Trouble shooting

[grannyknot]

8 hours ago, Zed Head said:

Are you using starting fluid just to be sure that timing is right, in between your fuel system troubleshooting?

No I haven't used ether yet but I set the distributor back to exactly where it was when the engine was idling well before tear down.  I picked up the Walbro replacement fuel pump today so I should have that installed by tomorrow afternoon, hopefully that will do the trick.

I also have a spare FPR so I'll get that ready just in case.

 

Edited June 26, 2019 by grannyknot

[grannyknot]

The new Walbro fuel pump is installed, still don't know the exact fuel pressure but the needle pegs at 21psi and stays there after I stop cranking but still no start. Still backfiring and puffing out the AFM.

Not sure of the next step, get a proper fuel pressure gauge, change out the FPR for my spare or a new one, go back and do the No Start tests again, or maybe find a new /77 ECU ? This really isn't my strongest area.

Thanks

 

[siteunseen]

Clamp off the return, builds up higher psi. See if it'll crank then. Good luck!

[grannyknot]

Installed a proper fuel pressure gauge today, turned the key to start and the needle goes up to about 35 psi and stays there, I clamped off the hose after the gauge and let the pressure get up to 60 psi then unclamped the hose and it came back down to 35 psi so looks like the FPR is working, do you guys agree?

I have gone through all the tests from page 47 to 71 and all were good except for test #1-3b air flow meter, resistance, ohmmeter leads between pin 7 and pin 8, there is suppose to be a small amount of resistance but continuity. My resistance was 144 ohms which doesn't seem small.  Also, test #3 - 3 cold start system circuit, voltmeter leads positive to pin 21, negative to ground, the results should be; Little to no voltage at first; then battery voltage after no more than 15 sec. My result was battery voltage almost immediately.

So still no start, I guess I'll pull the cold start valve tomorrow and maybe exchange it for my spare. Any patterns emerging to you sparkys out there?

[Dave WM]

do you hear the injectors clicking when cranking the engine?

[grannyknot]

1 hour ago, Dave WM said:

do you hear the injectors clicking when cranking the engine?

I think they are, the starter is too noisy to separate out the injector clicking. I did pull the spark plugs today and they were wet with gas.  Maybe I should pull the whole injector pack and fuel rail unit and see if they are spraying and or dripping. Grasping at straws now.

[Captain Obvious]

Fuel pressure sounds fine.

Don't worry about the  test #3 - 3 cold start system circuit when it showed voltage immediately. All that means is that your cold start injector never fired. Either your thermotime switch is burned open, or it was just too warm to close, but in any event, that's not what's causing your problem. I've been running with no cold start injector for years now, and it takes a little longer to start, but it still starts.

And I will double check my notes, but I don't think your AFM test #1-3b is a problem either.

Can we go back to basics....

Are you 1000% sure you have the firing order correct?
Are you 1000% sure you have the ignition timing correct?
Are you 1000% sure you are getting good spark on more than just one plug?

 

[Dave WM]

wet plugs means getting gas, good.

agree with CO, sounds more like an ignition problem. put crank at #1 TDC make sure cams are bunny ears (both up, valves closed, firing position). Confirm rotor is pointing to #1 on the cap.

I assume you have a timing light, use it to make sure timing is about 10 degrees advanced.

Edited June 29, 2019 by Dave WM

[grannyknot]

To use @siteunseen's phase,  I bow down in shame.  The engine is running fine now, my mistake is so humiliating I can't even admit to it yet. Thanks for your help guys I certainly know the FI system inside out now.

[Dave WM]

out with it, no shaming will be done, we all done stupid things, ask me about using vice grips to hold the TB open then slamming the hood down forgetting to remove them...

 

shall we guess, dist on backwards?

Edited June 30, 2019 by Dave WM

[Mark Maras]

I think Captain Obvious must have nailed it in his "go back to basics" post #19. 

[madkaw]

Timing ! 

We all make the mistakes . My latest project my Nissan 720 I put the dizzy 180 degrees out on my brand new rebuild .  Just wasn’t paying close enough attention . But wait - still wouldn’t start, just sputtered . Find out later that my carb adapter was not tight - AT ALL! Sucking a little too much air . After that engine fires right up