Underpowered XF



Hey Dudes, I'm new on the forum. I own an 86 XF Farimont Ghia. It is very underpowered for some reason and I can't figure out what it is. To give you an idear, If I put my floor it from zero, the engine will stop for a second, and then slowly crawl it's way up to thirty or so where it will gain slightly more power. Unfortunely I know almost nothing about the engines in cars so I can't diagnose it myself :oops: . The Engine is a late model 4.1 litre EFI Auto.
Ok, first thing first with an EFI Ford six; Check For Vacuum Leaks. Ford run a sealed block, and have manifold vacuum inside the block. If you develop a leak somewhere, the computer won't be able to determine how much fuel to deliver to the motor, hence it'll run poorly.

Another thing, how many k's has the motor done? Is it the original block? (engine number same as chassis number) if its approaching the 300,000+km mark, it'll be getting long in the tooth, if its had a fair amount of hard driving..
Does it have more of a hesitation to it, and then gain it's power at a specific rev range?

That could be an ignition problem. Also if the car is beginig to have trouble starting, or missing under load, then it's probably the modulator.

If it's nothing like this, then listen to maggo and not me....lol.

Hey Dylan,

I'm new here too! Bit more info would help...ie, is it the engine or possibly tranmission? I haven't dealt with autos too much, from recent dealings with a corolla I learnt torque converters on the way out have this symton...More revs = more fluid pressure, hence more go. How does the engine run in neutral?

Besides that, I'm probly not much use, haven't dealt with too many efi engines. A skyline I used to own did similar, ended up being mass airflow sensor....Block the intake ( a hand and plastic bag work well ) The motor should stall, if leaks are present fix them, then try again. Any leaks will allow extra air into the engine that isn't noted by the computer, hence a lean mix.. like tuning a carby too lean, when floored the engine will semi stall, then pick up...

Other than that, check your timing and vac advance if present on these engines...

Later, tom...
I would post the EGR to Dylan for target practice. Blank this devil off, tune up, then report back.
lol, knowing my luck ATM, I would get a ricochett, and knock out my own knee caps...lol.

Also I've noticed a mistake of my own. Don't bother with the modulator, as you don't have one!...lol. I forgot that you had a late model engine, hence the ignition timing is controlled by that god damn computer.

How's the Sham and the Pharaohs? (Sorry, obscure joke.)

OK, give us some more basic info on the car's engine. You say you're not an engine-head, but are the basics looked after? I mean, is the oil changed, the plugs checked, radiator OK, are the air and fuel filters good?

Overheating can cause loss of power. A badly worn valve train can really sap grunt. How many K's on the clock for the engine? As I mentioned, the EGR valve is a thing best removed. A restrictive exhaust can slow you down. Tranny (auto) wear will produce sluggishness at take-off or under load.

An EGR block-off plate can be made or bought from a wrecker. Do this, check and change any neglected filters, do the plugs (they never come correctly gapped in the box), check the leads are OK and the rotor button, too. A quick tune-up by hand/ear, and you've spent less than $100, most likely.

There's plenty more that can be done - just hang in there, feed us info, and enjoy the ride! At the other end of the process, you'll be able to pass on what you've learned.

Cheers, Adam.
Sorry that I'm late dudes, I've been pretty bussy the last few weeks (uni exams!). Ok, first of all, I have checked the engine for vaccum leaks and thankfully I can't find any. Everything seems to be well sealed!

I ahve checked out the engine and I am pretty sure that it isn't the original. The serial number on the engine block is '84 DA 601 5AA S' While the code on the Chassis is '85 815 C'.

According to the odometer the engine has only done 220426 km. I suspect that the engine has been reconditioned.

One thing that I find odd about is that when I drive it slowly it seems to change gear 5 or 6 times rather than 3.

And yes their is a delay when I start to accelerate. But that is only when I put the boot in!. It did used to gain all of it's power when you got to about 2900 revs, but that apears to have stopped now.
Sam, doesn't the body serial begin with "JG34"... As should the engine, if it's original.

Up, down, up, down... Kickdown issues, or tranny problems. Tranny slip may be the cause of the poorer results. When was it last properly serviced (full band adjust, not just refluid-ed)?

Plenty of crossflows are still going at 200 000+ kms, on original guts.

Can you afford to install a C4? If the BW's rogered, this is a superior replacement.

Also, what is the status of the basic mechanicals, like a couple of us asked? Do you know for sure that they are in decent shape?

Cheers, Adam.