'87 Suburban emissions parts

[RecklessWOT]

'87 Suburban emissions parts removal

So I've got an '87 suburban K(V)10 with a 350TBI and a 700R4. It is completely original (minus some maintenance items obviously) and unmolested. The truck has the high altitude emissions package on it because I bought it in CO but due to its age I am not required to pass emissions here in NH. This thing is so underpowered it's not even funny, slower than frozen dog ****. I know it's a big heavy truck and am not expecting it to get up and go, but it feels like it is choking to death. I had an '87 pickup a few years ago and it had way more balls than this. I want to do headers with cat-less exhaust, maybe an x-pipe into some 40 series, and an intake. I also want to strip as many emissions parts without screwing up the way it runs. I think that air pump may be seizing up somehow because when I get on it the belt squeals regardless of the tension on the belt. Not sure if that would have anything to do with it. Also, I'm not so sure what's different between the high altitude and federal emissions set ups, I assume it would be more restrictive to compensate for less O2 in the air and using 85 octane fuel? Any advice is appreciated, I'm looking to free up a little power without doing any real engine work. I want to take off anything non-essential to a proper running engine, especially stuff that may rob power.

 

[bucket]

Remove the smog pump belt and see if you get an improvement. Also check the timing, if anyone messed with it before, they might not have known to unplug the timing connector (single tan wire with a black stripe). That will cause the timing to be retarded and lack power, but otherwise run well. The factory calls for 0* of advance, but the truck will be MUCH more peppy with 6-10* of advance. Getting up around 10* you have to be careful with detonation though, might have to back it off a couple degrees or run mid-grade fuel.

Also would be a good idea to check your fuel pressure. The pump can be weak enough to cause a lack of power, but still strong enough not to cause any drivability issues. IIRC, you want to see 17-20 psi from a stock TBI pump.

 

[skysurfer]

IIRC, you want to see 17-20 psi from a stock TBI pump.

The average pressure from a stock pump is more in the 15-16 psi range. If you're seeing higher than that consider yourself lucky. There's nothing wrong with a pump that's *only* putting out 15 psi since the stock fuel pressure regulators are set with a loose tolerance of 11-13 psi and anything above that is just returned to the tank. For a stock engine though, you want to be at the high end of the range and see 13, even 13.5 psi. If you're seeing less than that an adjustable fpr and gauge should be on your list of things to do.

Keep in mind that with 210 hp your truck is never going to feel fast and the 4x4 is an extra weight penalty. I drove a friend's '90 4x2 Suburban with the same engine I have and even though his was poorly maintained it felt like it had a 50 hp advantage.

 

[RecklessWOT]

Thanks for the responses guys!

So taking the air pump off won't mess with anything? It really doesn't serve a purpose other than emissions? I always thought it had something to do with the way the fuel injection system works. Good to know, I'll try that and see what happens.

And I actually was thinking about advancing the timing somewhat because I know it will help, though I hadn't thought about the possibility of the fuel pump being on its way out. I'll have to check that out too.



As far as the truck feeling fast, I realize it's a big heavy suburban and it will never feel "fast". But this thing feels exceptionally underpowered, like 305 kind of slow. Every other square I've ever driven has felt much more powerful than this. The '87 pickup I had felt a lot better than this, and it had the exact same engine and tranny. I know the p/u is lighter than a burb, but this feels like more than just a little extra weight here. Even when the bed was completely loaded with scrap metal it felt like it had more balls than this. I guess it is possible that truck could have had 4.10s or something cause I was like the 4th or 5th owner and the gears could have gotten changed anywhere along the line, and I am positive my suburban has 3.73s. I don't know though, I really feel as though this truck is not performing at 100%, I find it hard to believe this truck had such a hard time moving itself around when new. 210hp isn't a lot, but it's not terrible either, plus it makes much more torque than that.
Also, the 2wd feeling faster than the 4x4 is more than just the added weight, any 4x4 loses more power through the driveline than a 2wd truck because of all the extra moving parts.

 

[skysurfer]

Too bad you're not closer, it would be fun to have a 1/4 mile race between our burbs. If yours is anything like mine we would have to do the timing with a calender instead of a stopwatch.

 

[RecklessWOT]

Hah

Yeah I'm running 8 seconds in mine
for the 60' that is anyway.