If so, take a look at this and if you need more stuff selected, just let me know.

This is a capture of an attempt to hold a steady 1500 rpm's. If you notice, the rpm's drop to about 1300 with no change in throttle position. After the trigger point, all i did was take my foot off the gas and the rest was all computer/motor.

Listed are all new: Plugs, wires, cap, rotor, air filter, fuel filter.

Fuel pressure is 42.5 after priming the fuel rail and 39 when idleing. WOT goes to about 50 (I say about because it was late and I didn't want the hippy neighboors bitching )

I didn't put any load on the motor with the pressure gauge because I didn't want to lose my alternate side of the street parking.

If you have any thoughts, ideas, hints, questions, just type them in.

Thanks,

Scott

 

This is in park with no load?

 

Yup. Neutral and no load.

Happens everytime without fail and no codes are thrown.

It also happens in the entire rpm range meaning I could rev to 4000 or 1000 rpm's and take my foot off the gas and the same thing happens.

I also noticed something last night and today, my fuel pump doesnt prime everytime I cycle the key off/on and, with the key on and the motor off, my oil pressure gauge "twitches". It's just a little and it doesn't move out of the red but it shouldn't twitch. It doesn't twitch with the motor running.

From my understanding, that switch is connected to the fuel pump no? If so, how much control does it have?

I'm stumped.

 

Post more of the scanner data, or record some more and list the data. Sounds like a mechanical problem. Is your tach needle bouncing at all? How does it drive under load?

 

What other options would be good to list? Better yet, when I get home, I could post up a comma delimited (Microsoft Excel or something comparable) file from the same scan.

Let me know.

Crap, I hope not.

At idle, barely. When reved in neutral, you can see and feel the fluctuations.

It's got pull when I hammer it, but if I'm just cruising along in the 900 to 1500 rpm range, especially in the lower gears, it bucks. Cutting out or missing is the first discription that comes to mind.

If I do the rev up then idle thing, about 25% of the time, it will stall. So if I'm in traffic or I'm paralllel parking, theres a chance of stalling.

Still stumped.

 

I'm back with something new.

First, this is a spreadsheet of the same scan

Auto X-Ray Scan Data

and second, now when it revs down to an idle, it really feels like something rotational is off balance. It's weird but as I was looking at my scanner, everytime the ECM learn mode was enabled, I would feel the imbalance (or whatever it is) but as soon as the learn mode was disabled, it would go away.

Good thing the weekend is going to be nice.

 

FWIW-

I just glanced at the Excel sheet, and notice:

1. You have no O2 sensor activity
2. Your fuel is flat-lined pig rich.

The two may be related; may be data error; or may be actual and individual phenonena.

In any case, that's where I would start looking for your idle problems. HTH

 

The blm's are at 108. You need to check for vacuum leaks in between gaskets, vacuum lines, etc. See if you can tighten all intake and runner bolts and more. How old is the o2 sensor?

 

I tried to change the o2 but it's tough to get to and it's nearly welded in there. At idle, there is o2 activity so I thought that was ok.

I thought a vacuum leak made the car run lean no?
Now I'm really confused.

Well, again, at least it's going to be a nice weekend to work on the car.

Any ideas on why the learn mode being disabled smooths out the idle?

 

I'm leaning toward vacuum leak and I'd check the fuel pressure regulator diaphram.

 

First of all, I'd like to thank everyone who tossing in their ideas and thoughts and next up...


There's no fuel in the vacuum hose of the regulator and the fuel pressure gauge didn't show any signs of pressure loss when the pump wasn't running.

 

Ok. So I lied. Over a 15 minute period, the pressure fell from 42 to 39. I tested the pressure with the fuel feed hose pinched and it lost about 1 over 10 minutes.

I then tested the pressure with the return line pinched and lost about 3 over 10 minutes.

I also drove around with the pressure gauge hooked up and the pressure is solid at 39 and jumps to 44 when hammered.

Assuming that the pressure loss stated above is normal, because I really don't know how long it's supposed to hold, could low fuel pressure cause improper fuel atomization, and in turn, incomplete combustion?

Scott

BTW, the fuel pressure rises when I stall or the rpm's wander around like in the graph. I guess that's from lack of vacuum on the regulator but at least it's not stalling because of fuel starvation. Maybe ignition?

 

That fuel pressure is normal, I can't remember whats an acceptable leack down rate, but that small of an amount shouldn't create the problems you have.

Doctor J is absolutely correct, Your BLM's and INT's are maxed out and you have almost no o2 sensor activity. Your fuel pressure is good. I have no clue about the MAP stuff, i've never tuned one. BLM's being a mile off like that can cause the problems your describing alone. This may be why it seems to run ok WOT. How did the plugs look when you pulled them out? I doubt its the injectors, but its worth checking I guess. A bad vacume leak should caused the BLM's to be maxed out at 160, but I think you should probably check for vacume leaks as well.

Also, I doubt its part of the problem, but my fuel pump voltage is almost always higher than my battery voltage, and yours is about 1 V lower across the board. I'm guessing its my car thats off, but maybe somebody else could share their scans.