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Username Post: my timing is too advanced with est plugged in.        (Topic#350010)
stapelman 
Infrequent Contributer
Posts: 30

Reg: 06-21-17
03-08-18 05:00 PM - Post#2726920    

have an 89 k2500. 5.7 tbi. truck warmed up. unplugged the advance wire. checked timing. dead on 0 degrees btdc. turned truck off. plugged in the advance wire. check again. at idle it is running over 8 degrees btdc. doesn't sound like it's idling too high. i just put a new iac valve in it. new egr valve, new egr valve solenoid. new map sensor. new rotor, cap, wires, and plugs. ecm shouldn't be advancing my timing until higher rpm right? also it does idle a little bit higher with the est plugged in, but not by much. the truck does have some problems starting up in the morning. have to crank it about 5 seconds before it fires up.



 
bowtie44s 
Valued Contributor
Posts: 4035
bowtie44s
Age: 35
Loc: wv
Reg: 08-29-12
03-08-18 05:48 PM - Post#2726923    
    In response to stapelman

8°-12° is normal idle.

Jeff

'88 Chevy K3500, aluminum head roller cam 511in³ stroker 10.5:1 compression, 96 NV 4500, 94-98 grille, 305/70-16 (33x12) BF Goodrich KM2s, 91 cluster swap


 
CowboyTrukr 
"7th Year" Silver Supporting Member
Posts: 4018
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
03-08-18 10:18 PM - Post#2726953    
    In response to bowtie44s

Check your fuel pressure.

Greg

'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500
'00 Explorer XLT 4.0 V6 Auto
'94 K2500 5.7 NV4500 ECLB - SOLD
‘87 GMC S15 SCLB 4.3 Auto - SOLD

"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke


 
stapelman 
Infrequent Contributer
Posts: 30

Reg: 06-21-17
03-08-18 10:29 PM - Post#2726954    
    In response to CowboyTrukr

it has a brand new fuel pump and fuel filter in it




 
CowboyTrukr 
"7th Year" Silver Supporting Member
Posts: 4018
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
03-09-18 01:04 AM - Post#2726962    
    In response to stapelman

Ok, but that doesn’t necessarily mean the pressure is good. Have you measured the pressure?

Also, when was the last time the coolant temp sensor at the thermostat was changed?

Greg

'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500
'00 Explorer XLT 4.0 V6 Auto
'94 K2500 5.7 NV4500 ECLB - SOLD
‘87 GMC S15 SCLB 4.3 Auto - SOLD

"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke


 
stapelman 
Infrequent Contributer
Posts: 30

Reg: 06-21-17
03-09-18 04:49 PM - Post#2727049    
    In response to CowboyTrukr

oh. haven't gotten around to it. will have to stop by the parts store and pick up the stuff to do that. coolant temp sensor hasn't been changed since i got it about a year ago. but the gauge seems to be reading ok. doesn't overheat. started it up today and both injectors are pulsing. did order a rebuild kit for the throttle body. i did get a quality pump. gonna clean the injectors with some throttle body cleaner and rebuild it monday. see if that helps.



 
Chevytech 
Subject Matter Expert - Senior Member
Posts: 3783
Chevytech
Loc: Twin Cities, Minnesota, U...
Reg: 04-25-04
03-09-18 05:15 PM - Post#2727051    
    In response to stapelman

The dash temp gauge uses a different sensor, on the engine, then the computer uses to determine how much fuel to inject.

After replacing the IAC, the system needs to relearn the IAC position. This takes drive time reaching specific criteria or manually invoking a relearn.

With the poor quality of replacement parts it is possible you are making more problems then you are fixing by replacing parts rather then testing things.

For a long cranking cold I would be testing the coolant sensor (that the computer monitors), fuel pressure, and make sure the IAC is working.

For those of you that are wondering why you are not getting replies to your thread:

Did you give the model, year, engine, fuel system type, and transmission information?

If your vehicle has been altered from stock, let us know about that too.


 
rockfangd 
"5th Year" Gold Supporting Member
Posts: 2474
rockfangd
Age: 32
Loc: Utica ny
Reg: 04-13-10
03-09-18 08:08 PM - Post#2727069    
    In response to Chevytech

I highly recommend looking into the ECM coolant temp sensor, located right near the thermostat housing.
You may need the pigtail also (hit or miss)
While you are there check the grounds on the thermostat housing stud.
A failing (failed) coolant temp sensor can tell the ecm that the coolant temp is very cold which will fully richen the fuel mixture.
It can also fail and tell the ecm that it is hot and be too lean

Old School GM fan FOREVER


Edited by rockfangd on 03-09-18 08:10 PM. Reason for edit: No reason given.

 
stapelman 
Infrequent Contributer
Posts: 30

Reg: 06-21-17
03-09-18 09:42 PM - Post#2727082    
    In response to Chevytech

my old iac valve was sticking shut. i cleaned it twice and it was still sticking shut. so i ordered an oem replacement. i can hear the rmp adjusting when i start my truck so im guessing its doing what it should. as for the coolant temp sensor, i had no idea there were two, one for the ecm. one for the gauge. i thought the one located on the side of the engine next to the header was for both. i could test it with my multimeter, and i may, but im gonna replace it. only ten bucks anyways. been spending a lot of time in my engine bay lately trying to get this thing running smoothly, and never even noticed that temp sensor next to the thermostat housing. i even replaced my thermostat a month back and didn't notice it. learning a lot though. thanks for the info. much appreciated.
edit: should add iv'e been sticking to quality oem parts for anything i've been replacing.



Edited by stapelman on 03-09-18 09:45 PM. Reason for edit: No reason given.

 
Skribble93 
Poster
Posts: 38

Age: 33
Loc: Upstate NY
Reg: 02-03-18
03-11-18 07:04 AM - Post#2727187    
    In response to stapelman

I agree as others said change that sensor and see if it clears up if that thing even starts getting bad it can mess with idle etc.. I myself learned the hard way when I was younger and kept forcing my old van to start and stay running in the end the coolant temp sensor was bad changed that and it ran fine for a day before spinning a rod and crank bearing from me keeping on the floor to stay running when it was to rich. Change that out see how it runs after just never punch out the factory plug in your TB over the idle adjust seen some go that route and it causes more harm than good. Goodluck!

If it's to loud your to old

93 K1500 Z71 step side 5.7 shorty headers and 2 1/2in straight pipes. 3in body lift and leveling kit.


89 K1500 4.3 rotted frame dubbed parts rig Sold


 
stapelman 
Infrequent Contributer
Posts: 30

Reg: 06-21-17
03-12-18 07:32 PM - Post#2727388    
    In response to Skribble93

the new temp sensor did the trick. installed it this morning and it fired up right away. thanks a bunch.



 
CowboyTrukr 
"7th Year" Silver Supporting Member
Posts: 4018
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
03-12-18 08:40 PM - Post#2727403    
    In response to stapelman

Sweet. Thanks for posting back with the results.

Greg

'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500
'00 Explorer XLT 4.0 V6 Auto
'94 K2500 5.7 NV4500 ECLB - SOLD
‘87 GMC S15 SCLB 4.3 Auto - SOLD

"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke


 
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