HELP! Really odd problems...

[TighTheChevyGuy]

yesterday i tested my tps. couldnt get a good reading thru the back of the clip but for one time and it was reading right about where it should for idle. it read .040 i do believe. didnt get to test it at wide open. just overhauled the throttle body though and my injectors seem to be doing better, for now. im gonna let it sit and run for a while. also, i didnt have my IAC programmed when i put it in and the pintle wasnt fully extended to where it needed to be so i pulled it out. is that okay?

 

[TighTheChevyGuy]

ran live feed scan today... the O2 is telling my motor that its rich, but the motor isnt listening most of the time. when it decides to run correctly, the O2 and MAP and TPS and IAC all run great. with the live feed i was able to adjust my throttle position to .5 at idle and it reads about 4.66 @ WOT. but when its running all ****** and missing out, its dumping fuel like nobodys business. i just put a brand new TPS on it after all the live feed data was ran though after i got off work. that hasnt helped any.

i was told to check my fuel filter possibly. and it has an airtex fuel pump in it. could either of those be my issue?

 

[retorq]

It would run lean if the fuel filter was clogged ...

 

[geo3xk]

Ive seen very similar issues if the egr is stuck open.

 

[TighTheChevyGuy]

i put a bolt in the vacuum line that plugs into my egr...

---------- Post added at 03:55 PM ---------- Previous post was at 03:54 PM ----------

but when i ran diagnostics the egr was reading at 99%... whatever that meant

---------- Post added at 05:41 PM ---------- Previous post was at 03:55 PM ----------

just pulled my drivers side plugs (they were the ones turning colors) and i took pictures of my number 3 and number 7 plugs. 1,3, and 5 were all scorched and dull like the picture and number seven looks how it does, although its ceramic was the darkest black, and there is a tiny little diagonal crack in the ceramic (much smaller than ones ive normally seen, kinda made up of a lot of smaller cracks making one larger one) so maybe thats why it looks different than the others?
number 3

number 7

---------- Post added at 05:42 PM ---------- Previous post was at 05:41 PM ----------

wtf? how do i post pictures???

 

[SunlitComet]

use "go advanced" reply button and click on the paper clip icon.

 

[TighTheChevyGuy]

this should be plug number 3




this should be number 7

 

[TighTheChevyGuy]

yup those are the correct pics. i have an old flip phone. sorry if the quality sucks

---------- Post added at 10:00 PM ---------- Previous post was at 09:56 PM ----------

i was told something about a sticking valve? but my mechanic said no way to that...

 

[retorq]

If your valves were sticking open while the engine was running, the color of the plugs would be the least of your worries.

 

[TighTheChevyGuy]

retorq could ya do me a favor and read thru my symptoms and maybe tell me if that could be the problem? though it does run just fine, even for days at a time on occasion. so...

 

[SunlitComet]

If scorched and cracked the temperatures are to high. Can't find a couple pics of own TBI but was thinking if each TBI barrel fed specific cylinders and not just all mixed together perhaps that can isolate a specific injector issue. Otherwise along with something else something might be goofed with ignition system. Maybe wrong plugs even.

 

[fire730]

I'm not sure if this will help any but I'm sure that truck is wearing you out by now.

http://http://www.chevythunder.com/gm_throttle_body_injection_pg_1.htm

If you scroll down to page 5 it specifically points outs conditions for running rich.

http://http://www.73-87chevytrucks.com/techinfo/TroubleshootingTBISystems.pdf

 

[TighTheChevyGuy]

to sunlit, i do believe that my injectors feed to their respective sides. when my right side was dumpin so much fuel. my right side was scorched. now theyre looking fine since i fixed the grounds on that side.

thank you fire, i will look thru those links and hopefully they will help. and yeah its worn me out. me any my wallet both. i have about ten dollars to last me til next paycheck lol. it took two hundred of my money and gave me no answers. im ready to just do a head job on it and replace everything from the gaskets up hahah

---------- Post added at 01:37 PM ---------- Previous post was at 01:23 PM ----------

the first link was good for some general info but the second seems to help a lot. yes my battery cable is quite messed up and i also have the old ACDelco 1 wire alternator... is that bad? and also, how do i measure my fuel pressure?

 

[retorq]

Have you verified the fuel pressure with a known good gauge?? If that's good then go get yourself a notebook (borrow a friends or drag your home PC out into the driveway), an OBD1 cable and any of the free real time scanning software and log the truck. I bet something in the log is gonna tell you exactly what the issue is.

---------- Post added at 01:32 PM ---------- Previous post was at 01:27 PM ----------

To measure your fuel pressure you will have to put a T in the line somewhere or get an adapter that screws into the back of the TBI. I cut my fuel line about an inch behind the TBI adapter and took about 3 inches of line out, clamped in double jacketed with an adapter to run a gauge.

 

[stoner]

Just a wim. Try a separate ground wire directly from the battery to each head of the engine. Use #10 wire and be sure the contact to the head is to the bare metal so you have good contact. Sometimes the ground can do wierd things as we have found on our race engines. Even though you think you have a good ground as is.

 

[TighTheChevyGuy]

no i dont have a mac, nor the programs youre talking about, nor a fuel pressure gauge... i have run the live stuff on a snap-on MODIS scanner, is that the same thing? i can probably get a fuel pressure gauge at work though. i just put an airtex fuel pump in it, but if the fuel pump was bad, wouldnt it throw less fuel rather than more?

and thank you stoner, i will try that.

also i am going to try and upload a video of the blazer running, is that possible on this site?

 

[SunlitComet]

modis is better if the software is up to date. and yes a weak pump would throw less fuel.

 

[TighTheChevyGuy]

everything on the modis looked correct. when it was running correctly the O2 was bouncing between lean and rich as normal, then when it ran like ***** the O2 stuck at rich and right when it started to die the injectors started dumping fuel so hard they whistled but that seemed to save it from dying.
what else should i have been monitoring?

 

[TighTheChevyGuy]

"Battery unhooked for a bit to clear computer, hooked battery back up. Jumped top right two terminals on OBD1 port, turned key forward, waited 30 seconds or so, turned key off, removed jumper, cranked truck.

Two things in that procedure can tell you you did it right: 1) the SES light flashing once, pausing, then twice for a code 12, which is normal operation, and 2) you can feel the valve body of the IAC pulsing as the motor repeatedly draws back."

^^^ so i tried this to reset everything, only i didnt have my SES light flash at me. i turned the key forward for at least a full minute n a half, and nothing. sup wit that?

 

[SunlitComet]

Coolant temp and manifold pressure as seen by computer could provide some helpful data. Also are you saying that in an attempt to initiate OBD you recieved no response from ecm. Otherwise the light comes on when the key is first turned on. Correct?