billschillin

Hi, I have a 1995 Plymouth Voyager with the 3.0 Mitsubishi engine. It has 219,000 miles on it. I have been averaging 24-25 mpg but was leaking 4- 5 qts of oil a day. ( that's no exageration ) so I put in new crank and cam seals as well as valve cover gaskets which were all badly leakiing. 3 days later I blew a head gasket ( dumb luck ) so I pulled it apart ( surprisingly good condition inside ) lapped the valves ( guides still snug) new valve stem oil seals, new cam seals again, cleaned tested and replaced lifters as needed, and thoroughly cleaned everything; The cylinder walls were in excellent shape with an insignificant ridge at the top that you could barley catch a fingernail on and in some places could not even catch it at all. put it all back together with all new gaskets. Then cleaned all 6 injectors off the car including reverse cleaning put in all new platinum plugs checked the distributor and rotor ( they weren't very old to start with and they are fine.) fired it up and it purrs like a new engine. I tweaked the timing to 12 BTDC and it runs great with plenty of power ( for a minivan anyway ) B U T now I am only getting 18 MPG... what did I miss?

I have also recently replaced as needed the half shafts, and tie rods. as well as new brakes and tires. not that would have a tremendous impact on MPG. I know it can some but 25% reduction afer improvements was not expected.

Any ideas??

440roadrunner

Well the absolute FIRST thing I'd do is check the speedometer. If you have a GPS that should be easy

billschillin

Even if I had no speedometer I know there is a 25% drop.
I drive the same route every day and have for years. It is a 100 mile round trip to work ( mostly freeway) and I have been filling up every 4 days for years. Now that I've "fixed " it I can barely make it 3 days. 400 miles \ 16 gals is 25 MPG. sometimes 24 . Now I'm lucky to get 285 to 300 miles for that same 16 gals.

Silverick

The new tires could have more resistance than the old tires.
I am telling you this from experience from replacing a set of tires on my pick up truck a few years ago.
My mileage went from 15mpg to 11mpg. Same size, different brand/style.

TVLynn

I would double check and make sure you followed the correct procedure for setting the timing. Sometimes you need to disconnect a wire from the computer or something like that. What did you clean the injectors with ? Did you replace the O rings

billschillin

The tires could contribute, but I can't imagine ( at least with passenger car tires anyway) that it would kill 25% of the mpg. I could see that with big ol' mudders on a truck but not with passenger car tires.

The injectors were pressure flushed with carb & choke cleaner in my home made injector cleaner and back flushed as well. all were giving a good steady stream after cleaning and all got new o-rings.

I did re-check the procedure for the timing and saw that the book says to disconnect the temp sensor first. I didn't do that, and I really have no idea what that would have to do with the timing, but I will try it. At this point anything is worth trying.

It may not sound like much but this is costing about $25-$30 a week more for gas at today's prices. That's over a hundred dollars a month. That may not seem like a lot to some people but to me, a father of 4 with a disabled wife no longer working, it is a lot.

That's why I'm driving a 1995 and doing all my own repairs.

Thanks for the feed back. If re-checking the timing doesn't fix it maybe someone out there will have a revolutionary idea for something I have overlooked.

Bill

78D200

I wonder if your injectors are injecting too much fuel, hence the "more power" feeling and drop in MPG.

Have you checked your compression? Are you getting any blow by at the rings? Clog in the exhaust (cat or muffler maybe)?

billschillin

I don't believe I'm getting any significant blowby, the exhaust appears clean and invisable although I am getting some gunk in the PCV filter inside the air filter housing. I haven't checked the compression yet that is certainly worth checking. I'll have to check it this weekend and report back. The cat converter is a possibility although I am not entirely sure how to check it beyond removing it from the car and peering inside. Any suggestions?

78D200

Actually, a clogged cat, muffler or any other part of the exhaust would cause your vehicle to not run properly. O2 sensor always reading lean so it's telling the computer to dump more fuel in? Check engine light on?

billschillin

Could be the O2 sensor, its hard to tell. The check engine light has been on for 5 or 6 years, can't seem to re-set it so if something really does go wrong, I don't know it. I tried the routine ( not recently but a while back ) where you turn the key on and off x amount of times then read the morse code on the CE light but the results were two codes one saying my battery had been recently disconnected and the other wasn't on the chart. I've been meaning to re-check the diag code but haven't had a chance to dig out my code chart ( I can't remember where I put it and don't recall where I got it) so far the O2 sensor is the only thing that makes sense.

Thank you

scotts74birds

I'm going to go with a sensor issue also. Too bad the 95's only had OBD I, not II. After rebuilding the top-end of my 99 Cirrus, with the 2.5 Mitsubishi, I was only pulling 20 mpg. The exhaust smelled rich, the oil smelled gassy, but the car ran very well. I hooked my scanner to it and found the upstream O2 was not reading at all. When an important sensor like that is not reading, the engine goes into what is called "closed-loop" operation. Meaning when it cant get the input from the sensors that it needs, the computer goes to a default program that will set timing, and fuel pulses that will make almost any engine run. "Open-Loop" operation is when the system can gather information from all the sensors, and make constant adjustments to the engines fuel and timing maps, according to the motors demands and operating conditions.
Long story short, my motor was in closed-loop operation. I replaced the O2 sensor, and mileage went right up to 26.8 mpg!

billschillin

I checked my CE codes and came up with a 21 and a 32. 21 is ...you guessed it, bad O2 sensor. 32 is Open or shorted EGR circuit.

sooooo Now I need to replace the O2 sensor and thoroghly check my EGR system. I have heard of people simply plating off the EGR but if I do that how can I keep from getting a EGR code and keeping my CE light on??

Any ideas

I just hope that replacing the O2 sensor takes care of the fuel ecomomy problem.

82mirada

go with the 02 sensor for sure, if not try your old tires for a day or so and see if just maybe..
try the old unplug the battery for 20 minutes to half hour then hook it back up to reset the computer, check engine light should go off if its nothing major, worked for my dads 98 ram 318 and brothers 01 ram 360 (i know its a stretch, but hey what the heck)

scotts74birds

the O2 sensor is the big dog in all the OBD systems! But is it giving a bad reading, or no reading at all? No reading, then probably replace it. Bad reading could probably be wires, plug, or least likely, injector. Not all O2 faults are O2 sensor failures. Some of them are the O2 sensor seeing things it doesn't like! The O2 is an input sensor

billschillin

Code 21 is " Oxygen sensor stays at center " / "never reads rich nor lean" so I'm betting the O2 sensor is bad. After 219,000 miles it's probably over due.

Any comments about blocking the EGR port mentioned above?

78D200

The EGR system takes the built up gas vapors and burns them during cold start ups and let the motor run better till it warms up. It also will burn the vapors while its running from time to time, mostly when you want/need that little extra bit of gas.

Do you need to have it, no. Is it a good idea to keep it, yes.

billschillin

OK, I put in a new O2 sensor and the sensor code no longer comes up in the sequence. I am still getting the EGR code tho. I found that the pin inside the elec. plug on the servo connected to the EGR valve is broken .
This is not the servo that is physically attached to the EGR but rather the one that connects to it with a vacumm hose. I cannot find any of these listed anywhere without buying the entire EGR valve. So.... I'm on the hunt for one of these.

The MPG seems better but I won't know for sure until I run a tank of fuel through it and I just filled up so I won't know for sure for a few days.

scotts74birds

Cool deal Bill! LMAO....I found the EXACT SAME THING with my EGR connection! I'm a cheap bastard, but I still couldnt find the replacement part alone. It is not actually a servo... but a transducer. A device that turns a physical motion into an electrical signal. Usually at a graduated rate. Basically like a throttle position sensor. The EGR should have little effect on mileage. I didn't say NONE, but possibly a little. But the O2 sensor, that can hit you for up to a 20% mileage loss like me.

blue 68 gts

You're pretty much correct, except "Open loop" is on start up with the motor running off a predetermined set of values written into the PCM. Running in open loop consistently will cause you to run rich, foul out plugs, ect.

The motor goes into "closed loop" after the oxygen sensor has come on board (as well as some other sensors).

TVLynn

My 98 Dodge B150 V6 had a similar problem. Failed it's smog test, No check engine light.... I replaced both the 02 sensors and the Cat Increased mileage and seems like it has more power or maybe my imagination

billschillin

OK everyone... I just ran my first full tank thru her and just barely squeezed 4 round trips out of it. Average MPG 24.1...Yeah!!!! Not quite the 25 I was getting before but a whole lot better than 18. That O2 sensor did the trick.
I went to a local junk yard and asked if they had any 86 thru mid 2000 mopars hanging around. They just happened to have only one old mopar anything and it was a 1995 Plymouth Voyager with a 3.0 engine how lucky is that. He pointed to it and said "see if what you need is in there". Sure enough the EGR servo( transducer) was there so I pulled it off and asked him what he wanted for it and he said HMMMMMM you can have it. So I immediately put it on my car and FINALLY for the first time in 5 or 6 years I am driving without the "Check Engine" light on.
I've made up a list of other parts that I saw were still present in that junk yard find and will be going back to scalp everything I can. There just aren't many 1995 mopar minivans in the junk yards anymore. If I had somewhere to put it I would probably ask him to just sell me the whole thing for a parts source.

anyway... I now consider this chapter over...thank you to everyone for your feed back.

Silverick

Sweet!!

billschillin

Almost over..... on the way home from the store tonight I blew a radiator hose....I can't win........