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

pearl91chevy

pearl91chevy

Donating Member
This started out of no where yesturday, i was driving down the street and got some gas.. Soon as i left and hit a bit of boost i felt the truck kinda hesitate.. Within 10minutes the problem got very bad.. even just easy driving the truck was bucking a bit, still would hit boost but with hesitation, wb still read ok.. so i changed out coil and cap which were shot after 2000 miles, i changed the dist a bit ago since it was the original. and now im having a issue where even if i put it in drive it more then likely dies, and wb reads lean ALOT. i cant even get it outta the garage without it cutting out and shutting off. seems to get worse the hotter the truck is also.. here is a log just in garage with idling, then putting into gear.
http://www.mediafire.com/download/zzwu25i2t5s5hbb/october_11_new_dist.rotor.cap.uni
 
Jimmy

Jimmy

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

Good fuel pressure?

Pressure stays up ?
 
Jimmy

Jimmy

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

Ok gauge with key "on" should hold pressure for like 5 minutes.

If pressure drops fast bad fuel pump probably .
 
pearl91chevy

pearl91chevy

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

ok thanks jimmy ill report back in morning about that.. sucks i just filled up to haha. i thought i happened to get bad gas, but friend filled up same pump with same 93 and his cars running fine
 
Jimmy

Jimmy

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

Pull the vac line off the FPR and see if it smells like gas.

Any trouble codes?
 
pearl91chevy

pearl91chevy

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

No codes at all, my vac gauge still reading between 18/20. Ill check the fpr also when I get home, had to come into work for a few hours
 
pearl91chevy

pearl91chevy

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

update.. fuel pressure gauge on, reads 42psi when running.. let it sit and it very slowly drops pressure when the trucks off.. pulled the vac line and i can very slighty smell fuel but its not strong.. Also just lettting the truck run, it smells super rich
 
pearl91chevy

pearl91chevy

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

i can barely get boost out of it. im sooo lost on whats going on. I have the fuel gauge hooked up, set at 42psi and i can watch it climb a bit when giving it gas.. and it does not drop when trying build boost. also would like to add its hard starting, kinda bla bla bla bla then fires right up

http://www.mediafire.com/?ktrzuj6dy7f8hcu
 
e95 Ty

e95 Ty

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

Check your plug wires. Esp #6...Just something else to rule out.
 
Jimmy

Jimmy

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

Ok the fuel smell means busted diaphragm in the FPR.
(Which is why the pressure is going away)
Fuel is leaking into your crankcase. Pull the oil dipstick and smell it.

Don't drive it.Change the FPR and oil.

You're welcome :)
 
pearl91chevy

pearl91chevy

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

just for shits and giggles.. what else could the problem be?? i checked the oil and it smells like normal used oil, no hints of gas..
I have the tb apart right now, the iac has a tiny vac leak on the plastic side where connector goes.. I pulled it out and its pretty dirty, noone in town has one in stock and there 80bucks. So i will try cleaning it first before i buy one since ive already spent 100 on a distributor that didnt fix issue. As of right now, issues are starts up, idle is kinda all over the place.. Sometimes even dieing out unless i give it gas.. It revs up fine and smooth.. Put it in drive and dies instantly.. If i put it in neutral, rev up to get peddle to drop, then goto drive when it doesnt die, and try to build boost, gets to maybe 2 or 3psi and thats about it and you can just hear the motor isnt happy. I also pulled the wb back out from under dash and everything is still fine and hooked up.. What else should i be looking for?


edit, pulled out the iac valve, cleaned it with brake clean and put it back in. tried to start it but wont run without pressing gas peddle now. i jumped the 2 ob1 ports and i cant hear anything spinning, only hear a click.. click is still there when i unplug the iac valve.

EDIT AGAIN: got dm hooked up, had to keep foot on gas for it to run.. heres what i got
1100RPM closed loop
map at 10.46
vac at 21
lterm/sterm both at 128
02mV at 906/128
BPW at .82/1.5
AFR/CRANK both at 12.7
Spark Advance at 23.2
knock16/knock8 at 1670/6
TPS at 5.1 "Remeber i had to have foot on gas to keep it running"
TPS Volts at 0.73
IAC at 100

And then trying to hold idle at 2000rpm
closed loop
map at 12.64
vac at 19.24
lterm/sterm at 128/124
02mV at 62/128
BPW at 1.10/3.7
AFR/CRANK at 15.1/14.0
Spark Advance at 38.7
knock16/knock8 at 1670/6
TPS at 12.9
TPS Volts at 0.98
IAC at 112

and heres the quick log
http://www.mediafire.com/?ftc1ctl9cxd7pcj
 
Last edited:
pearl91chevy

pearl91chevy

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

I ordered a iac from autozone which will be here this afternoon.. 86bucks later.. I found one on orileys site for 37 bucks, so hopefully autozone will price match it
 
pearl91chevy

pearl91chevy

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

alright spent 80 freakin dollars on a new iac valve, installed it.. the old one, the little shaft was extended pretty far out compared to the new one so i was hoping that was a fix.. installed it and no.. the idle kind of settled down, but i have a huge black spot where the trucks been sitting and starting. WB is reading all over place still.. i can drive it, but usually when i come to a stop it dies.. i hit boost a few times and got holy hell knock.. i also pulled the fpr vac line off, and hotwired fuel pump to be on, and have no leaks out of it. oil still smells like oil.. im sooooo lost on this...
this is just driving around the block..
http://www.mediafire.com/?dnnzsqht7n41j9c

this is stilling in driveway trying to break/build boost.. even 80% tps only get 3psi of boost
http://www.mediafire.com/?0609ov7rjoov6d5
 
randy merritt

randy merritt

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

Is there any easier way to post your data log file? That mediafire has lots of junk on it. I could try to help, but the access to you file is to much of a pain in the ass.
 
pearl91chevy

pearl91chevy

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

not sure how else to send it.. is it possible threw email?
 
G

GM TURBO

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

I'm with Jimmy. The fuel pressure shouldn't leak down that fast. It might not be the issue but it's an issue.
 
pearl91chevy

pearl91chevy

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

i got a tip it could be simple as the fuel filter..That i know of its never been replaced.. worth a shot, whats another 10 bucks

not trying to ignore you guys thoughts on this, just doing the few things i can before i go threw hassle of dropping that tank which i know will be a job in a half
 
Last edited:
0966Sy

0966Sy

Code what?
Check your wires, bad wire will make a rich cylinder. If anything pull the oil fill cap off while it's running and see if your getting blow by, or smoke out of the oil fill tube. You could have damaged a piston or ring land.
 
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