All 4 Cylinders Have No Compression

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ACEGOLFCARTGUY

Cartaholic
I'm hoping somebody could help figure out what went wrong with the engine in my 91 Toyota pickup. All 4 cylinders have no compression. I swapped the engine in last year and also replaced the timing chain about 1000 miles ago. It has been running great ever since until one day after school it wouldn't start. The engine didn't quit running while I was driving, instead the problem happened when I tried to start it up.
The engine sounds like it turns over way to easy and doesn't even attempt to fire. It is getting fuel and has spark. I did a compression test and all 4 cylinders have 0 psi. I pulled the valve cover off to look at the timing chain and its still on there.

Today I checked the valve lash and they were all way off. I noticed the compression felt and sounded weak as I was setting it to TDC. After adjusting the valves I'm not sure if its just me but it feels like there is more compression and it also makes a woosh. I tried again with the compression tester but it still showed a flat 0 psi.

I bought a new compression tester to rule this out but the results were the same. It sure does feel like its making compression now but why wont it show any psi?
 
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ACEGOLFCARTGUY

Cartaholic
Tried it one more time and I got 180 psi in the last cyl, 0 in all the rest. Would this indicate a head gasket problem or cracked head?
 
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DWscott

New Member
Sounds like you have your timing slipped as you said the valve lash was way off and you have no compression? Have you checked timing? I assume that the valves are moving as you checked lash, so must have slipped a notch. I have seen alot of that in later model autos. Timing belts if used go bad on Toyota more often than some other makes? Not that familiar with 91 toyota so could be wrong??
 
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johnny9

New Member
i think dwscott is correct..all tho im a chevy kinda guy it sounds like it jumped timeing for sure..id be carefull turning it over so you dont bend some valves if you havent already done that..
when i was young i put a 4 barrel carb and intake on a 200,000 mile mote carlo that had a 2 barrel carb,my dad said son,your makeing a big mistake,its possible it will jump timeing doing that..yeah right i said..damed if when i fired it up and hit the gas it jumped time..i think he cursed me cause ive done this before without a problem..to this day i always wondered where he herd that from and how it happened to me..still dosent make sense except that he musta had a voodoo doll of my car or something,haha,john
 
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85lebaront2

New Member
I hate to say it, but if it is the 22 or 24R engine and the timing shifted, you probably bent some valves. With the valve cover off, carefully turn the crank till you are at TDC. At this point, first, the distributor rotor should be pointing to either #1 or #4 plug tower on the cap, second, either #4 or #1 (opposite the distributor position) should have the cam lobes up with both rockers slightly up over the cam. The opposite cyl. will have the lobes down. If this is not the case, you have jumped time. You didn't say which way the lash was off, if it was loose, that is a good indication of bent valves.
You didn't say if it is automatic or manual. If it is manual, you can position each cyl. in turn to TDC, put the truck in 5th and set the parking brake. You can do a rough leakdown test at this point with air. Listen for where air escapes, intake or exhaust, bent vales or way out of time. Good luck with it!
 
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ACEGOLFCARTGUY

Cartaholic
Its killing me to know what the problem is too but I haven't been able to fix it yet. The other day I pulled the valve cover off again and checked if the timing chain had jumped a tooth. From what I could tell it did because when the the crank is set at TDC, the camshaft timing mark was at about the 3 o clock position. How would the cam get ahead of the crank if the crank is what turns the cam? I set the cam mark back to 12:00 and checked compression which is still at 0 in the first 3 cylinders, #4 is the only one with full compression or any for that matter.

I want to drop in a remanufactured engine for $1200 but really would like to know what went in the old engine just as much as I want the truck to run again. :dazed:
Oh 85lebaront, the valve lash was way loose. This looking like it bent some valves?
 
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DWscott

New Member
I dont think you will get compression back until you pull the head and replace bent valves and or pistons? The damage was done in just a few seconds of operation. I have seen rods broken off from just the same happening but thats an extreme.
Just wondering, keep us posted when you have time.
 
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ACEGOLFCARTGUY

Cartaholic
I'm curious if you normally feel the engine jump timing and bend the valves while its running? Can this also happen when you go to start it up? The engine was running good, I turned it off and it wouldn't start again. I never heard any clunks or noises... it just refused to start.
Thanks for the help and info.
 
Nubs

Nubs

Cartaholic - V.I.P.
if the valves were bent you would have compression coming though the carb! unless only the exhaust valves bent, and i think thats unlikely. :twocents:
 
Nubs

Nubs

Cartaholic - V.I.P.
99% of the time a timing chain or belt will jump when the engine is shutting down.
 
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