TruckU

I'm still trying to get my lightly modded '93 (see signiture block) to pass emission testing here in Western Washington (pass is 40% opacity or less) . I started out with Opacity of 65-70% on the first 2 tests, did some basic maintenance (cleaned the K&N filter oil out of the turbo blades, filters, fuel treatment, etc) and got an 80%!!! Had the truck checked out at The Power Shop in Enumclaw. They said it ran well, but smoked heavily before lighting off the turbo (gee ya think??), and recommended a 12cm WG housing to get the turbo spooled quicker. Estimate of $800+... and I've read that the 12cm isn't great with heavy loads and hills.

BTW, I should probably mention that the pump and injectors were (supposedly, but that's another story) modded by the original Dr. Performance, before he got bought out. What those mods were I don't know, but he advertised higher crack pressure, injector tip mods to alter spray and atomization, and "fuel delivery" mod's. It seemed to work well for several years, making 237.8 RWHP, but had gotten soggy lately, milage has been dropping a little, and more smoke under light load driving. I have to get it thru emissions to get Washington plates now that I'm retired military, before I get teh big ticket....

So, since the last miserable failure I've done the following: backed the smoke screw out 2 turns, backed the starwheel out 2 turns, took 90* out of the fuel pin, shoved a folded newspaper under the loud pedal, and replaced the red/green AFC spring with a factory (91) silver spring that is considerably stiffer. Truck seems to run MUCH better, almost no smoke in the side mirror when pulling away (slight haze if the light hits it right), doesn't lug from 1200 rpm, but does have a slight lag before the power starts to roll in on acceleration (probably need to put about 1 turn back into the smoke screw). Anyway, on today's test attempt it took about 12-14 throttle cycles (normal is 3-6) before it finally gave me a fail with 55% opacity.

So, here's the $5 question, What can I do to get it down under 40%, without going deeper into the pump. Should I back the Star wheel off like 5 more turns? I am going to double check the fuel pin to make sure I took out fuel and didn't add more, but I turned it 90% counter clockwise to the highest offset. I have the bone stock pump from the '91 if it comes to that, but would prefer to do it with my pump.

Sorry for the long post, but I'm still learning (first time in the pump!!!), but PLEASE give me your serious suggestions, besides modding the turbo, or professional pump work. I don't want to loose the Dr. Performance mod's completely as it was getting 18-19 mpg in town and 21-22 highway empty, and 15-17 mpg towing a 10K 5th wheel, and went up any pass at 60+ with the trailer.

Thanks,
Gary B> Truck U

Alwaysworking

you can turn the fuel screw out some,
buy a used 12cm exhaust housing for cheap, i found a good core hx35 on CL for about $150 in spokane so they are not $800 and changeable yourself, they work for towing but with mine with the same compressor housing you have and it surged, so then you need a comp. with an mwe slot which can be had for $205 and they flow more air, or if you can find a good hx35 you'd be doing good.

gear jammer 91"

I took my bosses slightly breathed on 93 that failed with a 49% here in clark county and got it to pass with a 4% percent. I rotated the fuel cone so it was as close to the front of the pump as possible, turned the starwheel up a couple turns, backed the smoke screw out until it was almost completely out of the top of the pump and backed the full power screw out one and a half turns. The truck was a gutless pig on the way to the test station but as soon as it passed I turned it right back up. If you need a hand and your in southwestern Washington send me a P.M. and I might be able to help you get it to pass.

pulltilbroke

Yea pull your pin and make sure the shallow side is towards the front, other than that what they said

big stinky

Im hoping when you say "back the starwheel off" you are bringing it up. Lowering it removes spring tension blah blah. The higher it is, the more preload on the spring, = less smoke before spool.
If you crank it right up the spring will bind cutting out a lot more fuel on top of a tight spring.

TruckU

Thanks for the replies, sounds like I'm on the right track... need to use the truck this weekend, so I'm going to leave it as is for now, and play with it more next week.

To answer some questions (and maybe ask a few more) Yes, I am raising the star wheel for more spring pressure. I'll check the fuel pin, but I thought highest side was less fuel, and most offset was most fuel (IE the little pin that rides on the fuel pin has less movement = less fuel, more movement = more fuel)

big stinky

Ya, your right...

Maybe check your downpipe for oil? As in bad valve seals or seals in your turbo...

apwatson50

Yep everyone's got you on the right track, just:

1: Back the star wheel counter clockwise until it just barely engages the latch.

2: Back the smoke screw out until it is flush with the inside of the top.

3: Turn the pin to the most shallow side.

If those 3 things don't make the truck pass then you'll need to back the fuel screw out.

Fred Swanson

What RPM are you running it up to? Try to keep it under 2500RPM too. I can make my 93 in my sig pass, by just putting a stock fuel pin in with the steep side forward, and bring the spring tension to the top, and make sure the smoke screw is almost all the way out. 16-17% every year.

Bone stock 3 years ago, it did 36%. That was revving it up to about 2800RPM.

TruckU

Mine starts cutting fuel at 2300, all done by 2500. I'll back everything down and see what it does next week.

Thanks again..

whereswaldo250

When I went in for emissions I failed the first time with 44%, but then when I put on the bhaf and set my high idle to only ~2300rpm, along with rolling my foot on to the throttle instead of abruptly smashing the pedal I blew a 2%.

My 2 cents

gomerpile

well you might be able to sneak away with a valet switch (check the sticky). i have one on mine and it goes from about 32psi of boost at full load to about 17-18psi, that and its easy to change.

also your smoke problem off of take off , b4 lighting the turbo, is probably the fuel pin gettin deep (or it was my smoken problem at least) or if you think the switch is too obvieous just remove the afc line, and put a 1/8 npt plug into the intake manifold to block it off and keep your boost.

i hope this helps, it helped me hide the true power of the beast from my dad for a few years,(until he was so sure of himself he said he wanted to race if you get my drift)

TruckU

Okay, so here's the mod's today, and the emissions test results:

I backed the smoke scew out until it was loose, 3 more turns up (counter-clockwise) on the star wheel, verified the fuel pin is on the highest side of the offset, and disconnected the boost reference line to the pump.

Last attempt (#5) was a 55% opacity, today was a huge reduction!!! I failed with a 54%

So, I'm a little ******, frustrated, and now, not sure what to do. I'm thinking that I may have one (or more) injectors bad, or the injector mod's may be like I've heard about PODS, just no way to get them to back down.

I've got a bone stock pump from a '90 that I can put on if I absolutely have to, but I'm thinking a set of bone stock injectors would probably help more than the pump at this point. I've got eh one for the spare pump, but they are the 9mm ones,and the '93 takes 7mm.

Any other ideas before I start getting too much deeper into this thing???

Alwaysworking

turn out the fuel screw

TruckU

where is the fuel screw? I'm still learning this stuff as I go, had never even been inside the pump until about a week ago