1993 Chevy Astro NO START, POSSIBLE TIMING ISSUE

Tiny
POET042005
  • MEMBER
  • 1993 CHEVROLET ASTRO
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 167,000 MILES
Where DO I start I recently replaced my 93 4.3 astro's engine with my 92 astro engine. All the wiring and major connections in the 93 were reused including the upper intake. Of course I had to remove the distributor in order to replace the upper intake. Now the 92 motor I must admit sat outside a full year not in use but before it was removed from another van I had it ran and ran good. But now I have it completely installed in the 93 astro and I cant seem to get it to start. I thought it was the timing at first because I could see that the spark plugs were socked in gas from trying to start the van meaning its getting gas and the coil sparked a good blue spark as I tested for spark. I have done the timing set procedure over and over again (#1 cyl to TDC by setting timing mark and aligning rotor with with #1 on distributor cap) but it will not start motor kept choking as if timing was off any advice would be helpfull. Just hoping I have missed somthing anyhelp would be great let me no Rich.
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Thursday, March 12th, 2009 AT 5:35 AM

8 Replies

Tiny
BMRFIXIT
  • EXPERT
If you have fuel and timing is ON
and not 180 off
firing order OK
my next step would be compression test
if compression is good
than I have to say timing possibly OK
and back to the distributor and firing order
let me know
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Thursday, March 12th, 2009 AT 6:31 AM
Tiny
POET042005
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I will be doing a compression test today. What is your opinion on this, before I installed the motor I took the rocker arms off and noticed a few of the rockers had a little excessive play in them, although I no they are to have some play in them, I tightened a couple up but without over tighting them, just to take up some of the slack. I always thought based on experience that even if the rocker arms are distrubed without the engine running it would still start up after the work has been finished. I'm wondering if this is my no start problem, what do you think?

I'll let ya no about the compreesion.

Rich
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Friday, March 13th, 2009 AT 5:23 AM
Tiny
BMRFIXIT
  • EXPERT
Hi rich
lets wait and see what the compression test brings
as for the rockers loose I would ve left them along until after the engine start, there because engine sat for a year before you installed it, oil will drain from the lifters causing the slake
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Friday, March 13th, 2009 AT 6:12 AM
Tiny
POET042005
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Ok heres the results I found after doing the compression test.
Cyl# 1's compression was 150psi,
Cyl# 2 was 125psi,
cyl #3 90psi,
Cyl# 4 was 90psi,
Cyl# 5 was 60psi,
Cyl# 6 was 150psi

After getting these readings I tried adjusting the rockers on cylinders 2, 4 and 6 and then re-tested the compression on those three only to find the same readings, possibly 3 to 5 points down but for most part the same.

Would you agree that rings are the problem or am I missing something else.

Rich
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Monday, March 16th, 2009 AT 5:21 AM
Tiny
BMRFIXIT
  • EXPERT
Very loose valve and or over tight valve will give low readings too try this 1st
and than do a wet compression test as add adding a bit of oil in the cylinder and than do the compression test
1. Rotate engine until No. 1 piston is on TDC of compression stroke. Loosen rocker arm adjusting nut until lash is present.
2. Tighten adjusting nut until lash is removed. Tighten adjusting nut one full turn. Adjust remaining valves (for piston at TDC) as listed below
3. Rotate crankshaft 360 degrees to bring No. 4 piston to TDC of compression stroke. Adjust remaining valves.
Piston At TDC Intake Exhaust
********No. 1 No. 1, 2 & 3 No. 1, 5 & 6
********No. 4 No. 4, 5 & 6 No. 2, 3 & 4
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Monday, March 16th, 2009 AT 6:21 AM
Tiny
POET042005
  • MEMBER
Well I readjusted the valves as instructed but the compression remained around the same numbers. After I did the adjustment and checked the compression I did a wet test on one of the cylinders and it increased from 90psi to 118/115psi.

I really appreciate your help in all of this. I figure I will just replace the piston rings and bearings while im at it.

But I got another question 4 you, I don't own the gauge used to measure the cylinderbores with but because there is signs of piston were do you think its a good idea to use piston rings one the very next size above the standard ones I think the size is like.010 0r.020. If not then I'll just have to invest in a gauge.
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Tuesday, March 17th, 2009 AT 7:48 AM
Tiny
BMRFIXIT
  • EXPERT
My suggestion is to check with local rent tool center Or part store as they my have one u can rent verse buying it or check local shops as they may have one that they will let you use

if not go for it and get your self a new one
good luck
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Tuesday, March 17th, 2009 AT 4:59 PM
Tiny
POET042005
  • MEMBER
Well I'm back after all this time and again at a brickwall. I pulled the heads off the motor and pulled the pistons to find that all the pistons rings were damaged or stuck within the 6 pistons. Because of this I did not replace all the rings only the damaged ones, I replaced the rings, cleaned the pistons oiled the rings and pistons and reinstalled them into the block. I also replaced the heads with used heads that came off a running motor. Only two of the valves were disturbed but these heads (off 93 astro) seemed to have the valves that adjust only as far as the valve bolts would let them (tighten only so far). Everythings been put back together but I still can't get it to start. It keeps poping somewhere when I crank the engine as if the timing is still off but I called myself reseting it 15 different times thinking that was part of my problem I had to at first figure out which mark on the damper was for #1 TDC, I did the finger over the spark hole trick to find it. Someone told me that number 1 on the dist cap is at the 5 o'clock place facing the motor from in side the car I though it was the third top left corner prong. I thougt even though I no rotor must face #1 plug wire but then wondered is the cap to be positioned a certain way in order to start.

I am going to do a compression test which I have not done yet even though the crank turns as if it has good commpression. What range should the pressure be within the cylinders and the variations between them.
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Friday, May 1st, 2009 AT 5:59 AM

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