1985 Voyager 2.6L Has Severe Hesitation

[Packard Don]

I have a low mileage 1985 Plymouth Voyager 2.6L (Mitsubishi) with the rare Magic Camper option. It has A/C and all power accessories and has barely 78,000 miles on it but after being in storage for a couple years while I moved and got settled it, when I brought it back home it now has a hesitation that is so bad that it will hardly start moving from a standstill unless I pulse the pedal to keep it from stalling but once moving, it's fine. It's only slightly better once it warms up.

It also no longer has much power for hills even though it otherwise seems fine in traffic and on surface streets. All the vacuum lines were replaced, the fuel pump is new and pumping a steady 6 psi, the carburetor was professionally rebuilt and tested for proper flow on a testing machine before installation so I am at a loss to know where to look next. Someone once suggested the vapor separator which is inline between the pump and the carburetor but it appears to be a part that is no longer made unless someone here has a source or at least can tell me how to test it for proper functionality. It does have a new dual EGR valve (probably the last new one in existence and cost a fortune!) and easily passes California's rigid smog testing. Any ideas?

Don

[89ARIES]

Welcome to the club Don. I am ecstatic to hear of a surviving 85 Caravan with a Mitsubishi motor. I would like to see some pictures of it, if you care to email me some at aries89@chryslerkcar.com. My guess
with you van is that the Mikuni carburetor is clogged. I have had many members tell me how their Mitsubishi K-Cars act sluggish from sitting. I can get you in contact with someone that has kept their Mitsubishi woody wagon running on the original 2.6 engine at 500,000 miles. Also, beware that these engines self-destruct if the timing gear or oil pump chain breaks. We can talk more. Call me after work tommorrow at 818-219-2587.

[Packard Don]

Thank you for the reply and for your friendly welcome. I'm virtually deaf so I do not use a telephone but thank you for your kind offer to talk. By the way, it is a Voyager, not a Caravan.

No, it's definitely not the carburetor as it's rebuilt, removed again and checked on a carburetor testing machine when the problem persisted. It has proper fuel and air flow with no vacuum leakage. It is also not the vacuum advance because that was checked so I'm hoping that someone here might suggest a sensor or two to replace that might help. As far as I know, it does not have a computer or any electronics but I've not yet gone through all the manuals to confirm.

A few years before the problem started, the head was replaced with a brand new one, it got a new exhaust manifold, new timing chain and sprockets, all new belts and hoses, which I did "while I was at it" during the head replacement. The cam seized which is why it required the head replacement. There is no wear whatsoever inside the cylinders and they look like new. It has excellent compression. The front brakes are new, the rears done only a few thousand miles ago but need to be checked for proper lubrication as one shoe is sometimes not returning properly.

When the head gasket was replaced again a couple years ago, the vacuum lines were not properly marked so it's possible that something is mis-connected. I have the chart on the firewall but do not know what the components look like so if anyone has some good, clear engine compartment photos of a California car showing the plumbing or who can help identify the various components, I would love to hear from them. I'm good with schematics if I knew what the components looked like!

I'm not the original owner but some good friends were and I've been around it since it was new when they bought it in 1984. I drove it many times through the years before actually owning it and I even still have the original window sticker. Sadly, it spent most of its life parked outside so it needs paint but the interior is quite nice if a bit dirty and the original owners threw away the Magic Camper tent that it came with, not realizing that it was part of the van. They thought it was something that the dealer threw in with the deal.

Just to be clear, it hasn't been in storage for several years now and is used regularly but it still has the problem. I thought it might have gone away with use but it has not.

Don

[K-CAR_WAGON]

..

[Packard Don]

The catalytic converter was replaced recently for the last smog test and I do have all the original 1985 manuals. The mechanical, electrical and body manuals came with it (with Caravan on the cover rather than Voyager) and I also have a third-party manual that I bought more recently. All are right her at my desk as I look through for clues.

Yes, it has excellent compression, the timing is set properly and advancing properly too, and it has a strong spark with Bosch Platinum+4 plugs. I had thought of putting in a more powerful coil but have not yet done so until I eliminate any other issues.

I have the vacuum diagram already but have no clue what the actual parts look like. I've tried to trace it all but have to make guesses which I would prefer not to do. Do you happen to know where each component is located? The manual simply shows the same diagram without pointing to photos of the components' locations.

Don

[K-CAR_WAGON]

..

[Packard Don]

The vapor separator is not even listed anywhere so I do not have the part number. Most sites list the vacuum canister but that's not the same part. The vapor separator looks a lot like the fuel filter except that it's after the pump rather than being before it.

Don

[Packard Don]

One thing to add: I said that the fuel pump is at a steady 6 psi which it is when measured directly at the pump. However, when measured at the output of the vapor separator, the gauge's needle is an unreadable blur until I speed up the RPM. Then it is more or less steady at the same 6 psi. Without disassembling it (which means destroying it) I have no idea what the vapor separator does or how it works so perhaps this is normal.

Don

[mona's k]

My 1982 2.6 had similar problems, feathering the gas to keep it running, no power, bogging down when stepping hard on the gas. Mine had been sitting for 5 years so I knew bad gas was part of the problem but even with fresh gas and several cans of Sea-foam it still had these issues. My mechanic unhooked the vacuum lines to the EGR and sub-EGR valve and plugged them. Made a HUGE difference. Replace the EGR valves and runs great! Did find out that this car is the only vehicle that I have (4 older/2 newer) that will not tolerate ethanol blend gas so the type/freshness of the gas may be part of the isssue. Because you replace the EGR valve(s) I would work on making sure the vacuum lines go where they are supposed to go.

[Packard Don]

This is an update as I've been out there looking at it for the last hour or so. Examining the more accurate diagram of the parts book, I see that several things are mis-plumbed. According to the schematic on the firewall, it appears that the advance connects to the upper side connector of the spark advance solenoid when the parts book diagram of the actual components makes it clear that it should connect to the bottom.

Also, the lower EGR diaphragm should connect to a multi-connector near the carburetor when instead it runs over to the spark advance solenoid. I'll need to enlarge and color code the parts book diagram to make it clearer and to actually put the van into the garage where I can get my work light in there to see what's what but there are clearly some things wrong.

My van appears to have a component that is not on any of these diagrams, mounted at the passenger side below the two solenoids. It has both large and smaller hoses going to it but as nothing down there was disturbed by any work, I'll presume it is connected correctly. I believe it's a vapor canister but, if so, I expected it to be much larger!

I did move the vacuum advance connection and, while I did not actually drive it, I did put it in gear with the brake pressed, then pushed the accelerator. It seem to want to get up and go rather than die!

As for the fuel, I had that thought too and I try to avoid the fuel with ethanol but I'm not sure if, here in California, it is at pumps even without being labeled as such. In any event, the fuel is fresh and clean.