Mechanics Help!

[NoWaistedSpace]

Any of you a car mechanic?
I have an 86 Honda Prelude 1.8 with dual carbs. It will start, but won't idle(just dies). I have to keep pumping the gas to keep it running. Doesn't act like the spark plugs. I turn the key on and I don't hear the fuel pump kick in. Does anyone know how much voltage should be going to the fuel pump? It has been a good car. I've never had any problems with it. It has set for 2 years and has always started, but now I have this problem. Anyone have any ideas on what it could be?

 

[Zaphod420]

I am no great mechanic by any stretch, but my youtubeFU is pretty strong

I hope that help NWS.

 

[Streetpro09]

I wish i could help but don't know carbs. Fuel pump should have battery voltage back to it while cranking the engine and maybe a 2 sec burst when the key is first turned on. I wouldn't think it would run at all if there wasn't power to the fuel pump but it could be low on pressure. Carb systems usually are something like 10-12 psi feed pressure to the carb.

 

[NoWaistedSpace]

My understanding, I should be hearing the fuel pump kick on with the key in the on position and I don't. With the key turned on it says it should be pumping fuel without it started. I can turn it over with starter engaged and it pumps fuel. But not with just the key turned to on position. That's what's got me confused. I ordered another fuel pump, but don't really know if that is the problem or not. What is the function of the fuel relay? It doesn't drop the voltage to the fuel pump, does it? This car has never failed me until I let it set for a couple years.

 

[NoWaistedSpace]

I am no great mechanic by any stretch, but my youtubeFU is pretty strong

I hope that help NWS.

As a matter of fact, I watched this video yesterday.

 

[Streetpro09]

My understanding, I should be hearing the fuel pump kick on with the key in the on position and I don't. With the key turned on it says it should be pumping fuel without it started. I can turn it over with starter engaged and it pumps fuel. But not with just the key turned to on position. That's what's got me confused. I ordered another fuel pump, but don't really know if that is the problem or not. What is the function of the fuel relay? It doesn't drop the voltage to the fuel pump, does it? This car has never failed me until I let it set for a couple years.

Sounds like the fuel pump has got power and any amount of flow should be adequate.

- key on engine off: fuel pump will kick in for about 2 min and then shut off until the engine is cranking. They do this to kinda prime the fuel system of any bleed back.

- key on engine cranking: fuel pump should run the whole time the engine is turning over.

- key on engine running: fuel pump should have power all the time.

Relay just takes low amps from the ignition switch and makes a switch contact internally for a high amp feed to the fuel pump. All that sounds good from what you're saying.

I would be looking at the idle jet inside the carb to be plugged. Did you check the air box for a mouse nest?

 

[Streetpro09]

Maybe a can of seafoam in the tank and run it for awhile to see if it'll clean the carb without you having to take anything apart. My dad will swear by that stuff.

 

[NoWaistedSpace]

Fuel pump is working. I run wires from the battery to the inline pump and it is clicking. I've got sea foam here for my YZ250. Will try it with more fuel in the tank. It was on almost empty and might have pulled crap out of the tank into the carbs etc. I hate to dig into the parts. There are so many vacuum lines and stuff. Will be a bitch. I'm not a mechanic but I did buy a service manual. Gonna check the rotor and will add 5gal of gas and the seafoam. It left me along the side of the road a couple weeks ago and hasn't run right since. I really need to get it running. It has never failed me in the 5 or 6 years I've owned it. It has always ran great.
Thanks guys!

 

[Big Terps]

Im not a mechanic but if it has been sitting for 2 yrs and had gas in tank that sat in tank that long , it could just be that u need to either drain ur tank or add more good gas with the sea foam.

Like u guys said it could be bad gas in tank, carbs could have debris inside clogging the jets, fuel filter could be plugged up, just throwing my guess out there.?

With the fuel pump noise, in past b4 it ran shitty, did u hear the pump prime system ? Some cars u can hear pump kick on with key forward, and sum u cant imo. The older vehicles in my experience, u could allways hear pump kick on, new cars ive had u cant hear it...?

Another thing that worries me is when u said your car has dual carbs? Both carbs havta be perfectly insink with each other. So if 1 carb has a issue itll throw off the whole system...

Hopefully dude u get this figured out, was just trying to help out with my 2 cents..
Good luck

 

[Fiddler's Green]

I'm no mechanic but, have you tried cal-mag?

You can also try a bottle of Chevron techron cleaner in the tank if there is any varnish, check grounds and fuses (they can be blown and not look it). Sorry I can't help anymore.

 

[NoWaistedSpace]

I changed the plugs and added 7 gal of gas and a can of sea foam and still no luck. Fuel pump is working. Changed the fuel filter. Tomorrow I will check distributor and rotor. I have started and drove it up and down the road in that 2 year span off and on and had no problems. It has almost a full tank of gas in it now. It will rev up but starts missing around 4 grand on the tach but won't hold a steady rpm, having to feather the throttle to keep it running, then dies at idle. Damned if I know. Never had any trouble in the 6 years I've owned it what's got me confused. When I decide to put tags on it to drive, it starts doing this. I'm hoping it's the rotor button. My brother died about this time last year, he could have told me exactly what is wrong with it. He was the mechanic.

 

[Turpman]

If it has carbs and sat for 2 years. They most likely dried up. If your fuel is like ours in Canada it has ethanol in it. Seems ethanol and its additives tend to leave varnish behind when it sits and most of it evaporates.
I hate the shit. I’ve never had so many carbs apart. If they sit hear for a year they are usually gunked up.
It Iikes to plug off small jets so you will need to strip down to bare bones.
Sound like your idle jets are plugged.

 

[NoWaistedSpace]

If it has carbs and sat for 2 years. They most likely dried up. If your fuel is like ours in Canada it has ethanol in it. Seems ethanol and its additives tend to leave varnish behind when it sits and most of it evaporates.
I hate the shit. I’ve never had so many carbs apart. If they sit hear for a year they are usually gunked up.
It Iikes to plug off small jets so you will need to strip down to bare bones.
Sound like your idle jets are plugged.

You are prolly right. I hate to tear into that motor. I don't have a soul to help me that knows anything. Nothing but a bunch of Meth heads around here. That shit has ruined about everyone.

 

[NoWaistedSpace]

Looks like distributor cap and rotor needs replaced. Gonna try that before I tear into the carbs. Quite a bit of wear.

 

[Turpman]

You can use a secondary source of hydrocarbon to enrichen the mixture. Little harder with 2 carbs but we used to use a small propane bottle 1Lish. With a short hose. Add some propane to the carb when running. If she runs better your are short on fuel.

 

[Streetpro09]

You can use a secondary source of hydrocarbon to enrichen the mixture. Little harder with 2 carbs but we used to use a small propane bottle 1Lish. With a short hose. Add some propane to the carb when running. If she runs better your are short on fuel.

Can of brake clean works well for this.