new issue

[scotts90ranger]

ok, went wheeling today and my truck started running BAD! like 4' fireball bad! serious rich misfire and it's fuel metering related. When running it wouldn't take any load at all, and just generally ran bad. I was of course 60 miles from home in the middle of nowhere. So I tried to eliminate things that control the engine, unplugged the ECT and it still ran bad, unplugged the O2 sensor and still ran bad, unplugged the VAM and it ran better at least drivable (I now know why they call it LIMP home mode, dang...) so that's where it is now. When it started acting up I didn't have a CEL, I'll pull codes in the morning or whenever I get up, I know there will be one or two about the VAM...

We had mostly eliminated the ignition system from being the problem as it seemed to have good spark after the VAM was unplugged. spark plugs were black but not fouled.

'86 TC engine, PC2? computer I think that's what it was.

any guesses?

 

[Davis]

one time i was out wheeling and hydrolocked the motor. it filled the intake tract with water and that in turn froze up the VAM door the next morning. i broke it loose and the truck ran fine.

 

[scotts90ranger]

this did involve a couple water puddles but nothing over 6" deep when the problem arose (I went slow as to not splash on stuff), stopped after the problem arose and didn't find anything, drove a little further and pulled the plugs and stuff, nothing looked drenched with water, pulled intake hose off of the VAM and it moved freely and looked as clean as when I put it in last.

only thing I can come up with is the jarring of the last trail I ran, 1/4 mile down hill with big rocks.

maybe I'll plug everything back in and see how it runs today after it had a chance to dry out...

 

[Davis]

another time off roading, i put a tear in the hose from VAM to turbo and that screwed things up royally. have you checked that?

 

[scotts90ranger]

looked at it, didn't see anything out of the ordinary (I don't have the ideal setup, need to replace that hose)

fired it up this morning and it ran just fine after I plugged everything back in, apparently something got wet and VERY unhappy. I'm going to clean the engine and everything up and try to clean up some of my wiring.

 

[scotts90ranger]

ok, started it up yesterday again and it's not right...

anyone have a spare LA3, large VAM and IAT with connectors?the bugs with the '86 setup are getting old... or maybe it's just a shot VAM but still I want to be able to run without pinging as much.

 

[scotts90ranger]

got a used small VAM installed and it runs!!!!!!!!!!!!

took care of a few other issues while I was there, this time I made a mount for the VAM, repainted the battery tray, fixed a broken weld on my coil mount bracket and beefed it up a little.

I'm looking forward to driving it more again!

 

[Davis]

good to hear!

 

[scotts90ranger]

put about 70 miles on it today, runs better than before! the most vacuum it pulled at idle before was 20, now it'll pull 22, will pull 25 when motoring down a hill where it used to do 22 (I know it's little, but it's a sign). And I believe I can get away with running regular gas again! the old VAM must have been iffy when I put it in... I was playing with it a bit and I think it's still getting better mileage than it had before, I'm guessing 15-17 which is better than the 10-15.

Still has some of the startup issues that it had before, the need to clear flood to start and the excessive fueling at startup (yes, related, whatever's causing it), other than that it purrs...

 

[scotts90ranger]

Ok, in early August the truck died again because it was loosing spark (like it left me stranded for 4 hours), changed coil and ignition module with my spares and still persisted... changed crank sensor and plug wires and it starts right up now.

New problem again though, runs smooth and good at most points like it should but has a lopey idle (sounds like I have a lumpy cam) with low vacuum (12" should be 20") and it's pinging at 5psi boost.

I'll drive it into work tomorrow and check the fuel pressure, see if it behaves like it should. Anyone have any other ideas?

 

[Davis]

Check all your intake piping/IC/connections for leaks of any kind.

 

[Stxrangerbumper]

Knock Sensor

 

[scotts90ranger]

Drove it to work yesterday, ran like it's supposed to, idled at 19" and took 10psi without pinging...

I must have reset the computer at some point and it was just learning monday night. I didn't have a computer at home yesterday or I would have reported back... I don't believe I have a knock sensor, it's probably that one sensor I don't have plugged in. I don't have an IC either, it's on the list...

ok, now to go wheeling! except I'm still broke, and need to do some more projects...