greyheadedguy

My engine in it's original 1985, 2x4 truck body, never vapor locked on me during the 12 years I drove it in that configuration. In 2015 I put this engine into the "new" 1987 4x4 truck drove it a year with no problems. Last summer I had a little trouble one time with what I figured to be a vapor lock, it was 116 outside in the shade... In September my fuel pump failed so I installed a replacement from the local walk in cheap parts house. Now every time we get close to 100 degrees I have problems I consider vapor locking.

I start the truck while I am putting my seatbelt on. I drive through the parking lot and pull out on to the street. No problems yet, I get my truck up to about 40 MPH and about 1/4 - 1/2 mile later and it starts sputtering/misfiring/dying. If I can keep the engine spinning it will pick up and start running fine. One day it did not, I could not get it started. I splashed cool water on the fuel pump and the 6" fuel line going to the carburetor from the fuel pump, the truck would not start. I got a can of starting fluid and got the truck started, and when I kept it running, it finally started running fine...

I had the original Toyota Type II fuel pump on my truck. Anyone know the specs for that fuel pump? What is the difference between a Type I and a Type II Toyota Fuel Pump for the 22R engine?

From the info I found the "Import Direct" fuel pump I installed from O'Reilly Auto Parts will run at a maximum flow of 20 gallons per hour at 5 PSI. The Spectra Fuel Pump at the place across the street runs at a minimum 29 GPH and a Maximum 39 GPH at a minimum pressure of 3. PSI and a maximum pressure of 4.5 PSI... That is a big difference between the two pumps, but I have nothing to compare it to the Toyota pump...

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scope103

I don't know anything about the 22r, and only a little about carbureted vehicles. But it sure doesn't sound like vapor lock. Vapor lock may keep the vehicle from starting initially (a bubble of fuel vapor next to the hot engine is leaning it out too far, OR the bubble is causing the pump to not pump). But once the vehicle is running, relatively cool fuel from the tank flushes out any bubbles and away you go.

Given your history, I would suspect dirt. Try changing the fuel filter, and probably open the carburetor fuel bowl to see if you have some crumbs in there.

For what it's worth, my fuel injected, automatic transmission, 6 cylinder uses 0.8 gal/hour at idle. 20 gallons/hour sounds like plenty for you.

RJR

I can only share the experience I had with my 1984 Suburban. It would vapor lock after a long climb up a mountain pass. Generally it would run fine going up the hill, where the fuel pump was pumping lots of fuel, but once you leveled off and started down the other side, and fuel flow greatly decreased, it would start mis-firing and stumbling. Changing the fuel pump made no difference. I finally traced it to a blocked return line. On the Suburban, there is a return line for excess fuel back to the tank. The purpose is to allow the fuel pump to continue to recirculate large amounts of fuel for cooling purposes even when the engine is lightly loaded and isn't using much.

I don't know if your Toyota has a similar setup, but you might want to check.

greyheadedguy

Thank you for the input, but if it is dirt why is it only a problem when it is near 100 degrees? That engine in the old body had no problems in Blythe in June. I made a bunch of stops between eating, getting gas, and visiting several stores in that town. Plus the first year I drove this engine in the new configuration (85 engine in the 87 truck body) I had no problems, with the fuel system anyway...

When I installed the engine something bugged me about the fuel tank. Just a gut feeling, so I changed the fuel filter before I ever started the truck. When I was changing the fuel filter I flushed some fuel out of the tank through the filter hose to see what was in the tank. It was clean, just kind of old.
Later I to had replace the fuel level sending unit, so I drained all the gas out of the tank. I did find sand on top of the fuel tank when I removed it to change the sender, but nothing in it...

It was September 2016 when I replaced the fuel pump I started out the troubleshooting by replacing the fuel filter. I did have a problem when I replaced the fuel pump. I had replaced the fuel pump and thought I was done so when I pulled out of the street I live on the truck got up to 35 MPH and suddenly the truck died... It was very hot out. As I went through the troubleshooting, I discovered the truck was starved for fuel. If I pour a little gas in the carburetor the truck would run until it used it up. Turns out that one of the fuel pump bolts holes was stripped and the fuel pump was not working. I installed a Heli-coil and everything bolted down fine and the truck ran well, but we were in cooler weather... Obviously I need to check to see if the fuel pump is tight.

At the worst that this truck has run it got 15 MPG, top speed I have ever done in the truck was 80 MPH, which works out to a whopping 5.333 GPH, so you are right, I can't see why it would need more the 20 GPH, but I posted it just as a comparison between the two fuel pumps... I'd like to know what the specs are on a factory Toyota fuel pump...

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RJR

Typical specific fuel consumption for a gasoline engine running full throttle is about 10-11 horsepower-hours/gallon, so if your 22r was truly making 120Hp, it would need 11-12 gallons/hour. That's probably the number, with some margin, that Toyota used to size the fuel pump, but in real life you never get anywhere near that 120Hp, so flows are much lower. However, going up I-70 west of Denver at 60mph at 4000 rpm in 3rd gear for example, fuel mileage may be down to around 7-8 mpg, which works out to 8-9 gph, so you do need some significant capacity.

MBR1218

I went through a similar problem with my 87 22r. Turned o it to be a combo of a clogged charc can and an aftermarket gas cap... actually im not sure which it actually was because i replaced both at the same time. Before that, id gone through the while fuel system and electrical trying to figire out what it was, kept doing it until I replaced those two.

greyheadedguy

I'll look in to those. My gas cap is an after market locking one that the lock on it has messed up... I need to see which charcoal canister I used, the 85 or the 87... My book shows me how to test the canister.

Thanks,

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greyheadedguy

Well the weather isn't cooperating with me here, it was only 99 degrees today and is not supposed to be close to 100 until Wednesday. Makes it hard to troubleshoot my "vapor lock" problem.

Anyway I considered MBR1218's post, "I can't see how a gas cap could cause a problem with how my truck runs. If I am wrong about that please someone correct me and explain how a bad gas cap could cause a vapor lock situation.

I am considering my charcoal canister. My truck, before I bought it was in water higher then my fuel tank (about 30"), or I think it was because there was sand on top of my gas tank when I pulled the tank to work on it. I figure that a hot truck running in 100+ degree weather with a half a tank of gas going into water that deep would create a vacuum that would suck all sorts of crap in to the charcoal canister and plugging it.

Looking at the testing method, a plugged charcoal canister would be about the same as a plugged vent on the fuel tank right? So I figure that pulling my gas cap would allow the fuel tank to vent. So I am going to drive my truck without a gas cap for little while, unless I continue to have problems. Then I will have to try something else.

I had errands to do today so I went driving. First stop was to put two (2) gallons of gas in my truck, and pull the gas cap and put it into the cab of my truck. I then covered the gas tank opening with a folded rag and closed the fuel filler door which holds the rag nicely in place. Then I drove expecting problems and had none. I took the long way to the closest hardware store, so instead of traveling a mile to the store I drove about 3 miles to it. I had no problems, but I did just put cool gas in the tank of equal volume or more then what was already in there.

I could not buy what I wanted there so I went to the good hardware store at 22nd and Kolbe, about 8 miles away. I vapor lock the last time I drove to this store in the day time with similar temperature, but unfortunately I spent a little bit longer in the store then I planned on, about 45 minutes compared to the 25 or so minutes I spent on the problem trip. Anyway I started my truck and drove home without any problems... Have I found the problem? I really don't know it was only 97 when I got home...

What do you think? Did I find my problem?

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scope103

It's not vapor lock, but a gas cap with a blocked vent will let you drive for a while and then kill the engine. The gas cap is designed to let air in, but NOT let vapors out. As you pull fuel out of the tank, if the cap doesn't let air in the pressure in the tank keeps dropping until the pump just can't get any more out. The pump on a fuel injected vehicle can actually crush a fuel tank if sealed up tightly.

So if the cap won't let vapors out, where DO the vapors go? That's the point of the evap system (charcoal canister). As you're parked on a hot day, the pressure in the tank starts to inch up, and the vapors get pushed into the charcoal canister (where they're adsorbed). When the engine is running, it pulls those vapors out of the charcoal and uses it to run the engine. (and keep it out of the air).

So is a rag in the top of the fuel tank a possible solution? NO. In addition to poisoning the air (fuel vapors used to be a big cause of HC smog), if you get in a rear-ender you'll be spraying hot gasoline all over the place. Just get a new cap; they're about $3.

greyheadedguy

That explains how the gas cap could cause a problem. But I have to ask, why does gas cap only fail when it is hot, about 100 degrees or more, but the cap will work if I can keep the engine spinning long enough to get gas flowing again?

Also the fuel pump has a return line feeding excess fuel back to the gas tank if working properly, right? If so then how is it creating a vacuum in the fuel tank, unless under acceleration the engine is demanding more fuel then available. That would mean nothing is being returned to the fuel tank and there could be a vacuum formed if the cap's vent is plugged, right?

So what happens if my canister is plugged? I know that this truck has been in at least 30" of water by finding sand on top of the fuel tank when I dropped it. I am thinking I may have both cap and canister faulty, either way I have access to another canister from my old totaled truck and I need to replace my gas cap if I want a locking gas cap on my truck, and I do because of problems with a neighbor...

Not using a gas cap is not even a consideration for a solution, it was only a method for troubleshooting. And since I still anticipate pulling the fuel tank, I have not had more the 3 gallons of gas in the tank since I have pulled the cap off. So when gas is added I have about 3 gallons of gas in a 17 gallon tank. I can see a big problem in a roll over or possibly a fire. I honestly have no intention of running without a gas cap any longer then I absolutely have to. The gas cap is basically a moot point since I need a new gas cap anyway because the locking mechanism broke and I can't lock it.

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scope103

Well, gee, it doesn't feed ALL the fuel back to the tank. (That sure would be great if it did!) The fuel used by the engine uses up the fuel in the tank. The vent in the cap allows air in to replace that fuel.

If the canister is plugged you should smell gas in the engine compartment. The system is designed to hold some pressure in the tank (on a warm day you'll get a whoosh! when you remove the cap), but if that pressure gets too high it will just push vapors out of the canister. Usually into the engine compartment.

I'll be the first to agree that a bad vent in a cap doesn't really match your symptoms. But for $3-4 you get to check it off.

Your problems sound much more pedestrian. Like ignition timing (you HAVE checked ignition timing, haven't you? )

greyheadedguy

Okay, that was an over estimation on my part pointed out to me by a friend who use to own a Auto repair shop in Indianapolis. So I stand corrected... But it does explain a vacuum being created in the gas tank and the engine dying. Since every time I have had this problem it has been after accelerating to 40 MPH

My truck has two charcoal canisters, one for the gas tank vent and a second for the engine emissions... If the canister is plugged and nothing is getting in to it how can there be a gas smell? Mind you I may have a flawed understanding of how this vent canister works. But if it took the crap I am figuring it took based on the other problems I have found on this truck, it is a fixed object, basically a paper weight. You would not believe the water I got out of the rear differential from going into this water... the vent on the differential was plugged solid. I could not force anything through it.

I wish I could get a gas cap for three dollars... Best price I can find for a locking cap is $15 plus tax, $16.20 after tax:

http://www.oreillyauto.com/site/c/de...eyword=gas+cap

http://www.autozone.com/fuel-deliver...ap/4393_0_5269

Timing is fine, but how could my timing being off cause a behavior like the engine being starved for fuel?

scope103

http://www.rockauto.com/en/catalog/t...+tank+cap,5900

(There is the cost of shipping of course.)

scope103

I don't anything about '85s (and not very much about 22re's, and nothing at all about 22r's). But here's the FSM on the '93 22re Evap system. http://web.archive.org/web/201109110...17evaporat.pdf

In very general terms, the evap system is there just to pick up the excess fuel vapor squeezed out of the tank. That's the emissions it works on; it doesn't have anything to do with combustion products (for instance). The evap system is plumbed into the intake in order to suck the stored vapors out of the canister. (Most vapor emissions are when the engine is off, so there the canister stores the vapors until the engine starts again.) I have no idea why you have two canisters. (or how they're plumbed)

greyheadedguy

I apologize if I come across terse, I don't mean to, I thrive on knowledge and want to understand what is going on with my truck. Almost everything I know I have learned the hard way or from reading books. I was raised by a single parent and the rest of the world was too busy...

I have attached the PDF of the Component Layout and Schematic Drawing, the vacuum line that is connected to the Charcoal canisters goes through a VSV (Vacuum switching valve) after going through a thermo Valve. Hmmm, a thermo valve? ( I will have to figure out how to test that.) I have the problem only when it is hot? HUH??? Both of these components came off my 85 which had no problems other then a badly bent frame from hitting head on with a mosquito, uh I mean a Geo Metro... Ttechnically we hit driver front wheel to driver front wheel. Unfortunately this 87 has been severely abused, even the speakers were useless. Open circuits when I tested them with Volt/Ohm meter. So after working on this truck for two years I have become suspect of anything that was on the truck when I bought it. By the way, the truck was not running when I bought it.

greyheadedguy

I found the schematic of the charcoal canisters, not sure what it is showing me, but I will look at it for a bit to see if I can understand it, book should show me how to troubleshoot the whole system right this diagram...

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scope103

Wow! And I thought the 3VZE setup was complicated.

But this all makes sense; a carbureted vehicle has a big puddle of gas sitting in the float bowl, and capturing the vapors from that would really help emissions.

But your problem is rough running; you can isolate the evap system from that just by disconnecting (and plugging) the line at the evap canister that goes to the intake manifold. You should be able to drive for hours that way; eventually you'll fill up the canister so this is not a long-term solution.

greyheadedguy

I just had my "vapor lock" problem with no gas cap... So it seems that two things affect this "vapor lock" situation, one is the temperature. The other seems to be the speed that I accelerate. If I accelerate slow, short shifting I will not "vapor lock", if I push it and use the full range of 1st through 3rd and then shift to 5th I sputter and the engine dies... If I can keep the engine turning by the inertia the engine will start getting fuel again and run. Today though I had a very low fuel tank with about 1/2 gallon of fuel and I could not get the truck running again until I pulled into a parking lot and popped the hood and sprayed starting fluid through the hole in the top of air filter lid after removing the wing nut. I had to do this three times before I could get the truck running again...

I am thinking the problem is a weak fuel pump...

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greyheadedguy

It was/is a bad fuel pump... After sputtering to stop with no gas cap I had to go with what was my gut on this and pulled the fuel pump and tested it and it failed all the tests... I don't know how my truck ran at all!
I did the following:
1.) Blocked the out and return port and the lever moved freely.
2.) I blocked the inlet and the lever moved freely, it was supposed to be locked doing this test
3.) I blocked all three ports and the lever moved freely, it was supposed to be blocked...

So it had a rupture diaphragm...
I think I need to still check out my charcoal canisters and will, I'll post the results

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greyheadedguy

This brought me full circle to my original post titled, "Vapor lock or failing fuel pump?"

It was/is a bad fuel pump... After sputtering to stop with no gas cap I had to go with what was my gut on this and pulled the fuel pump and tested it and it failed all the tests... I don't know how my truck ran at all!
I did the following:
1.) Blocked the out and return port and the lever moved freely.
2.) I blocked the inlet and the lever moved freely, it was supposed to be locked doing this test
3.) I blocked all three ports and the lever moved freely, it was supposed to be blocked...

So it had a rupture diaphragm or something...
I think I need to still check out my charcoal canisters and will, I'll post the results

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