Very rough idle, Wb lean, and more "datamaster log inside"

pearl91chevy

pearl91chevy

Donating Member
Re: Very rough idle, Wb lean, and more "datamaster log inside"

checked the blowby out the oilfill tube 0966, still normal.. no smoke or anything
 
G

GM TURBO

Sell Out
Re: Very rough idle, Wb lean, and more "datamaster log inside"

FPR is on the fuel rail. No need to drop the tank.
 
Slyclone

Slyclone

Well-known member
Re: Very rough idle, Wb lean, and more "datamaster log inside"

My truck does or did the same your describing. I have gone through the procedure of replacing everything.

My oil is still gas washed out. Even with a brand new fpr

I have large black dot simmilar to your black spot on ground startup, my a/f ratio is like super rich I think I fouled out the new sensor....the filter when you replace make sure you blow the opposite side out into a clean towel or clean cloth.this will allow you to examine the back up or see what could be restriction the filter. I gave a quick toot on mine and it was horrible. Doing that I know I did mend something.

Check your plugs examine them get new ones maby you cooked yourelectrodes
 
pearl91chevy

pearl91chevy

Donating Member
Re: Very rough idle, Wb lean, and more "datamaster log inside"

Slyclone said:
My truck does or did the same your describing. I have gone through the procedure of replacing everything.

My oil is still gas washed out. Even with a brand new fpr

I have large black dot simmilar to your black spot on ground startup, my a/f ratio is like super rich I think I fouled out the new sensor....the filter when you replace make sure you blow the opposite side out into a clean towel or clean cloth.this will allow you to examine the back up or see what could be restriction the filter. I gave a quick toot on mine and it was horrible. Doing that I know I did mend something.

Check your plugs examine them get new ones maby you cooked yourelectrodes
Click to expand...


my af is all over the place lol i have another sensor i could throw in for shits and giggles.. and sucks i just replaced the plugs maybe a month ago but will do so.. was the filter bad on yours then and replacing fixed the problem?
 
e95 Ty

e95 Ty

New member
Re: Very rough idle, Wb lean, and more "datamaster log inside"

Did you pull your plug wires of and ohm them yet? Check boots/wires for burn through? Again just one more thing to rule out. The wires should come out periodically to be checked anyway....
 
Slyclone

Slyclone

Well-known member
Re: Very rough idle, Wb lean, and more "datamaster log inside"

No. Was not the problem nor the fix. I parked my truck.


If you didn't look at your plugs recently I'd check them out.it is a real pain but maby it will lead you in the right direction.
 
e95 Ty

e95 Ty

New member
Re: Very rough idle, Wb lean, and more "datamaster log inside"

Pull the front wheels and pass side fender well off, plugs come out easy....
 
randy merritt

randy merritt

Donating Member
Re: Very rough idle, Wb lean, and more "datamaster log inside"

e95 Ty said:
Pull the front wheels and pass side fender well off, plugs come out easy....
Click to expand...

x2 on that. I pull both front wheels off, then remove both inner fenders to change the plugs. It's really not to bad once you've done it a few times. I have left the two bolts at the very front of the inner fenders out so it is easier to pull them.
 
0966Sy

0966Sy

Code what?
Very rough idle, Wb lean, and more "datamaster log inside"

Does it act the same on cold start or get better as it warms up?

Ohm the coolant sensor on the upper intake to make sure it's in range, although DM should verify this. Also make sure your o2 sensor is still cross counting at 2,000 rpm. If you have an extra map sensor, swap it out. I've seen bad map sensors do the exact same crap. Goodluck

And if you had the distributer out recently, go ahead and recheck your timing or make sure your distributer didn't work it's way loose.
 
pearl91chevy

pearl91chevy

Donating Member
Re: Very rough idle, Wb lean, and more "datamaster log inside"

Thanks for the tips guys I'll give this all a shot tonight. I have not changed or looked at plugs yet so I'll do that first thing. I usually take the wheels off but not the wheel wells. The wires should ohm out to 0 right?

0966sy yes it does seem to run better when cold, when it does actually start. If I crank it, it's usually a long long crank almost like the battery is dead, I let off the key then recrank and it fires up. But sometimes it will die instantly if I do not give it gas. What should the upper intake sensor ohm out at? I can't check the 02 right now since I'm in a iPad at work so I'll check when home unless one of you guys can see it in the dm logs above. I do not have a extra 3bar map sensor laying around right now.. And yes the distributor has been out since I replaced it, I checked timing last night and it's still dead on so I did put it back in correctly
 
pearl91chevy

pearl91chevy

Donating Member
Re: Very rough idle, Wb lean, and more "datamaster log inside"

Just outta curiously... These problems didn't start happening till I filled up from half tank... Could it really just be bad gas? The more I think about it.. I drove it night before in half tank, and it ran awsome full boost no cutting out stalling or anything.. Next day went to gas station and filled up, I left there with it running fine then about 5 min down the road I hit like 10psi of boost and felt/heard the truck kinda cut out.. Went down the road and it did it more and more.. Was only happening when in boost, I turned around and it got to the point it was even just normal drivingn it was acting up.. So whatever it was, it was a gradual problem that was getting worse and worse the longer I drove which would mean the gas was mixing more between the old and new.. Am I onto something here?
 
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0966Sy

0966Sy

Code what?
Very rough idle, Wb lean, and more "datamaster log inside"

Pull a sample from the tank, put it in a glass jar and let it sit over night.

The water will sit on the bottom, so try and get your syphon hose towards the bottom. You could also pull a sample from your fuel filter, should have been changed already. I change fuel filters every other oil change with a wix filter. Don't change your fuel filter until you confirm the fuel is good.

I can't remember what ohms the ECM coolant sensor should be. It's either high when cold and low when hot or vice versa. Just check it on your datamaster, it will be noticeable that the temp is off if the sensor is bad. That can cause fuel distribution problems, especially in open loop.
 
pearl91chevy

pearl91chevy

Donating Member
Re: Very rough idle, Wb lean, and more "datamaster log inside"

Will be doing that when I'm home also.. Ill be looking for a separation in the jar correct?
 
pearl91chevy

pearl91chevy

Donating Member
Re: Very rough idle, Wb lean, and more "datamaster log inside"

alright another update... Gas hasnt changed, still solid in the bottle.. truck still runs like poo.. i just found out though if i disconnect the map sensor the truck will idle "not smoothly but it wont die" and i can put it in gear and it will not die... but soon as i plug it back in, it dies every 20ish seconds and dies instantly in gear.. what does this mean???
 
0966Sy

0966Sy

Code what?
The truck I had the same problems with ended up being a bad map sensor ( new Borg Werner) so I never suspected it. The truck ran great for several weeks before the hard/no start symptoms suddenly started. It started and idled rough and died intermittently. After hours and hours of checking just about everything else I went back to the map sensor. Swapped it out with the map from my truck and ran great. Owned by a new Borg Werner map sensor with a lifetime warranty. Lol, I bet that's your problem.
 
pearl91chevy

pearl91chevy

Donating Member
Re: Very rough idle, Wb lean, and more "datamaster log inside"

Ive reset the chip numerous times.. Just changed out the black as hell 02 that was in there to and still no change.. I curious if the map sensor I got has a warranty on it, don't remember where I got it though. I also unplugged the coolant sensor by the thermostat, threw a cel but did not make the truck run differently.
 
atkonkler

atkonkler

Is this your bush?
Re: Very rough idle, Wb lean, and more "datamaster log inside"

Sounds like a poopy map! Change it out with a new one and were you using a 3bar or 2bar chip? Mine would idle like poop and then I just put a new map in. I'm sure somone on here has a map they could let you borrow or sell you. Bit if u buy one get it from hood he looks for made in China ones before ur buys take sure he doesn't buy Crappy ones.;)
 
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