I have a 1991 F150 XLT with automatic transmission and 5.0 engine. I recently had a no start condition and thought the timing had jumped. I replaced the timing chain and sprockets (timing did not jump).

I replaced the ICM on the side ove the distributor and now the truck starts and seems to have plenty of power. I disconnected the spout and set the timing to 10 before TDC. When I reconnect the spout it only advances about 2 degrees. Before the no start I retimed and when I reconnected the spout it would advance around 19 degrees.

When I drive the truck under load there is a rattleing nois (like a paint can). I am not sure if this is because the timing is not advancing. I also have white smoke from the exhaust but am not losing coolant and do not have coolant in my oil.

I ran KOER test and have code 44 and code 13. Is this a vaccume problem?

Please help.

Sorry for the long post.

Thanks.

 

Subscribing to this. My '94 300 was doing the same thing, and spout connector hardly giving any advance, and a bad rattle/racket coming from engine bay/firewall under load.



Extremely hard on gas as well...

 

Did you find a solution to the problem?

 

I didn't no, I blew the head gasket last weekend. Was coming home sunday afternoon, and was pissed off at it for using up a whole tank of gas in 120 miles, and that grinding/rattle noise it makes under load, I ran the living ***** out of it, said if something has to break, it's going to now.... and the head gasket went lol.

 

Knock does have a rattling noise and does cause white smoke in the exhaust, but it's caused by too much timing advance, so not having any vacuum advance will not cause knock, just bad fuel mileage ("performance" engines usually run distributors with no vacuum advance, I guess to simplify things since they don't need it).

Knock is really hard on the engine, so get it figured out before you wreck anything. It's basically caused by too much spark advance, too lean a mixture, too little octane, too much compression (or boost if applicable) or carbon deposits. Sorry, I can't help you with the codes to see if they give any clue.

 

Service Code 13 indicates that during Engine Running Self-Test, engine rpm could not be controlled within the Self-Test lower limit band.

Possible causes:
-- Improper idle air flow set.
-- Vacuum leaks.
-- Throttle linkage binding.
-- Throttle plates open.
-- Improper ignition timing (TFI vehicles only).
-- Throttle body/ISC solenoid contamination.
-- ISC circuit short to ground.
-- Damaged ISC solenoid.

ISC=Idle Speed Control

 

Rattle noise under load sounds like detonation to me. I would try backing the timing off alittle bit and see what it does. Did you have the SPOUT connector disconnected when you originally set the timing? It has to be disconnected to properly set the timing.

 

He said he did.............. But, I wasn't there , so I don't know for sure...

 

Not to question anyones abilities here........

There were several posts about the 4.9's and timing (I know, 5.0's are different).
Some of those problems were resolved by "enlightning" the OP's on EXACTLY WHERE AND WHAT TIMING MARKS to use.

Could this be the case here ?????

I've got a 4.9, so this may be irelevant......just tossin' it out there.

Bob

 

He is saying that the timing does change when the SPOUT is put in but not enough.
If the timing moves any at all it means that the computer is controlling it.
I have had the timing move a lot and then hardly move the next time on the same engine so I would not worry about the little bit of a change, just so it changes.

So the timing advance is not his problem. I think the "rattling noise" was well covered in post #5 above.
Except when it is cold out this could also be piston slap.

Also he has not returned after posting the first and third post in the thread.

 

So 1991FTRUCK and IDIDieselJohn had the same symptoms on two different engines (a 4.9L six and a 5.0 V8): reconnecting the SPOUT connector hardly advanced the timing at all at idle and lots of noise (rattle) under load. It seems like it can't be coincidence that both engines had the same symptoms.

I'm completely speculating here, so take this for what it's worth. And to give a little idea how much my speculation might be worth, I'm a mechanical engineer with a specialy in power and propulsion (hence the geek alert). I know the basics and theory of gas engines. But I have almost no insight or info on how Ford chose to implement the theory. So with that caveat, here goes.

It seems likely that the noise descibed in both cases is knock, so I'm going to assume that is the case (if that assumption is wrong, so is everything that comes after it). So both of these engines are knocking. Causes of knock again are:

• too much spark advance
• too lean a mixture
• too little octane
• too much compression (or boost if applicable)
• carbon deposits.

(I think I got at least the main ones).

Since these engines are computer controlled, it's likely that they have knock sensors. Assuming that is the case could explain why the timing doesn't advance much with the SPOUT connector plugged in. The computer could be trying to advance the timing by 20-30 degrees but is sensing knock at idle and is backing out timing until the knock goes away. If that's the case, the computer is almost running out of it's range even at idle, so it wouldn't be surprising if it then wouldn't be able to get rid of the knock under load (where it's much more likely to knock anyway).

If all this is true, figuring out why their knocking ought to fix both issues.

Too much compression (or boost)
Neither said their engines were modified, so I'm assuming it isn't this.

Carbon deposits
I'm no expert on this, but I don't think carbon deposits are likely to make things this bad. I can't rule this out completely, but it doesn't strike me as the likely cause.

Too little octane
Did you get some bad gas? Gas quality seems to be pretty good overall, so this doesn't seem really likely, but it might be worth draining the tank and starting with some fresh gas from a different station.

Too much spark advance
Both said they had recently set the base timing, so the only possibility here is if base timing was set incorrectly. We were assuming that that was done right, but to Truckin Bob's point... There's a sheetmetal pointer on the front of the engine, just above the torsional dampener (the pulley on the crankshaft) and probably slightly to the passenger side of center. Then on the outside of the dampener there are fairly shallow lines scribed in with some numbers (at least probably 0 and 10). They get pretty hard to see after time, so I've usually had to get under the truck and use some steel wool to clean them up, then I put some white paint on to make it show up better with the timing light (put paint on the pointer too). Then make sure you hook the inductive pickup on the timing light to the #1 plug wire.

Mixture too lean
This seems like the most likely culprit to me. Plugged fuel filter, bad fuel pump, plugged injectors, bad O2 sensor, probably even more things can cause this. Engine codes might shed some light on this, but again, I'm no expert on Ford's engine control system. But checking fuel pressure at the rail would be a good place to start.


OK, as I said, that was all speculation. I might have made a wrong assumption or two, or I may well have missed something. But those are my thoughts. I hope I didn't bore people too much.

 

Yep, we're on the same page here.
I'd bet the truck(s) in question don't have their "base timing" set correctly.


Bob

 

Nothing Special, great clues and possible causes. Lemme add to that some specs about my my truck.


It's always rattled/knocked under load since having it (did 5k miles in 4 months that I drove it this winter.)


Playing around with the timing didn't affect that rattle/knock at all, it remained completely unchanged. Although I did notice a small boost in get up and go power after setting correct base timing.


My engine is as quiet as a mouse cold or hot, idle or at 3000RPM sitting parked.


Now under load, it's not as noticeable if not at all, taking off in 1-2 and 3rd gear fallowing normal traffic, however, if I give it more gas to pass that traffic, I'll clearly hear it, and 4th and OD is the worst.


Especially in lower RPM's giving it more gas and lugging it (5 speed standard).


My truck has 151,000km (94k miles) on it, and oil is pretty clean after a 3k oil change interval, so i'm "assuming" it's had rather good maintenance. Never towed a trailer.



Lets revise the above posted, as far as I know it.

- Compression, never done a compression test, but engine is bone stock and low miles....so lets "Assume" it was good.

- Carbon deposits, in my case, that IS very possible. The truck was used at an auction lot for 6 years, just running around in a parking lot fueling up auction cars, it's had ALOT of idle hours and no free running highways to go on. Now thinking about this, I wonder if it does have carbon, and to much of it...causing higher compression by reducing the size of the combustion chamber???? Hmmm


- Octane, i've always ran 87 octane in it, fueling up every 3-4 days when I was working ridiculous hours this winter. Did a full tune up on the truck also before putting it on the road. Plugs, wires, dizzy cap and rotor, gas filter and air cleaner. I did run premium 91 oct once cause that gas station was out of regular, and it was letting the premium go at regular price, and don't think I noticed a difference.


- Spark advance, mine was the other way around, not enough. I did find the correct very small engraved line on the dampener, and was going by the timing degrees on the sheet of metal a few degrees to the drivers side of the block, it read 14 12 10 8 6 on it. So assuming I did set the correct timing.


- Lean mixture, well I did get a fuel pump code once, and only once, fuel pump circuit fault or something it was. Cleared it, and never had it again after. Otherwise, can't see what else would cause a lean mixture, and getting 11-12mpg driving like a granny.

 

IDIDieselJohn,
It sounds like you have piston slap. It only happens under load like starting out from a stop.

 

It happens anytime I put the engine under load, at any RPM (alot worst in low RPM's, giving it lots of gas). My old Buick had piston slap, I know what that sounds like. Mine sounds like theres a bunch of loose marbles loose bouncing around in the bell housing type of thing.