Zrout

ttt

any suggestions will greatly be appreciated guys.

Zrout

I tested the IAC and got ~60 ohms.

(it should be between 40-80)

guys I'm clueless here.

I'm ordering opti monday morning

how about the TPS ? any way to check that ???

Zrout

I checked the TPS , .5v at idle and nice steady climb to 5 on WOT

can ANYBODY suggest anything ?

Zrout

it's like I'm talking to myself here , LOL

would anybody venture to guess opticrap ? or some other cause ?

I'm ordering opti tomorrow either way , worst case is I swap it and it doesn't get better , then I'll just burn that ****ing car to the ground

kudah440

Ok, I sure cant tell you for sure what it is, but I'm eagerly waiting for you to try the opti...
as I've said in other threads i'm new to fuel injection, so I am having a hard time with this Z28.
My problems sound somewhat similar...but I just have trouble starting it, the cooler the motor is, the harder it is to start. First start in the morning I takes about 15 tries, and gentle feathering of the throttle to keep it going until its warm, then it runs great.
My approach has given me heartburn replacing the plugs, wires, MAP sensor, and general maintenace stuff ( Owned the car a week now) and I've got no trouble codes to give me any hints about whats going wrong.
I still havent gotten anywhere with the cold start problem, but at least I feel like I've put some effort into it....
Not even sure what an opti is but if it fixes yours I gotta have one too

Zrout

opti is the optical distributor that LT1 uses. GM was too f-ing stubborn to keep the old SBC setup and just HAD to invent something new and completely dumb , lol.

you may need it although I doubt it , but trust me , you don't WANT to change it , lol.

anyways , I'm still looking from ideas and I'll keep updating this post as I find out more

Zrout

come on guys , 108 views and only a few replies by other members (thanks to those that did reply !)

guess away , not like I'll sue you if you're wrong , LOL. (and it's not like I have any freaking clue what's going on , heck I'm just throwing parts at it at this point).

with diagnostic tools that I had to buy + parts I have $250 in this problem already and other than doing one major tune-up I got nowhere. That figure will go to $500 after I call jason and get the opti so please feel free to guess away

Zrout

holy **** ! LOL

that was the fastest way to spend $200 , I didn't even blink and I was saying "thanks a lot dal" (jason unfortunately wasn't in 'till 10pm today , lol , plus he's from FL and dal is from OH so that's half the distance from NH).

had him ship it overnight so hopefull tomorrow I"ll be putting the sucker in

btw... still looking for ideas guys ! LOL I know I'm repeating myself but I have really bad luck with cars sometimes so who the hell knows if it was the opti.

what else can I throw money at ? I Think I'll swap the EGR valve as it was throwing codes before this mayhem and either way it can't hurt to change it.

Zrout

ttt, lol

(I'm a persistant bastard )

Gripenfelter

Sounds like your fuel pump is gone or your fuel filter is clogged up really good.

Attach a fuel psi guage and watch your psi.

Zrout

I have, I bought a new fuel pressure gauge & kit just for that reason.

it is 44psi when the key is on and even when the key is turned off it stays at 44 and doesn't drop.

I believe it should be between 41-47psi so it looks to be just fine.

I totally agree the car could use a fuel filter change and I even bought it , but the nut seems to be somewhat frozen/rusted to the line , so I didn't want to chance breaking the fuel line as that would just suck (I'll attempt it over the following weekend just in case I do break it I'll have few days to work on it). but meanwhile I agree the filter is probably dirty but not a restriction.

also when the car finally evens itself out and runs fine it stays running just great, I don't think it would do that with a clogged filter (but heck I'm open to suggestions).

thanks though I just want to get to the bottom of this

so far $450 in the hole and awaiting opti to arrive tomorrow.

hopefully someone else after me can get some good info from this thread.

Green95Z28

hey man, i have the EXACT same problem as you. Let me know if the opti fixes it. If not I am going to take mine to the stealership. I have F-ed with my computer a LOT replacing chips (93 car). So if thats the problem I will letcha know.

Zrout

lol ok , that makes me feel a little better

I'll definitely post what happens after the opti.

see what sucks is that I'm used to 3rdgens , I have a carb , 3 sensors , 5 gauges and that's it , ECM has long been in the trash and the rest of the electronic design on that car is older than me , lol

all this sensor this sensor that bs on my dads LT1 drives me nuts.

wish there was a book that would walk you through diagnostic steps, like I said I don't mind throwing parts at it or buying tools to diagnose something but while searching on these boards I get anything from "it could be the vats key disabling injectors" to "replace the muffler bearings" , lol



I have a feeling it's going to be something dumb and cheap but I'll find that out after spending $450 on it

Green95Z28

well at least the car will run like a raped ape when its fixed If its my optispark I am gonna spring for a few (a lot of) extra bucks and get one of these
http://www.dynotech-eng.com/dynaspark.htm

Zrout

yeah that would have been my option as well , but at this point I'm trying to keep the total cost down , you're right though , none of the things I bought and replaced were wasted, car had 100k miles and was all original so it could use every part I bought , lol.

I'll make sure to post the gasmileage increase as well it was getting 20 regularly (half highway , half city).