Hmm where to start............
i have a 94 lt1 motor in a 87 s10 blazer... the motor came w/ the harness and computer and i spliced the harness together myself... i j/ put new stock heads on it due to a unfortunate incident w/ a furel rail bolt falling in an injector hole.... so...

the valves were adjusted then and i did it like the chilton said... obviously i had to put the intake back on, and i managed to get the common intake oil leak.

Once, it was running again, it ran great, it would miss a little but drove fine

i took it the exhaust shop and got and had the x-pipe welded on w/ the o2 sensors....
on the way to the exhaust shop, i broke the rear u joint... fixed that... and on the way back i ran out of gas(no gauge)... got more and made it home.... i drove it a lil but decided i need to raise the rear suspension because it was bottoming out on the driveshaft, and stopped driving it so much because there was smoke from burning oil coming in the cab from the intake leak...
since then its starting running badly....

it's hard to start.... it j/ takes a while of turning over when its cold.... then it will idle rough, sometimes up to 800 sometimes stays around 500... if u get on the gas lightly it will accelate ok , if u try to get on it, it will hesitate and sputter, sometimes, i think it backfires from the intake, doesn't happen much but i'm pretty sure i've heard it.

i've gotten 2 codes from the computer using freescan
1 is CODE 27 - EGR ELECTRICAL FAULT (ODM)
and CODE 34 - MAP SENSOR LOW

the egr system is removed and blocked off
i don't know what to think of the map sensor code

i have an excel file of the data i logged w/ freescan... i don't really know what much of the information means.... so if somebody would like to read it and help me out i would love that.... i realize this is incredibly long but i wanted to give all the details i could

there are a few things that look way off to me, but i don't really know... the tps isn't showing any voltage, and there is alot of knock, but no knock retard? if somebody would take a look that'd be great

 

some things i failed to mention... so far in troubleshooting i have

regrounded my fuel pump... its an electric inline pump... i forget what type but i put it on there when i installed the motor... and dumped out the fuel filter to see if it was dirty but it looked fine, it was also new when i put in the motor none of this stuff has very man miles on it at all.... i pulled the fuel rail and checked the injectors none were leaking, and none were sticking, they looked to be in good shape... i haven't checked the fuel pressure recently though....

i checked the plug wires they are routed correctly and they are new... i checked the plugs, didn't think they looked bad, but i went and replaced four of them... the easy ones to get to w/ properly gapped autolites... the rest are delco platinums

 

Upload the files to an FTP site and post the link, and anyone can look at them.

DTC 27 is from the missing EGR solenoid. It wouldn't cause your problems. MAP may be an issue. What does the data log show for MAP at idle? .... at WOT?

When you say there is "a lot of knock", are you basing that on the data log showing a high knock count? That really doesn't mean much.

 

Well i didn't go WOT on my data log, the most i revved it was up to 1500 or so and it was in park... but.... the map never changed from .1

would that point towards the sensor itself? or something w/ the motor?

i can do another datalog and get on the throttle some more.... but i'm not sure where i can host it, as far as an ftp site goes... i've never done it before... but i'd more than happy to send it to anybody...

 

A data log run simply by idling and revving the engine in park isn't going to show you much. But MAP should move with throttle movement. What units does your scan indicate for MAP - volts, kPa or "Hg? Whatever units its expressed in, seems too low. The harness connector on the MAP sensor is notorious for getting brittle, crumbling and causing poor contact with the sensor. Might want to start there.

 

Okay well, since i'm waiting on a clutch for my camaro.... i decided to really work on my blazer so i could have something to drive.........

i went and bought a MAP sensor the other day, and i had installed it w/ no change.... i wanted to change it out anyway because there was a crack in the casing from being overtightened.

last night i decided to adjust the valves because it i was getting some backfiring through the exhaust... when i was taking off the passenger side valvecover i noticed that i had managed to snag a wire in the last valve cover bolt at some point... also all 3 of those wires from the same harness were crimped underneath the valve cover... i guess thats what i get for working on my car at night... it was the ac temp sensor harness... i went and cut and spliced the wires back together. ( which is a couple of feeds and reference signals from the pcm)
so now i don't have a MAP LOW code and my tps and map readings are showing up on Scanmaster... soo... definately a good thing....

however, its still running poorly...

its very hard to start when its cold. you will have to give it a little throttle to keep it running and the idle stays low.... about 550, and it idles rough.
last night when i adjusted the valves... after the motor had warmed up, i could j/ turn the key and get it to run and idle great, right around 800...

some things i've noticed using scanmaster, that i would like some feedback on are....

"fuel trim cell" settings... what should it be at?
mine starts out at 16 and when revved high... up to about 4000 rpm, it will fluctuate up to 18. the reason i asked this question is because it is always highlighted in yellow....

"egr dc"... i figure this isn't a problem for me, since my egr stuff is removed and blocked off.. but when i rev, it will fluctuate from 0 to about 75... and is it highlighted yellow... not something im worried about but, i thought i would mention it....

ok heres the big thing.... the motor isn't running real great in open loop... rough idle, bad throttle response, hard starting..... but once it gets goin, it will usually stay running until it gets into closed loop... at the point it will run really rough sputter and die.... this is the first time i've noticed this..... when its happening it shows...
the Lterm and Sterms counts.... which i imagine is the long and short term fuel counts..... dropping from 128 to 111 at the lowest and they are highlighted in a light pink at that time.........

my 02 sensors were j/ put on w/ the exhaust.... thats the only thing i can think of that would maybe cause something like that.... what other sensors get used only in closed loop? i've noticed that it has been running rich at times... i didn't know wether or not it was in open or closed loop because i wasn't using a scanner but it would blow a lil smoke out the pipes when revved hard.... if anybody would like to actually see the datamaster file i would love to send it to them, and any feedback is greatly appreciated thanks for reading

 

can anybody help me? would anybody like to see the datamaster file? i'm gonna go and fix the intake oil leak soon, is there anything that i can look for while i have the intake off??

 

If you want to know what the numbers you are seeing on your ScanMaster mean, read my online manual:

http://members.aol.com/InjuneerZZ/ScanMast.htm

But it doesn't sound like you are using a ScanMaster. When you start describing things as being "highlighted in yellow" it sounds like you are using DataMaster on a laptop. If you are scanning with DataMaster, post the data logs, or send them to me via e-mail.

Fuel trim cell is a grid defined by various combinations of engine load (MAP) and engine speed (RPM). Cell 16 is the "idle" cell, 01 is low MAP/low RPM on up to 15 for high MAP/high RPM. 17 and 18 are mathmatically derived from the other Cells. 17 is used for deleleration fueling, and 18 is used for open loop (cold start) operation, and some odd combinations of closed loop.

An engine that does not start well cold, but starts fine when warmed up may indicate a faulty coolant temp sensor.

 

You are absolutely right, i'm using datamaster, i was exhausted, like always when writing that...
i put my datamaster file on an ftp site like u asked... it is the actual datamaster file, lemme know if u need it as an excel file..... i

http://files-upload.com/294175/gh_acel_eng.uni.html

i've replaced the temp coolant sensor, the one on the waterpump, twice i believe. as well as the pigtail for it.... is there a way to check the "continuity" or "ohm out" that sensor or the wiring to check if its good or not? im sure if there is, it will be on shbox.com

my plugs are also fouling out very quickly.... i couldn't get the motor to start at all today... i went and put 4 new autolite plugs in it(its quite a task to get to some of the plugs due to the s10 conversion headers).... and it didn't make any difference but the old ones looked really bad... i sprayed a little ether in the motor and it fired up but didn't last long.... i dont have a fuel pressure gauge, but i pressed on the schrader valve and it was pressurized....thanx for the response...

soomething i should mention, i setup my electric fans, using the same relay system as camaro's as i've seen in schematics. I used both of the signals from the pcm.(the blue and green wire). and the fans stay on, all the time. i know that there are certain dtc's that will make the fans come on w/ the motor, but last time i was running it the only code was an "egr electric fault" and the fans were running constantly.... i can definately see where the temp coolant sensor could make the fans come on.
i will go and tune out that egr code out and see if they go off