SCPI to MFI upgrade kit...

[blanz]

gmpartsdirect.com now has a kit to upgrade from the poppet valve injection to MPI. Kit comes with the spider, bracket and o-ring kit. Part number is PK12568332 (SCPI to MPI upgrade kit) and was $239.90 with shipping.
Shipping was a little high, but the total package price was still a good deal to get rid of those POS poppet valves.
Looks like a good Thanksgiving weekend project to me!
Bill.

[02_Black_XBlazer]

Take lotsa pics. If the install turns out well it might make for a good sticky.....

Good luck, keep us posted.

[J_Rod]

IIRC, this isn't a new kit....came out in 02-03. Couple guys on here already purchased/installed and didn't see any dramatic difference.

[Rhotpursuit]

Quote: Originally Posted by J_Rod

IIRC, this isn't a new kit....came out in 02-03. Couple guys on here already purchased/installed and didn't see any dramatic difference.

Performance wise...probably none...bad poppets...a lot of difference.

[J_Rod]

yes, that is true. I wasn't thinking leaky poppets.

[meyers2211]

i did it with no major difference

[nater006]

Correct. The kit was designed to eliminate the issue that made the poppet nozzles get stuck open or clog, not as a performance kit. There's a GM tech bulletin about it that says pretty much that. Definitely no performance increase, unless you're comparing it to currently stuck/clogged nozzles..

[blanz]

Quote: Originally Posted by nater006

Correct. The kit was designed to eliminate the issue that made the poppet nozzles get stuck open or clog, not as a performance kit. There's a GM tech bulletin about it that says pretty much that. Definitely no performance increase, unless you're comparing it to currently stuck/clogged nozzles..

With over 100k on her, I'm really only hoping to get a more consistant (i.e. smoother) idle. Those poppet valves are a POS and will eventually gum up and stick with time. Knowing that GM went to the MFI on later 4.3's, I'm really just bringing it up to the latest technology. BTW, the excuse to the wife is that it will improve the gas mileage ;-)
Any excuse to get under the hood and tinker.
Bill.

[nater006]

Ah, well, I daresay you won't get much resolve on the idle issue. Loads of threads about it. The bottom line is the 90 degree oddfire V6... is gonna shake at idle. Don't even spend a penny trying to fix it!

FYI, I've got 167K on stock '96 injectors, and they're still behaving nicely (knock on wood)

[blanz]

Quote: Originally Posted by nater006

Ah, well, I daresay you won't get much resolve on the idle issue. Loads of threads about it. The bottom line is the 90 degree oddfire V6... is gonna shake at idle. Don't even spend a penny trying to fix it!

FYI, I've got 167K on stock '96 injectors, and they're still behaving nicely (knock on wood)

Our 4.3L is not an odd fire engine as you have described.
Excerpt from www.engine.firebirdv6.com\V690.html

"In 1985 a 262 cid (4.3L) engine (4.00" bore x 3.48" stroke) was introduced with a true even fire sequence of 120 deg; the internal block dimensions are identical to the 350 cid small block. This even-fire sequence was accomplished by increasing the offset between adjacent crank journals to 30 deg. In order to give the 30 degree offset the rod journal diameter had to be increased from 2.10" to 2.25" to provide enough overlap between offset journals. Connecting rods in the 4.3L V6’s are not compatible with any other Chevy engines. The 262 cid engine had 1.94" intake valves and 1.50" exhaust valves. Fuel induction systems for the 4.3L engine included quadrajet carburetors, throttle body fuel injection (TBI) and central port fuel injection (CPI)."

[02_Black_XBlazer]

Quote: Originally Posted by J_Rod

IIRC, this isn't a new kit....came out in 02-03. Couple guys on here already purchased/installed and didn't see any dramatic difference.

Understood, still doesn't mean a good walkthrough with some good pics wouldn't be useful for the search archives.

[TECHRF]

this is what you speak of. I had to do my LIMG and decided to do the injectors while I was at it.

[nater006]

Quote: Originally Posted by blanz

Our 4.3L is not an odd fire engine as you have described.
Excerpt from www.engine.firebirdv6.com\V690.html

"In 1985 a 262 cid (4.3L) engine (4.00" bore x 3.48" stroke) was introduced with a true even fire sequence of 120 deg; the internal block dimensions are identical to the 350 cid small block. This even-fire sequence was accomplished by increasing the offset between adjacent crank journals to 30 deg. In order to give the 30 degree offset the rod journal diameter had to be increased from 2.10" to 2.25" to provide enough overlap between offset journals. Connecting rods in the 4.3L V6’s are not compatible with any other Chevy engines. The 262 cid engine had 1.94" intake valves and 1.50" exhaust valves. Fuel induction systems for the 4.3L engine included quadrajet carburetors, throttle body fuel injection (TBI) and central port fuel injection (CPI)."

Yeah, I misspoke... sorry, I was half thinking of something else at the time.

The bottom line of it is, they are inherent shakers at idle...

[tuckin20s96]

gm has a t.s.b. on those poppet valves sticking. mine used to have hards starts and rough idle because of it and i replaced them and it idles smooth and starts up fine now

[blanz]

Quote: Originally Posted by blanz

gmpartsdirect.com now has a kit to upgrade from the poppet valve injection to MPI. Kit comes with the spider, bracket and o-ring kit. Part number is PK12568332 (SCPI to MPI upgrade kit) and was $239.90 with shipping.
Shipping was a little high, but the total package price was still a good deal to get rid of those POS poppet valves.
Looks like a good Thanksgiving weekend project to me!
Bill.

Installation went pretty smooth this weekend on installing the MFI conversion. Taking the upper intake manifold off revealed 113k miles of carbon build-up and soot.


Removed the old Sequencial Central Port Fuel Injection Spider from the lower intake manifold and realized how much crap was built-up on the entire assembly.


Here's a couple of close-up's of the business end, better know as the infamous "Poppet" valve that gums up over time.


You can see the spring-loaded ball at the end of the poppet valve.


Here's a shot of the underside of the upper intake manifold. The build-up looked like tar from inside of a chimney.


Spent some time thoroughly cleaning the lower intake manifold before putting the new injector bracket on that came with the kit.


Here's a shot of the new unit fresh in the box. One strange thing I did notice was that the injectors were facing the wrong way. I had to rotate all the lines 180 deg. around to get it set up properly.


I inserted the injectors into the lower intake manifold holes according to the cylinder numbers. The new injector had the cylinders clearly marked so as not to screw up. I used a heat gun to make the injector lines a little more flexible to get the body of the injector to snap down into the mounting bracket. The fuel lines are real stiff, and at one point I though I was going to kink them, so I played it safe and got them more plyable with the heat gun set on low.
Here's the final shot with the new unit installed before closing her up.


I used a little silicone grease on all the new gaskets and o-rings which made re-assembly go a lot easier.
One thing I want to mention here is it is best to buy the intake manifold gasket set from your local auto parts store just to get the two fuel rail O-rings that go at the junction between the fuel rail and the incoming fuel lines by the firewall (rear of engine). Unfortunately, you cannot just buy them seperately. Maybe the dealer might of had them.

On a difficulty scale of 1-10, this probably rates around a 6 or 7. You just need some $, time and patients and your there.
We'll see if the gas mileage goes up from the current 15 MPG city. On the plus side, cold weather idle is already noticeably better. We'll see if there are any other tangible benefits from this conversion. One thing is for sure, the Butt dyno already likes it ;-)

Bill.

[payne]

Is there supposed to be a vacum line attatched to the fuel pressure regulator? Or does nothing get attatched to it?

[blanz]

Quote: Originally Posted by payne

Is there supposed to be a vacum line attatched to the fuel pressure regulator? Or does nothing get attatched to it?

Nothing. I thought the same thing the first time I saw the nipple on it.

[payne]

Quote: Originally Posted by blanz

Nothing. I thought the same thing the first time I saw the nipple on it.

Yeah, i replaced my regulator awhile back and have always had second thoughts about if i forgot to install it properly. Thanks

[nater006]

Looks good. Did you pull the intake manifold to clean it up like that, or just a lot of paper towel?

[rat]

Quote: Originally Posted by payne

Is there supposed to be a vacum line attatched to the fuel pressure regulator? Or does nothing get attatched to it?

It is inside the intake manifold. It gets all the vacuum it needs.

[brokeitagain]

i did the injector upgrade on my 99 and it idled and ran smooth for about a month then it went back to running shitty and idling rough,i have given up on trying to fix it

[blanz]

Quote: Originally Posted by nater006

Looks good. Did you pull the intake manifold to clean it up like that, or just a lot of paper towel?

A bunch of shop towels, carburator cleaner and elbow grease.

[nater006]

Quote: Originally Posted by blanz

A bunch of shop towels, carburator cleaner and elbow grease.

Looks like you did a good job! Amazing how much junk gets built up on that... ugh.

[WarpathRacing]

Looks awesome. I had to replace the pressure regulator a month ago when the truck died completely (stuck closed/too much pressure?), and wish I could have gotten the upgraded spider. It has a pretty noticeable bog on cold mornings in the winter, and I think the poppets may have something to do with it. Maybe around tax time...

[pshawnpee]

i have that poppet vavle problem too i think. imy 98 blazer runs like crap, and then after 45 mins it starts to bog out and mis and and i cant go till i let of the gas, could i need this kit or do u think its something eles like a fuel pump or cat problem???? thanks guys.

98 blazer 4.3
4 in drop

[minitrkntillidie]

im not sure if this is my problem or not my 99 4.3 has a hesitation when i first start driving it in the morning when its cold and i push on the gas to get going until i get about 25 30 miles per hour. it has new cap and rotor wires and plugs the code says cylinder 1 and 2 running lean and multiple misfires it will go away after 15 minutes of driving and does this trck need the iridium plugs?

[InkedNJuiced]

Wow I just got my '97 a couple momths ago and had a starting problem when it was cold. And when i say "problem" I mean it wouldn't start unless i sprayed carb cleaner in the intake. So after changing my flter, plugs, cap and rotor - my mech said it was probably the CTS, so i replaced that, still had the problem. Took it to him and he checked my pump and said it was good but getting low voltage(which i knew because my voltage gauge was only running at 12 instead of 14) so he threw in a new alternator and battery and said he thinks it fixed it. And it did, until just the other day it took 4 times crankin it over to finally start and now it's hesitating off the line and in mid rpm range, high rpm and idle is fine. I just put a full intake system on it the other day and thought it was ironic it started having problem sright after that but really didn't think the problem was related. I took it to the parts store and had em plug it in and i didn't catch the code but it was "too lean - bank 1". I was lookin at gettin a walbro pump just cause i don't know what else to do-then i found this thread. I bought the truck from AZ and it could be from cali, i don't know. Is there a way to know if doin the MFI swap will fix my problem?

Thanks for the help

[InkedNJuiced]

Okay and it doesn't do it all the time. I ran some seafoam thru the system and it's not hesitating as bad and the codes i'm throwin are:

P0171 - Fuel Trim System Lean Bank 1

P0174 - Fuel Trim System Lean Bank 2

[TECHRF]

I would suggest that you have you oil analyzed before going into the engine. after having my oil checked there was a problem w/LIM gasket. keep in mind that I noticed no loss of anti-freeze at all and check once a week. here is the place I used. here is the paper work. for $25 its cheap insurance, it sure beats spinning a bearing. also see my other thread

[InkedNJuiced]

Quote: Originally Posted by TECHRF

I would suggest that you have you oil analyzed before going into the engine. after having my oil checked there was a problem w/LIM gasket. keep in mind that I noticed no loss of anti-freeze at all and check once a week. here is the place I used. here is the paper work. for $25 its cheap insurance, it sure beats spinning a bearing. also see my other thread

Um, that wasn't in reply to my issue, was it?
I don't see how contaminated oil could cause my engine to be running too lean...

[TECHRF]

I'm just putting it out there b/c I had similar problems and found it was 2 fold. the coolant was screwing w/ignition and the popetts didn't help.
here is the long version on SSF what I didn't mention in either post was the fact that the gasket was leaking into the #3 and#5 cylinders.
again just something to consider. I'm going to run another analysis w/next oil change just to see what shakes out.

[pshawnpee]

if i install these on my 98 blazer will my stalling problem stop lol.
i changed the fuel pump and everything eles. but not this
only stalls in the afternoon . so some thing is getting hot

[gchemist]

I made the same upgrade to my 96. No more misfires since the upgrade. Worth ever dime!!
Pictures available here.
http://rides.webshots.com/album/557928095EiAjZP
MFI spider #12568332
Upper plenium Seal Kit #17113215

The kit is only two gaskets. One for the throttle body and the other for the uppermanifold. You don't need orings for the fuel lines. The orings are inserted into the new spider. Just push down the fuel lines into the spider and bolt down. Order the GM spider from GM parts direct. Pricey shipping but worth it. I spent <$210 for both part numbers.

You need these parts too.
1 can of throttle body cleaner
1 can of carb cleaner for the upper manifold
1 can for the air intake sensor
1 10mm deep socket for the manifold gaskets
1 5.5mm socket for one of the TB bolts
1 small tube of thread lock or sealer. I use the small blue tube type.
A small hex set to remove the air idle valve.
Clean the EGR valve and idle air valve too.
I recommend changing the map and throttle posistion sensors.

Key notes:
1. Disconnect the battery
2. Releave the fuel pressure
3. Pull and remove the harness wire connections from the air intake sensor all the way to the sensor on the passenger side of the intake.
4. Layout all the bolts and parts on a flat surface so you know where to put them back.
5. You can bend the fuel lines back far enough to remove the intake just be careful. Otherwise to remove the fuel lines, you may need the wrenchs that can go on a socket.
6. Route the spider fuel lines just like the originals. All should run forward from the FI spider bracket. You should only loop back the #5 and #6 lines.
7. Use the carb cleaner to remove the junk from the intake.
8. Don't drop anything down the runners.
9. Once the new lines go into the intake they won't come out!!! Snap the new lines once you are sure that you won't need to remove them.
10. Use a dab of grease on the upper portion of the spider that slides up into the manifold. Use a dab of grease on manifold opening that goes over the spider. This will save you the trouble of having to push down hard on the intake to seat it.
11. Clean the TB really good. Remove the plastic weird looking thing on the TB opening plate. This will increase air flow.
12. GM did a good job on the gasket design. Just tighten the bolts to a snug. You can go back later and tighten them a little after the engine has warmed up and coold a few times. However you don't need to do this if you use the thread sealer.
13. Bolt down everything and connect the hoses.
14. Before installing the air intake hose, check for fuel leaks. Connect the battery and turn the key to ignition. Let the pump prime the line. I did several times so the pressure will buildup. If you don't see any fuel leaks, install the air intake hose, misc hoses, reconnect the sensors and wiring harness.
15. Start it up and check for fuel leaks!! Let it idle up to normal operating temperature before going for a test drive.

This is my first time doing a FI injection job. It was fairly easy. Just take your time and be careful. My Jimmy runs like a champ. I bet even my fuel milage will be better. I was down to 14 MPGin the city! I can already tell it's back to up the 16-17 mark and maybe more. Throttle response is awsome!! Idle is smooth. You'll like the conversion.

[Yogi]

Quote: Originally Posted by blanz

...... On a difficulty scale of 1-10, this probably rates around a 6 or 7. You just need some $, time and patients and your there.
We'll see if the gas mileage goes up from the current 15 MPG city. On the plus side, cold weather idle is already noticeably better. We'll see if there are any other tangible benefits from this conversion. One thing is for sure, the Butt dyno already likes it ;-)

Bill.

Bill -
Any gas mileage improvements that you can post yet? I have a '98 Blazer with 204,000 miles on it and I am considering this mod. I'd also be interested in any other before / after comparisons you can give.

GChemist-
Lots of good pictures in your post! Is that the idle air controller in picture #14-53 (29 of 38)?

[TECHRF]

gchemist nice pcs.
Yogi my mileage has gone up to 20mpg since the work was done on my truck. looking to flash the PCM soon ,might get a touch more there.
I also ran another oil analysis and it came back OK for the work that was done, will do one more before the fall.

[Yogi]

Quote: Originally Posted by TECHRF

gchemist nice pcs.
Yogi my mileage has gone up to 20mpg since the work was done on my truck. looking to flash the PCM soon ,might get a touch more there.
I also ran another oil analysis and it came back OK for the work that was done, will do one more before the fall.

Thanks, Techrf!

[ltdguitarplaya89]

hey i have a question after this swap has onyone had a high idle problem i just finished this swap up and now i have a code p0507 engine idle higher than expected im thinkin i could look for some vaccum leaks and all but im really wonderin if anyone has had this problem and knows a fix im also getting a slight misfire to after this any help would be awesone and sorry for stealing the thread :/

[vespasoul]

[quote=Yogi;5066525]Bill -
Any gas mileage improvements that you can post yet? I have a '98 Blazer with 204,000 miles on it and I am considering this mod. I'd also be interested in any other before / after comparisons you can give.QUOTE]

i recently did the upgrade on a 97 4.3 and went from high 13 mpg to high 17 sometimes 18 mpg. and i always drive with a heavy foot.
on top of the i'm constantly running a p0340 code so i'm getting those results with system in semi limp mode.

[Yogi]

Thanks for the response. Looks like you're getting a nice mpg gain there!

The p0340 code is for the cam position sensor (CMP). You must not have put the dizzy back in on the right tooth.

Good luck with the repairs, and thanks again!

[MikeInCtown]

OK, this may be a dumb question, but this "kit" with the new injectors... What years exactly will it fix? I have a 96 and have problems at times when cold with hard starting. My mileage a year or two ago was over 20 easily on the highway with mixed city and now I get like 17 with a light foot. This is with all new ignition components among other things.

I also noticed that the 2001 W code Jimmy that I was looking at buying not only idles smoother but idles about 200 RPM lower than my 96 S-10. I'm wondering if perhaps spending the money would save me down the line since gas is now $4 a gallon here. (and I now have 190k on my truck)

if anyone can explain the different years and fuel systems I would appreciate it.

thanks
Mike

[Yogi]

I believe that it fits '96 thru '01 CSFI motors. In '02 they went to MPI at the factory.

Edit: According to this post it applies to '96 - '02 4.3s

[96Dropped-dime]

damn i need this upgrade BAD!

[cardboardbox]

Quote: Originally Posted by 96Dropped-dime

damn i need this upgrade BAD!

Do it!

I did mine a week and a half ago. No regrets.

[96Dropped-dime]

no $$$$ i have a used stock replacement,more poppets YAY!!!
my truck was running really bad for about a month but is doin good now,
im waitin for it to start again

[jwykes]

I did mine on monday and I love it. I never knew how bad my engine was running until I did this. refer to my thread if you want the whole story
http://www.s10forum.com/forum/f107/d...ectors-351481/

[sparky2613]

I hope this works just ordered mine!!

got it on vid.

http://s120.photobucket.com/albums/o...t=100_0361.flv

http://s120.photobucket.com/albums/o...t=100_0364.flv

[gchemist]

If you go through the upgrade, and your intake gasket is original, take my advice and change out the intake gasket!! No better time to do it!! I had to remove the entire intake again 1 year later after my upgrade to replace the intake gasket. The intake gasket from factory sucks. Use a Fel-pro replacements. No water leaks to worry about for years!

[sparky2613]

ive done it twice this year

[hkellogg]

Quote: Originally Posted by sparky2613

I hope this works just ordered mine!!

got it on vid.

http://s120.photobucket.com/albums/o...t=100_0361.flv

http://s120.photobucket.com/albums/o...t=100_0364.flv

your issue seems like a distributor issue.... check your cap and rotor and wires and such but it really does seem like a bad cap and rotor in the video or possibly even a shot distributor...is your check engine light on or does it come one ? connect a code reader to the car if it is and see, when I had the FI problem get a code P0300 or P0302, P0301 etc...

[sparky2613]

well since last year (june) my truck has been running bad.... it runs fine in cold weather! when its a hot day and it run like s*** but only after a bit of driving.... you feel it at max rpm and from there the more you drive it the lower in rpm you feel it until u can give it gas or it will die or to the point where it wont even idle

fixes ive done

had a bad intake gasket - Fixed it Twice
had a vacuum leak - Fixed it
had a radiator leak - Fixed it
had the fuel pump go bad 3 tries later - Fixed it
had a leak in the engine oil coolant lines - Fixed it

added new plugs, wires, Cap, and rotor,

3 weeks ago i spent an hour under my truck replacing the O2 sensors with the old, but working one's from my dads corvette...

problem never really went away

Sunday.... the first beautiful, sun, really nice day we've had, i went for a good, nice long relaxing drive..... so i thought, it was fun trying to get it home.....



runs a bit better on prem. fuel

HOT OUT= Runs Bad
Cold OUT= Foot To The Floor, Do What I Want To It, And It Runs Fine

today im going to drive to work (about 20 mins) and it run fine
When i come home to night, same drive but hot out, it will start running bad by the time i get a mile from home