Retitled: 83 Scrambler resto-mod finally gaining momentum

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Back to basics... thinking through why I may not getting a start.

battery is good
fuel and fuel pressure are good
signal to the fuel injectors has been verified by noid light/tester
I just did a dry quckie compression test (on a cold and newly rebuilt motor) and got 110lbs quickly built on #2 cylinder
I've verified that I'm getting spark at a spark plug
I've verified (I think) that my TDC and timing are set at 0: air pressure at #1 spark plug hole, timing mark at 0, rotor at 1, and piston at the top of its travel.. this is one area I'll definitely check and re-check again...

I pulled three of the (brand new) spark plugs.. one appeared to be covered in sort of a wet/black soot, the next two appeared to be bone dry (shortly after multiple attempts to start the engine).. no wetness, no gas smell, could be a sign that only that one plug is getting fuel?

- when I was purging the fuel pressure gauge, I did get some dark fuel out of it (all the fuel is fresh, so it must have been cleaning the bottom of the (previously cleaned out) fuel tank and the rust/dust out of the fuel lines which have sat dry for over a year mounted in place

things that I'm thinking may be the culprit:
- timing: as stated, I'll re-check
- actual injectors: these are the original injectors from before I rebuilt the engine, which ran fine before I rebuilt it.. unless the initial purge of rust/dirt from the dry fuel lines clogged up all 6 of them, I'm not sure how they could all be bad.. that said, I'm surprised after all the start attempts that i've got dry plugs coming out of the cylinders..
- a ground somewhere in the system.. maybe something to do with NSS or park sensor. I've grounded what I think may need it, but not sure if I've overlooked one, or perhaps did one wrong. If I did miss a ground, would it still allow me signal to the injectors and start signal to the starter? I'm thinking those would be interrupted?

I like to learn, but this is getting to be a PITA. :banghead:
You might want to go back and verify your wiring connections, too:twocents:

We had a similar problem with an LT1 we swapped into a YJ. Had fuel pressure, correct timing, getting spark, but it would only run on 2 or 3 cylinders, never all 8. It was hard to start, barely ran, etc. Checked the injectors with a noid light, eventually replaced the injectors. Never would run. Finally, after two weeks, I went back to an original GM wiring schematic. Sure enough, the company that built the plug and play harness, had 4 wires in the wrong pin slot of part of the harness. Put the pins in correctly, fired right up and has been running great since then:D

I know it will suck, but it might be worth while verifying the wiring:twocents:
 

Bushmaster6

Legacy Registered User
City
the Springs
State
CO
two weeks idle while I had other things going on...

I re-re-verified (I re-think, again) that I'm at TDC/compresson on #1 when timing mark is 0 and rotor is under plug #1 wire at the distributor cap.

I pulled the distributor a number of times attempting to set it one gear forward/back, and never got any better results than my current "sounds like it wants to fire" starts.. when I advanced/retarded the gears (and tried it 180-out), I get continuous start with no sound of it firing.

I finally received/installed the new fill hose from Morris and added another couple of gallons to the tank.

I've used the ohm-meter function on a multi-meter to test continuity on all 6 injectors (all 6 registered correctly in the high 13s). I have not pulled the injectors to see if they just "look" dirty. I may go ahead and replace them all just to eliminate the possibility that all 6 somehow went bad during the rebuild (or got completely clogged up with bad initial push of fuel when I first tried starting it).

I just used a funnel and sock to do the "wet gas rag" method of fueling directly through the throttle body.

The motor starts immediately upon gassing it via the TB. It ran for probably 10 seconds on that load of gas and eventually stumbled to a stop. It's a little hard to tell how well it runs when doing this as the open header drowns out most other noise.

I did a second attempt with the gas-rag. It stumble-started again and ran for a few seconds. I heard one "poof" of a backfire and pulled the funnel/rag when I saw open flame coming out of the TB.

I attempted to start it via the ignition and it continued to sound like it wanted to run, but never fires enough to go.. I'll get some pops out of the exhaust during this but it never really gets going.

Frustrated.

Does my backfire/flame at the TB indicate anything specific?
May swap my injectors next.
Any other ideas?
 

bigwalton

Picture cravin' AK Postal nut
Staff member
SOA Member
City
Dexter
State
MI
If you have fuel pressure at the rail, you verified the injector signal and you got it to run with the funnel sock (I would think it would be running really ragged on totally unmetered fuel and the backfire could just be that it took in too much fuel from the sock) I don't know how it could be something other than the injectors. Maybe just the ones that had the dry plugs are bad and that's enough to keep it from catching?

Swap the dry/wet cylinder injectors and see if the plugs come out differently? Otherwise I'd say swap them all out for new :shrug:
 

Randyzzz

Blown Budget
LIFETIME
CJ-8.com Member
SOA Member
City
Redmond
State
OR
Pull the injectors and have them tested. I've found injectors seem to "freeze up" after sitting about a year. I found a way to bench test mine at home using a Frankenstein contraption involving a length of fuel-filled clear tubing and my air compressor, and a battery for actuation. You want a nice atomized spray, and no dripping when under pressure closed.
 

Bushmaster6

Legacy Registered User
City
the Springs
State
CO
made some calls today and found one local store that does bench testing/cleaning of injectors so, pulled them tonight and will drop them off tomorrow...

when I drained the fuel rail there were some decent sized chunks of crap (not alot, but noticeable) that flowed out into the rag.. and of the 6 injectors, I'd say that one (the #2 cylinder) looked wet on the working end.. which about matches up with my experience in examining the plugs (only pulled 4 of them)..

here they are in order (sorry, low light photo with iPhone):


hard to see in pic but #2 (2d from left) is the only one moist with fuel on the inside.. not sure if that's a sign or not, but I took it to be an indicator of my possible problem
 

bigwalton

Picture cravin' AK Postal nut
Staff member
SOA Member
City
Dexter
State
MI
Houston, I think we found the problem :fingerscrossed:

Any crud coming out of the fuel rail has to be a sign. Is there any easy way to run fuel through the rail/line to flush it while you have them out? Maybe disconnect/remove the rail and pump some fuel out of the line into a container (carefully!) and flush the rail with carb/choke cleaner?
 

Bushmaster6

Legacy Registered User
City
the Springs
State
CO
Oh yeah, I will definitely flush the fuel rail, removing the rail and injectors is about a ten minute job, the whole rail is still out now. Hope to get same day service on my injectors but I have class tonight so usually don't get home until late.

Something still makes me skeptical that this is "it", but I'm hopedul. Each troubleshooting step has taught me more about the jeep so, that's a side benefit. If its not injectors, I'm not sure where else to look.

Related note, ALL of this stuff was thoroughly cleaned when I had it apart... Shows that time, travel, and oversight can still leave you with "crud" to account for. I can only suspect at this point that this came from inside the fuel lines after sitting for a year (dry except for a big blast of Wd40 I sent down them before reinstalling them). All the filters, pumps, and rubber lines are brand new.
 

Bushmaster6

Legacy Registered User
City
the Springs
State
CO
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bobbysjeep

Legacy Registered User
City
Charlotte
State
NC
No...Tried the link, but is was not there.

Ok, figured out how to do it.

1-Play your video on FB
2-In the video popup window click options, then click embed video
3-Another popup will open with the video link, highlight right click and save
4-On your post (CJ-8.com) click the globe icon and paste
5-Sit back and enjoy
 
Last edited:

jims chop shop

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
stafford
State
va
I just posted a video on test thread
I have a photobucket app that I upload the vid too
Then I copy the direct URL and them paste it in
It didn't work the first time on tapatalk , but it does now
 

Bushmaster6

Legacy Registered User
City
the Springs
State
CO
well, the fun continues...

now trying to pare down the leftover wires from both the CJ and YJ harnesses...

the CJ harness hasn't been so bad as the majority of the engine harness connectors required are in use, and there are a few leads for sensors (oil pressure, water temp)that obviously need connecting, and then I can cut basically anything that used to run to the starter, ignition, alternator that aren't in use anymore..

items from the YJ PDC that I know I'm not using (ie: YJ horn, the A/C system) I've cut at the old YJ bulkhead connector, labled, and rolled up underneath the PDC/battery tray in the event I want to use the wiring/relays for something else later.

Stuff I'm still trying to figure out:

the YJ has effectively three main harnesses coming through to the engine, one of which terminates in a 10-pin connector under the instrument panel (called "IP Conn #2). Most of the wires run through the actual engine harness through this connector to the old YJ instrument panel. I think I can basically trim them all, but wondering where I should cut them/if I should save any portion of it for future use.
 

bigwalton

Picture cravin' AK Postal nut
Staff member
SOA Member
City
Dexter
State
MI
YES!!! Big congrats!

I would bundle all the wires up and leave em for now Wait a while and get it driving before going any further on the wires. Just in case. My :twocents:


Sent from my iPad HD
 

Randyzzz

Blown Budget
LIFETIME
CJ-8.com Member
SOA Member
City
Redmond
State
OR
That's awesome! Gotta love the SEG (S%!# eating grin) we all get when our stuff fires for the first time. I see the wife was happy too! Congratulations!
 

Hawaiian8

Basic User
City
Sierra Vista
State
AZ
Great job with the build!! Can't wait to see the engine bay once it's all cleaned up and put away.

Bushmaster6; How long have you been in?
 

Bushmaster6

Legacy Registered User
City
the Springs
State
CO
Thanks guys, trying to work my way thru the hundreds of "little things" so I can get her out of the garage and give her a shake down cruise...soon.

H8; I'm right at 20, with probably 4-5 to go.
 
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