EvstaG

Oh I think you just have the names backwards then.. Open loop is for engine warm-up and WOT the like, using the information as you described. Closed-loop is when there is a closed feedback circuit with the O2 sensor and others, thus closed loop for idle and "normal" operation... This is according to the FSM for my 89' at least. But anyways-enough petty conversation ( I just didnt want there to be confusion) and back to getting your problem dealt with!

damageincracing

Dang it, yeah I had it backwards. It's been a long couple of days and my brain is a little scrambled...

damageincracing

Ok, todays little episode with the Jeep... Changed the O2 sensor, reset the TPS (had to leave it just a hair off- I was a bit rushed, but that's a story for the Turbo Dodge site...), and fired it up. Shut it back off, unhooked the better so the idle would reset (doh!), and fired it up again- Idled fine, not perfect, but much better. Took it for a quick spin through my shops lot, and there has been a vast improvement, but something still is not quite right. Drove it home (back roads again) and it still stumbles a little, but nothing compared to before (scale of 1-10, I'd give it a 7). If I hit the gas hard (not stomping on it) it seems to pick up ok at first, then when it shifts it stumbles. Noticed this happens mostly into third, then it seems to rev high before it shifts into 4th. Once the overdrive kicks in, it's good for a little bit, then it will stumble. If I push down on the gas to get going (or when I'm trying to go up a steep hill) it seems to hesitate and lose power really bad, like it's choking out. This is what it was doing LAST week when I thought it had bad gas. I'm going to try and hook it up to the scanner at work and get another "live data" list again. I'm also going to try to pull the plugs and do the "redneck timing chain check"- put it in neutral, pop the oil cap, and turn the crank by hand and see how long it takes for the rockers to move.

Once I got home from work, we had to go to the store (down the road from my work). When I tried to start it, it didn't want to fire. It would crank and ALMOST catch, but it took about 5 minutes to get it fired, and when it fired, it idled ROUGH. I burped the gas, it cleared out, then idled fine. I DID notice a miss right after this, but it cleared out and I didn't notice anything after that. That was the only time it did it. Started good (as good as it ever did, anyway) after that. I did notice on the way back home from the store tonight it seemed to run better. It still had some sputtering, but it didn't seem to hesitate. This was over roughly over the last 2-3 miles of the trip.

STILL trying to get hold of a pressure gauge, too...

damageincracing

*bump*

cruiser54

No bump. Fuel pressure test. Go from there.

damageincracing

LOL! I think I'm going to have to bite the bullet and buy myself a fuel pressure tester. CRAPA has one listed, so I'm going to stop in after work today and buy it IF it has the fitting.

On a brighter note- only stumbled once on the way to work this morning (back roads again). No shift issues, no falling flat, no having to "clear it out", so there is much improvement. Still gonna pull the live stream before I leave work and do all the other checks after I get home. I'll post findings later...

cruiser54

I think they're $45.

damageincracing

Yeah, that's what I saw. Plans for later are a little sketchy now- calling for rain all afternoon, and I have no garage... Figures...

damageincracing

Ok- todays scanner live data. Pulled under the same conditions, cold start, ran long enough to pull info. Running MUCH better.


RPM- 800ish
O2 v- Bouncing (switching)
Inj. (mS)- 7.7
Loop- Closed
Exhaust- Bouncing rich/lean
ST Fuel Trim- 180 (bouncing)
LT Fuel Trim- 166
MAP SNSR (V)- 2.0
MAP (kPA)- 49
MAN Vac- 52 (missed this on the first live data)
TPS (V) .82
Throttle (%)- 16
Throttle SW- Closed
Fuel Sync- "+"
Coolant- 53C
Charge Temp- 33
Knock- 0
A/C Switch- Off
A/C Request- No
Battery Volts- 13.9

Fuel pressure test coming later today...

cruiser54

Looking better. How fast is the 02 sensor switching and what are the low and high numbers?

damageincracing

It's switching FAST. As for the numbers, I can't get a good read (since it's switching fast), but I saw "0" for a first number a few times, and "4" for a first number a few times. All seems to be well with IT at least... Fuel pressure, not so much... Got the gauge and fired her up (after much cranking and a good kick on the gas tank- hint hint)... I get a whole whopping 16 psi. Unplug the regulator- no change. Good news is, I already have a spare fuel pump... Bad news is, I just put another 10 gallons of gas in...

Not only am I having issues with my Jeep, the rear cam seal on my wifes 88 Shelby Z went south and it's dumping oil out of the rear of the cam... Man... I just can't catch a break...

cruiser54

[QUOTE=damageincracing;1717914]It's switching FAST. As for the numbers, I can't get a good read (since it's switching fast), but I saw "0" for a first number a few times, and "4" for a first number a few times. All seems to be well with IT at least... Fuel pressure, not so much... Got the gauge and fired her up (after much cranking and a good kick on the gas tank- hint hint)... I get a whole whopping 16 psi. Unplug the regulator- no change. Good news is, I already have a spare fuel pump... Bad news is, I just put another 10 gallons of gas in...

That's a real good oxygen sensor then!!!

What's your fuel gauge reading?

damageincracing

I went with the OE Delphi sensor, it better be good! LOL!

Gauge reads 3/4 tank. Replaced the sending unit about a year and a half ago- wasn't reading anything before. Unfortunately, I cant get into the return line to pinch it off to see if pressure rises. If I give it gas (moving throttle linkage), pressure remains the same. If it's the pressure regulator, I'm just going to spend the little extra and get the regulator for the "neon" injector mod (using the Ford 19lb injectors).

I did find out that fuel pressure drops to nothing as soon as the engine is cut off, so the check valve is gone...

cruiser54

Sounds like time for a pump.

damageincracing

That's kinda what I figured after seeing the pressure readings. Luckily I already have a spare, I just can't change it until Monday at the earliest- We have a fuel pump for draining a tank and a tank jack that is going to make this a LOT easier than last time...