[zerostar]

So my friend's Dodge Caravan (93 3.3L V6 long wheelbase) crapped out in my front yard when they tried to leave one day. Apparently it had been overheating, but now when you hit the gas it falls on its face and you really have to baby it to get anywhere, seems around 2K RPM it gets a little steam, hitting the gas above that and it craps out. It runs fine out of gear and has great throttle response. As soon as in gear it runs terrible, backfires and generally sucks.

Luckily we had a dodge scanner, hooked it up and everything is pretty much checking out perfect. So I start some process of elimination. I notice the exhaust flow is low even when revving it. I figure the cat is clogged, so I dropped that and took it for a spin, besides being horribly loud no change.

I have checked airflow, fuel pressure, timing, everything I can think of.

Any ideas on what next? I am kind of at a loss, my friends have no money to drop in to this and I was hoping I could figure it out with my limited knowledge.

Unfortunately I don't regular any car forums, but I know some car buffs are on here and I thank Ca$h for helping me last time with the Civic (it is also their car and still running like as champ despite their best efforts! hahaha)

p.s. I noticed the O2 sensor looked like crap when I dropped the cat, but readings are fine on it.

[Mel O. Drahmatik]

Check the head gasket. Is it blowing any steam or smoke? Check the handle which moves the window up and down. It might need a driver upgrade. Can this possibly be any more dramatic?

[zerostar]

Head gasket seems good and the electric fan comes on at the appropriate time, temperature seems good as well. No coolant loss and no steam.

EDIT: Never mind on the rest, I didn't realize you seriously have nothing better to do.

[seanc]

Are any of the hoses split, blocked or crushed?

[Mel O. Drahmatik]

Check the spark plugs and plug wires. Check the radio. Also, I have seen in cases where the antenna is tuned to Rush Limbaugh that it goes a little slower and might fail in idle.

[Sherman Homan]

Running fine in neutral, "babying" it to get any response in gear sounds like a fuel delivery problem. A clogged filter will let in enough gas for neutral. The fuel pressure may even check OK. But when it comes to enough pressure for drive there just isn't enough flow.

[EricTheRed]

Originally Posted by zerostar 

So my friend's Dodge Caravan (93 3.3L V6 long wheelbase) crapped out in my front yard when they tried to leave one day. Apparently it had been overheating, but now when you hit the gas it falls on its face and you really have to baby it to get anywhere, seems around 2K RPM it gets a little steam, hitting the gas above that and it craps out. It runs fine out of gear and has great throttle response. As soon as in gear it runs terrible, backfires and generally sucks.

Luckily we had a dodge scanner, hooked it up and everything is pretty much checking out perfect. So I start some process of elimination. I notice the exhaust flow is low even when revving it. I figure the cat is clogged, so I dropped that and took it for a spin, besides being horribly loud no change.

I have checked airflow, fuel pressure, timing, everything I can think of.

Any ideas on what next? I am kind of at a loss, my friends have no money to drop in to this and I was hoping I could figure it out with my limited knowledge.

Unfortunately I don't regular any car forums, but I know some car buffs are on here and I thank Ca$h for helping me last time with the Civic (it is also their car and still running like as champ despite their best efforts! hahaha)

p.s. I noticed the O2 sensor looked like crap when I dropped the cat, but readings are fine on it.

Check the air filter and be certain that it is clean (I can't tell you how many cars with a power loss I sorted when I was an auto tech) and, with the engine off, open up the throttle plates and clean the carbon built up behind them with a good carb cleaner, R&R the fuel filter.

[Oneota]

How does this cat feel about being dropped on/under a running engine? Is it landing on all fours?

[Chooglin']

Take it to a real auto mechanic and pay the bill to have it repaired professionally. If you can't afford it, then bite the bullet, sell it, and buy a bicycle.

I think most people would agree that driving a junker car around that you can't afford to repair pollutes our air and is a real danger to other people on the road.

[Aeternus]

I'm thinking fuel pump or fuel filter.

[zerostar]

Now it is showing 15 psi on the fuel. Was perfect when i checked it before. Guess we need to drop the tank and replace the pump.

[vmarks]

There is a filter in the tank and a filter in the engine bay.

The other thing I've found is that the screens on the fuel rail side of the injectors can get clogged if the filters aren't filtering as well as they ought.

So you can have plugged up filters and plugged up injectors.

I've taken out the injectors, tapped them upside down on paper towels, put them in an ultrasonic jewelry cleaner with injector cleaner (put them in a glass jar so that the solvent doesn't eat the ultrasonic cleaner basin) and gotten so much carbon out it's absurd.

Then put it all back together with new filters in tank and engine bay, and you'll be fine. The computer can't register this as a problem because as far as it's concerned the injectors are firing at the right moments.

Of course, you can check with a meter and see if the injectors are in fact moving the pintle, but I believe they are if it suddenly failed in the manner you describe.

[Aeternus]

One last ditch attempt before you take anything apart:

Go to the hardware store. Buy a gallon of either Xylol or Toulene. Both are solvents, and both are primary ingredients in gasoline. Dump about half a gallon into your next tank. You should notice improved acceleration, and with any luck, it will dissolve any carbon/gum/varnish without having to even turn a screwdriver. Both are the same **** as 'heavy duty injector cleaner', only much cheaper, since you aren't paying for special packaging. Toulene eats paint though, so I usually use xylol. As an added benefit it should be quite a bit faster too.

[zerostar]

Unfortunately the car wont get that far, I can't even drive it around the block. the fuel pressure was at 15psi and should have been at around 50, plus as soon as the car is turned off it drops back to zero, so the pump isn't even allowing the pressure to stay so when you start it it takes several tries before there is enough gas.

Anyway I will try the fuel filter first and see if that does the trick, but I don't think that would all of a sudden clog that badly in one day.

[Railroader]

Originally Posted by zerostar 

but I don't think that would all of a sudden clog that badly in one day.

You'd be surprised. Have they bought gas recently?

[zerostar]

hmm, i don't think so, but I will check the filter first probably tomorrow.

[design219]

Originally Posted by zerostar 

Anyway I will try the fuel filter first and see if that does the trick, but I don't think that would all of a sudden clog that badly in one day.

It can clog suddenly, or at least appear to. I had that happen to me on a trip once. Just suddenly started dropping power on hills. I think gunk builds up and the pump compensates until it hits a threshold where it starts affecting performance.

The good news is it's a cheap fix.

[zerostar]

Well tried the fuel filter, had some gunk in it, put in the new one and the pressure is still around 14psi, the new pump specs say 49psi. So tonight is the night, I wish the tank wasn't 1/2 full it would be easier to drop & change, I should look for a way to syphon it perhaps....

[Sherman Homan]

True, it will be heavier, but remember that an empty fuel tank is more of an explosion hazard than a full one. Be careful with those electric tools around it!