Fuel pressure test 5.7 vortec

[GXpress]

I just finished working on the engine and nothing no start. I took the distributor out again, had someone bump start the engine until i felt compression on my finger at cyl #1 then by hand moved the crank to align with notch on timing cover. The distributor has a dimple which i aligned with the line on the distributor shaft i inserted the distributor with rotor pointing towards cyl #1 as gear engaged it finished testing with rotor pointing to where the edge of the distributor has a bend.

Did i do it wrong? By the way fuel pressure while cranking falls to 42 psi and then as i let go of the key it shoots up to 60 and stays there.

Engine has not run after timing chain replacement. Iam in this hole
Because the van shut off on me without any warning. Being i had changed out the distributor for a different reason three months ago i never got to time the engine with the scan tool but it ran excellent except for slight pinging when going into overdrive.

Being the engine shut off on me i thought maybe the slight detonation killed the timing chain, stretched it out, because as far as I know the chain is original and the van has 220k.

Here is the biggest clue in everything that i think is crucial. When the van shut off and I went to restart it, it sounded like the ignition timing was off because it did the typical chevy engine start where it cranks then slows up then spins up…

Shouldnt it at least start? Ive taken off the distributor several times in the past and it always started and i timed it using a scan tool afterwards.

 

[L31MaxExpress]

Have you checked the sensor readings with a scan tool? I have seen a faulty CTS prevent an engine from starting.

Barring some weird anomaly; if it has compression, fuel and spark it should fire. Have you verified that it has compression?

 

[Schurkey]

I just finished working on the engine and nothing no start. I took the distributor out again, had someone bump start the engine until i felt compression on my finger at cyl #1 then by hand moved the crank to align with notch on timing cover.

That should be TDC-Compression for #1. Good.

The distributor has a dimple which i aligned with the line on the distributor shaft i inserted the distributor with rotor pointing towards cyl #1 as gear engaged it finished testing with rotor pointing to where the edge of the distributor has a bend.

The service manual shows the alignment marks, 6 cyl uses different mark than 8 cyl. They're marked "6" and "8". Service manual can be downloaded from links on this site. See "sticky" section in the Engine Performance + Maintenance sub-forum.

fuel pressure while cranking falls to 42 psi and then as i let go of the key it shoots up to 60 and stays there.

When the van shut off and I went to restart it, it sounded like the ignition timing was off because it did the typical chevy engine start where it cranks then slows up then spins up…

Low fuel pressure when cranking. Normal otherwise.
Cranks goofy--slow, then fast.

CHECK YOUR BATTERY VOLTAGE.
Should be 12.6--12.7 with no load.
Not less than 10 volts when cranking. More is better.

If voltage at the battery is good, verify the cable connections AT BOTH ENDS.

Engine has not run after timing chain replacement.

As said...check cranking compression. Maybe the cam is mis-timed.

But since this issue began with the engine stalling on you, I bet the original stalling problem has never been fixed.

Connect a scan tool, verify all the sensors (O2 can't be verified without getting the engine to run.)

 

[GXpress]

Have you checked the sensor readings with a scan tool? I have seen a faulty CTS prevent an engine from starting.

Barring some weird anomaly; if it has compression, fuel and spark it should fire. Have you verified that it has compression?

I have a basic scan tool with live data. When I crank the engine i see all sensors give out data. The MAP, MAF, RPM(CPS??) engine has spark and the questionable thing here is the fuel pressure i saw u posted somewhere the MPFI needs less pressure than the poppet valve system. I noticed my FP shoots to 58-60psi then drop quickly about 5 psi. Today tested fuel pressure again and it goes down to 42 psi while cranking and when i let go, it shoots to 60psi. I am debating if i should throw a fuel pump on it. I have spark air and fuel but is it enough fuel pressure to start. Once in a while, it will start but barely barely run and i give it gas and it doesnt go up in rpms

 

[GXpress]

That should be TDC-Compression for #1. Good.


The service manual shows the alignment marks, 6 cyl uses different mark than 8 cyl. They're marked "6" and "8". Service manual can be downloaded from links on this site. See "sticky" section in the Engine Performance + Maintenance sub-forum.




Low fuel pressure when cranking. Normal otherwise.
Cranks goofy--slow, then fast.

CHECK YOUR BATTERY VOLTAGE.
Should be 12.6--12.7 with no load.
Not less than 10 volts when cranking. More is better.

If voltage at the battery is good, verify the cable connections AT BOTH ENDS.


As said...check cranking compression. Maybe the cam is mis-timed.

But since this issue began with the engine stalling on you, I bet the original stalling problem has never been fixed.

Connect a scan tool, verify all the sensors (O2 can't be verified without getting the engine to run.)

By the way i forgot to add ive been working on the van with a battery charger connected so i dont kill the battery so its always topped off. It cranks really well. Do you think compression just magically went the day the van shut off? It always had excellent power until the day it shut off. No hints at anything going bad before it shut off… do u think maybe fuel pump dropped in pressure a little bit enough for it to keep it from starting? Doesnt sound plausible tho.. i think it should at least run, rough.

I am more for that the timing chain stretched

This is a video of the timing chain play:

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.

 

[GXpress]

That should be TDC-Compression for #1. Good.


The service manual shows the alignment marks, 6 cyl uses different mark than 8 cyl. They're marked "6" and "8". Service manual can be downloaded from links on this site. See "sticky" section in the Engine Performance + Maintenance sub-forum.




Low fuel pressure when cranking. Normal otherwise.
Cranks goofy--slow, then fast.

CHECK YOUR BATTERY VOLTAGE.
Should be 12.6--12.7 with no load.
Not less than 10 volts when cranking. More is better.

If voltage at the battery is good, verify the cable connections AT BOTH ENDS.


As said...check cranking compression. Maybe the cam is mis-timed.

But since this issue began with the engine stalling on you, I bet the original stalling problem has never been fixed.

Connect a scan tool, verify all the sensors (O2 can't be verified without getting the engine to run.)

This is the old distributor. For reference this is how the rotor points when the new distributor falls into place, and rotor is facing cyl#1.

 

[Schurkey]

For reference this is how the rotor points when the new distributor falls into place, and rotor is facing cyl#1.

That appears correct based on the '97 service manual, page 6A-243.

Will likely need to be fine-tuned using the scan tool--but that should be close enough to get the engine running.

WHAT IS THE BATTERY VOLTAGE WHEN CRANKING? Are the battery cable ends clean and tight at both ends of each cable? First you say it cranks fast, then slow. Then you say it cranks "really well". Which is it?

The timing chain in the video is not loose enough to stall the engine or prevent it from starting.

How old is the fuel filter? Your list of items replaced doesn't include the filter.

 

[GXpress]

That appears correct based on the '97 service manual, page 6A-243.

Will likely need to be fine-tuned using the scan tool--but that should be close enough to get the engine running.

WHAT IS THE BATTERY VOLTAGE WHEN CRANKING? Are the battery cable ends clean and tight at both ends of each cable? First you say it cranks fast, then slow. Then you say it cranks "really well". Which is it?

The timing chain in the video is not loose enough to stall the engine or prevent it from starting.

How old is the fuel filter? Your list of items replaced doesn't include the filter.

The engine originally cranked as if it were out of timing but I fixed it by re stabbing the distributor. It shows almost 11.2 volts while cranking. Cables are clean and dont show any wear or fraying.

Fuel filter was changed last week as it was recommended by a mechanic when I changed the spider system.