn with the 8th spark plug out but all the others in. To be clear, this effect is unique to the 8th spark plug, which makes me think that the problem is not battery/starter related (although, as before, my logic may be flawed here).

I plan on hitting the garage again tonight/over the weekend, so please let me know if you have any additional theories. As always, thank you so much for all of the help!

-Nick

[Bob Cowan]

Pull the valve cover, and watch the rocker arms on cylinder #7 and #8. Do they move up and down the same amount? When all the valves are closed (or rocker arms removed), are all the valve tips at the same height?

[michael everson]

Where are you located? Someone needs to come over and give you a hand. Not sure why it will spin with out the eight plug in but I bet its irrelevant. Get another battery and try it. Sometimes even jumping a car with a bad battery does not work.
Mike

[skullandbones]

Hi Nick,

What was the problem with the car before (can't remember) and what was the solution? Inquiring minds need to know!

I have a couple of thoughts. Sounds like the engine was flooding which could be an issue in itself. Also, the battery and starter are in question. It is possible for both to be involved in some way. Have the starter tested in the cabinet to make sure it is not dragging a little. If your battery is not up to speed, trouble shoot with a new one. You have too many variables going right now. I think you also need a extra set of eyes on the problem to help as a sounding board. Consulting with me, myself, and I can be non-productive sometimes (makes you think too hard). I agree with Mike, that plug thing is probably not relevant.

Good luck,

WEK.

[Hallque]

Hello All:

Another update. Spent a few hours in the garage with a couple of buddies (and more than a couple of beers) and I think we found the problem. We tried turning the engine by hand with the 8th spark plug out and noticed that on the down stroke of the piston, a lot of fluid was expelled from spark plug socket. We figured that it was fuel at first, but some of it got on my hand and so I smelled it, and was absolutely not fuel. On a hunch, we removed the intake manifold to see if it was possible that water/coolant was leaking into the piston chamber. Turns out that is exactly what was happening. The gasket that sits between the head and the intake was broken at the spot between the 8th piston chamber and the coolant line in the head. You can see in the attached picture (picture is too large to upload, use this link: https://goo.gl/photos/1UKE9Dov9vE4prZL8) that the 8th piston chamber is full of coolant. If there was coolant/water in that chamber, it explains why the car wont turn with that spark plug in (can't compress fluid) but will with the 8th spark plug out (it just expels the fluid through the spark plug socket). If the water/coolant was preventing full combustion of the fuel in that chamber, it also explains the black smoke I got when the car originally stopped running. Still a lot of work to do to put everything back together, but this feels right. If anyone thinks I am mistaken, please let me know.

Thanks again!

-Nick

P.S. Skullandbones: the original problem was with the fuel pump. Turned out to be just a loose grounding line, although we didn't figure that out until after we tried replacing the pump.

P.S.S. I am beginning to find that I like when things break on this car, because working on it is almost as fun as driving it.

[michael everson]

Well, I will take my foot out of my mouth now. Good find. Hopefully this will be the end of your problems.
Mike

[jrcuz]

Nick,
Great news, I wonder if the beers helped?
JR

[skullandbones]

Glad you found the answer. Good work! I had a friend to have a similar problem but I had never seen that before his intake to head gasket failure. I didn't think it was something you would see more than once but lesson learned.

Nick: drive it hard and I'm sure you will be back for another adventure.

WEK.

[edwardb]

Hopefully there's no damage from the cooling leak into the cylinder. Hydraulic lock can bend and break things. Let us know how it turns out.

[CraigS]

Replace the intake gasket w/ felpro like this w/ the S3 suffix which stands for a steel core. There are several numbers for different port sizes but be sure you have the S3 version. Put a thin coat of your favorite sealer around the water ports. Torque the gaskets and then re-torque a couple of times after driving.
http://www.summitracing.com/parts/fe...view/make/ford