fresh desmog, no start. DIAG (1 Viewer)

[masonbarnard]

i just finished up my desmog today and it didn't start.

I would crank the engine for 5-6 seconds, choke pulled and pumping gas. It almost starting to idle, then a loud pop would come out of the carburetor. like a back fire. i also installed a jim c recurved dizzy.

i figure since the car was running pretty well prior the desmog about 3 months ago, it must be a spark or air/fuel problem instead of a vacuum problem.

I think installed the distributor correctly. TDC #1, line on the fly wheel, removed plug and piston at the top. rotor pointing just left of #4 plug while fully seated and i think i installed the carb currently. (with new insulator plate and gaskets.

Does the Jim C carb come with a base tune thats good enough to start?

 

[Output Shaft]

Dissy needed to be installed #1 TDC - compression.

If you have any doubt that maybe the dissy got installed at TDC exhaust (180° off) just swap all the spark plug wires on the cap 180° and try to start the engine. If it runs fine like that, the dissy was installed wrong.

 

[LAMBCRUSHER]

you got the ICS hooked up?

 

[masonbarnard]

Dissy needed to be installed #1 TDC - compression.

If you have any doubt that maybe the dissy got installed at TDC exhaust (180° off) just swap all the spark plug wires on the cap 180° and try to start the engine. If it runs fine like that, the dissy was installed wrong.

I hope this isn't too dumb, but literally put spark plug #1 wire on #6, and 6 on number one, 2 on 5, 3 on 4, etc.?

Also what are thE Benefits of the green wire mod?

After work I'm gonna tinker some mores

 

[Output Shaft]

Yes. To check if the distributor was installed 180° out, just swap each spark plug wire to the terminal on the opposite side of the cap and vice versa.

The "green wire mod" permanently grounds the fuel cut solenoid on the carb. This workaround is done when the emissions computer isn't working correctly any more or it has been removed.
When the ignition is turned to ON, the FCS should click on. You should hear it click.

 

[masonbarnard]

Okay,
I just swapped the wires around, did nothing.

Removed the distributor and got the pointer perfectly at the line on the fly wheel. Removed #1 spark plug and verified piston at the top. removed oil cap and felt the very tiny play from the valves (which I've heard
Means that's compression) Turned oil pump slot just past the #5 plug. Installed distributor, got the rotor pointed just before #4 plug.

This is a video of what's happening.

 

[LAMBCRUSHER]

turn the diz so it's mounting bolt is about in the middle of the mounting slot and try again. your spark might be a bit retarded still

 

[NeverGiveUpYota]

I had a backfire twice after my rebuild. I hadn't played with my diz at all. It scared the pants off me for sure seeing a pop of flame tho it went out as soon as I turned the key off. I tried again with the air cleaner cover on and she fired up tho I did have to tweak my Idle Mix screw on the carb. I had also rehosed all my desmog lines. I still need to get the timing adjusted. The guys above have far better diagnostic suggestion than I do but just thought I'd pipe in on the backfire. Be sure your carb bolts are tight.

 

[LAMBCRUSHER]

GOOD POINT...could just be a lean pop as fuel is making it's way thru the carb...try with the AC on as @NeverGiveUpYota recommends...I was going to suggest making the idle mix a tad richer, but it's a JimC carb; I would NOT touch the settings without exhausting resources and talking to the MAN first.

 

[masonbarnard]

GOOD POINT...could just be a lean pop as fuel is making it's way thru the carb...try with the AC on as @NeverGiveUpYota recommends...I was going to suggest making the idle mix a tad richer, but it's a JimC carb; I would NOT touch the settings without exhausting resources and talking to the MAN first.

to late, ive touched the screws lol. i got it to almost idle on its own at 300rpms with the chose fully pulled. Is there screw procedure that works enough to start the car. (example: fully seat the screw then back off a certain amount)

 

[gregnash]

to late, ive touched the screws lol. i got it to almost idle on its own at 300rpms with the chose fully pulled. Is there screw procedure that works enough to start the car. (example: fully seat the screw then back off a certain amount)

According to previous posts from JimC you want to set the screw to where it JUST BARELY bottoms out then back it off (opening) about 3-4 turns. This should be a good STARTING POINT for the desmogged truck. From there look at your timing to see where it is at and then advance to the BB (7* BTDC) and see how she is running. After that then start working on dialing everything in with the LEAN DROP METHOD found in the FSM.

 

[micruz60]

Idle should be around 650-690 rpms when within spec....

 

[NeverGiveUpYota]

to late, ive touched the screws lol. i got it to almost idle on its own at 300rpms with the chose fully pulled. Is there screw procedure that works enough to start the car. (example: fully seat the screw then back off a certain amount)

Maybe you clarified further up and I missed it but be sure you are only playing with one screw at a time... Idle Mix in fully then out 2-3 full turns (that is the brass screw that is hard to reach on the back side of the carb when facing it from the left fender). Idle Speed is the INNER screw that is hard to see on the right side of the carb when standing at the left fender and Fast Idle is the furthest out to the right and back some standing in same spot at fender. I made the mistake of tweaking both those two which makes it hard to distinguish whats doing what. IF this is a Jim rebuild then I'd imagine he set the screws at optimum position for you. We have all made the mistake of playign with too many screws at a time... They are all too inviting.
As Greg said above... timing plays a huge role as does truck being desmoged and hoses all lined tight. Pull your flywheel cover and add whiteout to the BB and the BTDC lines so they will show up better with a timing light.

 

[Output Shaft]

A backfire out the carb can be caused by very lean burn.

 

[LAMBCRUSHER]

yeah, so reset mix screw as stated don't get to frisky turning it in or you'll damage the seat; just bottom the screw and back it out about 3 full turns to start. the speed screw I like to back out all the way and then turn it in to just barely touch the plate and a quarter-half turn. this sets the idle speed super slow- a well built AND INSTALLED carb will keep the engine spinning down to around 200rpms. is it really cold where you are? you might just make sure you didn't turn the high idle speed screw in too far- or at all, as well if you need to use choke. I'd say try starting without choke first. and if it doesn't just go for you, next step would be to see what it does when you give it gas manually(pour a bit into the carb throat...) and see what it does...if it still sputters, I'm back to my first impression...timing.

 

[masonbarnard]

okay, I'm spending lots of time tomorrow on this, and trying all suggestions. if it fails ill take pictures of everything to see if theres something obvious I'm missing.

- I'm going to pull my distributor again, but do i install the distributor at the line, or at the BB mark? i feel like I'm getting different answers, I've been using the line. my dist is recurved by jim, does that change the answer?

- is it okay to have the mounting bolt on the distributor to be slightly loose while its running so i can try moving it around a bit? (i don't have a timing light as i was waiting till it runs)
- I haven't touched the charcoal canister at all. should i of?

 

[LAMBCRUSHER]

install dizzy at the line.
leave mounting bolt looseish till you dial in spark timing(using the BB)
you should test the VCV that allows flow thru the canister, and verify it works. leave the canister functional. you should not have yanked it out...

 

[masonbarnard]

install dizzy at the line.
leave mounting bolt looseish till you dial in spark timing(using the BB)
you should test the VCV that allows flow thru the canister, and verify it works. leave the canister functional. you should not have yanked it out...

Yeah that's still there, I've blown through it. Based on everyone's pictures it's installed right

 

[masonbarnard]

****there is dripping oil or gas around my exhaust manifold... I got it much closer to idling by adjusted the screws to the above stated positions. while it is barely idling there is no ticking, nocking, or unusual engine sounds. I HAVE oil pressure while its attempting to idle. i say gas or oil because it has a slight gas smell and may be dirty just cause my engine has had its leaks before.

*** when i floor the gas pedal it wont go above 500rpms*** after 5 second i saw smoke around the carb, noticed it was coming from the manifold. checked out the exhaust manifold and THERE IS OIL OR GAS GOING ALL AROUND THE GASKET BETWEEN THE DOWNPIPE AND EXHAUST MANIFOLD. AS WELL AS TWO DRIPS DOWN THE SIDE OF THE BLOCK FROM THE EXHAUST MANIFOLD. ** i did notice that one of the 3 bolts was loose that i had forgotten to tighten. would an exhaust leak somehow create that.

* last time i drove this car it was running good until the smog pump seized on the highway and burnt the belt with it. Prior to all this it was running good. I'm guessing it was overheating for a couple minutes before i noticed and pulled off.

I sent the distributor out along with the carburetor to jim C. While waiting for them to come back i replaced the thermostat, radiator/hoses, pcv, did the desmog, new carb gaskets, insulator. got a new temp gauge, spark plugs, wires, oil change, belts, double checked every line, removed the cat, did a OME lift, got new tires, wheels, rebuilt the rear brakes, ect. What the hell is happening. $2k worth of s***.

 

[masonbarnard]

she's mint too.