Im gettin fuel and spark for sure but when crankin the flapper door of the VAF makes a sound was told by my instructor that may have a intake valve stuck open has this ever happen to any one and how much did it cost for repair parts?
what was the conditions leading up to this, did you drive it, shut it down then go to restart? As long as you have fuel spark and air it should fire or try to fire stuck valve or not. how did you check for fuel pressure?
I have had this happen. Bad fuel caused my valves to gum up and stay open. They were clanking against my pistons very loudly but a bent valve should not prevent the truck from starting. It would run pretty rough but should run. You can check a bent valve by running the truck and pulling each plug one by one and listening for a difference in the motor. If you had a bent valve on one cylinder there would be No diff. in the motor when you pulled the plug. If you are getting spark to all cylinders and fuel I would think it was a timing issue. Make sure your chain didnt snap and your timing marks are lined up. Check all ground wires as well.Good luck
Checked valve clearances all our in spec instructor thinks its the igniter which is not a cheap part. Not sure of fuel pressure but know it smells like gas when crankin it. Someome told me to adjust the valves but not sure what they meant loose or tight there in spec so how would that help?
I had a 7.5 amp fuse blow and mine would'nt start.It would crank over and the lights on the dash would light up. Mines an 84 Sr 5 also.
If you checked spark at the plugs it would mean that your coil is still good. Pull the plug lay it down near a ground but dont let it touch and crank it and the spark should jump to the ground or zap itself (plug). You will need a friend to help so you can either crank or check for spark. Do this on each plug. To check fuel pull the fuel line going into the carb and crank it. Fuel line goes into the banjo bolt on the upper side of the carb.. What led up to this problem. What were the symptoms. You might want to do a compression test. Double check all fuses. There is an ignitor fuse.
If it was running prior to this problem I would say a valve adjustment is not an issue. As Malessohomegrown says, check for spark...I have used a phillips screw driver in the wire and lay it close to a ground, I have found it easier to see, or spend the $6.00 and get a spark tester. On another note I have seen trucks not start due to an extremely restricted/plugged air filter. I believe you mentioned the VAF, which indicates a fuel injected engine and you can smell fuel when cranking it..How long cranking before you smell fuel? you may have a stuck injector flooding it. Too many things can cause it not to fire and is hard to pinpoint without more information. Keep us posted.
I used 3 diff spark testers doin it those other ways are not accurate, since the air gap of air is greater than the combustion chamber. One looks like a spark plug with a clip for a ground and plug wire connects also adjustable gap plastic style with clear tube to see spark. Havent done any fuel pressure testing to see if it is injector problem. Found a igniter from texas for cheap and its new tested my igniter and it was not producin 5-8 volts when i used a 1.5 volt battery hooked to the pink and white wired connector from dis to igniter with a dvom one neg side of ign coil and body ground. Its a mitchell on demand test. Im goin to yuba college auto department. I have done alot of testing in the last few classes. Thanks for the help if its not the igniter, which even the instructort thinks its is and my buddys cressy did the same thing, ill check injectors next.
Too bad you don't live in this area.there's a place that will diagnos it for free.Good luck,I feel your pain.Have you tried cleaning the MAF?http://www.japaneseautocenter.com/
The VAF flapper door knocks back and forth when crankin so mayb it is broke but its a 144 dollar part so idk idk after i put igniter on and it dont work i may be sellin it to a guy that owns a yota shop for like 1200
So since the trucks been misfirin due to low compression and cyl leakage my cat clogged up. Took my o2 out and it fired up for some reason temp gauge said it was runnin hotter but may be timing since we were adjusting it to see if that was why it wouldnt run. Cut pipe at cat inlet so i need to have a test pipe made. I knew the cat was gonna burn up but didnt have money for a test pipe.
x2 Just had to change out this fuse today. Exact same symptoms. Engine would crank/spark/gas....no go though..... Pain in the ass looking through all the fuses & going through everything to dwindle it down to this. Also changed my PCV Valve
