Van seem to lose power and struggles to drive highway speeds

Just recently I decided to take a few of my friends from San Diego, out to Niland, CA. In between the coast and the desert, there are some mountains to get by, and on the way up and especially on the way back, I noticed my van struggling hard to get up the roads. It started to overheat at one point and I had to pull off to let it cool. Then when I got back in, I decided to take it only 15mph until I reached the peak and then coast down the rest of the way. If I revved the engine any faster, it would overheat. It drove really well as long as I was going 15mph and I was attributing this to the extra people I was carrying. However, today just me and my wife decided to go for a drive, and we drove some hilly roads in the area, and it was still struggling really hard to get up hills, and it would seem to lose power very quickly. Then on the way back we were on the highway, and it would barely make it above 50mph unless we were actually on a downgrade. It just got so slow and without all the extra people in the back, I really started to think something was wrong. I did notice that when I start driving the van from a cold engine, it drives better and the engine is much quieter. Once I have been driving for 15 minutes or so, the engine starts to make more of a sputtering or spitting sound. One of my friends said if there was a leak in the exhaust somewhere, it could cause some sort of loss of pressure and make it lose power, and that leak could be more prominent once it heats up and the metal expands, but I know so little about exhaust. It also seems to be burning through gas a little quicker. Do any of these issues seem to point towards a common problem? Does anyone know what can be done about it?

Have you checked for codes?

Gwen

I haven't and I don't have a code puller. Would the check engine light have to be going on to pull a code? I'm not sure if that would give me an answer, but in case it does, do you have any kind of recommendation on what kind of code puller I should get? and where do you hook it up?

Your van doesn't need a code puller. It has a self diagnostic feature that's self contained. To learn how to read codes CLICK HERE. Tim

Thank you for the info Tim. Wow, I really like reading everything on here and learning how this van works, it really is fun. I did pull the code on it. Check engine light flashed in intervals of 4. Which looks like coolant temperature sensor signal. I am thinking at this point that the only reason it is pulling that code is because I have the generic coolant tank in my car right now and it does not take the sensor that is meant for the original tank, therefor it is disconnected. Does that seem to make sense or do you think I'm not seeing another problem? I noticed again yesterday on the highway it was in a pretty high gear and I was on a very slight incline and my van couldn't make it past 40. I pushed the pedal down to the floor and heard the overdrive kick in, it was really loud, but I could barely feel a difference - No pick-up, no faster. I don't get what is going on.

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Originally Posted by Usaviator

Thank you for the info Tim. Wow, I really like reading everything on here and learning how this van works, it really is fun. I did pull the code on it. Check engine light flashed in intervals of 4. Which looks like coolant temperature sensor signal. I am thinking at this point that the only reason it is pulling that code is because I have the generic coolant tank in my car right now and it does not take the sensor that is meant for the original tank, therefor it is disconnected............

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That isn't the sensor it's indicating is faulty (coolant level switch doesn't interface with ECU). It's indicating the ECU coolant temp sensor is faulty, and that can definitely make the van run bad. These are cheap, readily available, and easy to replace. Here's a link to a recent thread that will show you it's location: http://www.toyotavantech.com/forum/s...this-sensor-is

It's the one marked "B"

Ahah. So I looked inside near the radiator cap and i see this thing completely disconnected. take a look.
Attachment 1612

As you can see the connector is deteriorating and no longer holds onto the male connector anymore.
Attachment 1613

Here is a view from the top with all 3 sensors and switches in view.
Attachment 1614

Although it now seems obvious that it was that unplugged wire that was causing the issue, it seems by matching it up to your other post that it was the cold start injector time switch that was unplugged? But you said that only matters when the engine is cold. The van has been running great cold, but when it gets hot, its horrible. Do you think this unplugged wire is the sole reason for this problem or do you still think the temperature sensor is to blame? Also I am depending on this van to get me to work today. It's about a 15 mile drive. Do you think it's safe to drive it? Or could more damage result?

After 30 years it's possible for the temp sensor to still look good externally, but have failed internally. Since your ECU is saying the temp sensor is bad, and the van is running bad, and it's inexpensive, and it's readily available, and it's easy to replace, and, and, and.................Just saying you should replace it :dizzy:. The cold start injector time switch connector probably doesn't have anything to do with it, but whenever any connector looks like that I'd replace it regardless. You can get these connectors at Napa and/or most other auto parts stores for just a few bucks. It's worth mentioning that these universal Bosch style connectors don't have the specific keys that Toyota uses and will interchange with all the Bosch style connectors (so if you go universal you'll need to start keeping track of what goes where as it's possible to plug things in wrong).

Those symptoms sound like things I've run into in the past on various vehicles. The first thing to check is the fuel filter. Any constriction there and you won't get the gas you need at higher speeds or under heavy load(like going up hill). The second thing that comes to mind isn't a leak in the exhaust, it's the opposite. A clogged catalytic converter will give those exact symptoms as well.

As always I bow to Tim and others far superior knowledge with these things. If it where me though I'd start with what I've suggested then if the problem isn't solved move on to other possibilities. K.I.S.S.:lol:

I agree, but was assuming (probably wrongly) that normal maintenance intervals (like filter changes & tune-ups) have been adhered to. If the vehicle is simply driven into the ground (long term use without maintenance), then yes, things like clogged filters, bad spark plugs, worn distributor cap/rotor, etc become issues. Long term driving with problems like a bad ECU temp sensor, faulty TPS, failed o2 sensor, etc will likely lead to a plugged up cat. I cannot stress enough how important it is to keep up with routine maintenance & getting quick resolution when sensor problems occur. Skipping these things may save a little money short term, but will end up costing you much more long term and/or bring on the early demise of your van. Tim

I agree 100% with you. I just got this van about a month ago, already done some work on it. Now I'm in the process of using it as a daily commuter, so it's hard to find a large window of time to get things done on it. I did pick up a new coolant temp sensor and installed it, and also bought a couple new connectors as you saw the old ones were deteriorated. I haven't put the connectors in yet and I have to leave for work in a few minutes. The connectors come with the terminal and wires to be spliced in with the existing wires. Is there any preferred way of splicing wires in this area? Just twist them, cap them and tape them? After I get these things squared away, I'm guessing next step is to pull the EFI fuse to reset. Run it down the road a while, see how it does? Check codes again after running several miles. If this all does the trick, I will still eventually check the fuel filter and see how the cat is doing. It's just hard to soak a lot of time into this all at once.

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Originally Posted by timsrv

I agree, but was assuming (probably wrongly) that normal maintenance intervals (like filter changes & tune-ups) have been adhered to. If the vehicle is simply driven into the ground (long term use without maintenance), then yes, things like clogged filters, bad spark plugs, worn distributor cap/rotor, etc become issues. Long term driving with problems like a bad ECU temp sensor, faulty TPS, failed o2 sensor, etc will likely lead to a plugged up cat. I cannot stress enough how important it is to keep up with routine maintenance & getting quick resolution when sensor problems occur. Skipping these things may save a little money short term, but will end up costing you much more long term and/or bring on the early demise of your van. Tim

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Originally Posted by Usaviator

I agree 100% with you. I just got this van about a month ago, already done some work on it. Now I'm in the process of using it as a daily commuter, so it's hard to find a large window of time to get things done on it. I did pick up a new coolant temp sensor and installed it, and also bought a couple new connectors as you saw the old ones were deteriorated. I haven't put the connectors in yet and I have to leave for work in a few minutes. The connectors come with the terminal and wires to be spliced in with the existing wires. Is there any preferred way of splicing wires in this area? Just twist them, cap them and tape them? After I get these things squared away, I'm guessing next step is to pull the EFI fuse to reset. Run it down the road a while, see how it does? Check codes again after running several miles. If this all does the trick, I will still eventually check the fuel filter and see how the cat is doing. It's just hard to soak a lot of time into this all at once.

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Tim sometimes the fuel filter can be a problem even with regular maintenance intervals. I used to own an 87 Jeep Wrangler. I purchased it used and proceeded to give it a full tune up and brake job. While I was at it I lifted it with 3" of suspension and 4" of body. SO after my new tires are mounted to the new rims I take it for a drive. A very long drive up into the Catskill mountains to do some four wheeling and fishing. It runs like a champ. I leave to go back home and stop to get some gas. After filling up I get maybe 100 miles down the road and all the power from that 258 straight six was gone. I babied that thing down an interstate for the next 60 miles. As I got closer to home I realized there was no way it was going to make it up a small 300 foot grade. I pulled into my buddies driveway at the bottom of said grade. He was nice enough to give me a ride home and the chance to look into it at his shop. Yep, I'm always that lucky. So the next day after work I stop by to start the troubleshooting. The Jeep starts up just fine. Idles no problem. Goes up to high RPMs with no load. As soon as I drive it under load it bogs hard. Timing? Cat? it can't be the filter because I just changed it right? So we time it and it's fine. We pull the exhaust. What a PIA. So know I take my newly tuned, lifted, exhaustess, Jeep for a spin. By now you can most likely guess the outcome. It is still bogging under load. WTH? So I finally pull the filter. As I try to blow through that thing I'm sure I looked like Myles Davis. It's almost completely clogged. Less than 200 miles on it. I to this day still don't know whether is was extremely crappy gas or whether my four wheel adventure broke crud loose from the tank. Either way it was a newly installed filter that created the issue. Sorry for the long winded post but I felt like I owed the community here a descent story to back my claim. If you liked the read ask me to tell you about the time the cat clogged in my van. lol:lol:

Guiness World Record for fastest clogging fuel filter! :clap:

I might just call them to verify. It would be nice to have some type of world record though.:LOL2:

Yes, There's exceptions even when regular maintenance is provided. Filters have a lot of pores, but not an infinite amount. Contaminated fuel and/or a contaminated tank can clog one quickly. Still, seeing new filters clog isn't something we see very often. On the other hand it's very common to see clogged old filters on vehicles that don't get maintained. The symptoms you described are precisely what happens when a fuel filter clogs. In the case of your Jeep, that probably would have thrown me for a loop too. If the next filter didn't clog, I might even suspect you got a defective filter. Tim

Tim

I couldn't agree more. The issue with the Jeep was solved by dropping the tank. A small pressure washer took care of the cleaning. In the next 18 months that I owned it there wasn't a single issue. It's made me realize things in the auto field seam really mind blowing. Hence, K.I.S.S.

If you rule out the obvious then you look for what's left. If you do that in reverse you'll be chasing your tail for way to long.

Ok, I am a little in shock right now. I took the van to a shop that has a history of working on this van for years. They seem very reliable and have great reviews, so I suspect no bending the truth here, but this is what happened.

A few days ago, on my way to work, right after replacing the coolant temp sensor, only about 500 feet from my driveway, the van stalls and wont restart. It cranked fine, but no ignition. I was in a tight spot and needed to get it towed. So I had it towed to the place it normally went. I had many things to point out to them concerning the losing power on the highway issue, but they said first things first, we need to get it started. So they found that it was a main fuse that had blown - great! Not a hard fix, now it's back up and running. They took it for a test run for about 10 minutes, said everything sounded fine and could not notice anything going wrong with the engine. When they told me this, I told them, you need to take it out longer, 15-20 minutes, let the engine really heat up and then try and notice what I am talking about. So they did this, and the guy who was driving it noticed it losing power and the engine got really loud and he said he heard a knocking kind of sound that they suspect is from the lower part around the oil pan. Their first course of action they said is removing the oil pan, also removing the overhead and checking everything out and see why it's struggling. Just to remove the oil pan and overhead to look at everything (not including any actual repairs) would be at least 600 bucks. My mechanic said if he finds any metal in there, he's going to condemn the engine unless he were to send it to a machine shop and having it completely overhauled which would be 4 to 5 thousand. He said the best thing to do would be to find another remanufactured engine to put into it's place, but even labor costs for that would be minimum of 2,000. I'm banging my head against the wall right now trying to think of what to do :wall:. I asked him if any kind of oil additive would work in case the problem was just engine sludge, but he insisted that fixing this would really have to involve looking inside to see what's going on. Unfortunately I think I may have to sell the van as is, unless anyone here has any other suggestions. My time with this van seemed to be short and sweet. I wish it could have lasted longer. Only had it a little over a month. Does any one have any advice, or should I be nailing the final nail into the coffin on this one?

My guess is you have stuck lifters, pretty easy fix and not costly assuming you are decent at working on vehicles. I had the same symptoms a couple years back, I replaced the oil pump thinking that would solve the problem, it didn't and removing the pump was not very easy. Replaced the lifters problems solved for me. As a simple test I would take off the valve cover and turn the engine over if you see oil spraying around your pump is fine. Just my thoughts not an expert. Listen to Tim he knows these vans!

Is the engine quiet when running cold? even now after their test drive?

Just because they used to service it, doesn't mean they enjoyed doing it.
Big repair estimates can be a tool used to discourage customers.
If they can't dissuade you, they're gonna make sure to get their pound of flesh and then some.
There are easier ways to make money fixing vehicles, than working on a TV!

If it were my van, I would want to at least drop the cat and make sure it isn't damaged (partially plugged).
I have seen plugged cats cause the exact symptoms you detailed in your first post.

Tearing the engine down for "inspection" seems premature to me, even if it's noisy all the time, they should be able to at least diagnose WHERE the noise is coming from (top end or bottom) before tearing into the internals.
If you can't hear it when running cold, you probably won't be able to see it, once its all apart.

Selling it with a potential engine problem isn't going to improve your bank balance any.
BB

I see your point, BB in dissuading a customer to come back for repairs on a vehicle they don't like to deal with. It is possible.

Yes the engine does run quiet and very nicely when cold. What still boggles my mind is what it could be. They did tell me the knocking was coming from the lower portion. That would mean that valve lifters wasn't the issue correct? And a clogged cat would cause a knocking sound from inside the engine? I consider myself quite mechanically inclined when it comes to working on cars in general, but there's still much I'm inexperienced with. If I want to pursue the cat, what does that entail? Is there a way to clean it, or does it need to be replaced? Are they easily accessible and easy to remove and put back? And how can you tell for sure that the cat is the problem? Visual inspection, or another kind of test? I have a nice socket set, so I'm usually able to get pretty far with that working on the van, I have a wrench set and a few other tools, but other than, what I have to work with is very limited. At this point I'm willing to try anything, but I need to be careful not to put too much money into the van just in case my mechanic is correct and ultimately its a money pit.