truck wont start

[1lo620]

Well I have an issue with my truck. It broke down coming back from a show, it was running a bit rough, like it was running a cylinder down, then it died. I thought it might be points,changed them still no luck. Icehouse came over and looked at it and tried a electronic ignition...nothing. Then a friend who does Hotrods came by and looked at it...timed it, changed it back to points just to be sure...??? still no fire..Now comes the crazy part..it has spark, it has gas just wont fire. He set it to top dead center and the timing mark is in the wrong place, but eveything lines up....He checked the timing chain to see if it might had skipped a tooth but it seems fine. Checked fuel and carb and plugs all get spark and fuel..When we pulled the plugs it seemed that only 1 and 4 had sparked, 2 & 3 where still fresh...??? All plugs and points are gapped correct and the cam is moving as well as the distributor...Sorry if none of this makes sense but I hope it does, Because if I cant get help here, it will have to go to a shop. I am not a mechanic....So if you can makes sence of this email I would appreciate your help and advice....(Jeff if you can add anything go ahead)....thanks all....Big Dave 1LO620:(

[BEEBANI]

Check your ignition switch to see if any of the wires have power while cranking. Mine was doing the same thing and I figured out it was a bad ignition switch. Just a thought.

[]2eDeYe]

Pull out plug no. 1

With it connected to the wire (plugged into the cap)

Gound the spark plug thread body to the motor and crank it over.

You should see it spark at teh electrode.

 

Check all your plugs in this fashion to eliminate spark as an issue.

 

If this checks out, do a compression test..

 

You could be looking at a blown head gasket...

 

If any don't spark use one of the wires from one that does to eliminate the wire.

[datzenmike]

1lo620:.....When we pulled the plugs it seemed that only 1 and 4 had sparked, 2 & 3 where still fresh...???

 

I think ]2eDeYe may be on to something. Did this once with an L-16, barely started, would not run with clutch engaged.

 

You may get it started if you disconnect wires 2 & 3. It's just a hunch that 2 & 3 are messing up the manifold vacuum. This would (maybe) allow you to pull it off onto a side street or around the block but little else.

[banzai510(hainz)]

Jeff was there and installed a Pertronix and said he was getting spark. But new dist was 180 off so Jeff moved the plug wires.

 

Dave said there was a heavy gas smell so I THINK its the float valve is stuck flooding it out. But Im just wingin it and he didnt call me today as I would have cked the timming and do some basic trouble shooting.

But replacing carb or the awful L20 intake and exhaust manifold NO Im not doing it !!!! Alot of emission stuff.

I have a stock L20 carb to trouble shoot if needed

 

Maybe if Jeff and I go there together we can do something but after work I loose alot of motivation esp if its other peoples stuff.

[521Lvr]

a motor only needs 3 things to run. compression, timing/spark, and fuel. start with a complession test. may have blown the head gasket between 2 and 3. if compression is below like 90lbs you have a prob.

then check for spark again. instead of taking the plug out and connecting it to a plug wire. I don't like to get shocked. leave the wires connected as usual and get a timing light. hook it up as normal and hold the trigger while cranking, watch the light and see if it is flashing. check all the wires this way. if some are flashing and some are not then maybe the cap and rotor button is bad or the plug it is connected to is fouled.

also if you do have flashing while cranking watch that as soon as you let off of the key that you still might get flash. check each wire a few times for this. if no spark when you let off the switch then the ignition switch might be bad. does that make sense?

if all these check out.

check to see that you are getting fuel. get a can of .99$ starting fluid. spray a 1 sec squirt in the carb. if it runs for a sec or 2 the carb or fuel pump or filter or lines or tank.

hope some of this helps. peace

[lynchfourtwenty]

i had a problem like that once, and i know you mentioned the plugs bein "ok" but my problem was 1 bad spark plug.. for some reason that 1 plug totaly prevented my truck from starting period.. as soon as i replaced it.. it fired right up as if never a problem. now im not sayin thats your problem.. but spending 5 bux on new plugs couldnt hurt.. funny thing is the plug that went bad was brand new.. also check the cap for corrosion and maybe a crack.. and check the wires make sure they're not bad..

[banzai510(hainz)]

Jeff said it was getting spark

He or Dave replaced the points then went to the Pertronix.

 

They smelled gas so I would think the fuel pump was working, Possible flooding out and fiuling the plugs.

[datsunaholic]

I've seen them "Get Spark" and still not run, when the coil went bad. Coil was putting out spark at low RPM (and cold) but got weak quickly. But it would still start and run for a minute or so.

[lynchfourtwenty]

it could be flooding it.. its possible.. since my gas tanks not mounted in its proper location if i over fill it it over powers the carb and floods my truck.. maybe check the accelerator pump on the carb.. altho when that happen to me i could Watch the carb fill with gas...

[]2eDeYe]

I have yet to be shocked checking plugs that way...and it's the only way I know to find out if the plug is working.

 

Just because the wire works doesnt mean the plug does ;)

 

Accelerator pump will not affect idle, hence the name.

 

I'm still thinking blown headgasket...but without a compression test...

[lynchfourtwenty]

if the accelerator pump is stuck open it will flood the vehicle either killing it or not allowing it to start, trust me it can happen.. its happend to me i could watch the gas pooring in and the only way to prevent the truck from completely flooding was to turn it over now an then just a tad to prevent the cylinders from filling with gas and hydrolocking them eventually my friend showed up an manualy choked it with is fingers and i was able to start it.. (my choke doesnt work) and i've tried fixing it and i cant but if someone wants to help that'd be great! anyways ya it can happen man :P

[datsunaholic]

An accelerator pump is a plunger pump. It cannot stick "open" because it isn't a valve. It can stick in one position or another, but either way nothing happens except bound-up linkage or a bad hesitation.

 

What gets stuck open is the float valve, either from too much line pressure forcing the valve open (webers are VERY prone to this, especially with electric pumps) or a sunken float. Solving this problem is simple, but it involves putting a stock part back on that some folks think unneccesary.

[lynchfourtwenty]

well whatever the problem is it happend to me gas was leakin from the "accelerator pump area" once i got to under a half tank the problem went away.. and hasnt came back since.. except that one time i put too much in but after an hour of freeway travel it was ok

[datsunaholic]

"Accelerator pump area"? This a Weber or a stock one? Sounds a LOT like a float valve issue. Having the tank in the bed would increase head pressure and gravity feed the carb if the float valve was stuck or weak. Especially downhill. Then the bowl would overfill and run out the bowl vent(s). That's a very very bad thing. The tank top really should be lower than the carb base. Relocating the tank is the ONLY solution to that problem. That or fuel injection.

[lynchfourtwenty]

agree'd, but i've looked under the bed many times and cant seem to locate any mounting areas although the tank has brackets on it and all the ones i've seen had te same ones the holes just dont seem to be there i dont know waht the deal is i was thinkin of takin the brackets and having them welded under there then mounting the tank to them.. but i dont want it to fall down so i dont know if welding it is the best ideal.. but at the same time drilling holes kinda sucks too