94 blazer computer/injector problem?

[frustrated94blzr]

ok guys--

im not much of a mechanic, but i will share all i know about my problem and what i have done up til now the best that i can.

94 s-10 blazer
4.3L W motor - got the spider thingy on top

a few months ago, the blazer started running rough and surging at low idles. although the check engine light came on, i never had the codes pulled. one morning it would not start. since i recently had similar symptoms on my 93 silverado, i thought fuel pump and filter

i replaced fuel filter and fuel pump. it took me 2 tries to get the correct pump @ 55psi. still not starting. called a mechanic to come and look at it.

he checked the fuel pump - pressure was correct
he checked the plugs - they had fire
**fuel was reaching engine, but injectors not firing
he thought computer, which we replaced. still not starting.

his determination was that the computer was not communicating with injectors. he ran a jumper wire to trick the injectors by manually breaking the ground. as soon as i turned the key, the injectors fired and the blazer tried to start.

where is the problem? electrical i assume? is it wiring? a relay, or module?

thank you in advance!!
[email protected]

[BlazerLT]

Sounds like a bad ground for the computer and engine.

I would seriously think about looking into the cpi injector for leaks.

What fuel pressure did it have.

[frustrated94blzr]

Originally Posted by BlazerLT

Sounds like a bad ground for the computer and engine.

I would seriously think about looking into the cpi injector for leaks.

What fuel pressure did it have.

fuel pressure is good. its been a couple of weeks since i checked it but it was reading in the high 50's. it is getting fuel. remember from my first post, once my mechanic friend "tricked" the ground, it tried to start right away.

any pointers on troubleshooting the ground for computer and engine?

[BlazerLT]

yes, find the ground on the back of the driver's side cylinder head and the negative ground at the fron of the engine are clean and tighten them and also make sure you negative post connection is clean and tight.

[frustrated94blzr]

all

i checked the grounds. all are good, clean and tight. any add'l suggestions. i am all ears.

anybody want to buy a blazer???
i am in ILLINOIS

[BlazerLT]

Go get the code scanned.

[rlith]

Have you pulled the plenum? Just because it's getting pressure (is the pressure steady when you turn the key off or does it drop?) You could easily still have a bad CPI and/or nut kit...

[BlazerLT]

Probably best to get the codes scanned first before we start opening up the engine.

[frustrated94blzr]

excuse my inexperience, but since we put in a new computer will there be codes? the check engine light does not display

[rlith]

No codes should be in a new computer... When you turn the key to the run position the SES should light for a couple of seconds and thats it..