18R-C running problem, intermittent

[o_man_ra23]

Im at my wits end ppls, Brother's car has a nasty intermittent problem where it will run fine, plenty of power, idle ok etc, then it loses all guts, wont idle, and wont rev up (even with no load).

Was thinking coil... changed it out, already has new plugs, leads, dizzy cap, rotor button, points and condensor (leads are semi-suspect). There is heaps of spark from the coil... got some about 3cm long when I pulled the coil lead from the coil. Timing and dwell are spot on. Tried 2 different carbies, one I know works fine the other has been kitted and cleaned. eliminated any possible intake manifold leak suspects. Tank was filthy and badly corroded, clogging the fuel filter, so I changed out the tank, and blew compressed air down the fuel line to clear it. Also changed the fuel filter. I think there is still some garbage in the fuel line, but surely not enough to clog the filter again.

So yeah, cant be compression as its a freshly built motor, and runs great sometimes. Carby isnt a likely suspect, fuel is new, spark is ok, timing is good, no manifold leaks, fuel pump is good (checked the output and thats fine). Will try new plugs leads and fuel filter again, but anyone else got any ideas?? The dizzy has some play in the shaft, but would that be enough to cause this?? Checked the voltage to the coil during play up period, and it seems fine... even ran a direct wire from the battery just in case.

Cheers, Owen

[river]

Hi,

Does it lose its power when going along nicely, or when you back off to idle... and then won't run when you give it some throttle?

Also, when you say it won't idle, does that mean it runs rough or stalls? I guess no amount of throttle makes a diff when it's being cantacerous? How does it come back on song again? How long does it run rough? Is it when cold or warm?

seeyuzz
river

[o_man_ra23]

it was just when warm, and lost power after going along nicely (doing 80-90 then suddenly no power). Runs rough and tries to stall. Sometimes can stop it stalling by playing with the throttle, but usually thats fruitless. The problem has spread to being fairly constant now.

EDIT: coming back on song usually meant leaving it stopped for a few hours.

Cheers, Owen

[airfireman1]

Hi, 4 more items that may be suspect, even though you have done a filter change, crap can still get into the carby and it is worth pulling the carby down and cleaning it with a suitable product like throttle body and carby cleaner. Second is that the fuel pump may be suspect and not supplying the fuel to the carby at the required rate. I know that you have checked the timing but the rubber vibration damping between the balancer may be suspect and the timing can be way out. I foun this was my problem and it was abou 7 degrees out. Check that the fuel cut of solenoid on the carby is not fauly, connection may be bad and it its stuttering between on and off.
Cheers

[hemi twofifteen turbo]

Still sounds fuel related i think. If possible when it goes funny quickly pull over and check the float bowl sight level. Although you seem to have done everything to eliminate any fuel blockages and supply problems already, it would be a good test to see if there is fuel in the carby. Another one you could try is putting fuel in your washer bottle (or a spare washer bottle as some fuel can hurt) and stick the hose down the carby. give the washers a squirt when it goes funny and see if you get a difference. Hope this helps

[o_man_ra23]

thanks fellas. The fuel pump isnt all that old, and seems to be pumping well. Ill re-check the float level too. Trying everything at this stage.

Cheers, Owen

[briney]

i had the impression these carbs had a small gauze filter upstream of the needle and seat.
might be worth a look.

[o_man_ra23]

thanks briney... will have to look at that too. Just seems strange that both carbies do it.

Cheers, Owen

[Dazza]

Unscrew the fuel cut solenoid and pull the plunger out with the needle that cuts your fuel off. You can screw the solenoid back in without the needle and it will run. If this fixes the problem then it could be a faulty solenoid or wiring or maybe the fuse is dirty or corroded. Also check the gauze filter in the banjo bolt on top of the carby.

[leso]

OWEN, Just had a thought haha yes i had one...reckon it could be the small wire inside the dizzy that earths the moving plate ..if that makes sense. Is he gunna buy the silver thing ???

[o_man_ra23]

Still looking at the silver thing Les. Yeah, the earth wire looks ratty, but doesnt look dead... dont wanna come round tonight with some wire and crimp lugs eh?? Heck, make it dinner time and Ill cook you up a good feed.

The silver thing finishes about 9pm tonight, so he needs to look at his top line, its currently sitting at $310, and somebody seems keen on it. will have to sniper it.

Cheers, Owen

[hosking1991]

OWEN, Just had a thought haha yes i had one...reckon it could be the small wire inside the dizzy that earths the moving plate ..if that makes sense. Is he gunna buy the silver thing ???

i also had a similar problem but this wire was out side the dizzy it was earthing out on the block (taking all the spark from the dizzy so there wasnt enough spark the ignite the fuel) i just taped it up so just check any wires aren't earthing out anywhere

cheers luke

[kristian]

i had a similar problem once and it turns out it was the type of fuel i was running, my ra23 wont run on anything but premium, and my vn will do the same thing as u say when i put blend fuel from fredom in it.

[o_man_ra23]

The fuel in question is BP regular unleaded. Considering the car is an 18RC, and the problem is intermittent, I dont think that is the problem (you have an 18RG dont you Kristian... they dont like anything but premium or better)

Cheers, Owen

[river]

Hi,

THe little 4AC in my AE71 prefers premium. I put in normal unleaded and it pings a bit and runs hot while driving at 100-110kph on the freeway. It's fine potting about the suburbs, but not on a longer faster trip. According to Toyota the 4AC runs best with premium unleaded. So, I use that now and the engine is happier. I wouldn't put Ultimate in the AE71 as there is no benefit.

My 18R-G will be very tempremental with standard unleaded and it pings and gets a bit annoyed with premium. However, it does run perfectly and well on BP Ultimate... which is all I give it now.

Now Owey-babes... you didn't answer my questions I asked earlier (did you?) regarding how this 18R-C mucks up.

seeyuzz
river