TrevorT
Forum Newbie
Posts: 30
Loc: Calgary Alberta
Reg: 03-12-12
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03-20-12 01:30 PM - Post#2205168
My truck has been giving me a bit of grief lately it has been hesitating at take off and wanting to stall at idle(almost dies but will catch it self but on occasion will stall out and starts everytime). anyways i cant find a vacuum leak anywhere(using the carb cleaner method), my fuel pump/filter/relay are all new,O2 sensor new, EGR holds vacuum when i depress it and plug it and i replaced the EGR solenoid for shits, i also had bosch platinum +4 plugs which i just replace with regular champion copper plugs. after doing the plugs and egr solenoid it seems to be 90% better (doesnt hesitate but still sound like it wants to die when im slowing down to a stop (but not nearly as bad)but im still getting a code 44 after driving it for about 15-20 min. im running out of ideas and my mechanic is booked solid for a week or more, does any one have any suggestions for me while i wait.
| '94 Chevy C1500 5.7l 4l60e Ext Cab LB |
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TrevorT
Forum Newbie
Posts: 30
Loc: Calgary Alberta
Reg: 03-12-12
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03-20-12 03:16 PM - Post#2205197
In response to TrevorT
i just adjusted the timing which made it 99% better but still wants to die when im slowing down and still giving the code 44. I just have a question or 2 about the timing
1) ive timed it with the bypass unplugged but when i plug it back in the timing's way different and its way off, i assume the unplugged reading is right and there is no need to look at it with the bypass plugged in. is this right?
2)ive timed it to TDC or O on the mark and seems slighty rough at 30-50km if im off the gas idleing could this mean it needs to be adjusted one way or the other?
| '94 Chevy C1500 5.7l 4l60e Ext Cab LB |
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 someotherguy
Moderator
Posts: 23387
Age: 43
Loc: Texas
Reg: 08-01-03
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03-20-12 03:32 PM - Post#2205205
In response to TrevorT
Factory spec on the base timing is at zero with the engine warmed up and bypass wire unplugged, and that's where you should have it set. When you plug the wire back in you can expect it to advance quite a bit as the PCM is now controlling the timing. What would be important here is if it did NOT change - then you have a problem.
You got some good advice in your other post ( http://www.chevytalk.org/fusionbb/showtopic.php?ti... ) and it looks like you've maybe followed some of it, but have left some important things hanging. EGR valves are considerably more tricky than the inspection you've given it so far; purchase or make a block-off plate to rule out the EGR once and for all.
Also I know you've replaced your pump and filter but at no point have we seen a fuel pressure reading.
If you still have those Bosch Platinum +4 plugs in there, get them out, and replace with the correct AC Delco CR43TS gapped at .035 to 0.045 (factory spec is .035) - may not solve the problem but will prevent you having trouble with those +4's, our engines simply do not like them.
Richard
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drifterdude
Frequent Contributor
Posts: 1282
Reg: 09-04-08
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03-20-12 03:35 PM - Post#2205207
In response to someotherguy
With the EGR off also check the ports in the intake as they can block up and rock solid with carbon.
After checking that and trying a block off plate and getting fuel pressure readings we could swing this a little better.
But without that the only other thing I could thing of is IAC.
92 K1500:350 bored 30 over,built 700r4,Comp extreme energy cam,double roller timing set,shaved heads,Rancho RS9000XL series shocks with wireless my ride system,35 inch Mickey Thompson Baja Claws,Relocated 4x4 switch to rocker on Dash.
Other mods.. |
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someotherguy
Moderator
Posts: 23387
Age: 43
Loc: Texas
Reg: 08-01-03
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03-20-12 03:59 PM - Post#2205222
In response to drifterdude
The EGR ports can definitely get carboned up, but I wouldn't expect clogged EGR passages to create a lean condition. I'm thinking EGR valve opening early due to weak spring (or incorrect EGR in some cases) or bad EGR solenoid contributing to lean condition is a possibility.
I spent a good amount of time writing an EGR troubleshooting document but it's difficult to test for an EGR that opens too easily, other than simply removing it and blocking it off to see if that cures the symptoms.
Richard
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TrevorT
Forum Newbie
Posts: 30
Loc: Calgary Alberta
Reg: 03-12-12
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03-20-12 06:32 PM - Post#2205325
In response to someotherguy
i appriciate the help 100%. Im going to try the block off plate tomorrow, i bought one the other day and it turned out to be the wrong one so i havent been able to exchange it yet but i will tomorrow and ill see how that works for me.
| '94 Chevy C1500 5.7l 4l60e Ext Cab LB |
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drifterdude
Frequent Contributor
Posts: 1282
Reg: 09-04-08
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03-20-12 06:50 PM - Post#2205333
In response to someotherguy
Thank you richard for clearing that up. EGR to me is just a headache so I just replace. I know the carbon causes issues but I trust your opinion over mine.
Now onto the improper EGR. Richard will agree with this. Find the part number to a OEM model egr and then search it on amazon. you can find it cheaper there most of the time with quick shipping.
92 K1500:350 bored 30 over,built 700r4,Comp extreme energy cam,double roller timing set,shaved heads,Rancho RS9000XL series shocks with wireless my ride system,35 inch Mickey Thompson Baja Claws,Relocated 4x4 switch to rocker on Dash.
Other mods.. |
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TrevorT
Forum Newbie
Posts: 30
Loc: Calgary Alberta
Reg: 03-12-12
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03-20-12 07:51 PM - Post#2205366
In response to drifterdude
Im in Canada so unfortunatly for me amazon wont send me parts and amazon.ca doesnt even have parts(and even if it did id probably have to pay canadian prices) so im lookin at $120 for an EGR valve but aw well either way ill try the blocking plate and if its bad then theres nothing i can do but replace it.
| '94 Chevy C1500 5.7l 4l60e Ext Cab LB |
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TrevorT
Forum Newbie
Posts: 30
Loc: Calgary Alberta
Reg: 03-12-12
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03-21-12 10:51 AM - Post#2205584
In response to TrevorT
Well i went to exchange the block off plate and they told me they didnt have one that would fit and after calling around and having no luck finding one i just decided to get the valve it self after installing it the code 44 seems to have vanished (knock on wood), the only thing was the erg looks different than the original, and the little stub that you hook the hose to is on the other side so i had to get a longer piece of hose to make from the valve to the solenoid(but seems to be fine for the time being). now i just need to tackle a few other small jobs and my chevy should be tip top. THANX SOOO MUCH FOR ALL THE HELP in this post and my last!
| '94 Chevy C1500 5.7l 4l60e Ext Cab LB |
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Anonymous
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03-21-12 11:02 AM - Post#2205594
In response to TrevorT
i read all the stuff it is not clear some more suggestions please.
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Allan In NE
Contributor
Posts: 903
Reg: 12-27-11
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03-21-12 11:09 AM - Post#2205597
In response to TrevorT
Good for you Trevor!
Yeah, that one just "smelled" EGR related. 
Allan
| Lifelong GM automatic transmission specialist |
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someotherguy
Moderator
Posts: 23387
Age: 43
Loc: Texas
Reg: 08-01-03
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03-21-12 11:13 AM - Post#2205599
In response to TrevorT
I'll wish you luck with that aftermarket EGR. If you'd peeked at the EGR troubleshooting write-up I did that is linked in our FAQ post you'd see my recommendations on using an OEM AC-Delco (or at least a Delphi) EGR and suggestions on where to buy one to save a good chunk of change. These TBI engines are very, very picky about proper EGR operation and many of the aftermarket valves don't cut it.
Hopefully this one behaves for you...
FYI a simple block-off plate for testing purposes could be fashioned with any suitable small piece of scrap metal and a couple holes drilled in it, using a gasket for the template to mark the stud holes. A little anti-seize lube on the gasket lets you re-use that once you're ready to replace the valve.
Richard
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 CowboyTrukr
"2nd Year" Silver Supporting Member
Posts: 700
Loc: Salt Lake City
Reg: 06-20-09
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03-21-12 11:15 AM - Post#2205601
In response to Allan In NE
Hey, Allan, I just PM'd you about something else.
Greg
'94 Silverado K2500 4X4 5.7 5spd Xcab LB
RV cam, Pace Setter Headers, TBI spacer, Flow Tech air cleaner adapter, Hypertech street chip
"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke |
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350whip
Contributor
Posts: 116
Reg: 02-24-12
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03-21-12 11:18 AM - Post#2205606
In response to TrevorT
woohooo treverT god job!
RickT.
- 1989 chevy k1500
- regular cab, shortbox
- chevy SB350tbi (little piggie!)
- L60E Automatic 4speed
- corvette servo
- 30"BFG AT's
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TrevorT
Forum Newbie
Posts: 30
Loc: Calgary Alberta
Reg: 03-12-12
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03-21-12 07:05 PM - Post#2205852
In response to someotherguy
I'll wish you luck with that aftermarket EGR. If you'd peeked at the EGR troubleshooting write-up I did that is linked in our FAQ post you'd see my recommendations on using an OEM AC-Delco (or at least a Delphi) EGR and suggestions on where to buy one to save a good chunk of change. These TBI engines are very, very picky about proper EGR operation and many of the aftermarket valves don't cut it.
Hopefully this one behaves for you...
FYI a simple block-off plate for testing purposes could be fashioned with any suitable small piece of scrap metal and a couple holes drilled in it, using a gasket for the template to mark the stud holes. A little anti-seize lube on the gasket lets you re-use that once you're ready to replace the valve.
Richard
Well i took your advice and went and got an EGR valve from the dealer, because with the aftermarket one in my truck it just didnt feel right and it was rough at half throttle(luckily i was able to return the aftermarket one) but with the OEM one it runs damn near perfect and i dont really have anything bad to say about the drivability, but it still keeps popping a code 44 and i have no idea why it has none of the symptoms it had before (so far, that is)
| '94 Chevy C1500 5.7l 4l60e Ext Cab LB |
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CowboyTrukr
"2nd Year" Silver Supporting Member
Posts: 700
Loc: Salt Lake City
Reg: 06-20-09
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03-21-12 08:01 PM - Post#2205896
In response to TrevorT
Trevor, here's a list of relevant things to check.
Test description:
1.) Code 44 is set when the O2 sensor signal voltage remains below .3 volts for 50 seconds or more and the system is operating in "closed loop".
Diagnostic aides:
The code 44 for lean exhaust is most likely caused by one or more of the following:
1.) O2 sensor wire - Sensor pigtail may be mispositioned and contacting the exhaust manifold.
2.) Check for an intermittent ground wire between connector and sensor.
3.) Poor ECM to engine block ground.
5.) Vacuum leaks can cause a lean condition and/or possibly a high idle. Check for cracked hoses a bad gasket or a faulty EGR or PCV Valve.
6.) fuel pressure - system will go lean, if pressure is too low. It may be necessary to monitor fuel pressure while driving the car at various road speeds and/or loads to confirm. This last one is relevant and has been referenced before on this post. It would be worthwhile to check yours.
Check out this post to give you an idea for the O2 sensors.
http://www.chevytalk.org/fusionbb/showtopic.php?ti...
Greg
'94 Silverado K2500 4X4 5.7 5spd Xcab LB
RV cam, Pace Setter Headers, TBI spacer, Flow Tech air cleaner adapter, Hypertech street chip
"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke |
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TrevorT
Forum Newbie
Posts: 30
Loc: Calgary Alberta
Reg: 03-12-12
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03-21-12 08:26 PM - Post#2205906
In response to CowboyTrukr
i read your post about the spark plug fouler over the o2 sensor and it made me think, could the fact that i have no catalytic converters make the o2 sensor give me a lean exhaust code? just wondering
| '94 Chevy C1500 5.7l 4l60e Ext Cab LB |
Edited by TrevorT on 03-21-12 08:35 PM. Reason for edit: No reason given.
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CowboyTrukr
"2nd Year" Silver Supporting Member
Posts: 700
Loc: Salt Lake City
Reg: 06-20-09
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03-21-12 08:44 PM - Post#2205914
In response to TrevorT
I wouldn't think so. Mine has no cat (shhhhh) and I have no codes.
'94 Silverado K2500 4X4 5.7 5spd Xcab LB
RV cam, Pace Setter Headers, TBI spacer, Flow Tech air cleaner adapter, Hypertech street chip
"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke |
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someotherguy
Moderator
Posts: 23387
Age: 43
Loc: Texas
Reg: 08-01-03
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03-22-12 05:22 AM - Post#2205983
In response to TrevorT
i read your post about the spark plug fouler over the o2 sensor and it made me think, could the fact that i have no catalytic converters make the o2 sensor give me a lean exhaust code? just wondering
If your truck was older, or a manual transmission, then yes - as you'd most likely have a one-wire O2 sensor that is non-heated and depends on exhaust heat to light off (must get to 600F) and begin reading. Your '94 w/automatic should have a three-wire O2 sensor which is self-heating and far less dependent on exhaust heat. I don't have a cat on my '94 5.7/4L60E truck, and the exhaust is dumped right past the Flowmaster 40, and I've never had any codes related to fuel mixture.
Richard
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CowboyTrukr
"2nd Year" Silver Supporting Member
Posts: 700
Loc: Salt Lake City
Reg: 06-20-09
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03-22-12 12:28 PM - Post#2206136
In response to someotherguy
I was concerned about this for my unit when I put the headers on. Good thing was that the headers came with an O2 bung, so I plugged the factory bung on the Y pipe and get wonderful heat with the sensor only 12" from the head. 
Greg
'94 Silverado K2500 4X4 5.7 5spd Xcab LB
RV cam, Pace Setter Headers, TBI spacer, Flow Tech air cleaner adapter, Hypertech street chip
"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke |
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