88mjblue

Readjusted throttle body according to tip #14, still the same. I did some other testing: - CPS test: 0.6 AC volts cracking, so all good there - EGR valve test: passes valve closing test, but did not see anything moving with valve opening test.. could this be my problem? Anybody have a picture/video of what EGR opening should look like?

Possibly, but not probable. Revisit your TB adjustment. I plan to take TB off completely again and adjust that stop screw from scratch. I also had the thought that maybe the TB gasket was not seated properly. Is there a possibility of the butterfly being too closed? I mean as long as it is not digging into the metal, I adjusted it so it is resting on that screw, but it should be closed down as much as possible, right?

Oh, and I noticed the knock sensor had some frayed wires, would this affect anything? I couldn't figure out how to unplug it to test for continuity to ecu...

Some updates: - Re-tested oxygen sensor, heater is working supplying 13.8 V, and 5V to ECU - Tested for continuity from O2 sensor plug to ecu, all good. - tested coolant temp sensor, got 243 ohms at operating temp - coolant temp sensor continuity good back to ECU - air intake temp ohms correct, signal reaches ECU as well - air bleed torx screw adjustment did nothing - tps retested and still at 0.83 V Idle was fine before I removed throttle body and cleaned it out and adjusted butterfly stop screw, I must have done something during that job... Right now I'm tempted to adjust Bob's stop screw and get it back to normal, even if it's masking the real problem.

What about adding some ATF when you flush for some real detergent cleaning, anybody do that?

Subscribed

The wood stick worked for me, but I will keep this in mind for other softer sounds, and for sounds that occur when driving. Update: the rattling noise is gone! Noriyori_Kudo^ was correct, it was in fact the front alternator bearing. Rather than taking the alternator case apart and replacing the bearings, I decided it was time to upgrade, and put in a new Bosch 100A alternator I got for cheap.

Definitely going to be on the lookout for a 14 bolt – rear end labor gets expensive. It's good to know they're still available and affordable it seems. Loving the SM465, that Granny low is superb for 4 Hi semi-crawling when you don't need to go to 4 Lo just yet, and when you do put it in 4 Lo, even with stock 3.73 gears and 285 tires, it's INSANELY low range (from what I'm used to: ax15/np231 low range ratios). The 3rd gear 1.0 ratio is okay for highway, keeping it at 55 mph though for the mileage. I do miss having 5 gears though, but this transmission is legendarily bulletproof from what I've been reading. Needs work inside and out, I bought it for cheap, and plan on having it as a project car, I don't trust it for long trips just yet, and have not registered it yet until I can get it to pass emissions and complete other repairs needed to be safe. Major repairs on the list so far: - radiator/cooling system overhaul - steering box replace - rear end replace - full tune-up, fluids, cleaning/degreasing - oil pan gasket - exhaust overhaul: hangars, tail pipe, cat, muffler (probably keep stock manifold) - pads + rotors, wheel bearings packed - windshield - headliner

1987 3/4 Ton Chevy Suburban 350 SBC TBI SM465 Trannsmission 285 Mud Tires Front + Rear A/C Stock Suspension GM 14-bolt 9.5" ring rear end Dana 44 Front NP208 T-Case Leafs All around Needs a bunch of work, including a headliner needed badly:

I recently picked up an '87 suburban with a TBI small block 350 (my first V-anything) and need to learn the in's and out's of this engine, and these vehicles in general (the '73-87 GM pickups, blazers, and suburbans). Where should I look to read up and learn more about this? My question is if there is anything out there as good as Comanche Club, but for chevy truck stuff. I am very new to GM, everything I know about cars is from Chrysler/AMC XJs, MJs, TJs, the renix 4.0 and the cryco 2.5L What's the best forum for these trucks? Anybody on CC that are chevy guys too? (I've found gmsquarebody.com, chevytalk, 67-72chevytrucks.com) Interestingly, I found that some forums required you to pay? Thanks comanche club for being free! Also, the rear end (14-bolt full floater) is toast. The mechanic I took it to before I bought it, estimated repairs were at least $750 for a ring and pinion to get started, could be more damage once opened up. Should I try and fix it myself, or just get a whole new axle from JY?

Hey everybody, thanks for trouble shooting me through this, what do you make of this recent discovery: - I have the engine at operating temp, idling low at 500 rpm - I loosen TPS, adjust it up till idle goes to 750 rpm, tighten T20's back down - idle stays there, I think everything is back to normal, yay! - I drive it around for a bit, rpms go back to 750 like it should at idle - I get back home after a 5-10 minute drive, the idle is back to 500 rpm again..... Maybe I don't fully understand the tps, and that is normal behavior. Anyway, I re-adjusted the tps using 17% of 4.88 = 0.829 V, and I'm back to square one here. Also, I went through the throttle's full motion and watched the tps voltage, smooth throughout the range. Is it safe to rule out the tps, or did this adjustment test prove anything?

O2 sensor heater is working, and although I don't have an analog meter, I did see 1-4 volts alternating, so I think O2 sensor + wiring is good. i read it could be related to intake/exhaust gasket, and I did notice this checking it out: Seems like just one bolt is missing, not sure if that's a big deal, but I will get a replacement from the junkyard soon. I also have the 746 injectors and am thinking I will combine jobs by taking fuel rail off, replacing intake/exhaust gasket, re-torqueing with all bolts present, then putting in the new injectors.

Checked the relay, it's good. (clicked 85-86, and 0 ohms 34 to 87) Checked the wiring to the O2 sensor: - could not get 12-14V from the heater (orange wire) - got 5V solid for O2 signal to ECU - 0.01 ohms ground to neg battery (A = orange (heater); B = black (common ground); C = grey (O2 - ECU) <---- This is correct, right? For the heater test, do I need to have the engine running and back-probe? Or can I just have ignition on?

I've got a brand new NTK O2 sensor in there.

I read through another thread on here that had a similar problem, and thought it might be the O2 sensor. I replaced the O2 sensor today since the one in there was one from 1990 and I wanted the peace of mind. Anyway, that didn't do anything, still the same. I thought I read that renix 4.0s don't have a warm-up idle, is that true? It seems once the t stat opens up the idle drops to 500, weird...

Also, it's still exhibiting the "hunting idle" syndrome (or HIS)

Still having trouble with my idle here... I thought it could have been the IAC valve since I tried cleaning that really well and thought I may have damaged it with all the throttle body cleaner I used. So I purchased a new one and installed it today. No luck, may be even worse now. I have the same problem: idles around 750 rpm, but once it gets up to operating temp, then it drops down to 500 rpm. However, this time I noticed that when I revved it up it almost stalled when it dropped back down, so I shut it off and left it at that. What could that be? Why would a brand new iac make that condition worse? For what it's worth, I bought the Standard Motor Products AC12, I read that was a good quality one.

You are exactly right! I went through my fairly detailed maintenance history and it does show a "flywheel sensor" done in March of 1989 from a Jeep dealership. I'm assuming that's the CPS? What would be the reasoning for a CPS bypass?

Do you mean the CPS? (crankshaft position sensor) Because that is what you see in the background - that's the connector that goes to the cps.

I was just looking up alternator bearings, they're only ~$10, so maybe I'll give it a shot if it's not too difficult. I am almost 100% certain it has the original alternator, and it has 110k+ on it.

I think that could be it. I got the belt off again, and used some wood to listen up to the alternator best I could, sounds like it was coming from there, but couldn't rule out the harmonic balancer, hard to tell - I put the pole to the oil pan near the balancer, but not as clear as up to the alternator. Take a look at this vid I took of the alternator spinning freely. Is this a normal sound for alternator? All other pulleys sounded fine. (Except balancer, I could not spin it, obviously) From the maintenance records I have (which are pretty detailed) it seems (and looks) like the original alternator - it works fine, just might need to be lubed? https://youtu.be/yPi22M04xaE

What about the harmonic balancer? Can I rule out the balancer or not? Spinning with the belt off doesn't make the noise, but maybe the load of accessories would make it sound?

Here's a better picture. Hard to tell color because of fading due to heat/age. But it looks like yellow w/tracer and pink w/tracer. Also has C B A on it.

Revisiting this Cruiser tip, I have a coupe questions: 1) What size socket for those bolts the tubes? (Last time I had the cover off I didn't have an SAE socket that was small enough) 2) Confused on where to drill the hole. The first picture in the tip follows the instructions and has hole drilled near end of tube where cut was made: The next pictures show the hole drilled close to the base where it attaches to the valve cover: Finally, holes facing rear of valve cover? Does this mean facing the firewall? Or facing the driver's side?

There's only 1 O2 sensor, correct? The O2 sensor that goes into the bung around the collector is plugged in and is wired underneath the intake/exhaust manifolds.