Blazer Forum - Chevy Blazer Forums - 1995 4.3l V6 Vortec SPUTTERING/MISFIRE on acceleration

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- - 1995 4.3l V6 Vortec SPUTTERING/MISFIRE on acceleration (https://blazerforum.com/forum/engine-transmission-35/1995-4-3l-v6-vortec-sputtering-misfire-acceleration-70915/)

Go to rockauto.com they have everything you need for the conversion

Quote:

Originally Posted by stephen5217 (Post 521030)

Alright, today I got the fuel pressure testing gauge. I followed all of the directions that were included and got the running test, acceleration test, and battery (system priming pressure) test. The pressure range that my Jimmy is supposed to stay at is 56-66... That seems like a large range.

So I turned the ignition on, but not the engine and the fuel pressure jumped up to 64, but then instantly dropped. It took it about a minute to reach 20. After that I turned the ignition on and off to pressurize it more and it did the same thing... it just couldnt hold pressure.

I then turned the engine on and the pressure jumped up to 56/57 and stayed steady for the most part. If I pulled on the throttle it would jump up about 1 and as soon as I let off it would drop down to 52/54. I tried the same in neutral and it was just a bit more extreme, but not too much different. (The car sputters while in neutral, but not park)

So what it seems to me is that my fuel pressure is low, and it does not hold pressure while the engine is off (which it is supposed to I guess). So what now, can anybody think of any other ways to test it, or different things I could try before I return the pressure tester?

Thanks... let me know

If its got silver blotches inside the plenum its the injection system for sure.

Inside the engine

Okay, so I pulled it all apart and there is a slight difference in the passenger side from the driver side. There was also some pooling of what seemed to be oil! The wiring for the injector is starting to fall apart, and some of the poppet clips are cracking, so I will be replacing that stuff.

Quote:

Originally Posted by 50lb_cat (Post 521199)

Go to rockauto.com they have everything you need for the conversion

More Information for AIRTEX / WELLS 4G1887
AIRTEX / WELLS Part # 4G1887 {#12568332, 19210688, M1045}

Would that work with my engine?

Avoid airtex like the plague! It will fail on you again probably within a month. Stick with delphi, it costs more but at least you know when you finish the job you won't have to do it again. There should be a discount code floatin around somewhere to. The "oil" was more likely gas that has been turned black from the carbon on the intake.

Quote:

Originally Posted by 50lb_cat (Post 521221)

More Information for DELPHI FJ10565
DELPHI Part # FJ10565 More Info
Actual OE Part; SCPI to MFI Conversion - Complete Assembly

Yup, that's what you need. There is also a new bracket that you need for the upgraded spider. I don't have the part number for you though.
Edit: don't remember if the bracket comes with it, contact customer serive, they will get back to you asap. After looking closer I'm kinda shocked that delphi is cheaper than airtex lol. Stick with oem.

DO NOT order that part! You cannot convert the older CPI system over to the newer setup. The MFI upgrade only applies to the 96 thru mid-02 SCFI trucks, not to the 95 and older CPI engines.

Quote:

Originally Posted by swartlkk (Post 521237)

DO NOT order that part! You cannot convert the older CPI system over to the newer setup. The MFI upgrade only applies to the 96 thru mid-02 SCFI trucks, not to the 95 and older CPI engines.

Thats what I was wondering. I have the generation 2, but I guess it still wouldnt work. So Just stick with a Delco with the poppets still?

Unfortunately, you only have the 2nd gen body. The engine is still the old CPI engine used in the later 1st gens. So yes, you have to stay with the older CPI spider.

When you are ordering parts, do not forget the 'nut kit' (internal lines). These are notorious for leaking after being disturbed. Another item worth replacing is the electrical connector to the cpi spider injector (also called the 'maxi-injector'). It's cheap enough and has caused a few members to pull their hair out and toss countless dollars into other parts after they were sure that the fuel system was good. The part number for the connector has been posted before and a search for "cpi+injector+connector+part+number" (without the quotes) should turn it up.