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Hey guys, Im new here but not new to toyotas, just new to one this old..
Long story short, I purchased a 1979 toyota with a 20r. Heard it running prior to purchase. I was told it needed a fuel pump, because the tank had rust. The previous owner dropped off the truck, an external tank, and a external inline fuel pump.
Ive ran the fuel pump inline to a fuel filter, then to the carb. bypassing the previous tank/pump all together.
So once i try to crank it, I get fuel to the carb, but it won't stay running without my foot on the gas, smells extremely rich and backfires through the tailpipe before dying..
Ive adjust the idle screw all the way down and out a half turn, and tried again. It started for a moment then did the same thing with a backfire the second i let off the pedal.
as you can see the previous owner made a mess of the vacuum lines, also the wiring was spliced and cut up everywhere. I noticed it has a ford ranger ignition coil etc. Can anyone point me in the right direction? Its getting fuel, its getting spark, its getting flooded, and then its backfiring..
I failed to mention that a neighbor had told me it won't work with an inline pump, that it has to be an internal, in tank pump to function properly, is this correct?
Ok cool, update I lifted the bed to get to the topside of the tank, got the fuel gauge working now, had almost a full tank.. Problem was it was blue dyed outboard boat motor gas.. people amaze me, working on the vac lines while i let it drain out now.
Update again, dropped the tank, it doesn't have a pump in it, no spot or block off plate for a mechanical pump on the head either, just the hook. Called the parts store, they carry the in tank pump for 51$. said they thought a regulator wouldn't help the electric pump I'm using because its a volume issue, not pressure..
Id like to do away with the stock tank if possible and use my external tank, is there anything electrical i can install inline with the pump to reduce its flow? the parts guy said the majority of their pumps are the same psi. 3-7
Its missing the timing marks, the pulley has multiple indentions from years of wheeling im assuming. I reset it at top dead center based on removing the first spark plug and getting it to top dead center on the compression stroke. removed the distributor and reset rotor to face 1.
I don't remember anymore what pressure these carbed trucks like, but it's low. 3 might be ok. I wouldn't, however, trust parts guys at a store, unless you have especially good ones
It looks like you have a Weber? Not a stock carb, anyway. Find out what carb you have and see what pressure it likes. Weber and other people make pressure regulators, none are electric.
Yah its a stock aisin, Im under the hood as we speak, i blocked off all of the ports and tried to start it on ether, it ran for a few seconds then backfired. Couldn't tell if it was through the carb or exhaust. This thing is a mess, I just wanna run over stuff..
With these old trucks, it's so hard to tell, unless you have the equipment and knowledge to run real diagnostics. Not hard, but not everyone knows how or has the simple tools. I would guess there are multiple things going on.
I'm absolutely not going to spend your money for you. But...if it were me, I'd start from a baseline. When I buy a new truck, I always:
Replace cap, rotor, wires, plugs, air filter, fuel filter.
Check timing with timing light.
Adjust valves.
Change all fluids.
Beyond that, ignition coils are cheap. I'd get the right one.
After that you can start doing more in-depth stuff, but I can't guarantee that after you spend the money on the above stuff (probably $200 when all said and done) it will run. Could be the carb needs to be replaced. Not a big deal, but another $300.
I gave up on the old Aisin carbs and went Weber. They were great in their day, but they're so, so old now, and they take a lot more skill to tune correctly.
Also, what's going on with the crankcase vent? Is it plugged? That's not good either.
And what does volume vs pressure mean? From the parts store guy? I don't know physics really at all, but you have a standard size fuel line. The amount/volume of fuel going through it, it seems to me, can only be adjusted by increasing or decreasing the pressure. Right?
Is that some newish throttle cable all loose and bolted to the firewall?
Update. I got it running, it ran for about 5 minutes, sounded rough but it was running none the less. I ran the pump from a 1 gallon hand tank. Took an hour break and went back to installing external tank and lines, had a smoke then went to move it, started fine, ran for about 20 seconds then died. Now when i go to start it, it won't again..
debating on buying a carb rebuild kit, most of them i see are just a bunch of gaskets though.
Fuel window shows half, to full depending on how long i have the electric pump running.
What i don't understand at this point is why it would work being pumped from a hand tank (1 gallon) but won't run on its own with the external tank.
Gonna take a breather flip through my haynes and think really hard about how much i want it to be a turn key operation.
Also, what's going on with the crankcase vent? Is it plugged? That's not good either.
And what does volume vs pressure mean? From the parts store guy? I don't know physics really at all, but you have a standard size fuel line. The amount/volume of fuel going through it, it seems to me, can only be adjusted by increasing or decreasing the pressure. Right?
Is that some newish throttle cable all loose and bolted to the firewall?
haha this is all previous owners doing, the throttle cable is a hand choke installed. the case was capped off, i did away with that.
Ok. When I bought a Weber I went with the manual choke. I liked it.
Fuel bowl full is obviously not good. It's getting too much fuel. It could be the float needs adjusting, but if it was sitting half for a while, then it seems like it's ok.
So if you go back to the smaller fuel tank, it runs longer? Or did you just try it once? I'd go test both out a few more times to make sure that's actually what's going on, and not something else.
But the fuel bowl definitely shouldn't be full.
Slack in the throttle cable is fine. But that's a pretty funny install...
All carb rebuild kits ever are is a bunch of gaskets.
Unless you're real good, I wouldn't expect to have good results...I would also make sure to buy a high-quality kit. It really matters. No reason to go through all that work and have bad results because of crappy gaskets. It really matters. But I'm going to go out on a limb and say "most" people who rebuild their carbs don't have good results. Some do. I think most don't.
You may already know this but that hook seems to be doubling as a block off for the mechanical fuel pump. Have you considered going back to the stock pump?
Yeah I think it was over on the Marlin Crawler site that I learned this. It is odd! I would have argued with people, before that, if they had claimed otherwise
My 78 20R had an electric pump, and no block-off plate on the head.
Update: The flooding of the engine was solved, i added some extra line to the pump and it seems to like it better. Maybe the distance it has to push it is allowing it to fill properly. Remaining at half full on the eye.
HOWEVER: Today I went to start it again, no start. Pulled the plugs, fouled. So I went to buy new plugs, replaced them. Still no start. Nose around a bit more and find a spliced connection into the distributor going to the pickup coil. Removed it and fixed the wires accordingly. Prior to this I was getting spark, after no spark. Pulled the wire off plug one, no spark, pulled the plug off the ignition coil, no spark..
As I sit here I'm wondering if i pulled the distributor without setting it at tdc first. Would that cause a no spark issue? I also pulled the plugs again to see if they were even getting wet, they look brand new. Rock auto has the pickup coil for 4$ but the local parts store wants 57$ Can anyone confirm incorrect timing would create a no spark before i place an order? I won't be able to check time until tomorrow in the daylight.
04-19-2016, 07:52 PM
