GSMblue

Hi,

I am new here. I got my 1985 F150 5.0 EFI 4x4 4AOD a couple of moths ago and it has been running great as a daily driver. I have done some work on it - tie rods, weather seals... nothing big.. I have been crusing a bunch of old threads for fun since!

Yesterday I was out in it, the temp dropped from about 65 to 40 in the 2 hours I was away from the truck. When I tried to start it it would turn over at normal speed but not catch, it almost did a couple of times.... I tried that a couple of times, waited then when I tried again it would turn over and then just stop turning - it was pretty sluggish at this point. Thinking it could be a battery that was not happy with the temp drop I got a jump from a friend, same thing - sluggish turnover and it would not fire up. It would crank a few times and then then just stop.

This morning I got back to the truck after it had been sitting over night with another jumper and turned the key, a few cranks and it nearly fired up, then nothing. then tried again and got the same sluggish couple of turns and then it locked up.

Any suggestions as to where to start hunting for a problem? My first thought was the starter may be shot so I am thinking of pulling it and taking it to the shop. at the same time pull the battery for a good charge and let the whole thing sit for a couple of days and let the ECC forget about all it's problems!

Today I did plug in a OBD reader and it did give the following codes:

21 (o) Cooling temp out of range or ECT out of range
24 (o) Intake air charge temp Tem (ACT,IAT) sensor or vane Air temp (VAT) sensor out of range
84 (o)EGR vent fault
18 (c) Loss of tachometer input IDM circuit failure/SPOUT circuit grounded

Not sure how real these all are...

Now, when I bought the truck the previous owner said he did put in a new distributor, HT leads, plugs and changed out some of the sensors. He also gave me a spare ECC and the guy did say "if it starts doing anything funny try changing out the ECC"

Looking for suggestions on where to start the hunt as I am new to this! Please let me know if I can provide any extra info.

GSMblue

Well, I ordered a new starter motor, figured it would not be a bad investment as I do want this truck to be around for a long time, I want to fix it up nice over the next couple of years

Still hoping for some advice about how to troubleshoot this issue if this does not work out..

GSMblue

So I changed the starter, new battery, new +ve battery cable, new starter solenoid and new coil.

Only code left is the 84 listed above and I have no idea what that means..

The problem persists, I turn the key, I hear the whirring of pumps, then I click round to start and all I get is one “thunk” from the starter motor...

Any suggestions would be welcome as I am out of ideas.

GSMblue

Just had a thought... when this problem started on Sunday, I did have the engine turn over a lot. I suspect that there was no spark.... hence the code 24.

Is there a chance I have a cylinder full of gas somewhere??

Should I pull the plugs and try starting her up?

88xlt

Try turning your engine over with a socket and breaker bar. Put the socket on the bolt on the front of the crankshaft. Turn in a clockwise direction. If you can turn the engine with a socket give it at least 2 full turns. That will tell you if the engine is hydrolocked, ie cylinder(s) full of gas.

GSMblue

Thanks for this, I did have a quick look yesterday, but I could not see where to get a socket on to the crank... I will look again today and report back....

GSMblue

So I pulled the plugs, one broke...but anyway, no plugs in, turn the key annmnnndddd....

The engine happily turns over and a whole lot of gas pukes from the #8 cylinder!!!

So I know know the engine was hydro-locked. I am leaving that spark plug out over night hoping some of that gas evaporates.

I got a crappy spark tester and stuck it on the end of the HT lead out of the coil and got a spark. My HEI tester arrives tomorrow so will try again then

Not looked for spark at the end of the spark plug leads yet, I will do that with the HEI tomorrow.

Looks like the problem is between the new coil and the new spark plugs. The leads are cheap so I may as well replace them anyway which leaves the distributor to check out...

Making slow progress.. I will keep updating this in case it helps anyone in the future..

GSMblue

After getting the HEI spark tester I confirmed I was getting good spark at the end of the leads. Engine turns over but does not fire up

So next up check the fuel..

I have an early 302 EFI so I do not have the Schrader valve... I assumed as cylinder 8 had been flooded fuel was getting in...but no.

I checked everting I could at the dual rail, all looked good except the fuel regulator. I pulled the vacuum hose off and fuel went everywhere.

New regulator installed. Still no start.

As I can’t test fuel pressure I went for the easiest thing next. Fuel inertia switch.

I pressed the button and felt a soft click. The second time I pressed it nothing...

Sure enough, the engine fired right up.

I was always going to clean up the ignition system so I do think I wasted any time or money there. The coil was bad and the distributor cap/rotor had significant wear.

I will change the inertia switch out, I suspect that got activated when the truck got towed, it was banged around a bit...

Anyhow. Just wanted to close this tread out in case anyone finds it in the future...

GSMblue

So I thought I was all fixed, not so.

When it is cold she will start right up. The idle is really rough and she is definitely burning oil. (I think there is a fair amount of gas in the oil from the old fuel regulator so this is getting past the oil rings, the smoke is light white and smells of gas)

Eventually she will stop running, there is good battery power to everything, when I try to start her she will crank but not fire.

If I bury my foot to the floor and feather back and forth sometimes she will restart. If I walk away and let her cool down she will start again.

I am getting KOEO code 31 and 84 and I don’t know what to do about them.

If I manually move the EGR valve diaphragm the I can hear the idle getting worse.

I tried running the KOER and I got more codes, not sure if they are relevant as the engine was not warm and I have those outstanding KOEO codes. One related to running too lean,

I pulled the ECT and the resistance was good around 40k ohms at 50F

I have good vacuum at the fuel pressure regulator.

Any help would be welcomed!

GSMblue

Looks like I am on my own here

I couldn't test the ignition module, but some of the symptoms of not starting warm do point to that being ponentially bad. I switched it out and now I am getting better warm starts.

Since I had the whole cyl#8 flooding issue at the start I have been suspicious of that injector. So when the engine was running warm yesterday she would idle at 750rpm, no lower. I pulled the injector connector on cyl#8 and no change to the idle.

I suspect something nasty is going on with that cylinder... I will try and test the resistance on the injectors on that bank and I think I need to do a compression test too..

So this weekend:
change oil (I still have the gas laden oil from the failed FPR)
test injectors resistance on drivers side - at least...
compression test the cylinders

I am leaving the code 84 EGR alone for now, as I suspect that is vacuum related and I know even less about vacuum systems than the rest of this thing...

I will probably update this over the weekend...