I may have found the cure for Fuel Fail 44!?
I have owned my '90 Majestic for 6 years plus and 32k miles. I have had continuous and frequent problems with FF44 and FF26, bouncy idle and lousy
fuel mileage. Just about every system in my car has been rebuilt/replaced and the FF44 is still a problem, particularly in Florida's summer
heat. Last week I replaced the harmonic balancer in my car with a rebuilt. Idle, running and fuel mileage improved but I still had FF44.
Over the weekend I filled the gas and noticed the 10% ethanol label on the gas pump. So to make a long story short and after reflecting on the history and issue of ethanol
in American fuel and the era of my Majestic I decided to try some "Ethanol Fuel Conditioner". Bought a couple of pint containers of the Lucas product at Wally World over the weekend.
I have a new car! My Majestic hasn't run this good since I've owned it! Tremendous improvement in overall performance and NO FF44 or FF26.
So, if you're having similar problems to mine try some ethanol fuel conditioner. I like Lucas, Sta-bil makes an ethanol fuel conditioner and I would think others as well.

 

Thanks for the suggestion. Was the 10% ethanol the same as you have been using all along? I ask because here in the rust belt we can get up to 15% which I presume would be even worse.

 

Yes, as I was standing at the gas pump, the light in my brain went on! I thought about the possible chemical/combustion effects ethanol
may have on gasoline. In so doing, I thought of the period during which the XJ40 was designed and built and so forth - before ethanol was added
to American fuels (a payoff to agribusiness by congress). On my way home I stopped by the local Wally World, looked for a product that may/would counteract those
effects found products, purchased one and!
I drove a '95 XJS with the AJ16 and OBDII for 10 years and NEVER had such problems. Clearly then, the earlier OBDI with the later ethanol mixture, (and perhaps the external fuel pump AND ethanol) were really the cause of the FF44 and FF26 issue.

 

I'm sure the gas treatment seemed beneficial BUT if that were the case, you'd think the symptoms would bemore widespread ....however, with yours being the only car affected ... Let's say I'm skeptical!

Best of luck continuing to keep your rich running codes in check.

Larry

 

Over the years I've read many accounts of chronic FF44 problems in the early cars...?

 

Best result so far...
This AM I had a FF44 after cold start! No problems after restart and running comparable to yesterday.
High CO on cold start and carbon canister purge?
I do have a new carbon canister to install, and the purge valve/s...?

 

Sometimes a small unmetered air (vacuum) leak will be recognized as a weak mixture at the o2 sensor. This can cause the system to lengthen up the squirt duration to compensate, resulting in an over rich condition which will set either FF26 or FF44.

This symptom is sometimes eliminated on warming engines as components expand.

In my case, I chased an FF26 for years, following the engine management flowchart to the "T", eventually replacing the O2 sensor, temp sensor, MAF, carbon canister and purge valve. There were periods of short term success but after sometimes months of no check engine illumination, the code would always return.

The culprit was the intake manifold gasket. Once replaced, no more issues.

Good luck!

Larry

 

Hi Roger,

I'm no fan of ethanol gasoline myself. Ethanol is less energy dense than gasoline, it absorbs moisture directly from air, and in my small engines it seems to gum up the carbs. But I have to wonder it its use in an XJ40 could really trigger FF44 or FF26 any more than running "Regular" 87 octane gasoline. FF44 can indicate either a rich or lean condition - the oxygen sensor's signal is out of range in either direction. FF26 indicates the O2S is reporting an excessively lean condition, and possible causes include intake air leaks between the MAF sensor and intake manifold gasket (plenty of places where that can happen), fuel pump and/or filter issues, an exhaust leak, a failing O2S or a problem with its electrical circuit, etc.

But I also like Lucas products so I'm going to give their Ethanol Fuel Conditioner a try. Why not?

Cheers,

Don

 

The intake manifold gasket is the last thing. I have replaced or rebuilt just about every system chasing that FF44 phantom with the last two remaining items
being the intake manifold gasket and the carbon canister. I have a new i.m. gasket and a new carbon canister. So...it looks like my new gasket will be installed.
Thanks, I have another project.

 

My car does run smoother using the Lucas product so I'll continue to use it. My new intake manifold gasket will be installed shorty.
I've replaced several AJ16 intake manifold gaskets over the years and they are a snap. I am concerned about the oil fill tube on the AJ6
engine. Once in there I'll replace the 30 year old fuel lines, bas-turd hose and heater valve and hose and everything else I can - I don't like doing the same work twice.