Strange (lack of) performance 318

[68fury]

Hi Mopar experts...

I have a 1986 5th Avenue which I have had about 2 weeks now. And theres something really odd with the performance.

I'm sitting at the lights, they go green, I squeeze the gas quite hard and off she goes. Not rocketship speeds, but hey, its a stock '86...

So I'm cruising along at 35 with my little toe just tickling the gas pedal. I want to accelerate out to pass some guy or merge onto a faster road, so I stick the gas pedal down and nothing happens! The car slowly drags itself up 1 MPH at a time until its doing about 50-55 and then it wakes up and goes.

It almost feels like driving a turbo car with a load of lag.

Sometimes she won't pull hard from a rolling start either, like at a junction where you slow down, roll up and hit the gas again at 5 mph or so. Not so bad as the symptom above, but sluggish performance. And yes, it kicks down OK.

Now if it wasn't for the fact that it CAN pick up and go well, I might be tempted to put it down to damned smog era junk, but this can't be right.

The car has had a fresh service just before I got it (I checked the filters, plugs and wires all appear to be new). I peered down the throat of the carb and thats all clean like a new pin. One of the reasons I bought the car was the motor all looked real clean and well kept...

Cheap solutions are best as I'm trying to get the cash together for disc brakes for my Fury!

[68fury]

Oh yeh, theres no "symptoms" either. Its doesn't splutter, run rough, back fire, or anything. It just "goes slow"

[NZ 440R/T]

My Challenger had the same kind of thing, I would be doing 15-20mph and floor it, it would kickdown then kind of shut off then slowy work its way up to speed.
It will be your chamber not feeding fuel through properly, too much air

[68fury]

Sorry to sound a little dumb here, the "chamber"? You're suggesting its leaning out basically, so is this to do with the lean burn system / carb?

The damned engine is covered in pipes I can hardly see it! Not used to this...

[NZ 440R/T]

Sorry to say mate, but I don't exactly know myself.......Only what the problem is, not how to fix it But I'm sure a carb Guy will be able to help I wouldn't mind learning as well

[dwc43]

Originally posted by 68fury
Hi Mopar experts...

I have a 1986 5th Avenue which I have had about 2 weeks now. And theres something really odd with the performance.

I'm sitting at the lights, they go green, I squeeze the gas quite hard and off she goes. Not rocketship speeds, but hey, its a stock '86...

So I'm cruising along at 35 with my little toe just tickling the gas pedal. I want to accelerate out to pass some guy or merge onto a faster road, so I stick the gas pedal down and nothing happens! The car slowly drags itself up 1 MPH at a time until its doing about 50-55 and then it wakes up and goes.

It almost feels like driving a turbo car with a load of lag.

Sometimes she won't pull hard from a rolling start either, like at a junction where you slow down, roll up and hit the gas again at 5 mph or so. Not so bad as the symptom above, but sluggish performance. And yes, it kicks down OK.

Now if it wasn't for the fact that it CAN pick up and go well, I might be tempted to put it down to damned smog era junk, but this can't be right.

The car has had a fresh service just before I got it (I checked the filters, plugs and wires all appear to be new). I peered down the throat of the carb and thats all clean like a new pin. One of the reasons I bought the car was the motor all looked real clean and well kept...

Cheap solutions are best as I'm trying to get the cash together for disc brakes for my Fury!

Just picked up a loaded 88 5th last Monday for 625. It even has leather. I stole that sucker. It's a little slugish too unless you really get on it. When I put the plateon it I ran my hand under the exhaust. Plenty of flow, but it was hotter than hell. Clasic case of the cat converter stopping up after running for 15 years. Just have it hoolowed out or removed all together and your power will return and your mpg will improve too. Let me know if you have any more questions about it. I'll be glad to help you out.

[68fury]

About the only good thing about living in this over-taxed nanny state country (UK) is that we have no requirement to run a catalytic converter prior to 1992 model cars. I already plan to junk it, along with any other emissions "crepe" on the car as mileage is important (at nearly $6 per gallon, you bet it is!)

I'm tied into a couple of other projects so I don;t want to be pulling too much off the 5th or getting it all in bits as its my daily driver.

I'll pull the cat and slip a flexi over it, and see if I can't loose some of this other stuff too.

What else is an "easy win" to junk? So long as I can run a nice clean burn I'll pass emissions so no worries on that.

I'm suspicious about the carb, just because I hear its computer controlled on this model? My budget just now doesn't hold out for another one but can I improve on what I got (in nice easy one afternoon steps)?

Apart from being a little lazy on pick-up its running real clean, real smooth and real reliable.

[dave571]

The converter is a good place to look.

I'm assuming the vehicle has had a pampered life, as such, it probably hasn't been matted much. It could simply be, that the secondary fuel bleeds are plugged from lack of use.

You stomp it, the secondary throttle plates open, and bring lots of air, but no fuel.

Just a thought.

[NZ 440R/T]

Originally posted by dave571
You stomp it, the secondary throttle plates open, and bring lots of air, but no fuel.

Thats what I was meaning

[dwc43]

Originally posted by 68fury
About the only good thing about living in this over-taxed nanny state country (UK) is that we have no requirement to run a catalytic converter prior to 1992 model cars. I already plan to junk it, along with any other emissions "crepe" on the car as mileage is important (at nearly $6 per gallon, you bet it is!)

I'm tied into a couple of other projects so I don;t want to be pulling too much off the 5th or getting it all in bits as its my daily driver.

I'll pull the cat and slip a flexi over it, and see if I can't loose some of this other stuff too.

What else is an "easy win" to junk? So long as I can run a nice clean burn I'll pass emissions so no worries on that.

I'm suspicious about the carb, just because I hear its computer controlled on this model? My budget just now doesn't hold out for another one but can I improve on what I got (in nice easy one afternoon steps)?

Apart from being a little lazy on pick-up its running real clean, real smooth and real reliable.

Dont use a flex pipe in the exhaust. It will hurt the fow due to the fact it gets it to spinning inside the pipe and the velocity slows down. On most of these if it just has one cat you can drop the pipe and take a pry bar and hammer and beat the inside out of it. If not take it to a muffler shop and get them to cut a pipe for you to install you self if you like, but dont use the flex stuff. The air pump and all of it's lines can go too as well as the egr valve, but I doubt it will pick up much milage that way. Loosing the cat will gain you the most.

[68fury]

OK folks I see a plan forming

de-cat it with a proper pipe, strip & clean carb, junk the air pump if I have time

Thanks all!

[dwc43]

Welcome, anytime.

[rumblefish360]

Does it have a 4bbl carb on top?

[71RR]

Good luck with it, remember they only have 140 horsepower and weigh just under 2 tons. An Aries/Reliant with the 2.2L has a better weight to horsepower ratio.

[68fury]

Thanks for reminding me of that 71RR!

I think mine is 160 or so though as its 4 barrel and got they 9:1 CR for '86. Still, not exactly a quarter mile warrior!

Its not the number of the horses that counts though. When it behaves it goes quick enough to beat stuff like a Mondeo away from the lights, they are 140 BHP and only about a ton. I guess its the torque that counts for city driving.

Its a nice winter car, it'll do. Compared to the kind of **** British / European junk I could have got for the same money (Volvo 740, BMW 520, Ford Scorpio) I'm happy to put up with the flaws the 5th Ave has. Come summer I might consider having a proper play with it (when I'm done spending money on the Fury)

My '68 Sport Fury has the 318 two barrel and weighs more than 2 tons and is quicker than the 5th Ave. IIRC its about 220 BHP?

Might just have to pull the 318 from the Fury, drop it in the 5th and get a proper motor for the Fury.

[rumblefish360]

The reason I sked if it had a 4bbl is if it's secondarys are opening at part throttle to cause bad mileage.
Whats a Ford Scorpio? Have a picture?

[GaryS]

My '85 5th Ave was the same way. It's just they way they have it set up for mileage. Between rear end gearing, torque converter and spark control, it was a slug until RPM's built up...but it did get 25 mpg on trips.

[68fury]

dunno if I can insert inline images but here goes:

This is the Ford Granada Scorpio Mk3



This is the Ford Scorpio



They are both the same car really but restyled and the "Granada" name bit dropped in 1992 or 1993.

Its RWD, power comes from a gutless 2.0 litre through to a quite hot 24V V6 2.9 liter by Cosworth. Also a 2.5 turbo diesel which IIRC is made by Peugeot in France. Its the same size as the 5th Ave prety much. Its kind of the British Crown Victoria. Big RWD cars are not popular here any more so Ford dropped it about '99 and it was not replaced. Biggest ford is now the FWD Mondeo.

Resale on these is appauling. You can buy a good '95 Scorprio Ultima for the price of a '90 Toyota!

-

GaryS - Thanks, you are confirming what I had suspected all along! Upgrades comeing as cash allows!

[rumblefish360]

68fury;
Thanks. That looks alot like a Contour, or Taurus. The Taurus is big and the Contour is mid sized. The Taurus is popular here.

[68fury]

Aha, the Contour is called the Mondeo in Europe.

Rumour has it we were going to get the Taurus to replace the Granada/Scorpio range but it never happened. Vauxhall have just dropped the Omega (the car which is kinda the same base vehicle as the Holden Monaro on which the new Pontiac GTO is based) so thats the end of the line for mainstream RWD sedans over here unless you go BMW/Mercedes/Jaguar and thats a price level up.

MG-Rover have got with the program though. They have converted their comfy FWD "75" sedan to RWD and are buying 4.6 liter V8s from Ford for it. No price yet but its targetted at the BMW 540 and M5. Go MG-Rover, time to kick Bavarian ass

Shame they couldn't have got hold of the 5.7 Hemi for it...