I have a 86 Z was 305, now 355 roller. The motor is brand new, the censors are old & for a 305.

will a knock censor for a 305 (not 350) cause the no start when motor is warmed up?? motor will start fine when cold, but after warm up, it will not start , untill cooled.

if more info is needed let me know.

joe

 

A bad knock sensor will cause a SES light, its not responsible for your no start.

Why don't you post a few more details of what's happening when it doesn't start? Does the engine crank at all? Starter make any noises? If the starter doesn't turn over, have you tried rapping on it a couple times with a stick or a hammer? They tend to get hot and not kick in properly. If that's all it is, replace the starter.

 

car will start (will not idle w/o foot) after heat up car will idle (surging a little) if you turn motor off, starter will turn motor freely
has good spark at plugs, and injectors (at the no start time)

I also have a code 33 (have new EGR & sencer, just have not put it on yet)

 

anybody??

somebody has had to have run across something like this.

joe

 

I had a similar problem with my L98 TPI engine. Turns out one of the injectors was bad and when it warmed up, it went to ground and pulled the other injectors with it, causing them to dump fuel. Car did not want to start when warm and when it did, it ran pig rich. I remember I had the car at a friends house in Savannah GA and had to get home to Jax FL. When I finally got home, I swear the plugs had no gap! I think the MSD box was the only thing keeping the car running. Not sure if this is your problem but this problem kicked our butts for weeks.

 

thanks, I will check the injectors when the no start happens.

thanks for the post. joe

 

Defintiely ohm the injectors, seen what he said a lot more than once.

Anything under 12 ohm is junk according to GM(may or may not tell the whle story, but if still stock, it prolly will)

Bad temp switch could do this too.

Ignition parts are another good thing to fail under heat as well.

The pick up coil and ign module jump to mind.

Also, u never mentioned if it cranks or not. If it doesnt crank hot your solenoid is going bye bye.

later
Jeremy

 

motor cranks fine, good spark at plugs, and injectors.

thanks to all that posted. joe

 

i think i'm experiancing something simular to this... any updates joejoe?

 

I assume you swapped out your old prom when you dropped in the new engine? If your crank pulsewidth values aren't matched to your new engine and larger injectors, you might be running too rich at startup, which is especially noticeable when warm. Hold the gas pedal to the floor to enable flood clear mode and see if it starts.

 

just for my own info what makes the solenoid not work when its hot? just something ive been wondering about

 

no updates yet!?!??

 

Bnoble: still no start

TexasB4C: heat expands cracks, or will open a cracked wire.

 

Gounds on the back of the head clean and tight? Make sure you don't have any paint on the ground stud.

What do your plugs look like when it is running?

Can you verify the injectors are firing when you have the no start condition? Have someone crank the engine over, and place your fingers on the injector bodies. You should feel them clicking very rapidly.

 

Are you still using the 305 (19#) injectors with the 355? If so, the start fuel with a warm CTS may be inadequate. You need to install 350 (22#) injectors and a 350 calibration (PROM) or reprogram what you have.

 

My 353 ran great with the stock 305 prom APYS ( but I had 22lb injectors) . Now I have the corvette bin ( APYP ) and I have idle issues .

Change that knock sensro over to the 350 one for starters . Sounds like possible injector thing ...or that CTS sensor.

Did you ohm them out yet ?

 

I think its a bad temp switch. and I also have a sensor kit comeing from TPI parts.com. (all sensors are 20 yrs old)

VADER: it dose have #22 SVO injectors and a hypertech for 350 TPI (you are right about needing a new chip)

92 blue: all grounds are clean & tight

D's89IROC: injectors are brand new, but will check.

joe