last issue on my vette could be a big one though????

it was verified by a local mechanic that all ignition was good so humor him and lets assume spark plug wires delteq ignition and spark plugs are good (not saying they are but lets play along)

the light flashes doesn't appear to suffer from an unbearable loss of power but definitely has a loss also idles REALLY rough

replaced the fuel filter fuel psi seems good injectors is a possibility of course cant think of what else could cause it. any diagnostic tests i could run? really want my car this week is suppose to be sunny weather throughout

code is on a 1996 lt1

 

Honestly, cylinder random misfires can be anything. Thankfully, or not, whatever it is, it is effecting the entire engine. I would start by driving the car and monitoring live data from the ECM with a scan tool looking for something a miss. (Pardon the pun).

Also, did you verify fuel pressure while driving?

How as the spark verified?

How much and when does the CEL flash? Cold start up, warm start up,idle, driving, Open Loop, Closed Loop?

FYI, I would NOT drive the car until you figure out why you have a miss(es). That is unless you like buying Catalytic Converters. They generally do not respond well to raw fuel being dumped into them. Tend to get hot, then melt, then clog, then you got more problems...

 

it seems to me like its mainly cyl 7 misfire i took an infrared thermometer to the manifold and when cyl {1 and 2 were at 250+ F (6,4 and 3,5 were at 330 ish) and cyl 7 was at 180} cyl 8 could also be a little to blame it was at like 220 but i just think its cuz i couldnt get a clear line of sight for the therm.

i did not check while driving and i did not check after the pressure regulator

NOTE the CEL doesnt flash at idle! but.. it does at 1900 to 2100 rpm and starts to lope rpm when throttle is held steady (does this at about 1400 rpm then will drop to 1200 and back up) i can clearly hear the miss when the car is jacked up on the passenger side, on the ground on drivers side and running (i know.... not safe) sounds kinda hollowish? lol forgive my diction

 

it should have another code 301-308 along with p0 300 to determain what cylinder what brand wires are on it and opti spark possible a egr problem

 

nope unfotunately thats the only code that shows up. im not sure of the brand but they look relatively new and the optispark is not necessarily "running the ignition" its been somewhat bypassed via delteq.... but im ruling all that out as of right now i paid $105 for them to tell me that was good to go. egr is a possibility i suppose, i havent heard any whistling from vacuum lines i dont think.

 

Out here it was allmost always plugged up injectors caused by MTBE in the fuel and GM extended a 10/200 warranty to avoid a CA recall. Too late for that now and MTBE is long gone - but you might want to look into getting yours cleaned or depending on mileage (150,000 seems to be the limit), replace them. Can't believe a mechanic didn't have the Trouble Tree to verify. Service Manual outlines all the possibilities and injector flow test is one of the first listed for a 300 for all makes.

 

DO you have a Field Service Manual or FSM for short?

 

im at 140,000 right now so thats a possibility lol idk they just saw i was a kid and decided to rip me off...... figures or they were mad i was driving a car like mine but in my defense i saved up for awhile for it....


no i have nothing except maybe an old haynes but i think its lost now since we moved.

 

id look at the wires if there a part store repacement they can cause u grief in less then 6mo i only use factory wire set or a hi performance set like msd or taylor

 

IF you plan on keeping this Corvette, working on it, etc....I would defiantly get a FSM. More info than you can imagine, worth its weight in gold.

As far as that Haynes manual is concerned. No loss. It was only good for a poor back up to toilet paper. They are worthless even for that.

Without the FSM, you might be hunting around in the dark. Or a decent scan tool for that matter. Running ok at idle is fine, but moving is not so performing tests moving is out of the question.

At that mileage injectors COULD be bad, only a test will confirm. I would check fuel pressure at idle, and running down the road, tape it to the windshield. Also, pull the vacuum hose off the fuel pressure regulator and see if it is wet with fuel in the hose. You might also do a injector leak down test, key on till you get fuel pressure, then let it sit for a while (10 min. or so) and note how fast the pressure goes down.

A scan tool would be a big help, being a 96 it actually monitors for misfires and can show you real time which cylinder is misfiring.

The thermometer trick is a good one, but it told you have a poor running engine with a tendency to misfire on 7, but has other weak cylinders.

Things like this have to be approached logically and a plan. Throwing parts at the problem rarely solves it in a timely or wallet friendly fashion.

 

hmm where do i get one? im sure thats a stupid question... haha i havent ever used the haynes because i knew it was worthless thats half the reason its lost now. yeah i agree well i pulled the injectors off again today and noticed all were moist at the tip except cylinder 7

 

Ebay or this forum are good choices for used ones. A lot less money than new from vendors.

Only get the red ones, the white ones are only preliminary manuals.

I would ohm test those injectors. Should be around 13 or so. Also, you might want to verify that the injectors are getting a pulse from the ECM. You need noid lights for this. Some parts stores have these for rent. Just plug in the injector connector and if ok, you will see the light flash. If this is good, time for a new set, by the sounds of it.

 

ok it was definitely cyl 7's injector causing all my problems... havent checked for an fsm (ohm test read all 14-15 ohm) i did a noid test awhile ago they all checked out... i just replaced one of the injectors with an old 89 that seemed to work great! i just need to get a drivers side cat (maybe a passenger exhaust manifold) and im good to go

 

Nice job. I would replace all 8 given mileage and age. If one fails, the others cannot be far behind.

 

yeah definitely a concern i just need to get more $$$$$ and pass inspection first