87 Chevy 5.7 will not run while in gear

[riverbanks]

Took me a bit to find it,www.fieros.de>code42,it's all there

[87chevys5.7]

That is a lot of good information, but have been through all of what he was saying.  I ran the truck today with a vacuum gauge on it and it is pulling 20 to 21 inches at idle.  Then when I rev it up to about 2k or so, it drops to 15 inches then comes back to 19 inches.  I am assuming through timing and iac position.

[87chevys5.7]

What do you mean by screw contacts?  I am waiting for the engine to cool down now and will re-gap them, and let you know.

[riverbanks]

The module hold down screws,and you mentioned the plug wires,do a spark leak test,keep hood as low as possible,peek in,look for arcing,

[87chevys5.7]

I did not find any leaks in the wires and the module screws are good.  I did finally get my data logger in so I could log some data.  See what you think.

16_46_26_analog.csv

16_46_26_malf.csv

 

I ran it for a bit, revved the engine for a bit, stopped it and started it, then once I saw the loop closed, I put it in gear the truck still died.  I am not sure if it fell out at the same time or not.  I cannot tell.

Edited July 7, 2019 by 87chevys5.7
more description.

[riverbanks]

Can't open file

[87chevys5.7]

Try opening it with excel, that is the program it opened up.  If that does not work, then I can save it as an XLS file

 

Analog.xlsm

Malf.xlsm

Edited July 7, 2019 by 87chevys5.7
Added excel sheets

[riverbanks]

Got the second one to open,90% blank, but the first column showed a drop big-time,blm or integrator,can't tell,you still got a code 42?I would check all wires,a guess is you are shorting to ground somewhere,02 wires,oil pressure sending unit?

[87chevys5.7]

I am not sure why the file will not open.  I am thinking it could be a shorted O2 wire.  What I did find was that when the engine is at about 2k RPM, it goes into learning and it surges.  It goes from really rich to really lean on the readings.  Whether or not the the loop is open or closed it does the same thing.  

[87chevys5.7]

Ok, sorry I have taken so long to update this, I got laid off and put a lot of my truck work on standby until I started my new job and got rolling.  

 

So, I replaced my O2 sensor and got the sensor to start reading properly (that did not fix it), I replaced my spark plug wires with resistor type wires to ensure no EMF interference, I pulled my distributor to inspect the pick up coil and noticed that the magnets were not very strong.  When I took it to the parts house to compare, there was an obvious difference in magnet strength so it would not be able to create the proper sensor voltage.  I replaced it and found that the crank sensor pulse is switching from "No" to "Yes" randomly.  I am not sure why that would happen.  I looked at the previous logs and found it was doing the same thing.  At this point I was able to put it into drive without it dying. 

 

Now, I can drive it for about 20 seconds and the fuel cuts off.  I shorted the oil pressure switch to make it close to ensure that a faulty sensor was not the problem and it still cuts out in drive or idle.  After looking at the wiring diagram, there is a "Hot Fuel Module" that is wired in with the relay and the oil pressure switch.  I have no idea what it does or where it is located.  Everything I have found says it is by the steering column on the fire wall under the dash.  However, I have not been able to locate a box that has only 3 wires going to it.  

 

Do you have any insight?

[massbowtie]

Check the distributor. The shaft wears and causes that condition. Had an 87 5.7 blazer that would die if left in gear at idle. Put it in neutral and it was fune. Truck had no other symptoms but stalling in gear at idle. Pull the cap and check for play.