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Did the pressure check today and it was on the money at 12 to 13 pounds at prime and steady at 12 in cranking mode. so if the fuel is insufficient to fire it must be the  spray nozzles.  

your compression sounds kinda low...

by the way.. on the lower left of any post YOU make... there is a tiny link that says edit post... you can click on that at any time in the future to add information to that post...   you should also try to post what problems you are having ...  not just the test results...

for a TBI 4.3... 12 to 13 is  good pressure...  dirty fuel filters and bad fuel pumps will make for hard to find problems on these models....    are you getting a good spray from the injectors???/  use a timing light aimed at the spray pattern.. should be a nice crisp cone shape...  i have seen some cars just recently.. that ran like crud...  i thought it was the fuel pump... or the fuel filter.. turned out it was the cat...  it was mostly clogged...   you seem to have a few tools... do you have a vacuum gauge???

if so ... hook it to a manifold vacuum source without unhooking things like the MAP Sensor..    if the engine will start and idle... look at the intake manifold vacuum reading... start bringing the RPMs up slowly.. watch the vacuum reading... it should rise in numbers.. it may idle at 12 inches of vacuum...   and when you bring the rpms up... the vacuum should go up beyond 15 to 23 pounds of vacuum..   if it drops with a slow increase in engine RPM you probably have a restricted cat or blocked muffler...    when the cat fails... the grid crumbles... the high temp packing around the brick of material in the cat can block the muffler internally..


is the check engine light on??????? if so... find someone to scan it..      96 and newer.. thats OBD2.. much easier.. prior to 96...  you have several options...  

let us know more about it...

wayne.

the nozzles you are describing are electronic fuel injectors...    the power wire gets power when the key is turned on..  the ground side is controlled by the ecm...   it varies the pulse width to control the amount of fuel being sprayed out...  

ok.. i see some of your other posts.....

i answer a lot of post on many boards.... it all becomes a blur.. if you think other boards.. just log in and click on my name...

first... the timing chain was replaced....  the distributer was out...

who double checked the timing marks before putting the timing cover on...    oops...  thats something that was set up in most repair shops and engine rebuilding shops...  it does happen...  i have gotten them wrong..  i know keep a mirror in my tool box so i can see the marks straight on... through the reflection...

is there any way to drop the exhaust off the manifolds and use a shop vacuum over the end of the tail pipe to verify that the exhaust system is not clogged...   use a tennis ball to block the open side...  i hope it does not get sucked in.. it is will be a pain to get it out...

did  all the system grounds get reconnected... one the 4.3's that i have worked on.. i have to replace the ring terminals on the grounds to the intake on almost every one.. just wrapping the stripped wire around the stud won't work.... you have to have the proper ring terminal size and ring diameter.   remember the ecm gets all of its grounds from the intake manifold grounds...

did you also replace the intake manifold gaskets?????  they go bad on 4.3's ... leaking coolant out....

i see that you have a compression tester...   do you have access to a air compressor...  or have a load range D or E tire on a rim to act as an air supply...    so fix up a hose with a quick disconnect that can hook to your compression tester hose...
take the valve core out of the end...    bump the motor over with a hand held remote starter switch.. so you have some fine control...   take one spark plug out at a time...   screw in the open ended compression tester...  bump the motor till you get it right at TDC for that cylinder..   with the radiator cap off ..  hook up the compressed air..   Warning.. if the engine is not at TDC it will move... and move fast... don't get caught up in any rotating part...  when you pressurize the  cylinder.. if you have any leaking head gaskets... you will have bubbles coming up in the radiator.. or the coolant blowing out.. this is all with the engine off...   this is an easy way to prove or disprove leaking head gaskets...


oh.. did you check for spark from the ignition coil...   and again for spark at the plugs...?????  rotors have burned through..

while you have your head in there... if it is a push on rotor...   take a bright flash light with you... look straight down the distributer shaft...   see where the reluctor is riveted together.. you can see some of the magnet exposed under the first layer right next to the shaft... look carefully to see if it is cracked...   if it is... instead producing nice smooth sine waves as it passes the pick up coil pole pieces... it produces weird patterns...   remember... after starting... the module controls the timing... so it uses the previous spark trigger and a clock to control the spark timing... so it can advance the spark beyond the 15 degrees btdc the base timing is set at...

oh.. you can also set the timing dead stick...   by bringing the engine to 15BTDC on the harmonic balancer...  moving the distributer so the pickup coil tips and the reluctor teeth line up exactly...   then lock it down...   when i learned how to do this.. i can start a rebuilt motor with just a turn of the key...  makes me look like a magician...    all the parts on the floor to all put together and it starts on the first try... without having to move anything...    hehehehe....  

Let me start by saying that I do have a few tools, I turned wrenches in the sixties, most of my work is around the trucking industry,I drove in heavy haul for thirty two years. I could never stand giving money to shops that did what I could do, so I continued to learn about the newer(to me) systems. I guess I just love to learn. I have rebuilt my old truck in different parking lots over my career.
   I have to say that I am the one who put the chain in and yes I double checked my self after it failed to start. In fact it has not fired up at all, that is the reason I continue to trace down the problem. I will list all I have looked at in this post.
 spark is good I made a plug welded to an old vise grip to check for fire good at coil and at wire ends.
 compression is low 150 is the mark best is only at 105.
fuel pressure is good in prime and run or (cranking),the compression may come up if the spin rate of the starter dose increase. I have yet to do much in the starter
area, though today I will pull the starter and see if the bat leads are creating restricted flow of electricity.(amps)
  the preset of the timing is good though I set it at 12, will re due that for 15.
the engine acts as though it wants to start but just can't get the fuel and spark together. each time I pull the plugs they are dry.  the fuel spray is pulsing as I watch it when the key is turned to start.
  timing light pointed at spray pattern, thats new to me will try it.
  The unit was pulled into my place as a non starter, so I have looked at almost every thing so far, trying to fix it for the man, and not spend a fortune to do it, though we will have to talk about the compression and the oil leaks.
  yes I did wire one in the wrong rotation once, felt like a real dummy.lol
 when I pulled the radiator cap the water was up to the top and the owner had not had trouble with loss of fluids, other than oil, so I have not disturbed any thing like intake.  The grounds will be cleaned and checked after church. My wife made me quit early today so I never got to do anything to the truck, she gave me her list and made sure I did not slip back into the shop.  Will keep you posted.  

i take it that you have a timing light... can you hook it up to the number one spark plug wire...  see if the light flashes right at the proper timing mark while the engine is being cranked...

i have had to fix so many cars that failed to start do to the distributer being 180 degrees out...    i even had one.. the firing order was right...  and the compression on the number one cylinder lined up with the rotor position..   there were 3 professional mechanics there checking the motor...   the firing order was right.. but it was going the wrong way... oops... i did not do it..  but i was the one who spotted the problem..  

today was the topper to a week of foul words and interruptions for honey dues, but I got to napa and exchanged the starter, I did the timing light on the fuel spray and it had a fair cone on both sides.  so lets recap,
1 distributor had to be put back in proper time
2 timing chain had 14 degrees of free play, replaced it.
3 made a T fitting to connect pressure gauge, pressure good.(fuel)
4 checked relay switches, checked good.
5 removed grounds cleaned corrosion and reassembled.
6 cleaned and greased bat terminals.
7 checked ohm reading on battery cables, good.
8 checked ohm reading on spark plug wires, good.
9 cleaned plugs
10 replaced dis.cap and rotor.
11 did compression check, rechecked compression after starter lowest 100.
12 removed and exchanged reinstalled starter.
13 battery draw test
 Engine turned over very well took maybe ten revs. and lit off like it should. The job is I would say looked over with care and most products seem to be in working condition, The owner may get another year or two from this power plant, I recommend he start to think about a recon or rebuild what he has, in two years he should be able to save enough money.
The slow spin of the starter was in the end why it would not light off, I know it seems strange for that to just come about so suddenly, but who ever worked on it be for I got it, must have spent long periods of cranking the engine over trying to start it.
 Hope this will help those who come looking for info about there trouble, Wayne thank you again for your help and your stimulating my mind into a working tool again.