Ok, so i got this car ('73 1.7L) about 2 months ago. single carb - yes i know this isnt the best fuel intake, but i am going to try to make it work. I tried to drive it home - about 90 miles, but it only went about 15 miles before it slowly crapped out. losing speed unitl i had to pull over. it would start again and drive, but couldnt go fast for long.
so, I: changed fuel filter, spark plugs, oil, cleaned oil screen, pulled gas tank and ran all new fuel hoses and clamps (found a kinked line which i thought was the problem - also found the vent in the gas tank to be smashed, so i re-opened that and ran a new hose to underneath the car) the lines looked fine running through the car - and when i blew them out they seemed to be free of any clogs etc.
I reconnected everything, and started her up today. same problem. she ran a little better and could run all day around town, but took her on the highway and she would only stay in 5th gear for like 20 seconds then started tanking in speed - down-shifted to 4th.....3rd...then pulled off the highway...noticed some smoke in the back so i pulled over to let her rest. the smoke was coming from the HE's - both sides on the "opening" closer to the muffler. the PO had screwed in wood screws into the gap i'm assuming to keep them from rattling, and that gap is where the smoke was flying out of. after a 15 minute rest i started up and drove for another 15 minutes with no major problems.
Why wont she go on the highway!
I'm stumped!
I'm new to the mechanical arena so overexplain things if you think you need to.
whats my next step? someone told me the timing may be messed up, 'cause when you switch to carbs you to need to adjust?!?!
help!
Thanks for all the help in advance, so glad to finally join the 914 world!
ill have pics of my bag of bolts soon!
-R.B.
What are you running for a fuel pump? The carbs need a low pressure (~3.5 psi pump), but if there is not enough flow, you will not be able to run at speed.
I've had the same thing happen when a fuel pump was going south. Just a thought.
Welcome to the jungle!
Ive had a hunch that its the fuel pump this whole time, but everyone tells me that the little bugger i got is fine....i guess its worth replacing - anyway to test it?
i have the fuel pressure regulator set to 4 - i cant get it to turn over for anything less than 4 (2.5/3 psi IS recommended for my carb).
i forgot to mention also i rebuilt the carb too!
any other thoughts?
You've only got three areas to look: fuel, spark and mechanical.
I think we can rule out mechanical as it runs well at lower speeds.
As for spark, could be, but no indications yet.
Fuel. OK, you're running a single carb, which you recently rebuilt. We see fuel pump issues pretty apparent in the Fuel Injected engines, as there's either fuel pressure or there isn't fuel pressure. With the carb, you have two main areas; 1. The fuel pump must provide enough fuel to the carb so that your engine doesn't become starved for fuel. 2. Your carb float must be properly adjusted. If the carb float is not properly adjusted, then no matter what fuel pressure you're running, the float may not be allowing fuel into the carb itself.
As fuel pump failures are pretty rare (not that they never ocurr) I would take a look at your carb float adjustment.
Keep in mind, the only difference between running around in town using high rpms adn driving on the highway is merely your transmission gear. Therefore, you should be able to recreate your problem by driving at higher rpms around town.
Eric Read
One time I sucked a plastic bag into the fan...covered about half of the inside of the fan.
Could drive around town all I wanted, but the first time I hit the freeway it made it a few miles then I had to pull over and let it cool down.
Check the fuel pump by getting a bottle like a 2L Coke bottle, disconnect the carb, put hose into it, turn on ignition, you should see significant fuel flow. If not, there is a problem in the fuel delivery system (clog in line, clogged filter, fuel pump issue, or fuel pressure regulator issue).
Before doing this, I would get a fire extinguisher handy and remove power from the coil (to save the points/coil or Pertronix as the engine will not be running).
While I don't disagree with Blitz about looking into FI or dual carbs, people run single carbs all the time and are able to maintain highway speeds.
You have checked everything up to the carb with fuel delivery. Now you need to check the carb. Make sure the float is set right, and that the carb is in good condition.
Do you have a CHT gauge? What are head temps at failure?
Could you describe your exhaust leak more? What color is the smoke?
And just because, have you done the basic engine diagnostic stuff? Compression test and valve adjustments? Probably not a central issue, but it may be a contributing factor. An out of tune engine could be more likely to overheat.
Zach
My vote is a cooling issue. My type II did the same thing. I found I had blown off my heater hoses. It's real fun if you get it hot enough that you blow the plugs out of the heads. I'd check the fan, tins and thermostat.
This issue may not be fuel related. The verdict is out. I'm still waiting to hear about head temps.
Fuel filter?
Yeah, sorry no head temp gauge (should i get one? what do they cost? easy to install?)
No compression test. No valve adjustment. My neighbor is supposed to run me through timing adjustment soon ( I am a serious novice with this type of stuff). I've read about how to do a valve adjustment, but seems like something i want somebody to show me the first time i do it - anyone in the bay area? And whats up with compression tests? - something i need to do at a shop?
Fuel filter was replaced first thing and double checked it before yesterday.
Exhaust leaks are pictured. Smoke was blue-ish and poured out for some 5-10 minutes after stopping.
So i guess my next step is to examine the fan and making sure that fuel is making it to the carb (eliminating fuel pump/fuel pressure regulator problems). What are you saying is "significant fuel flow"? like what rate would be good with the pressure regulator set to 3 psi?
I'll probably adjust the float level as well - I'm assuming there is some kind of "how to" on line.
Amazing support guys! Heres a question for you....Everyone I ask offers different and sometimes blatently contradictory advice - who the hell do I listen too?
Thanks again!
-R.B.
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eep, I was just wrong!
Sort of. My premise was right I bet. You have oil leaking into the heat exchangers somewhere. the blue smoke is that oil burning off.
I bet if you turn on the heater in the cabin, it stinks of burned oil.
Zach
By the way. Is the bottom of that heat exchanger painted black, or is that accumulated oil scum?
A CHT gauge is a great thing to have on these cars. Otherwise, you have no clue what the head temps are. If you are out of tune and running hot, you'd never know it until you dropped a valve. If you want a stock look, you can get a VDO CHT gauge. Its not the best, but its better then nothing. A lot of guys here like the Dakota Digital gauges. They DO NOT look stock, it has a digital readout. But they are temperature compensated, accurate gauges. If your head is not pre-drilled for a VDO CHT sender, get the spark plug type sender and put it on the no3 spark plug. That is your hottest cylinder (usually).
Cost will be about $200 ish for the Dakota Digital. Dunno what for the VDO.
Zach
My heater isnt connected to the cabin right now. Hoses just stop (torn) as they enter into the fuel tank bay.
And I guess this is a good time to mention that the heater air hose on the driverside (coming from the blower) is ripped - what does this affect?
AND what does this leak in the HE's mean in the grand scheme of things? Focus on this first? Any best way for determining where the leak comes from?
Thanks,
R.B.
And - NO thats not black paint...
Check around your valve covers and pushrod tubes for oil leaks. That smoke is probably just oil dripping onto the heat exchangers.
Personally, I wouldn't put the HE leak as the top priority - that's not causing your running issue. That HE tin can be loose or have leaks and it would only affect your cabin heat. If you have actual exhaust leaks (hear some ticking or popping, getting some backfiring) then that's more important.
I would be most worried about the head temps - you will kill the engine if it's running too hot. Your symptoms fit. Gotta rule that out. Get a gauge. If you find out it's not running hot, it was still worth the investment and you'll know which way to continue troubleshooting.
I experienced a similar problem. Basically a "James Bond" oil cloud once the engine heated up. At the prodding of this BBS members, I replaced the oil cooler seals, push rod tube seals, and any other seals I could easily get to.
Since I'm in SoCal, I really have no need for the HEs, and since my HE's were really rusted out, I ripped them off the exhaust pipes. I found about 3/8 of an inch of really thick oil goo on the bottom half of both the HE pipes. You guessed it, once the exhaust pipes heated up, the goo started smoking.
Now I have zero oil leaks, and no smoke cloud!!!
Eric
I agree with everyone else - sounds like you are not getting enough fuel. I had a car that did the same thing. I had cracked fuel lines that only opened up when the car warmed up.
I know you said you replaced them so my guess is there's another fuel delivery problem. Sounds like your carb is not getting enough fuel in the higher RPMs. You are draining your bowl faster than it's getting filled when you're burning fuel more rapidly.
BTW - My 914 runs on a single no name carb. Runs very well going 75 on Washington, DC beltway. I think I have the the fuel pressure regulator set to 3 PSI.
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