Engine cranks/turns over but won't start

[vipersinu2]

1st lets see if the passenger cam shaft is spinning. Remove the oil fill spout and have someone crank engine over. See if the cam shaft lobes are moving.

 

[shucker1]

That's why we are all here...

 

[robbiwan]

It seems my spark plugs are fouled.

I also did a compression test. I did the compression test with all coils and
spark plugs out. Wonder if that is the reason why i got low compression.

Cylinder 1 = 90 psi
Cylinder 2 = 60 psi

Will do the rest of cylinder test tomorrow.

I disconnected black box in the engine near the passenger compartment;so,
i can get to the last spark plug. Wonder what that is.

 

[vipersinu2]

Hello you say cylinder 1 & 2, are you testing cylinder 1 & 4?

If cylinder 1 front passenger side is at 60 psi. Did you verify thru oil fill tube that the cam lobes are spinning. That low compression can be a valve half open and compression escaping thru the open valve.

The pistons are going up and down creating compresion, if the cam shaft in the head is not turning because of a broken timing chain you will have low compression because of a valve half open.

To answer your question about checking compression with all the spark plugs out.
You can check compression will all of the spark plugs out. If there is no crack in head or cracked in the head gasket, Each cylinder should have it's own compression chamber and not interfear with each other.

Did you have the timing chain rattel on start up?

Definitely check those cam lobes for movement and let us know.

 

[shucker1]

Fouled plugs will not cause low compression but looking like they do I doubt you are getting any spark.

After you first compression test recharge your battery and re run the test after putting some oil in each cylinder through the spark plug hole.

No much oil, perhaps 1\2 - 1 Oz?

Increase in compression pressure after putting oil in the cylinder would indicate worn rings.

No increase in pressure would indicate valve train issues. I.E. Slipped chain, Bent or Burnt Valve.

 

[robbiwan]

hi Viper, Shuck

I checked the cam lobes, they seem to be not spinning after the engine cranks.
I am thinking of loosening a bolt in the exhaust because i suspect it might be a plugged exhaust as a last resort.

Here are my compression results i redid it with all plugs out. There is compression in all cylinders! I am starting to feel this engine is bewitched.

1 = 120
2 = 100
3 = 110
4 = 110
5.= 125
6 = 100

I replaced all the spark plugs and same effect. Just cranked and no start.

I do not have oil with me, i will try to get one and do another compression test.

I see a lot of fuel in the fuel injectors they are very soaked with fuel. I found a discount noid tester at amazon at a great discount. Will arrive by next week.

I had a rattle yes, but that rattle seems to come from the catalytic converter; it may seem to be the timing chain after all.

 

[vipersinu2]

The cam lobes not spinning is a very bad thing, it's not worth fixing. Very expensive.
You will need a new engine. A used engine will be easier and cheaper.

To fix those timing chains, the engine needs to come out. So just swap engine.

 

[robbiwan]

The cam lobes not spinning is a very bad thing, it's not worth fixing. Very expensive.
You will need a new engine. A used engine will be easier and cheaper.

To fix those timing chains, the engine needs to come out. So just swap engine.

Thank you Vipersinu2 for all the help. God bless.

 

[shucker1]

If you had a bad cam or broken chain those compression numbers would be way different.

I replaced all the spark plugs and same effect. Just cranked and no start.

Did you install new plugs or put the same ones back in the hole? I don't think those old plugs will fire with all that goop on them.

I see a lot of fuel in the fuel injectors they are very soaked with fuel.

Next go around you may want to crank it with the plugs out for a while.

You may have so much fuel laying around in there the mixture is way too rich to burn.

P.S. While cranking hold the accelerator pedal full to the floor.

WOT (Wide Open Throttle) during cranking should shut the fuel injectors off.

 

[vipersinu2]

I replaced 3 of these sohc engines for broken or slipped chains, For the cam shaft on the passenger side. That chain seems to fail 1st. It is sandwiched between engine and transmission. So the engine needs to be pulled to work on it. And if those chains were rattling for a long time who knows what other damage might have happend.

When you thought the exhaust was rattling it probably was your timing chain between the engine and transmission.

Between parts and machine shop time rebuilding the head, you can find a donor engine cheaper.

Once I got lucky and found an engine from a roll over with 1800 miles on the truck, I got the engine for 1200 bucks.

Any 4.0 sohc block will work, you will just have to swap over your parts.

If you decide to swap the engine, buy new orings for the air intake. They leak air and you get a vacuum leak.

 

[FR-425]

The definition you have for p1121 is also misleading. p1121 is set if the correlation between the TPS and the MAF do not agree.

This can be do to an open or shorted circuit i.e. a broken wire (rodent damage), crusty green corroded connections or chaffing.

It can also, and this is most likely, a bad MAF. Easy way to test this is to unplug the MAF then clear the code. (the PCM turns of the injectors in this situation to prevent uncommanded wide open throttle) Then the engine will start on the default fuel strategy. It will run rich as hell and badly but it will run. However if you do have a shorted wire anywhere on the 5 volt reference you may not learn anything from this test. A good visual inspection of the wiring may be time well spent.

This condition in my experience is the MAF shorted to ground internally. Or the resistor element is actually broken, which you can easily see visually.

 

[vipersinu2]

The definition you have for p1121 is also misleading. p1121 is set if the correlation between the TPS and the MAF do not agree.

This can be do to an open or shorted circuit i.e. a broken wire (rodent damage), crusty green corroded connections or chaffing.

It can also, and this is most likely, a bad MAF. Easy way to test this is to unplug the MAF then clear the code. (the PCM turns of the injectors in this situation to prevent uncommanded wide open throttle) Then the engine will start on the default fuel strategy. It will run rich as hell and badly but it will run. However if you do have a shorted wire anywhere on the 5 volt reference you may not learn anything from this test. A good visual inspection of the wiring may be time well spent.

This condition in my experience is the MAF shorted to ground internally. Or the resistor element is actually broken, which you can easily see visually.

FR-425, How is this engine ever going to run if the cam shaft is not turning on the passenger side?

 

[shucker1]

@vipersinu2

1 = 120
2 = 100
3 = 110
4 = 110
5.= 125
6 = 100

How can his compression numbers be so consistent if the cam is not turning on one side?

The OP would have smashed a valve by now leading to low compression numbers on a least 1 cylinder.

 

[vipersinu2]

@vipersinu2



How can his compression numbers be so consistent if the cam is not turning on one side?

The OP would have smashed a valve by now leading to low compression numbers on a least 1 cylinder.

These valves are non-interference.

 

[shucker1]

So at least one should be open at all times correct?

 

[vipersinu2]

It's been a while since I tore down one of these heads, I know cam shaft springs into place if there is no chain holding cam gear in time, what position the valves spring into open or closed I do not know.

 

[massacre]

Don’t they make tools to hold the cam in place?
Aren’t there followers or lash adjusters you could remove so all valves remain closed?

 

[FR-425]

Misunderstood though he said the cam was turning.

 

[vipersinu2]

Agreed kinda vague, Robbiwan say "they seem to be not spinning after the engine cranks"

When cranking engine cam lobes should be turning.

 

[shucker1]

Don’t they make tools to hold the cam in place?
Aren’t there followers or lash adjusters you could remove so all valves remain closed?

Correct but the heads are still on the truck.

The timing chain would completely have to snap to keep the cam from rotating. What's left of the chain would wad itself up inside the engine somewhere and really make some noise.

Didn't see any mention of that.

Possible that the bolt on the back side of the cam snapped and the sprocket is just spinning on the camshaft.

Even with that possibility one valve should be partially open causing low compression on the RB side..

O.P. said he has spark. Therefore we can surmise that the cam synchronizer, attached to the RB cam, is indeed sending a signal to the ECM to fire plugs.

If the cam were not spinning he should get a no spark condition and a fault code to go with it.

I'll follow the lead of @FR-425 and feel we have a wiring issue somewhere.