5.0 Help in a truck

[StangChik]

I have an 86 Ford F150 with the 302 fuel injected engine. I could really use your guys help, because we cannot figure this thing out.

We put a new (used) engine in the truck a while back. It ran great, better than it ever did before. Then all of a sudden it quit and we haven't been able to get it running since. We did a full tune up on it, and its getting plenty of fuel pressure. However it will not fire consistently. When you put a timing light on it, its blinks randomly and you can get a read on it( Yes the light is good, we checked it on my cobra). So then someone told me to put a new coil on it. This made it better, but still no constant fire. Its tries to fire up, but just doesn't have enough to get it going. BTW, i also took the module off and it tested good.

I really need to figure this thing out, because we need it. And advice and suggestiong would be very helpful. There may be some other things that i left out, but hopefully someone can make sense of this. Thanks:chug:

[militarymustang88gt]

check the gear on the distributor. if it is ground at all or if the bearing is loose it will cause the rotar button to wobble and not hit every cylinder on the cap. just take the cap off and see if the shaft moves at all. it shouldnt and if it does it should be so minimal you would have to be paying hard core attention to it.

[StangChik]

well, we thought at one time it may have been a distributor problem, so we swapped it out with one from another running truck. No change and it looks ok, from what i can tell. We though about buying a new one, just to be sure. But it seems like we are spending a lot of pointless money, when we still don't know what the problem is.

[militarymustang88gt]

get a set of jumper cables and hook a red and black to the motor and then a red and black on the other side to the body. cause a ground issue for the motor could be the problem. that is just easy to check and everyone has jumper cables, so you dont have to find or make one and find places to bolt it up if it doesnt need one.

[StangChik]

ya i was thinking about ground problem at one time too, because of all the swapping we had to do. I'll look into that.

[StangChik]

so you just hook the cables up anywhere to the motor and the body? ANd you use both ends, pos and neg?

[militarymustang88gt]

or just one of them. both will ensure it is grounded good.

[StangChik]

k i think we are gonna try that.

Also, is there a way something could be turning backwards? I'm not sure if i understand it right, but someone said if the wires are not in the right order, it will fire backwards. But i'm pretty sure we have the firing order correct.

[militarymustang88gt]

is it an HO or a regular 302

casue the HO firing order is 13726548
and the regular one is 15426378


you might have an ho and have the regular firing order or vise versa.
had a problem with a crown vic motor being put in a mustang and was wondering why it was stubbling when we finally got it to crank.

[EHardy1971]

Sounds like it jumped time to me.

is it an HO or a regular 302

casue the HO firing order is 13726548
and the regular one is 15426378.

She said it ran great to begin with,so I doubt it's the firing order. On a side note,the Ford truck/van 302's started coming with the HO/351 firing order in '95.

[StangChik]

someone else told us that it may have jumped time....However wouldn't still have a constant fire? It would just be out of time, but it would still be firing right?

[EHardy1971]

I thought you had fire? When you say fire,are you saying it's trying to start,or it's getting spark at the plug?:shrug:

[StangChik]

its not firing consistently, its random. It will spark at the plugs i think, but it will not fire enough to run a timing light.

[EHardy1971]

its not firing consistently, its random. It will spark at the plugs i think, but it will not fire enough to run a timing light.
Ok,the timing light is'nt going to tell you very much,you need to check fire at the plug. But from what you're saying about it firing intermittently,my money still says it's jumped time.Check fire at the plug,and give us an update.

[StangChik]

it will fire at the plug....but when we try to check the timing, we can't get a read.

[EHardy1971]

Do you have a compression tester?

[StangChik]

ya he check that a while back.....good compression. I think one cyl was a little low but not major.

[militarymustang88gt]

well it really just depends on what the new motor came out of. it could be a mustang motor or a 95 truck. but since it ran fine before it prob isnt firing order like you said.

[EHardy1971]

ya he check that a while back.....good compression. I think one cyl was a little low but not major.
Did he check compression after it stopped running?

[militarymustang88gt]

i would really almost put money on a ground issue or wiring issue like a short in the positive or neg going to the coil pack.

[EHardy1971]

i would really almost put money on a ground issue or wiring issue like a short in the positive or neg going to the coil pack.
I know what you're saying,BUT.....

it will fire at the plug....but when we try to check the timing, we can't get a read.

.....it still sounds like timing to me,I've had a few jump time on me before. I could be wrong,but a compression test now will be a good indicator if it's in fact valve timing or not.;)

[EHardy1971]

Oh,I forgot to add,that if you're trying to check it with a timing light,and it's jumping all over the place,you need to pull the SPOUT connector out.

[StangChik]

not sure what the spout is....I'm still fuzzy on some of this stuff.

As far as the wiring issue you are thinking, I keep leaning towards that too, because the connector on the coil plug is gone and it has wires with end terminals plugged into it. I'm not sure that stuff is correct.

I can't remember if he checked the compression on it after it went down, but i know he did before.

[EHardy1971]

The SPOUT connector is going to be a little black,or gray square thing plugged into a socket on the wiring harness near the distributor on a wiring pigtail.

[militarymustang88gt]

the colors for the connector on the distributor should be from the top to bottom: blue yellow red (another wire cant tell what color) then black at the very bottom.

[StangChik]

its the connector on the coil not the dist. We have had 2 wires running to it, and they are brown and yellow i think.

What what worries me is the manual i have shows 3 wires.

[EHardy1971]

What what worries me is the manual i have shows 3 wires.
That's because with a factory tach,you'll have 2 wires coming off the negative/(-) side of the coil. I have a '95 F-150,therefore both Haynes and Chiltons that will cover your wiring schematic.BRB

[StangChik]

so we are missing a wire then?

[militarymustang88gt]

oh get some kind of material and stick it between the two prongs. if you dont have plastic or anything and it is just sitting on the connectors it will collapse the field inside the coil before it has the dwell time it needs.

[militarymustang88gt]

http://i236.photobucket.com/albums/ff82/militarymustang/Untitled.jpg

[militarymustang88gt]

i thought you were talking about the connector on the dis. that is your whole prob. if you look at the stock conector on the coil it has a whole bunch of plastic so it wont collapse the field. if it is just in the open it will colapse the magnetic field early and you may get 10,000 volts to the spark plug and look like you have spark but in reality you need 30,000 at least to run on these motors.



ps i suck on paint

[StangChik]

good deal....I'll try that, because this is the first thing we noticed when it quit, but didn't think it was serious. Pull a part, here i come.

[waypastcrazy]

pull number one plug bring #1 piston to top dead center of compression stroke pull dizzy cap and see where rotor button is sitting if its jump time it will be off from #1 terminal make sure 0 is lined with timing pointer on harmonic balancer if all is well check your vaccum line running to your map sensor. shot in the dark but had that happen on a friends bronco but it would crank just wouldnt stay running they worked on it for over a year.changed everything even the map.they finally gave up and came and got me and i lucked up and spotted the vac line had melted to back side of exhaust manifold. i am not familiar with your year model just figured i would throw something out there. good luck.

[EHardy1971]

its the connector on the coil not the dist. We have had 2 wires running to it, and they are brown and yellow i think.

What what worries me is the manual i have shows 3 wires.

Ok,on the coil,you should have 2 wires on the positive side,one is black that is supposed to go to the radio noise filter,the other is red/light green from the ignition switch. On the negative side it shows a dark green/yellow that goes to the ignition box. That brings up another possibility,being an '86,it has the duraspark ignition,and those things are notorious for going bad with no warning. If it has'nt jumped time,I'd take the duraspark box to the parts store to get it tested.

[EHardy1971]

Well,any luck? :shrug:

[StangChik]

haven't got back to it yet....haven't house trouble now