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Rough idle, Fuel in oil, Hard start & Loss of Power + Bad Gas Mileage

5K views 6 replies 4 participants last post by  Kondmax 
#1 ·
Hi everyone, this is my first thread here, I'm looking for some help.

I have a Dodge Caravan 1992 with a SOHC Engine V6 3.0L 6G72, automatic. This engine has new head gaskets, valve seals and oil retainers. Installed new fuel pump and fuel filter. Now here's the problem:

During a trip to another city in my country (around 70 miles). I was climbing a hill in 2nd gear, engine was doing good, then when i reached the top, the engine suddenly started to sound weird, like engine misfire. I pulled over a gas station and the engine was shaking hard. At first i thought i was a cable of one of the spark plugs because it was loose. After that i noticed there was a fuel smell coming from the engine. When the engine is hot, it stalls and it is hard to start up, take about 8 seconds with the gas pedal to the end.

I searched at Google, and found that maybe is the fuel pressure regulator that is busted. I proceeded to test the FPR but there was not leaking fuel from the vacuum hose. Few days later with the van at home I noticed that the oil had a strong fuel smell on it, another symptom of the FPR.

I'm about to order a new FPR, but I'm not sure if thats the cause of the engine shaking hard. I also suspect of the ignition coil or some busted sensor, still i have no CEL Code. Recently i found that maybe the timing belt slipped a tooth, because it gives the same symptoms.

Any advices? :( :cry:
 
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#3 ·
Welcome to the site Kondmax.
A quick thing to check is to see if the EGR valve is stuck open, a symptom of this is the intake manifold will be hot to the touch when the engine is warmed up.
After that checking the valve timing is a good idea especially since the heads were recently off.
As for the FPR, have you tested the actual fuel pressure with a gauge?



The 3.0L uses a single coil and distributor, no coil pack.
 
#4 · (Edited)
A quick thing to check is to see if the EGR valve is stuck open, a symptom of this is the intake manifold will be hot to the touch when the engine is warmed up.
I didn't check the EGR valve so far. I thought that would not matter. Even so the manifold temperature is right when engine reach normal temperature operation, judging by myself putting my hand on it, it's not extremely hot.

After that checking the valve timing is a good idea especially since the heads were recently off.
When the heads were assembled again, everything got timed right, with a bit effort because was hard to find TDC... The engine ran well for a couple of months.

As for the FPR, have you tested the actual fuel pressure with a gauge?
I'm sorry, I do not have the tools to do this, neither the mechanic I think. Even so, the symptoms point to the FPR by these facts i found so far:

1. Blackened and Wet (on fuel) spark plugs
2. Fuel in Oil
3. Not-Burned fuel smell in engine while running.
4. While engine is off a few days, after I try to start it up again, it starts pretty quickly (Half revolution before ignition) and revs a bit high, then it goes normal idle (rough still).
5. Engine might run pretty decent as long as is cold, but after a few miles, and the engine is warm, it stalls on idle and it is hard to start it up again. When engine starts again there is black smoke coming out from exhaust pipe and i have to keep the gas pedal pressed to avoid stalling again..
6. Engine vibration as if 2 or more cylinders are misfiring or not burning all the fuel. 1 Cyl. Misfiring does not give me this problem, because i had a damaged spark plug once but engine ran pretty smooth back then.

I'll take your suggest to check FPR pressure with gauge 1994Sport.

Any other tip would be highly appreciated :)

Thank you for your support, I'll keep you all updated.
 
#5 ·
Put noid lights on the injector harness and see if the fuel injector circuit is actually pulsating.

That 3.0 runs on batch fire(2 injectors firing at once) and if one of the circuits is putting out constant voltage it will flood it out and give symptoms you are describing.

Try hooking up a DRBII or doing a key dance to see if it has any codes.
 
#6 ·
UPDATE:

I did replace the Fuel Pressure Regulator and spark plugs. No change. Still Same issue.

Now i realized something. After installing new valve stem seals, the van started to throw smoke from exausht when doing cold start. It dissappeared after a while running. I think that issue may have damaged the valves causing that some of them would be burned/warped/pitted, though producing the low compression effect (it can be feeled on steering wheel while idling).

Another theory, it is that the Intake manifold has a leak which i find impossible since all the gaskets are brand new.

Key Dance show only fan codes (that was because i removed the relays to keep them always running, long story, hi temp issues).

I can't find the EGR Valve on this model, nor i don't know where is located also.

I'm thinking about removing the heads again to check the valves but that would be another 500$ spent just for nothing, (including new gaskets).

Thank you for your replys.
 
#7 ·
UPDATE:

I found out what the culprit was:

It was a broken camshaft. The one affected was the front left bank, from cylinders 2,4,6 ... #4 and #6 stopped working, then the fuel injectors flooded themselves.

Now i have a question:

When i rebuilted with new head gaskets, it is a MUST to bleed the hydraulic lifters before putting the engine all togheter again?. My mechanic says that was the cause for incorrect valve clearance, allowing for a bad oil flow, resulting in poor camshaft lubrication.

Now i fear that the new camshaft will break again eventually. i have a doubt of cam journals if they are damaged.

Regards.
 
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