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Close...but no start

Posted: Fri Jan 17, 2020 4:12 pm
by rodo
1981, not run in years but was kept clean (if that matters).

I am so close and I keep thinking I'm missing something simple.
To wit:
I have gone all the way through my ignition system tests. I have spark. (I saw the spark!)
Engine turns over very smoothly
Engine has never once fired.
I did the dog-flap test and the fuel pump buzzed happily. (Yes, I actually have enough fuel in the tank.)
I have not done any other fuel tests.

So I have spark and the electrics are getting to the pump but when I turn the engine over I get no firing.

Timing? I did replace the belt, carefully, but did not turn the distributor at all. Pick up gap is good.

I've rapped on the dual relays but maybe they are more than stuck?

What else has to be "green" for the fuel to flow and the spark to spark?

Re: Close...but no start

Posted: Fri Jan 17, 2020 5:04 pm
by TX82FIAT
Some reading material. http://www.hiperformancestore.com/ljetronic.htm

LJet is pretty robust. Test to see if the injectors are squirting fuel. Sounds like you have spark and air. New fuel put in tank??? Test fuel delivery at various points from tank pump all the way up to the injectors.

Re: Close...but no start

Posted: Sat Jan 18, 2020 8:59 am
by rodo
Very helpful link, TX82FIAT! Thank you. Just last evening as i was texting with a friend he suggested that while my fuel pump may be making noise, I've not confirmed that it is actually pumping fuel. I will do that test today. Then I will tuck into the L-Jet link. Good times.

Re: Close...but no start

Posted: Sat Jan 18, 2020 9:02 am
by aj81spider
If it hasn't run in years there's a possibility the injectors are not firing. The gas may have turned to varnish and glued them closed.

Re: Close...but no start

Posted: Sat Jan 18, 2020 9:45 am
by RRoller123
Another possibility: Be absolutely positive that the timing belt was replaced with cylinder #4 on the compression stroke. You can easily pull the valve covers to see that the lobes of both cams would be pointing sort of up and in when #4 is at the TDC, as indicated by the mark on the crankshaft. Both valves closed. It is so easy to line everything up with the cylinder at TDC of the opposite side of the 4 stroke, and it will cause a tremendous backfire in the exhaust eventually, if fuel and spark are present. Everything can be 180 degrees out, and seem fine, the marks all lining up. (I am a self-imposed victim of this. :roll: )

With Ignition off, Pull off the large black air hose, open the throttle plate, and take a whiff inside the throttle body, and if you smell a strong fuel presence, there is injector spray, and this is probably what happened. DON'T try to start it again if you smell fuel there, unless you recheck the belt installation timing.

Re: Close...but no start

Posted: Sat Jan 18, 2020 11:17 am
by 18Fiatsandcounting
The above posts are good ideas, and I'll add one other thought: Bad (old) gas. If the gas in the tank is 2 or 3 years old, you might still be OK in terms of getting it to ignite, but if it's 10 years old, I'd definitely drain the gas and refill. At that point, you'd probably need to do a pretty thorough cleaning of the tank, fuel lines, pump, etc.

Given that the engine ran when you last started it, it sounds like your issue is probably fuel related.

-Bryan

Re: Close...but no start

Posted: Sat Jan 18, 2020 3:01 pm
by tima01864
Are the cam wheels adjustable? Otherwise that is very odd

Re: Close...but no start

Posted: Sat Jan 18, 2020 3:09 pm
by rodo
Okay, I've been running back and forth with this. My cam sprockets do have a hole each. (Not adjustable sprockets.) Those holes are supposed to line up with a "pointer" on the block at the back of the sprocket, right? Then, if I am on the money, my crank and aux pulleys ought to be on their marks and the dizzy at #4...right?

Re: Close...but no start

Posted: Sat Jan 18, 2020 3:18 pm
by rodo
Follow up:

Fuel is clean and new, filter and hoses all clean and new. Have yet to confirm pump is pumping as I want to do that and not set myself on fire.

Just checked timing: yep, #4 in position, both sprockets lining up, crank on its mark. Bam. Don't have to take that damn thing apart again.

So, right this second anyway, fuel pump. Will attempt a test. Suggestions? remove the line from my cold start valve, put it in jar, push the dog flap , see if there is any action?

Re: Close...but no start

Posted: Sat Jan 18, 2020 3:19 pm
by tima01864
That is correct Sir, When #4 is at relative TDC, In the manual or search posts to test the cold start injector. Try tapping the injectors this may help free them if theyy are stuck I have been told

Re: Close...but no start

Posted: Sat Jan 18, 2020 4:16 pm
by rodo
Glad to know that I am at least this one step ahead: all injectors have been rebuilt/cleaned.

So, instead of spraying fuel from a line, I hit the doggie door and listened. Pump is loud, then grew quieter as, IMHO, it started moving the fuel. Gave it about five seconds, not cranking. I thought I heard leaking so stopped. No, no leak, no smell. Assumed pressure was up in the lines and tried starting: just a couple of seconds of sounding like almost/maybe, then just turning over. Could it be just a very weak pump?

Re: Close...but no start

Posted: Sat Jan 18, 2020 5:11 pm
by tima01864
So you do have the big hose hooked back up to the plenum and AFM and everything else connected when you try to start? Maybe a shot of starting fluid? Never have used starting fluid on an EFI so?

Re: Close...but no start

Posted: Sun Jan 19, 2020 2:35 pm
by RRoller123
With the ignition OFF and the large black air hose removed, can you smell fuel inside the throttle body, with the throttle opened? If so, you are getting gas through at least one or more of the injectors. Please report back after trying this, very easy to do.

Re: Close...but no start

Posted: Sun Jan 19, 2020 2:37 pm
by RRoller123
Check this too: There are 2 ground wires with ring-terminals, that are attached to the air plenum top at the driver's side, rear of plenum. Usually on 2 different mounting screws of the plenum, but sometimes stacked on one. If they are not making electrical ground connection, the injectors will not fire.