I have a good looking blue spark. And before I throw a BFP at her I'm going to dig some more. I've been at this so long now I don't want to just roll over & say "well maybe it's this or that".
I will up grade to a BFP. That's always been in the plan.

I'm going to get somebody that knows what they are doing to do a leak down test. It very well may be 1 or more injectors leaking.

Question....teach me something. I have 1 injector that I can "rotate". Kind of like twist a little from side to side. Like you would turn a door ****. Is that normal? The other 5 are tight. No movement at all. There are no external leaks. I have verified that but I wondered about this twisting injector.
Next question......anything in the distributor assembly on an 89 that would cause HNS?

thanks

 

I can rotate all of mine, but they're not the originals. I lubed the o-rings up with oil when I installed them a few years ago.

What happens if you spray throttle body cleaner around the injectors?

Suspicious of the sync generator in your dizzy? Unplug it and start your Jeep.

 

I unplugged it & she purred like a kitten. How about a drive until hot then try the HNS test?

 

Why not?

 

I suppose the sync generator is eliminated. She ran fine for 12 miles until I shut her down. HNS. Raised the hood & had to wait 15 minutes before she struggled to another ruff start.
She tries really hard to run but just can't quite get going when it's hot.

 

Have you tried a shot of starting fluid when this happens?

 

Have you seen whats missing from the equation when no start occurs ?

 

Oh yea.......does no good. Spins like crazy trying to catch, but doesn't. The ONLY solution(s) I have found are between letting it cool down or pressing the pedal as if to clear the flood. If I let it cool, smooth start & perfect idle. If she catches hot it's ruff as you know what.

I have good blue spark. I have fuel pressure according to my gauge(which is still strapped to the windshield)

Again, I'm no mechanic. But it feels & sounds flooded. It doesn't feel like she's starving for fuel.

Gotta be getting close to the end now..lol.......I hope.

 

Something easy to check. In the middle of the night I remembered your trouble started after the injector change. I knocked off and busted my Map tube once changing mine:

There is a brittle little tube. It comes out of a rubber plug, low on the engine side of the throttle body. It runs back to the firewall, then up to your MAP sensor sort of high up there near center on the firewall. CRUCIAL!! The MAP will tell the ECU to dump fuel with less/no vacuum. Any crack or blockage and it will be pig-rich. (black smoke, fouled black plugs). You can pull the line off the MAP and feel for vacuum with your finger. If it runs!

Also you can see in post #40 how I checked my injectors for leaking.

Also the #on the Bosch injectors? (the one starting 280-

 

have plugs been really wet when this happens

 

DFlint all my hoses & tubes are brand new. I have pulled em all off & replaced them & I'm getting just what you would expect. So everything is fine in that regard.

I just ran her back up to op. temp. & waited 5 minutes. HNS was full blown so I snatched the plugs out to see if I could catch one wet during the HSN time frame. All were bone dry, whiteish in color with no dirty crude or build-up. No smell of fuel coming from the plug holes.
By the time I was done putting them back in it had cooled enough to start with no problem. I mistakenly left one plug cap off & she ran dang near as smooth on 5 as she does 6.
Bone dry & white in color. That's not a flooding appearance is it? Maybe I have this *** backwards. Maybe it is starving for fuel when hot.

WTHDIK......

 

X2. Yea dry and clean with no fuel would not be flooding. (glad that is "put to bed". I'm guessing since you have nice spark ether the starting fluid was too much, or too little, or there is an issue with compression. I might see if a few easy to reach manifold bolts are loose. Heat "migrates", while it's sitting. Areas that don't run so hot, can get hotter when the air and water are not moving. What I'm thinking, s'never bad to checkm' and a remote chance the manifold warps when it's sitting.

Two thoughts...at HNS, does the cranking sound normal, or "freewheeling" as if compression were low.

And just to be thorough, (complete, :

Vacuum leaks suck. I go around with short little shots of starting fluid, if you hit one the sound of the engine will change. Small little shots! You don't want that stuff to accumulate. It's a fire hazard, but It evaporates right away. Also with a tube, or a section of hose you can listen for it. Don't forget the lower O rings on the injectors need to seal as well. (uppers would leak fuel).
The manifold bolts have a habit of loosening, especially that rear one. On anything like that you never want to tighten only one. It can warp/bend, even crack things. If I found that any that where easy to reach where loose, I'd pull the air cleaner and tighten them all, starting in the middle and working out towards the ends. I go over about three times. It's a bear of a spot to get a torque wrench on them all. Just don't ape on it. If its firm and not turning, no point in going on to break it, a REAL *****. The rearmost bolt underneath takes a little doing, but it can be done with the right extension. For that very back one by the firewall I use way long extensions (18"), with a swivel at the socket. Anyway, that's a good thing to check on any old Jeep.




Also I once had vaguely similar symptoms. (normally started, but bucked and backfired)(once I didn't turn it off all day!). My heat shield would expand and short the (mis-routed), wires to my lower sensors in the time it took to go in and buy a pack of smokes. One of these days I'm gonna pull the tape and see exactly which.

 

I'll check those but let me say this. About a month or so ago I pulled the engine & replaced all of the freeze plugs. While there I replaced the rear main & timing chain seal in the front. Welded a small crack in the exhaust manny. & replaced all applicable gaskets. Going back in put in a new radiator & all the trimmings.

The HNS was happening well before that operation. Since then all of these new sensors & modifications. Since I had a buddy help me check those bolts cause I kept seeing where Cruiser mentioned it, but I'll do it again.

I keep checking for shorts & messed up wiring every time I raise the hood

Now to answer your question. Yes at times it free-wheels. Usually after I have tried it a time or 2 during HNS. Last compression check was done the day before the engine pull (January) & I got 105 down the line.

Now I realize some will say that's low. It may be. 204k. Doesn't leak or use a drop of oil. No smoking or anything. Runs strong as new rope. If you kick it she'll put you in the back seat.

I asked local "mechanic" about 105 down the line & he says with the age & mileage ain't nothing wrong with 105. Especially since they're all even.

BWDIK???

 

Does it maybe try/fire once or twice at HNS? (before oil pressure comes up)
Being even, within 10-15,%, is really what counts. At some level you are also testing your battery, starter ect.

See what others have to say...one guy had an issue with his push-rods getting tight somehow. Said it would start when he loosened the rockers. Nutty I know, but if compression plumits after heat has has time to migrate, and predictibally, like clock-work it starts cooler...

That might involve ether checking compression right there at HNS, and/or seeing that you can spin the push-rods with your fingers.

I'm headen to the party, catch you later

 

Exactly. The first 2 attempts it almost starts(semi). Then it begins more of a free-wheel spin. At that point sometimes it will catch if I depress the pedal. But it's a real struggle. I can raise the hood , wait 5 minutes, depress the pedal & it will probably start. But as I say it may die or run ruff as Hades.
That all depends on how long into cool-down she is.