Another CPI How-to (focus on regulator)

[rlith]

Originally Posted by leadalto

I hooked up the fuel pressure guage and by using the key-on, ign-off or connecting the fuel pump pigtail connector direct to the + battery terminal, I get 60 psi which holds "forever". I cannot see any signs of gas leakage (pin hole or otherwise) on either side of the plenum (regulator or nut kit side). What gives? Shouldn't there be gas spilling into the plenum or a strong odor of gas if I have a leak? I'm looking right into the open plenum!

I pulled the plugs and they are not fouled but all were just sooty, as they would be from running a very rich mixture as I reported (black smoke in exhaust). The plugs on the left and right banks look the same.

I'm very reluctant to pony up to $350 - $450 in parts to fix a leak that I'm not seeing or smelling.

I cleaned the EGR a few days ago because I had an EGR code. That did not fix the problem. I'll do it again because it's so easy to do with the upper manifold removed. As a matter of fact, it's so easy to remove the upper manifold and the gasket is relatively inexpensive that it may be worth it (to service the distributor or even the EGR unit), to avoid needless aggravation.

I'm anxious to solve the problem but not to throw money at it.

A lot of times the leakage happens when underload, not always when you just prime it... That said, the regulator is only $40 bux and the nut kit runs about 60.00

[rlith]

Originally Posted by BlazerLT

Rlith,

Didn't you just replace your whole cpi injector only less than 2 years ago with a new unit?

Yep....Entire CPI unit..

[BlazerLT]

Originally Posted by rlith

Yep....Entire CPI unit..

Wow, I wonder if this is my problem.

I am suffereing with some serious low city mileage but it is cold up here and I do a lot of short trips.

Highway mileage is still over 21mpg so I am wondering if it is this or just poor driving conditions and lots of short cold driving trips.

It is weird that you are bringing this up seeing I to have had some poor starting if I don't prime it completely everytime.

[Gabe25]

Originally Posted by BlazerLT

Wow, I wonder if this is my problem.

I am suffereing with some serious low city mileage but it is cold up here and I do a lot of short trips.

Highway mileage is still over 21mpg so I am wondering if it is this or just poor driving conditions and lots of short cold driving trips.

It is weird that you are bringing this up seeing I to have had some poor starting if I don't prime it completely everytime.

Rlith, excellent posting. I wish I new about this a year ago. I could of saved some money.

LT, I replaced a whole CPI unit and nut kit on my "94", then about a 14 months after my regulator was leaking. So I replaced the CPI again. Had I known that the regulator could of been replaced. I would of done so. So I think I'm going to have to keep a regulator on hand as spare parts around the house.

Rlith, Thanks again.

[BlazerLT]

My city economy is 12-13mpg with a lot of stop start driving and cold weather nothing higher than 32f so the engine is never really getting up to temperature.

Rlith, not trying to overstep my word here, but I would take a toothbrush and some TB cleaner and scrub that TB butterfly, it looks a bit grubby.

And maybe consider the PCV catchcan to stop that oil and gunk getting into your intake if you want.

Just a thought, nothing implied.

[ldr1ff]

I have a 96 w-code 4.3L in m blazer. It doesnt look anything like this. Does this problem also occur in my style of 4.3L?

[BlazerLT]

You can have a leaking regulator but in most cases it won't show the same problems as the 1992-1995 as is stated in this thread.

[s10blazerman4x4]

http://www.babcox.com/editorial/us/us30098.htm
http://www.asashop.org/autoinc/feb2000/techtotech.htm
I know i posted these awhile ago but in case people dont search here they are again incase you are confused and want to read up on it.

[BlazerLT]

Rlith,

Notice any performance improvement?

[BlazerLT]

Sorry to bring this thread back up, but I need to see who has done this and what improvements they have seen?

[OverBoardProject]

Does your city mileage still suck BLT?

And are those HELP parts any good? I've often looked at them but never bought any thinking that they look cheap.

[rlith]

Only improvement was gas usesage went back to normal as well as power and pressure.

[ZL1power69]

just a thought...anyone know the likelyhood of a newer ac delco replacement cpi w/regulator going bad within a year of being replaced? i forget how long they are under warranty but they are "suppose" to last 5-7 years.

[BlazerLT]

Originally Posted by OverBoardProject

Does your city mileage still suck BLT?

And are those HELP parts any good? I've often looked at them but never bought any thinking that they look cheap.

Actually, I think is has gone up rather significantly.

80% city and I will be getting close to 18mpg which is not bad at all.

It is just weird sometimes. Somtimes the truck seems to be peppy, and others it seems to be a dog.

Wonder if it is the regulator or the coil?

[krackerjack9]

what exactly is the better decription for the nut kit? I want to order this or go pick one up and need some sort of part number that is for this Thanks Geo