wouldnt hurt to at least check the timing

 

Haven't checked timing on one of these motors in an while. Can I get a quick run down?

 

Just finished ohming a few sensors, and the MAP sensor (the junk yard replacement) failed. Hoping that this replacement will fix said above problems.

 

I bench tested the map sensor and it functioned correctly under a vacuum pump. When installed on the motor however, it read as expected at idle. But, when opening the throttle in park, it indicated that vacuum did not increase as I assume it should from the motor sucking in more air. It actually went down. I'm going to do the fuel pump since I already ordered it to see if that remedies the fuel pressure drop off. Also going to do a.cylinder compression test because I'm starting to suspect the motor itself might be not doing so hot.

 

vacuum goes down when u hit the throttle because the throttle blade is open to not allow vacuum to build. Highest vacuum is at high rpm with the throttle closed. (Ex: right after you rev the engine and release the throttle). Since your fuel pressure still drops off then the fuel pump isn't holding pressure or something didnt get put back right.

 

Compression test sat. 165# on all cylinders except 4, at 155#, which should be fine. Bed is off awaiting new fuel pump.

 

So I replaced the fuel pump, and found some ghetto rigged stuff. If you look at the picture closely, there is a hose clamp right above the damper on top of the pump. It was supposed to hold the damper down on the pump (which they probably replaced) but didn't do a good job. To sum it up, the pump was pumping a lot of gas right back into the gas tank. Won't be able to test drive it for a few days, but the fuel pressure test was phenomenal, only dropped to 40 psi after as few minutes of the pump being off. Also found a missing o ring for one of the pressurized lines coming from the pump. Fixed that too. Always hate how its the last part you replace that fixes the problem.

Thanks for all the help!