Odd Problem

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MOPARJ

MOPARJ

What can I upgrade now?
Joined
Nov 3, 2006
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Location
Thousand Oaks, Ca
I am having an odd issue with my Duster. All of the sudden, it will not idle in drive well, and not at all when in drive with the lights on. It will idle ok in neutral and will respond to idle adjustments on the carb. The car cruises ok, but comes up in engine rpm slowely and falls on its face when the trans shifts. At speed, it accelerates well at higher rpms.

Starting is not as easy as it should be as well.

I have swapped on another Eddie carb I had, along with another distributor, ballast, voltage regulator, coil, ignition box, plus checked the obvious vacuum lines and ground to the ecu. All of this did nothing.

Plug wires are ok. The voltage is 14 volts at idle, 13.5 in drive, 13 with lights on in drive. This has been normal for a while. Oil pressure is fine, no abnormal noises.

What I have noticed is that fuel pressure is 8.2 psi, which is about 1 psi above where it usually is. The fuel filter is completely full of fuel. Could the pump be faulty, pumping too much fuel into the carb? What else?

Maybe bulkhead or charging system insufficiency?
 
To me, Sounds like Ignition or Timing. I would have leaned toward ignition with the lights thing, but you've already swapped out the ignition box.

Have a spare starter relay? They have some play on ignition, maybe swap one in that you know is good see if it makes a difference, but I dont think that would be it.

Where you've already swapped in a module, distributor, coil & other, I have to wonder about cam timing. Anything strange happen recently. How old is the timing chain? Think you may have jumped a gear?
 
chewy said:
To me, Sounds like Ignition or Timing. I would have leaned toward ignition with the lights thing, but you've already swapped out the ignition box.

Have a spare starter relay? They have some play on ignition, maybe swap one in that you know is good see if it makes a difference, but I dont think that would be it.

Where you've already swapped in a module, distributor, coil & other, I have to wonder about cam timing. Anything strange happen recently. How old is the timing chain? Think you may have jumped a gear?
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Switched in a spare alt and nothing, along with a new dizzy cap.

Fuel pressure is 6 psi at one minute, and 8.3 the next. I almost wonder if the pump is not functioning correctly and pumping more air than fuel? The gauge just might be reading inaccurately high. I swapped out the pump with a spare tonight, so I will find out in the morning. I did hear fuel perculating in the carb after i shut it off after running this evening. This is what is raising my fuel suspicions, but it must be lack of fuel or vapor lock, as it does it when cold.

It feels like it is going up against a wall from launch, with a lack of power, but as the car and motor gain speed, it takes off with usual power and cruises nicely without missing or popping.

I dont have any popping or backfiring while on the gas, so I doubt that it is cam timing. The motor has 20000 miles on it and it using a double roller chain. nothing strange or abrupt happened of note. I just noticed it develop while driving around on Sunday.
 
I am starting to think vacuum leak based on idle, maybe brake booster vacuum diaphragm?
 
fuel pump pressure surge change filter other than that vacuum leak
 
gopar said:
fuel pump pressure surge change filter other than that vacuum leak
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Fuel pump and filter changed already.

I doubt that it would be an intake leak, as Id expect popping, backfiring, missing, and oil burning. Maybe the vacuum valve on the brake booster?

Oddly enough, I tried swapping one or two ballast resistors and neither would work......unless I swapped on wire over to another post. The existing resistor is the only one that will work with the existing wire to post location. I find this odd, actually.

I doubt the odds are very good that two ecus could be bad.

This all started Sunday after some driving. The only thing that I did to the car was retard the timing just a hair before driving and it ran fine for a while, then developed an issue. I tried readvancing the timing, but it did nothing, and yes, the timing is right: 17* of initial as always. When adjusting timing, I only loosen the bolt just enough to twist the dist via the vacuum can, then retighten the bolt. I cant see how it could of jumping dist timing.
 
could be as simple as bad gas or mabe the ethenol stuff
 
Judging that it revs fine and there is no missing at higher rpms and only refuses to idle in drive, no matter the carb setting, I am beginning to think intake gasket? Opinions?
 
Is your distributor loose?Do you own a vacuum guage?
 
Distributor is fine. Swaped a spare in to no avail. The gear is in its correct place and timed right.

I do own a vacuum gauge and I should probably use it to check for a leak, such as for the intake.
 
i have had same thing happen to me, it was the rear intake gasket cork piece of junk
 
Ok, I replaced the intake gaskets to no avail, other than to stop an annoying oil leak. So far, I have replaced, but mainly swapped in the following:

1) Distributor
2) Coil
3) checked wiring
4) ECU
5) Ballast resistor
6) distributor cap
7) swapped on a spare Edelbrock carb, which is the same as the one previously on it.
8) intake gaskets
9) checked distributor timing and gear position
10) all valvetrain looks in check and the lobes on the XE268 look great
11) swapped spare alternator, which actually works better
12) voltage reg
13) checked all of the grounds
14) fuel pump and filter (filter above pump)


The voltage is now a steady 13.5 at all speeds and gear selection. Fuel
pressure is 7.5 lbs. I am starting to suspect a slit in one of the fuel lines or possibly a partially clogged in tank filter sock. The plugs are all dry, so ignition is present, but I am wondering that even though pressure shows high if alot of that is just air? The idle speed can be whatever I sell it at on the carb in neutral, but gradually comes down some. No matter the idle setting, the idle in drive is 500-550 tops and is rough. accelerating from a stop results in a significant hesitation until above 1000 rpm and rolling, then it is a bit better. Oddly, there is no misfiring during hesitation. It cruises fine at speed, but when I floor it from a 5mph roll, it pulls more sluggish than normal and there is a distinct surge or two between four and five thousand rpms.

Being that there is no miss at speed, but the hesitation and surge at high engine speed, I am down to either clogged fuel tank pickup, or possibly the torque converter is playing in? The TC is above 4000 miles old.

Ideas?
 
Well, I changed the gaskets last night and as always I did not use the end gaskets, just rtv.

I also checked the pcv and the brake booster check valve. Nada. I tried spraying carb cleaner n all vacuum areas. No obvious fluctuations in rpms. There is about 11 hg of vacuum at 750 rpm idle in neutral and it is rough, but not missing. When I put it in drive, it drops to 500 rpm and about 6 hg. The vacuum does come up with revs above 1000 rpm, upwards of 20 hg. The cam is a Comp XE 268 with 8:5:1 compression.

When working the brake pedal, there is ever so slight rpm fluctuation.

What I did notice was slight suction from the tail pipes and smoothing of the idle when I cover them up. Again remember, there is no missing, just a hesitation when bringing the revs up from idle in drive. No pinging, no popping or backfiring through exhaust or carb. No valvetrain noise as well. Great oil pressure and the valvetrain is tight when checked.

For the record, the TC has 4000 miles on it and is a modified stock size converter with a 2800 stall rating.
 
how's that intake manifold sit on the heads? Are the angles between the intake port face and the head different? What you're describing sure sounds like a vacuum leak; it could be leaking in the lifter valley.
 
It does sound like a vacuum leak. Is the needle steady on the vacuum gauge, or does it bounce around?
 
seems like you have tried everything. about the carb you put on, is that confirmed to be good? other than that, this is a long shot. vent in the gas cap? if it were not venting i would expect it to just die but with trying all the hard stuff already might be worth a shot.
 
66dartman said:
how's that intake manifold sit on the heads? Are the angles between the intake port face and the head different? What you're describing sure sounds like a vacuum leak; it could be leaking in the lifter valley.
Click to expand...

X2 he should have used the cork/rubber end gaskets, the dodge dealer sells ones that have little tabs that you instert into the block and it holds the gaskets they work great then
 
66plyValiant said:
X2 he should have used the cork/rubber end gaskets, the dodge dealer sells ones that have little tabs that you instert into the block and it holds the gaskets they work great then
Click to expand...

I have been using rtv on the ends for quite a while when using these manifolds. Before the issue began, I had had the manifold on with the rtv for over 15000 miles. I tried new gaskets and rtv again...no change.

I dont use the end gaskets, as they never seem to prevent the oil leaks.
 
Well, I have pretty much ruled out engine issues or electrical. IT seems more and more like something is slightly awry with my 3000-4000 mile converter. It pulls fine in first, although launch is softer than normal, but when it shifts to second under light to moderate acceleration, it lacks some punch, but the motor is running well. I have to depress the throttle 3/4 of the way down for it to downshift. After that, it will move easier. If accelerating from low engine speeds in third, a downshift is needed to really get moving. At speed in third, acceleration is ok.

I have a feeling that the converter is partially locking. Is this possible? It seems possible that is will only idle at 550-600 rpm in drive, but will idle at 950 rpm or slightly more in neutral/park.
 
This is a long shot....take the gas cap off....see what happens....I had some crap like this happen to me back in the 70's and the lil "breather thingy" in the cap was plugged caused a world of **** until I found it....cleaned the lil hole out with gumout carb cleaner and WHOOP no probs.... not sure of your year you might have the return hose set up...anyway what do have to lose?
 
66cuda said:
This is a long shot....take the gas cap off....see what happens....I had some crap like this happen to me back in the 70's and the lil "breather thingy" in the cap was plugged caused a world of **** until I found it....cleaned the lil hole out with gumout carb cleaner and WHOOP no probs.... not sure of your year you might have the return hose set up...anyway what do have to lose?
Click to expand...

I already checked all of that out. Replaced a worn cap and checked vent tube from the tank.
 
ide be bald from pulling my hair out with this problem,,,very hard to figure out over the internet,,,good luck,,
 
fstfish66 said:
ide be bald from pulling my hair out with this problem,,,very hard to figure out over the internet,,,good luck,,
Click to expand...

I dont have any hair to pull at my young age. Lol.

The car runs and still is fairly quick and runs ok and on all eight holes, but it is sluggish in spots while driving in the past week and a half. After all of my testing, I think its down to an errant converter, or vacuum leak that is hard to find.
 
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