Is it the infamous hot soak......

[timsrv]

Hi Tim - I found this thread while researching electric fan options to cool my van when sitting in traffic with my A/C on. I like this electric fan location the most, and wanted to reach out and see if you think this fan location is reasonable for a second fan while driving around.

My fan clutch is in great condition and keeps the van cool with the A/C off (and when driving with the A/C on) but my temps will creep to 201 F when A/C is on and I am sitting still in the GA heat.

Would you share your input on if this electric fan location would theoretically work for my use case, assuming I hooked up a pull fan. Any thoughts or concerns would be appreciated!

Thanks,
Hugh

Hi Hugh,

Sorry I missed your post until now. The fan I put on this radiator was only to combat the heat soak issue. I have it set on a timer (shown earlier in this thread) that runs it for 15 minutes after the van is shut off. This ventilates the engine compartment and keeps the fuel from boiling in the rail (it works well). I also rigged it to a manual on/off switch so I could run it at other times. Although the fan works good for the heat-soak issue, it doesn't seem to help much (if at all) to combat overheating while stopped in traffic on a hot day with my AC on. I would recommend this set-up if you are having a heat soak issue, but don't expect it to help with overheating. Tim

PS: Experiencing overheating problems while sitting in traffic on a hot day with AC on is a pretty typical issue with these vans. If you find a solution to that please share as I'd be thrilled to be able to use my AC in those conditions .

[MyToy]

Hugh:

My hot sock issue may not be as bad as many but it did have some effect on the operation of the van. I am down here in Florida and mid day heat can get pretty intense. The engine runs very cool so there is no issue there but if I stop for 5 or 10 minutes the it restarts rough, where you have to feather the accelerator peddle for about a minute or so. Then it smooths out.

It did annoy me so I added a small timer and an extra air bypass valve to the system.
The high pressure sensor, which Tim recommends to ground at all times, is also tied to the same timer. I did that because when my high pressure sense wire is grounded it stays on for ever and should shut off in 2 minutes as per Tim's research. Mine didn't so I tied it to the same timer with the air valve. My guess is my computer may have an issue in that department.

I then calibrated the amount of idle increase I needed with both the high pressure active and the extra air valve to force the engine to maintain idle. I was going to use a sensor but Tim's timer idea really worked vey well for me also. It works flawlessly and is much less work. I have mine set for about 40 seconds. So for 40 seconds the idle, if no hot soak is in effect, idles a bit high, but only for 40 seconds.

In fact it worked so good I am considering building a small stepping motor drive to a motorized air valve and monitoring the tach where when the throttle control hits the idle stop the air valve adjusts itself to 800 RPM. This would mean you would intentionally set the idle screw in the mixture control unit to lower than normal idle and the air valve takes does the rest.

You may think of something yourself by knowing that the system has these dynamics. Again, the air bypass in this engine has all kinds of latitude to work with.

Think about it and have some fun.

MT

[hughdawgmmkay]

Hi Hugh,

Sorry I missed your post until now. The fan I put on this radiator was only to combat the heat soak issue. I have it set on a timer (shown earlier in this thread) that runs it for 15 minutes after the van is shut off. This ventilates the engine compartment and keeps the fuel from boiling in the rail (it works well). I also rigged it to a manual on/off switch so I could run it at other times. Although the fan works good for the heat-soak issue, it doesn't seem to help much (if at all) to combat overheating while stopped in traffic on a hot day with my AC on. I would recommend this set-up if you are having a heat soak issue, but don't expect it to help with overheating. Tim

PS: Experiencing overheating problems while sitting in traffic on a hot day with AC on is a pretty typical issue with these vans. If you find a solution to that please share as I'd be thrilled to be able to use my AC in those conditions .

Tim, just slowing down enough to get back to this myself. Thanks so much for the input! I braised together a shroud similar to yours, and am trying to figure out how I should use it. Hats off to you because I modeled mine after yours, with just a few slight tweaks.

Given your input and MT's down below, I am trying to think through scenarios on how effective this setup will be for me. Quick question for you, do you think I would be OK to use this fan setup, and still leave my stock fan clutch in place? My main concern is in restricting the flow & effectiveness of the fan clutch. Open to your thoughts!

[hughdawgmmkay]

Hugh:

My hot sock issue may not be as bad as many but it did have some effect on the operation of the van. I am down here in Florida and mid day heat can get pretty intense. The engine runs very cool so there is no issue there but if I stop for 5 or 10 minutes the it restarts rough, where you have to feather the accelerator peddle for about a minute or so. Then it smooths out.

It did annoy me so I added a small timer and an extra air bypass valve to the system.
The high pressure sensor, which Tim recommends to ground at all times, is also tied to the same timer. I did that because when my high pressure sense wire is grounded it stays on for ever and should shut off in 2 minutes as per Tim's research. Mine didn't so I tied it to the same timer with the air valve. My guess is my computer may have an issue in that department.

I then calibrated the amount of idle increase I needed with both the high pressure active and the extra air valve to force the engine to maintain idle. I was going to use a sensor but Tim's timer idea really worked vey well for me also. It works flawlessly and is much less work. I have mine set for about 40 seconds. So for 40 seconds the idle, if no hot soak is in effect, idles a bit high, but only for 40 seconds.

In fact it worked so good I am considering building a small stepping motor drive to a motorized air valve and monitoring the tach where when the throttle control hits the idle stop the air valve adjusts itself to 800 RPM. This would mean you would intentionally set the idle screw in the mixture control unit to lower than normal idle and the air valve takes does the rest.

You may think of something yourself by knowing that the system has these dynamics. Again, the air bypass in this engine has all kinds of latitude to work with.

Think about it and have some fun.

MT

Great stuff, thanks so much! I'm going to have to think through all the options for a little while...I really like the timer idea you two have used.

I bought a little 'fuel pump' switch on Amazon and have been considering making it a manual switch for when I determine I need to "ground" the high pressure sensor. I haven't been fully confident my computer would switch off the high pressure after 2 minutes either, so I've been considering this route.

More to think through, but really grateful for the input!

[timsrv]

Tim, just slowing down enough to get back to this myself. Thanks so much for the input! I braised together a shroud similar to yours, and am trying to figure out how I should use it. Hats off to you because I modeled mine after yours, with just a few slight tweaks.

Given your input and MT's down below, I am trying to think through scenarios on how effective this setup will be for me. Quick question for you, do you think I would be OK to use this fan setup, and still leave my stock fan clutch in place? My main concern is in restricting the flow & effectiveness of the fan clutch. Open to your thoughts!

It looks nice but I'd worry about flow. I ran dual 10" high output fans on my cargo van (Post #13 in this thread) and although it worked okay I considered it barely adequate. The clutch fan will move a lot more air, but if you're planning on running it without the stock shroud I don't think it can do much (needs the factory shroud directing air flow through the radiator). Sometimes things will surprise you though. Since you've already got this much effort into it a little more experimenting wouldn't hurt. Good luck and let us know how it works out . Tim

[hughdawgmmkay]

It looks nice but I'd worry about flow. I ran dual 10" high output fans on my cargo van (Post #13 in this thread) and although it worked okay I considered it barely adequate. The clutch fan will move a lot more air, but if you're planning on running it without the stock shroud I don't think it can do much (needs the factory shroud directing air flow through the radiator). Sometimes things will surprise you though. Since you've already got this much effort into it a little more experimenting wouldn't hurt. Good luck and let us know how it works out . Tim

Thank you Tim! I will keep tinkering and get back to you all with what I land on!

-Hugh

[Carbonized]

I'm still, once in a while, tinkering in my head with the the remote bilge pump idea. So the other day I'm on this Porsche forum, here is this guy trying to cool the AC condenser with one of this:




This thing makes my bilge blower look and feel like a toy , comes from a server where they line up 5 of them side by side. See how this guy uses it here:
http://forums.pelicanparts.com/porsc...condenser.html . Long read but had to binge it .
The best part is the price! So inexpensive he buys a bunch and doesn't hesitate to experiment and fry them! Pick up some cool air somewhere push it through some SCAT and blast it directly on fuel rail and injectors ?

[trestlehed]

An idea I had a while back was to run a duct up the passenger side of the inner pillar next to/behind the passenger seat.
Have a small fan inside the snorkel duct, add your timer with relay. The big downside to this is you have to cut into the van body and subject your van to water leaks and rust. You would have to find an after market vent to mount to the the side of the van or even the roof if you are brave enough. Is that passenger side pillar kind of hollow like the drivers' side pillar where the ECU lives? If so, that might work for the vent.

A TVT member custom built a snorkel for 4x4 purposes (fjording rivers), maybe one of those could serve double duty by also venting the engine bay to mitigate "heat soak"?...

Option 3 would be to do the "rear heater delete", place your intake duct directly over the fuel rail area, then have your powerful bilge fan with relay dumping the hot air out the bottom of the van body behind the right front wheel. The rear heater delete might provide enough room for this.

Just some ideas...

[VanCo]

I've thought about taking a different approach. The fuel lines intimately snuggle the engine from one side to the other. Preheating the fuel with the engine block only makes sense from a 1980's comprehension of emissions standpoint. It is now known that cold fuel equals more power. More efficient power also makes less emissions. That's how we get cars with hundreds of horsepower that are EPA approved (that and corruption). I digress.

I'm thinking of running a new fuel supply line that connects to the factory hard line that goes to the filter. Run the line in front of the radiator to a fuel cooler then back to the fuel rail on the driver's side. All lines would be braided AN.

The problem I have is cavitation at the pump, in the tank. What happens is the fuel in the tank gets super heated from the return hose returning hot fuel continually while driving. When I park the pump can't get going because the fuel boils and causes cavitation.

If I'm going to do a ton of work, I want more power as a bonus.

[Carbonized]

[QUOTE=VanCo;41182 The problem I have is cavitation at the pump, in the tank. What happens is the fuel in the tank gets super heated from the return hose returning hot fuel continually while driving. When I park the pump can't get going because the fuel boils and causes cavitation.

If I'm going to do a ton of work, I want more power as a bonus.[/QUOTE]

What if you run the return line through the fuel cooler? You get a cooler tank = no pump cavitation = cooler fuel in the lines and injectors= more power, cleaner burn = less chances of hot soak No? I think that's what we ran in the Audi R10. Then again we where injecting at a gazillion PSI and inter cooling too!

[VanCo]

What if you run the return line through the fuel cooler?

I agree 100%; however, the supply line at that point would be easiest to manipulate for me. I may go full race van and reroute the supply and return for optimum cooling.

[Chardog1971]

It's been a while since I have been working on any of my vans. I don't have a good place to work on them out of the weather. I stopped driving the 89 4WD due to what I suspected to be the heat soak issue. That and the Ball joints. I have been parking on the street and moving it pretty frequently. I cruise around for a while to warm it up and keep the battery up to charge. I haven't had to re start it in a few years so, I forgot about that issue until I decided to fix the broken wiper.

I drove around a little and then pulled up to the shed to do the work. That is when I realized I wasn't close enough. Of course, it wouldn't start. Fired right up after lunch. Half hour or so. It was around 20 degrees f. so it cooled pretty quick. I know there is bad gas in the tank. I'm going out to drain it and start fresh.

After reading the last few posts, I'm wondering if the fuel pump heating up is the issue. I'm sure it hasn't been changed in years if at all. I suppose I'll try the opening the hatch after driving around for a while and see if that helps before I start adding fans, relays and whatever else is needed.

[Harbilly]

yes. The fan on the rad on our 1986 cargo is excellent for fighting heat sisk. Though, out of habit, we still park so we can drive forward once started - backing up sputtering is a nightmare. But the fan means we haven’t had a ‘fail to start’ since 2007.

Hi Hugh,

Sorry I missed your post until now. The fan I put on this radiator was only to combat the heat soak issue. I have it set on a timer (shown earlier in this thread) that runs it for 15 minutes after the van is shut off. This ventilates the engine compartment and keeps the fuel from boiling in the rail (it works well). I also rigged it to a manual on/off switch so I could run it at other times. Although the fan works good for the heat-soak issue, it doesn't seem to help much (if at all) to combat overheating while stopped in traffic on a hot day with my AC on. I would recommend this set-up if you are having a heat soak issue, but don't expect it to help with overheating. Tim

PS: Experiencing overheating problems while sitting in traffic on a hot day with AC on is a pretty typical issue with these vans. If you find a solution to that please share as I'd be thrilled to be able to use my AC in those conditions .

[89van]

Hey folks, apologies for a necro, but I saw this video recently and this got me thinking: is it viable? or am I out of tune for this idea...

Obviously, having the fuel rail hugging the engine is not ideal, but would this be a sort of band-aid fix or a viable option?

a Vapor Separator Fuel Filter. I will say, the guy in the video only mentioned it on carbureted vehicles however... dirtbikes, outboard engines, carburetors, maybe i'm missing the point entirely with it only being on carbureted engines unless it was used on a fuel-injected engine... Pressure differences between carb'd and EFI maybe? Not too sure, haven't thunk on it quite much but an interesting topic for an issue, and one that's now around the corner now that summer is here

Video link for reference: HERE

[Toyota2RZ-E]

Hi everyone..
I seem to have fixed my heat soak problem by simply installing a timer that turns on the fuel pump for 20 seconds on ignition. After about 10 seconds the fuel is cool and then crank and engine starts ok.
I have a lot more to add but dont seem to get a response from this site.. dont know what Im doing wrong..

[scotty]

Which type of timer did you use?

[Toyota2RZ-E]

Hey Scotty thanks for the reply..
Hi Im completely unfamiliar with this but I will try to tell you how i fixed my heat soak problem.

If I have managed to upload the diagram of the fuel system you can see that shorting the +B and FP terminals in the Check connector will make the fuel pump run whenever the ignition is switched to the run position (Engine not running)

I disconnected the return line from the fuel pressure regulator and found the fuel returning to the tank was hot (60 deg C) but became cool after a few (10)seconds..

so this actually fixes the hot start problem however overrides a safety feature ie the circuit opening relay. Designed to switch off the fuel pump when engine is not running say after an accident.

To fix this I installed a cheap ($6AU Ebay) power up oneshot timer that shorts out terminals +B and FP in the Check Connector and set the timer for about 20 seconds..

I trigger the oneshot from the accessory position which means the fuel pump runs for 20 seconds every time the ignition is switched on but you can trigger it from the start position and wait for 10 seconds till cranking the engine.

this has completely fixed the problem that has annoyed me for years.

I recently installed a thing called "Engine Guard" (www.engineguard.com.au) in my van it came with two temperature sensors so i bolted one sensor to the head and the other to the fuel rail. I found the engine normally runs at between 80 to 98 deg C but the fuel rail runs around 40'C (cooled by the fuel) however once stopped the fuel rail temp climbs to the engine temp and once over 60'C I would have to crank the engine for some time before start.

To test this. Temporally short pins +B and FP in the Check connector drive around and when returning to your hot van set the ignition switch to the start position (Fuel pump starts running) but wait for about 10 seconds before cranking the engine..

Good luck.Regards Mike.