Please help! 1991 Ford 460 7.5L crank, no spark!

[Hangshai]

So, from what I've seen online this seems to be a common problem with this engine. Thing is, none of the fixes seem to be able to fix mine. Originally when I bought the RV (1991 Fleetwood Tioga on an Econoline platform), it wasn't running. I had a friend come by and we traced the power going from the battery to the coil, but it wasn't getting to the distributor. Finally after fiddling with it for a few days, we got a used distributor from pick and pull, and, miracle of miracles it fired right up! Ran like a top, it did... So, I started it about once a week for a while until I drove it across town, and parked it. Left it parked for a couple weeks and then when I tried to start it... Nothing. Same issue. Power to coil, no spark after though. Tested the ICM, good. Coil is good. Installed a BRAND NEW distributor, no change. Tested the old pick up coil and it was ok anyway... So, now I'm down to chasing down grounds. Batteries are charged and topped off with a trickle charger. There is some extra wiring hooked up, but seeing as we got it running for a while I don't think any of it matters ( I think previous owner installed a new fuel pump, along with tree everse camera and some other doodads). I'm at a loss, please if anyone can help. I've checked the relays, they all click when I turn the key. Fuel is not the problem. I jumped the ODB 1 connector and got rt here codes one day... 21, 24, and 26. None of em made sense to me (I think one did and it was something about the MAP sensor) but still none of them had anything to do with spark.

Please, I need to get this thing started again so I can sell it. Can anyone help?

[justcheckn]

Does the distributor have the ignition module bolted to it?
P/M me your cell# and I’ll give u a ring
I’m a 45 yr retired ASE MASTER TECH
Maybe I can help
Bobby In Colorado

[RVfixit]

Originally Posted by Hangshai

So, from what I've seen online this seems to be a common problem with this engine. Thing is, none of the fixes seem to be able to fix mine. Originally when I bought the RV (1991 Fleetwood Tioga on an Econoline platform), it wasn't running. I had a friend come by and we traced the power going from the battery to the coil, but it wasn't getting to the distributor. Finally after fiddling with it for a few days, we got a used distributor from pick and pull, and, miracle of miracles it fired right up! Ran like a top, it did... So, I started it about once a week for a while until I drove it across town, and parked it. Left it parked for a couple weeks and then when I tried to start it... Nothing. Same issue. Power to coil, no spark after though. Tested the ICM, good. Coil is good. Installed a BRAND NEW distributor, no change. Tested the old pick up coil and it was ok anyway... So, now I'm down to chasing down grounds. Batteries are charged and topped off with a trickle charger. There is some extra wiring hooked up, but seeing as we got it running for a while I don't think any of it matters ( I think previous owner installed a new fuel pump, along with tree everse camera and some other doodads). I'm at a loss, please if anyone can help. I've checked the relays, they all click when I turn the key. Fuel is not the problem. I jumped the ODB 1 connector and got rt here codes one day... 21, 24, and 26. None of em made sense to me (I think one did and it was something about the MAP sensor) but still none of them had anything to do with spark.

Please, I need to get this thing started again so I can sell it. Can anyone help?

Hi Hangshai- So, there are several things at play here that need to be confirmed. Can you tell me how many miles are on this RV? We need to confirm that the fuel system is working, and that if there is or isn't spark. The quick way to check spark is to put a timing light on any plug wire and have someone crank it for you. If the timing light flashes, you have spark which leads you to fuel issues. Lets start with that and go from there.

Ill monitor this thread so I can answer your questions as soon as you respond. Thanks

[Hangshai]

Originally Posted by RVfixit

Hi Hangshai- So, there are several things at play here that need to be confirmed. Can you tell me how many miles are on this RV? We need to confirm that the fuel system is working, and that if there is or isn't spark. The quick way to check spark is to put a timing light on any plug wire and have someone crank it for you. If the timing light flashes, you have spark which leads you to fuel issues. Lets start with that and go from there.

Ill monitor this thread so I can answer your questions as soon as you respond. Thanks

Thank you so much for replying and offering to help. There is no spark *AFTER* the coil, so nothing leaves the coil, goes in the distributor, and out to the plugs. There is power going IN the coil. Also, fuel is not the problem. I can hear the relays and fuel pump activating when the key is turned and I can smell gas if I pump the gas pedal one or three times when I tryi to start it. Usually I don't press the pedal bcs I dont want to flood, I'm just saying I have before and I could smell the gas.


As far as I know the coil is good. Also I removed the igntition control module and had it tested at AutoZone and they said it was good. Although I was told it still may need replacing. Also the distributor is brand new.

[SafariBen]

Originally Posted by Hangshai

As far as I know the coil is good. Also I removed the igntition control module and had it tested at AutoZone and they said it was good. Although I was told it still may need replacing. Also the distributor is brand new.

What have you checked on the coil? they're not hard to check with an ohm meter, or swap out. The module still needs power to work, but I can't tell you how to check that, Ford forum is where I'd look.

[RVfixit]

So, you mention that there is no spark after the coil, how did you determine that? That year 460 v8 had an “exposed” type coil which was prone to failure.
There is a quick method to test that coil but you will need to know the values of the primary and secondary windings. If you get no continuity, the coil is bad. You mentioned that you replaced the distributor, did that come complete with cap, rotor and module and are you sure you have it installed correctly (timing wise) ? Do you have a timing light and a multi meter to do testing with? Please let me know, thanks

[Garlic_Rudy]

Explain “spark not coming out of the coil”
There is either spark or no spark.

I would do a warranty exchange on the distributor.
Have you tested the pick up in the distributor? Sounds like you are getting a signal”to” the coil. It’s either the ign module or the pick up.

I would start fresh again to eliminate.

After you pull the distributor , ground it to the motor, turn the key on and spin the distributor shaft.
That will help you determine if you have spark or not.

[Hangshai]

Ok let me answer to the best of my ability. I used a testing probe light on the positive going IN to the coil and it lit up, indicating it had power. But when I tried to arc the cable going into the top of the distributor, it wasn't giving a spark... So, power into the coil, but none coming out. As far as I know the distributor is good. In fact when I first got the RV it wasn't running, until I replaced the distributor. Then it started running again, until I drove it across town and parked it. I left it parked for a few weeks and it didn't start again after that.

Also,I had a real bad case of food poisoning over the past few days so I haven't been able to work on it at all. I think I'm going to try to return the distributor and get another one... I'll also try to check or replace the coil. Does any of this help?

[Hangshai]

Originally Posted by RVfixit

So, you mention that there is no spark after the coil, how did you determine that? That year 460 v8 had an “exposed” type coil which was prone to failure.
There is a quick method to test that coil but you will need to know the values of the primary and secondary windings. If you get no continuity, the coil is bad. You mentioned that you replaced the distributor, did that come complete with cap, rotor and module and are you sure you have it installed correctly (timing wise) ? Do you have a timing light and a multi meter to do testing with? Please let me know, thanks

I'm replying on my phone so I apologize for any errors. What I meant was when the power to the coil was tested, we confirmed that the coil was getting power it just wasn't sending it to the distributor. This was fixed when we replaced the distributor. After replacing the distributor it would fire right up. I started it about once a week until I moved it. I drove it across town and parked it and it wouldn't start after that. Would you please tell me how to do the tests you mentioned? Indo have a volt meter. What settings do i use to test it?continuity is tested just through the POS and neg correct? Where the power gets plugged into the coil?

[SafariBen]

You test a coil by ohms through the two small connections with one removed, and through the spark wire and the ground, low voltage is primary, and high voltage is secondary, I think. Primary will be something like 1 or 2 ohms, secondary will be like 5,000 ohms, but you'll have to find the actual spec for your year and coil, probably a range or a plus and minus figure.

[RVfixit]

The picture below illustrates the basic coil test. Disconnect the wiring before testing. The values may not be exact but will give you an indication if the coil is good or not.



Also, if a new distributor didn't fix anything it doesn't necessarily mean that it is bad but does indicate that you might be chasing the wrong thing.

Don't go down the OBD route just yet as codes can be misleading. In addition, I know there are jumper procedures out there but I don't recommend using that method, I would get a cheap code reader.

The Ford 460 is a very good engine but it does have a few things that do go wrong. If this is a high mileage engine (0ver 100k), the 460 timing chains do fail. A quick way to check is simply remove the distributor cap and crank it over. If the rotor moves, it probably isn't that, at least for now.

When cranking the engine over, does it do anything or even try to start? Does it do any backfiring?

Last, you say you smell fuel, have you done any kind of pressure testing to see if you have fuel pressure during cranking?

Let us know, Thanks

[Hangshai]

Originally Posted by RVfixit

The picture below illustrates the basic coil test. Disconnect the wiring before testing. The values may not be exact but will give you an indication if the coil is good or not.

Attachment 432966

Also, if a new distributor didn't fix anything it doesn't necessarily mean that it is bad but does indicate that you might be chasing the wrong thing.

Don't go down the OBD route just yet as codes can be misleading. In addition, I know there are jumper procedures out there but I don't recommend using that method, I would get a cheap code reader.

The Ford 460 is a very good engine but it does have a few things that do go wrong. If this is a high mileage engine (0ver 100k), the 460 timing chains do fail. A quick way to check is simply remove the distributor cap and crank it over. If the rotor moves, it probably isn't that, at least for now.

When cranking the engine over, does it do anything or even try to start? Does it do any backfiring?

Last, you say you smell fuel, have you done any kind of pressure testing to see if you have fuel pressure during cranking?

Let us know, Thanks

I'll try to answer your questions to the best of my abilities... I do want to emphasize rereading my first post because I feel like I covered some of this info there, but I'll try to recap.


When I first purchased the rv it wasn't running. It was cranking but not starting. I diagnosed no spark through the cable from the coil to the distributor and a screwdriver to arc and then a test light. Previous owner had replaced the coil, ignition control module. I purchased new batteries (starter and deep cycle). Then my friend brought me a used distributor from Pick and Pull in town and it fired right up. After that it started up every time, and ran strong. I didn't even have to touch the gas pedal to start, just turn the key. Oh yeah odometer says 52K. After I drove it across town a few weeks after I got it running, I moved it to its new location and parked it. I didn't start it for a couple weeks and now I'm back to where I was when I bought it.. it cranks but there is no spark.


Yesterday I went to autozone and purchased a Duralast coil, distributor, and gold spark plug cables. It rained today so I'm going to wait until tmw afternoon to attempt to put them on. Also, there is a negative ground cable from the battery to the chassis that feels loose on the chassis side. It goes behind the starter and I can't see the bolt it is on, I may have to remove the alternator to access it to tighten it: I can't seem to access it from beneath bcs the frame is in the way.


When I turn the key all the relays click on and the fuel pump activates. If I pump the gas pedal when I try to start it then I will smell gas so I haven't been pumping it when cranking it. When I crank it it turns steady with no backfire or lag. When it runs there is no backfire or lag, it runs good and strong. I have. Feeling it is something simple and stupid and someone with more knowledge than I would be able to fix it in five minutes.


Anyhow I will report tomorrow when I have the new parts installed. I'll also attempt to test the coil currently on the block to see what readings I get.

[Hangshai]

Ok just finishing up putting the new stuff on... got off to a late start today. Anyhow, I tested the previous coil that was on there with my voltmeter. I wasn't sure what to set it to(I have one of those red box meters), so I set it to the ohms on the first setting which reads "200"(not 200k, just 200. With the positive lead on pos term and neg lead on neg term the reading was 10.8-11, so within spec I think? I got no reading any other way I set the leads... esp on the center post. I tried every combination of pos/neg to each other and to post. Oh and when I did the continuity reading on pos and neg in to the coil I got a reading so power is getting thru, correct?

[Hangshai]

Ok great news! I went ahead and got new stuff from Autozone as I had said, installed the distributor and coil and she fired up again! The only thing is the firing order!! Man it's always something... anyhow, it started but was running real rough... tried adjusting the timing by rotating the distributor and it stopped running. We were using the 1-5-4-2-6-3-7-8 order but we also found a different order for rvs, according to google, and for Marine 460s. Is there anyway to id the block or vin to find the correct order?