Just starting to diagnose some driveability issues my relatively 'new to me' 92 22RE is experiencing.

I recently discovered the engine had ~25* or so base ignition timing. It's been like this since i've had the truck, ~ 2000 miles or so. A recent compression test shows #'s 2 and 3 way down on compression. Cam timing is spot on, so without a leak down tester i'm guessing a couple roasted valves or maybe i don't have any ring lands left/compression rings...

Anyone care to take a guess how these typically behave with that much base timing?

Thanks,

Matt

 

Not to be to much of a #ick to ya but do a search. Also if any moderators see this it would be nice to have a sticky to tell noobs how the timing thing works. This is brought up about 10 times a day!!!

Your TPS (throttle position sensor) is out of adjustment so you are not going into base timing (jumper connected for diagostic mode TE1-E1). IDLE and E1 terminals (I think that is what it is called) on the TPS must be a closed switch in order for the computer to give base.

When idleing that is what you get (20 somthingish advance) when the computer has control.

 

Check your valve adjustments. It has a very strong impact on compression readings.

 

They don't run well when advancing the timing that much.. Unless something else is wrong.


What is it with the timing posts this week?
Check:

1) Check your TPS adjustment (it impacts timing) - google "4crawler tps" for the right procedure.

2) Check your plug order. Make sure that when you're at TDC and the cam dowl is 11-12 o'clock that you're pointing to the #1 cylinder on the distributor.

3) you know to get base timing, you've got to jumper connectors, right?

 

I do appreciate your effort, and i do realize how 'noobish' questions can become very irritating, i've experienced it many a times myself.

I should have expanded more upon my initial description. I had already replaced TPS with known good TPS, and re-calibrated, then reset base ignition timing to 5* with the diagnostic jumper. Cam timing and lash are spot on. Nevertheless, I am down on compression on #2 and #3, period. I have a spare block and head, just wasn't quite ready to get into a new build.

So, i do thank you for your effort.

Regards,

Matt

 

my distributor did the same thing. It was at like 36deg. and wouldnt give me base timming when jumped.

I swaped in another dist. i had, and now it gives me base timming when shorted and is only at 10deg when not shorted.

why is the compression low? possible head / gasket if its low in 2&3. burnt vales?
hows the compression in the other 2? if they are heathly why not just pull the head and see whats going on. head gaskets are easy.