85 turbo - coughs on heavy accel load

My 1985 lebaron Town and Country convertible runs fine around town, no
idling problems, good get up and go. Only problem is if I happen to
have to really push the motor, like trying to accelerate up a steep
grade too quickly, or pass somebody and almost floor it, the motor will
hesitate and lose power momentarily, as if the gas or ignition has
almost been cut off, over and over again, till I lift off the gas a bit
and accelerate slower. Sort of a "chug" where power drops out like
it's going to die, then comes back quickly. What are the possible
causes of this? If the knock sensor detected enough knock could it do
this (I don't really hear knocking but I mostly ride with top down.)
Maybe I should try a tank of premium first. Timing is set at Calif.
factory setting. I think I changed the big fuel filter about 50K ago.
Could it be dirty again and cause this? thanks!

 

clarification, this is a 2.2 turbo, 121,000 miles...Frenchy

 

Depending on the timing of this "chug" event relative to when you mash the
accelerator, it could be that the computer is detecting an overboost
condition and is momentarily killing power to the ASD relay to bring the
situation under control, or it could be something less exotic. Your first
step is to check for flash codes.

To check the computer codes:

With the engine off, switch the ignition key on-off-on-off-on,
leaving it "ON". Do not
go to "start", just "on" during this procedure.

Watch the "Check Engine" or "Power Loss" light. It will turn on, then go
off, then will begin to flash-out any trouble codes that have been stored.
For instance, if it flashes:

flash <pause> flash flash
<long pause>
flash flash flash <pause> flash flash flash flash flash
<long pause>
flash flash flash flash flash <pause> flash flash flash flash flash

Then you have a 12 (one flash followed by two) a 35 (three and five) and a
55 (five and five). 55 means "end of codes" or, if by itself, "No codes
stored. Check the codes and report what you find.

Maybe you should diagnose the problem systematically and fix what's
broken.

Yes, you are overdue for a fuel filter by about 20,000 miles if you're
lazy, or 30,000 miles if you're smart.

What else is overdue on your car...?

DS

 

"Turbo" is key word. Sounds like over-boost shut down to me. Is the
wastegate failing to open? Trouble codes set?

 

Does the power loss lite turn on when this happens and then goes back out?
If so it is going into overboost, check vaccum hoses to and from the turbo
especially behind the valve cover and the hose at the bottom of the turbo,
But it could be a number of things though, tune up? plugs/wires breaking
down? Check for any fault codes in the power module............ Knock sensor
would not cuase this.
Glenn Beasley
Chrysler Tech

 

Ok folks I dumbly forgot to check for any problem codes first, I'll
check tonight. Did not notice the light coming on when problem occurs
but this is with the top down in the sun going 60 so wasn't exactly
looking for it, will observe it next time it happens. Will report back
what I find. thanks...Frenchy

 

Oops the car is right outside, duh. Ok even though I just cleaned the
battery terminals since the last time I noticed the problem (the time
before last that I drove it), I just checked and sure enough I have a
12 code (battery recent disconnect) and a 45 code (overboost) and 55
(end test). If I pull on the overboost rod HARD with both hands, it
moves away from the diaphragm and returns back ok. Free but hard to
move, normal I suppose. How far should the rod be able to be pulled?
Seems like about an inch. So what pushes the rod out of the diaphragm,
the exhaust pressure? And the small hose is a vacuum hose to modulate
it? Or are both hoses vacuum and they move the wastegate with just the
negative vacuum (boost)?
Have to wait till I get home to check the condition of the hoses.
thanks again...Frenchy

 

dont worry about how far the rod moves,,check the vacuum lines, at the waste
gate solonoid to the acuator, if your lucky you will just find it has a
broken hose,

 

12 = "Start of Codes" when read via the dashboard light.
45 = what I expected you'd find.

Yep, there should be stiff spring tension on it, alright. But, you may
want to remove the wastegate actuator rod from the wastegate lever and
make sure the lever swings freely. If it is binding, it will cause
overboost. Hitting the wastegate shaft with Mopar P/N 4318039AB
penetrating fluid (do not substitute) usually eliminates the binding
condition.

That's about right.

No, intake manifold pressure (under boost).

Your idea here is more or less correct, but there's no such thing as
"negative vacuum". Boost is considered positive pressure and is measured
in pounds per square inch (PSI). Vacuum is considered negative pressure
and is measured in inches of Mercury (in. Hg). Both are considered
relative to atmospheric.

If there is a leak anywhere in the hose running to the wastegate actuator,
overboost will result. Same if there's a faulty or sticking wastegate
actuator vacuum control solenoid.

And my question from before stands: You're long overdue for a new fuel
filter, so what else has been let slide?

 

Heyyyy, I just put on 4 new tires this week, noticed a busted CV boot
and had them fix that at same time and changed oil and filter, I always
keep oil and transmission fluid topped off, I slapped on a new timing
belt recently, new distrib rotor, and I keep the fake wood varnished.
I did notice I had let the power steering go almost dry so after
refilling it I had them flush it out and refilled it again. I was
thinking of getting a new Sebring but I can't let go of this darn
Woodster!...Frenchy

 

I've never heard of penetrating fluid before -- what's the
distinction between penetrating fluid and penetrating oil?

 

Pure slapstick!

 

OK, that's good, but you've also got 50,000 miles on the fuel filter...!
No insult is intended, just factfinding. How long since the entire
crankcase ventillation system was serviced (much more than just replacing
the PCV valve)? Spark plugs, plug wires, distributor cap? Air filter? How
long since the throttle body was cleaned?

 

It's the new name for what Mopar used to call "Manifold Heat Control Valve
Solvent".

Dunno, good question. 4318039AB (and its predecessor 4318039) smells quite
unlike any penetrating oil I've ever used, and the smell is definitely not
one of petroleum distillates. It also has a strange consistency. But
nothing else works even close to as well on heat riser valves and
suchlike.

DS

 

Bingo, it was the bottom vacuum hose on the wastegate, it's rotting
into friggin' cracked, melted rubber goo and had a big gash in it where
it connects to the nipple. Was out of sight, and out of mind : \
Guess this explains the damn wandering idle speed I tried to diagnose
but could never figure out too. Yes it's got newer plugs, wires, dist
cap, air filter, and I cleaned the throttle body like a clock back when
I was trying to fix the goofy idle but gave up and lived with it. It
would only do it sometimes, would quit doing it for a while, then start
up again, and depended on whether car was warmed up sometimes.
Apparently was just that rotten hose crack heating up and letting in a
bit more vacuum some times than others. Off to buy some new hose
tommorrow and will try to do better job of checking all the vacuum
hoses this time too (I've found and fixed a few cracked plastic tube
hoses in there before). Replaced the dist rotor once when the little
plastic alignment pin broke and rotor just spun freely, that was a
bitch to figure out!
And I'll get another fuel filter. What do I need to do to clean the
PVC system other than cleaning the valve? THANKS EVERYBODY!..Frenchy

 

There y'go. Easy fix.

*REPLACE* the valve if it's been on there a few years. Inspect *all* the
hoses and rubber elbows in the system. Don't forget the one at the left
rear corner of the camshaft cover, at the other end of which is a
crankcase inlet air filter that needs periodic replacement.

 

I figured that is what you would find, good for you!!!

 

Hey dicks back, hi Dick

 

DO NOT USE PLATINUM PLUGS OR BOSH PLUGS< USE ONLY CHAMPION< i belive they
were rn12yc, some plugs will mess with the timing of the power module and
cause all kinds of idle problems. Almost like it is searching because the
timing is flucuating so bad

 

DO NOT USE PLATINUM PLUGS OR BOSH PLUGS< USE ONLY CHAMPION< i belive they
were rn12yc, some plugs will mess with the timing of the power module and
cause all kinds of idle problems. Almost like it is searching because the
timing is flucuating so bad