Cascade Crew

Al Hasse · Posted: Thu Feb 01, 2007 11:17 pm Post subject: Rich, rich, rich...

Looking for some ideas to cure my off-the-scale wide-band rich condition which showed up on the dyno. I'd like to get the horsepower and mileage back up to where it should be. Any ideas other than computer or O2 sensor which were tossed around at the dyno? I called my local Chevy dealer today to price a stock computer chip, found out they are $100, special order only, 4 days out from Memphis. I might go this route anyway, but just curious as to what other sensors/components might cause the super rich condition at about the same RPM every time. This has been intermittently screwing with the EGR codes of late, but a little more frequent this week.

Xophertony · Posted: Fri Feb 02, 2007 1:14 am Post subject:

get a used computer from a junkyard. they are everywhere. and if it is NOT the problem (which it probably is not) you will only be out 20 bucks.

Twilightoptics · Posted: Fri Feb 02, 2007 9:19 am Post subject:

I'd be leaning more towards fuel system... regulator, vacuum, injectors.

I sincerely doubt it's the calibration.

If you're just rich WOT your milage wont change.

You need to get a scan tool on there somehow... never done it on the V6 cars before, and figure out if you're lean/rich other places.

Might check your tps sweep voltage too.

Al Hasse · Posted: Sun Feb 04, 2007 10:09 am Post subject:

I priced some of that stuff at the dealership yesterday. The pressure regulator doesn't come without the fuel rail, and if I replace that assembly, I may as well replace the injectors too - close to $1000 Shocked

I'll probably be looking in some junkyards for the fuel rail/pressure regulator assembly, then rebuild the diaphragm with a rebuild kit I found at the parts store. Or cheaper yet, just the rebuild kit and work on the one I have. But first is to find the problem....

Twilightoptics · Posted: Sun Feb 04, 2007 10:36 am Post subject:

I'd just rebuild it yourself. It's usually just a matter of unscrewing the housing and putting in the new diaphram

BigDaddyVu · Posted: Sun Feb 04, 2007 12:30 pm Post subject:

have you tried a pressure leak down after engine shut off this will determine if your reg and/or injectors are holding pressure. the pressure should drop slowly. thats how i found a leaking injector on my i iroc.

Al Hasse · Posted: Sun Feb 04, 2007 2:32 pm Post subject:

Not yet. When I find my fuel pressure test gauge. I took off the upper plenum this morning to "visually" check the injectors, and in the process I found a hole in the hard vacuum line that goes from the throttle body to the charcoal canister. Wasn't a large hole, but a vacuum leak none the less. Maybe it contributes to the fuel smell???

My injectors:

#6

#2, #4

#1

#3, #5

I don't know if the crud around #3, #5, #6 is from fuel or just from normal sediment

BigDaddyVu · Posted: Sun Feb 04, 2007 9:28 pm Post subject:

thats fuel stains

blue89 · Posted: Mon Feb 05, 2007 10:17 am Post subject:

al,

if this is for your V6, the fpr can be rebuilt. ask for the rebuild kit. $14. Then go to the junk yard and get some injectors out of a lumina or corsica. If you're still running the original injectors on your 2.8 they could be gunked up. The pintle 15lb/hr injectors do that, the new disk style you will find in a cavi-cors-lum will be 17lb/hr but will have better fuel control. Then I would get an o-ring kit for the new injectors and put everything back together.

Al Hasse · Posted: Mon Feb 05, 2007 11:33 am Post subject:

Thanks Travis,

I already tried to find the rebuild kit for the fuel pressure regulator. It is for my V6, but it's the 3.1. The kit is not readily available, even in all the aftermarket books in the parts store. It's available it seems for all other applications except F-body, come to think of it, all the others are front wheel drive. I may be looking for injectors only.

blue89 · Posted: Mon Feb 05, 2007 12:47 pm Post subject:

Hmm. Last I checked, the FPR was the same on the 350 and the 2.8. Try that route, but I'm sure they have the part linked to both engines. I'll give my parts shop a try. Maybe I can give you search advice.

When I swapped over to my 3400 injectors it made a huge difference. The idle was way better and it had more umph. If you haven't done this swap I'd recommend it since you have it torn open anyway. The easy way to tell is to look at the fuel port on the injector. If its one hole with a needle, its the pintle type. If it has 6 or so small holes, then its a disk.

Xophertony · Posted: Mon Feb 05, 2007 1:28 pm Post subject:

hmmm.... looks like Tony has a fuel injector upgrade to do.... Very Happy

3.4L FWD injectors eh? now to find a set in the junkyard that are not high mialage....

what is the service life on the 3.4 injectors? how high of mialage is too high? this info will be usefull to both Al and I. Smile

blue89 · Posted: Mon Feb 05, 2007 1:36 pm Post subject:

Jeez, I dunno. As long as they work I guess. Very Happy

If you really wanted to geek out, you could attach the injectors to the fuel rail, pressure up, and then power them hanging over the fender to check spray pattern. Thats what I did.... It was AMAZING to see how much better the spray pattern was. You can't go wrong with this swap. It will take a few runs so you ECM can get used to the extra fuel tho, but once it does it will be fine.

Mine came out of a 94ish lumina with gen II heads and the short runner intake. It was the 3400 block.

I just called my regular sales guy at the parts store, and he couldn't find a listing for the fpr. I'll get back to you again if I find it. I know it exists somewhere....

Al Hasse · Posted: Mon Feb 05, 2007 4:41 pm Post subject:

I found a set from a 93 Cavalier 3.1 with 1/2 the miles of my V6. $60 for the set. When I broke the fuel line apart, there was still pressure in it, so these apparently don't leak. Just had them sent out for servicing/testing, which should be about $35 more. Still I'm under $100 for the set of six!!! I had a new set ordered for $45 apiece plus $10 core, but canceled that when I found this set.

blue89 · Posted: Tue Feb 06, 2007 10:06 am Post subject:

Did the new set from the 93 Cav have the 6 holes like I described? If so, they should be the new style and most likely 17lb/hr. Don't forget to get new o-rings if needed. Also, to make assembly go easier and to reduce the likely hood of damage when you put it back together, lube the o-rings with lithium or another non-rubber corrosive lubricant prior to fuel rail assembly.

One more thing, you may want to do a resistance check on your existing and new injectors. Just to make sure they are about the same. The new ones will be a little lower, but my computer hasn't had any problems driving them.

Al Hasse · Posted: Tue Feb 06, 2007 11:28 am Post subject:

No, they're the older style - single hole in the end.

Thanks for the tips - always new o-rings when re-installing, for reassurance if nothing else. Made the mistake of not lubing the one on my dizzy when I installed that, what a mess that made. Shocked

Twilightoptics · Posted: Tue Feb 06, 2007 11:35 am Post subject:

Guys, don't be swapping around different rated injectors unless you adjust your fuel pressure to even it out.

Otherwise your milage will go farther to crap being lean or rich. ECM's don't like to compensate for fueling. They like to add the fuel listed in the chip and call it good.

Dewey316 · Posted: Tue Feb 06, 2007 11:38 am Post subject:

I don't know that I would just go throwing parts at it either.

Al, I didn't chat with you about this at the dyno. Was it only rich at WOT on they dyno? How did it drive the rest of the time? And how rich was it?

--John

Twilightoptics · Posted: Tue Feb 06, 2007 11:40 am Post subject:

IIRC it was rich WOT increasingly so as RPMs went up.

Needs to get a scan tool on it to see the rich/lean around town.

BLMS are your friend.

Al Hasse · Posted: Tue Feb 06, 2007 12:47 pm Post subject:

I checked the part number of these injectors against stock and they are the same, I wanted to be sure of that. Went off-scale rich at about 3500-3800 RPM. I can post the prinout when I get home. Seems to drive fine around town, but randomly throws an EGR code, sometimes smells rich after slowing down and stopping at traffic lights and such.