Is a fuel rail flush necessary?

Is flushing the fuel system a good thing to do? ...From a preventative maintainance point of view? ...Does it save you money in the long run?

First off, I don't know if I Throttle Body FI or individual injectors... If I don't have individual injectors should I just go with the basic TB cleaning approach or is there some additional benefit by doing the full fuel rail flush (using an in-line approach)?

My '97 Blazer has 115K miles on it and it runs fine (16 city, 19 hwy).



First off, my VIN # is

Additonal info: My VIN# 1GNDT13W5VK213530

Can anyone tell me what fuel system I have based on the engine code listed in my VIN?

from what I see your VIN is a "w". I am pretty positive the W is a cpi which is one injector. I have a Z which is a tbi which is 2 injectors.

from what I see your VIN is a "w". I am pretty positive the W is a cpi which is one injector. I have a Z which is a tbi which is 2 injectors.

Thanks....

Question: How can you tell what type of fuel injection system you have by looking at the engine?

Question: Has any felt their mis-fires or other problems were solved by doing a fuel rail cleaning? ...or is this just marketing?

Additonal info: My VIN# 1GNDT13W5VK213530

Can anyone tell me what fuel system I have based on the engine code listed in my VIN?

You have a CSFI system.

Central Sequential Fuel Injection

On regulator, six injectors.

Run a fuel injector cleaner treatment through it if you want to clean it.

ok than I stand corrected. my owners manual says that w is cpi but I guess due to the newer age for your vehicle I guess they changed it.

from what I see your VIN is a "w". I am pretty positive the W is a cpi which is one injector. I have a Z which is a tbi which is 2 injectors.

i have a 1998 with the w and my ride is tbi

no, it is CSFI

TBI = ended in 1995
CPI = ended in 1995

since 1996, they all have been CSFI.

no, it is CSFI

TBI = ended in 1995
CPI = ended in 1995

since 1996, they all have been CSFI.


Thanks again... Can you tell what type of system you have by looking at the engine?

Note: Behind the TB is an unusual device with electrical leads going to it. The other end looks like it goes into the manifold. Is this part of the Fuel injection system? ....Just asking. I'm thinking that it is.

Anyway, if I do have a CSFI (with 6 injectors) can you confirm I need to do the whole fuel rail cleaning and not just a TB cleaning???

the way to verify by looking at your engine is to check how many injectors you do in fact have. But if Blazer LT says that you have all 6 than you do in fact have all 6. To check your injectors you would need to pull off the plenum and I believe you should eb able to see them than. I may be wrong since I don't touch a fuel system in my vehicle. But I am pretty sure that is what you do by me watching this forum I have gained a lot of knowledge I will not use soemtimes. But it will eventually help me.

Thanks again... Can you tell what type of system you have by looking at the engine?

Note: Behind the TB is an unusual device with electrical leads going to it. The other end looks like it goes into the manifold. Is this part of the Fuel injection system? ....Just asking. I'm thinking that it is.

Anyway, if I do have a CSFI (with 6 injectors) can you confirm I need to do the whole fuel rail cleaning and not just a TB cleaning???

Are you having problems with them?

If not, just run a fuel injector treatment through it.

mine is a 01 blazer and I have a tbi system, I heard that they went back to it for fuel mileage

Maybe the 2.2 has tbi, but all 4.3's have the csfi 96 on.

Except I can't remember if vin z's were something different. I know w is csfi.

Both Are CSFI, there are NO TBI 4.3's after 1995.

What about the 2.2?

Nope, it is not a TBI.

Well what is it?

I own a Motor Vac brand Injector cleaner and carbon reducer. It is the best peice of equiptment I have ever bought. In the last 7 days I have repaired 7 cars by using this machine. It not only cleans the injectors and fuel rail it also cleans deposits from valves and pistons.

no, it is CSFI

TBI = ended in 1995
CPI = ended in 1995

since 1996, they all have been CSFI.
i am not really upto date on the new fuel systems and there names,
i guess csfi looks like a throdle body, i do know it looks like a trodle body to me
also i put a throdle body spacer on it, at least thats what the package says

i am not really upto date on the new fuel systems and there names,
i guess csfi looks like a throdle body, i do know it looks like a trodle body to me
also i put a throdle body spacer on it, at least thats what the package says

Those spacer do nothing for a 4.3L and actually have been tested to reduce power.

CSFI is Central (Point) Sequential Fuel Injection. It means that the injectors are individually fired at precise times in order to improve idle quality and fuel economy. There are systems (such as CPI) where multiple injectors were fired at once, called "batch fire" and that meant wasted fuel. So CSFI was an improvement.

CPI was Central Port Injection and was generally the "batch fire" system where injectors were not individually controlled and fired at once.

It sounds like you already know about the TBI, Throttle Body Injection.

no, it is CSFI

TBI = ended in 1995
CPI = ended in 1995

since 1996, they all have been CSFI.


CONCLUSION OF THIS THREAD: I flushed the fuel rail and now my engine does not have the same intermittent shake at idle. Also, acceleration seems a little more positive so I tend to enjoy that part too.

Note: I was not able to get this affect by putting fuel injector cleaner into the gas tank. In fact, each time I did it (3x) it tripped an engine warning light I needed to clear. Probably from the carbon momentarily attaching itself to the O2 sensor and then burning off. Also, my gas mileage before the cleaning was good (15 all around) and it's the same after the cleaning so miles/gal is not necessarilly an indication you should clean your fuel rail. Therefore, if your engine idles a little rough maybe it's time to spend $70 and get your fuel rail cleaned.... Especially if you have 6 fuel injectors you DON'T WANT TO REPLACE in the future due to one of them being clogged!

CONCLUSION OF THIS THREAD: I flushed the fuel rail and now my engine does not have the same intermittent shake at idle. Also, acceleration seems a little more positive so I tend to enjoy that part too.

Note: I was not able to get this affect by putting fuel injector cleaner into the gas tank. In fact, each time I did it (3x) it tripped an engine warning light I needed to clear. Probably from the carbon momentarily attaching itself to the O2 sensor and then burning off. Also, my gas mileage before the cleaning was good (15 all around) and it's the same after the cleaning so miles/gal is not necessarilly an indication you should clean your fuel rail. Therefore, if your engine idles a little rough maybe it's time to spend $70 and get your fuel rail cleaned.... Especially if you have 6 fuel injectors you DON'T WANT TO REPLACE in the future due to one of them being clogged!

15mpg is good?

15mpg is good?


Reply: I don't know... I'm a new '97 Blazer owner, and I get 15 in the city. and and 17 on the highway.

I once owned a '95 Jimmy for 6 months and it got the same gas mileage, so I assume I'm in the range of what's considered good gas mileage. What do you get in the city and highway?

unless you are agressive no the throttle, you should be getting higher than that.

Tuneup might be in order.

I used to get about 16 or 17 but I would be considered an aggresive driver definately. going 87 is soemthign a blazer wasn't built for I am sure of. Especially sicne my gauge stops at 80......I am currently getting about 14 or 15 now though.

I get right a round 20 mpg, and I lay into it pretty hard sometimes.

In the summer, I get 18 city, and 24mpg highway.

That 20 is city, I get about 26 highway. I figure that is pretty good being that chevy says 18 city 25 highway.

Like LT said, the TBI were gone in '95, so were the CPI injection. The 'W' code for '96 and on was for the CSFI. It kind of looks like a TBI with the throttle body going up like the TBI, but it is not a TBI. The air duct on the CSFI has "vortec" printed on it, the TBI's had a round air filter housing directly on top of the TBI unit. Out of all of them, I think without a doubt, the CPI system looks the best though(my two cents).