Acting Funky at startup. (2002 4.0/5sp Manual)

[96firephoenix]

So, I had a slight case of the coolant temperature blow-out plague a few weeks ago, and the truck's acted funny since.

I noticed a burning coolant smell almost constantly once the engine got heated up, but I at first dismissed this as splash-over cooking off. I'm not so convinced any more.

If the outside air temp is below about 50 deg. F, it stumbles and misses while in Open Loop at startup, but throws no codes. Idle smooths after about 30 secs max. I've verified with my Innova scantool that the smoothing occurs at transition from open to closed loop. Also verified that NO regular or advanced DTCs exist.

Strangely enough, this same issue exhibits when parked facing even remotely downhill for more than about an hour. I'm talking enough grade to roll a basketball, but not very quickly. God help you if you park it downhill in the cold. I don't think iit gets worse on steeper hills, but I live in central IN...my opportunity for steep hills is kinda limited.

thoughts?

 

[96firephoenix]

thoughts???

 

[Number4]

Is the fan clutch engaging at startup when it shouldn't?

 

[96firephoenix]

Update: I've got a definite exhaust leak - I can see puffs of exhaust coming out of the flange off the header. looks like it just wasn't tightened back up properly.

Is the fan clutch engaging at startup when it shouldn't?

you mean the fan isn't supposed to spin right when you first start the engine? Not a sarcastic question... I honestly didn't know.

I've only really had cars with electric fans, except this and my ranger...Never had any issues on the ranger.

I'll have to check in the morning to see if the fan is spinning right away or not, but what does this mean if it is spinning?

 

[Number4]

The fan will spin, but shouldn't be full force as the temp is too low for it too engage.

I've been told that at startup, if you tied a piece of string to the blade and 'car' it shouldn't spin and the string shouldn't break.

 

[96firephoenix]

The fan will spin, but shouldn't be full force as the temp is too low for it too engage.

I've been told that at startup, if you tied a piece of string to the blade and 'car' it shouldn't spin and the string shouldn't break.

Definitely spinning stronger than that... how does this relate to stumbling at startup?

 

[Number4]

It's an extra load on the engine that the engine doesn't need at start up.
When cold and with engine off, does the fan free spin?
Or, when you give it a spin does it not complete a rotation?

I'd say replace with caution, it may not be the issue. I'd get a second opinion.

 

[Joe in NY]

That is wrong info Number4. When a fan clutch has been sitting the fluid settles in the viscous coupling and the fan IS supposed to spin at full force until the fluid gets back to where it should. That is why you always hear the fans roar on a cold start for a min or so...

 

[Number4]

I do stand corrected. One more reason to ditch fan clutches for e-fans.

Open loop is why you aren't getting any codes at start up. But if the leak was sufficient enough to cause open loop issues, you'd think it would throw codes once it closed.

I'd certainly start with the exhaust leak before doing anything else.

 

[96firephoenix]

sounds about right... would the hi-flow muffler be influencing this? P.O. put a hi-flow cherry bomb on it.

Also, 100% right about the E-fans. been looking at the write up the last couple of days, then at my bank account, then back at the write-up.

 

[96firephoenix]

Bump to update: engine blew a head gasket 8 months after I made this thread. Combustion chamber to water jacket leak, so there was no milkshake. Just a gas smell in the coolant tank, and enough pressure in the coolant system to blow some seals.

Getting a crate engine soon now that my wife is going back to work.