'87 Suburban, help diagnose engine problems (long)

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To start with,, I would address the oil leak first. Since you've grown shy of mechanics or technicians, I would probably try an additive, I'm not generally in favor of them but with your situation I'd make an exeption just
to determine what's up with the leak. I would start with something like Lucas since it's the only one I can think of that's everywhere & works. Wait for a week or so after you put it in to see how it's working. Before you do this step tho,, you should confirm that it is in fact, an engine oil leak, & not the trans. OK ?? Surely someone close to you could determine the difference. Let us know how you do on this step. I actually had really good success with this situation just recently, and in a BBC motor too, mine turned out to be a really dirty crankcase,,so maybe it's not gonna be all that bad. Cheer up & Good Luck Rich

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Timing must be adjusted for altitude. Which way? I don't remember, but I can tell you this. Get a good consensus before doing it. I know, I know, thats what you are trying to get. Good luck, I really don't think anyone knows anymore.

Might have to do that one twice more. Seriously though, you do have to get the correct one, and few know which one that is. If you find anyone let me know.

Yes, keep changing it until you get all the bad gas out of the tank, then go to Standard or Texaco only. If you can find one. These older vehicles will not run on the shit gas of today.

Be sure you get the right ones. Delco, same ones that were on it originally. Good luck finding someone who knows what they were.

Ouch!
88 were plastic gears in the transfer case, and changing them will not help if you have non standard tires.

Probably bad injectors, or the wiring to them, or the connections. This could be several things, but it was my problem.

I would say if it does this, you probably do not have a bad camshaft, but its worth investigation before spending all the money for stuff on the outside of the engine.

It will be back.
DH says the exhaust is rich (raw fuel),

If its TBI, look at the top of the injectors. is there any corrosion?

Yes, but not black smoke.
The 1st set of new spark

Yep, consider the cam shaft again, main bearings too.

So? lean mix, rich mix, you decide. It don't mean shit.

Its an old rig, why would you expect any difference? Its not going to be fixed by all the outside stuff you want to try.

Rear main seal.
I think the leak had been slow,

Find someone who is a reliable rebuilder, and not over 60. Good luck. Check long and hard on this. I mean very long and hard.

Typical
The guy at the counter

Typical
Ha, ha ha. Get a second and third opinion, and don't give them a dime, get an estimate, then decide.
My Q: how

Yep.
He's full of shit.
And the

He don't, but he knows you don't. Blue smoke would be rings cause its burning oil at startup. Now don't go and change to blue smoke from black just to placate me, or yourself.
and he recommends I

He recommends this, because with a new engine, you will get a reman engine. Maybe a 30 day warranty or 1,000 mile if you are lucky. If you can find someone who knows thier ass from a hole in the ground, and I doubt it, present company excluded unless you bad mouth me. IF, and I say IF you can find someone to rebuild it, using a rebuild kit from Sioux City, Ia., and knows their shit, you will get a 12 mo., 12,000 mile warranty at least.
He'll do it for me for $6,000.
Wow! Only 4K too much. not bad.

Yeah, don't you know, we through them away at 100K. Jeesh. Not cost effective, but it is in his case for 6K.
So perhaps he

Diagnostics are a waste of time in this business, unless you know your shit and he don't.

10 minutes worth of bullshit.

Probably.
If so, do I need a new one? I plan

Then spend the money, but not with this guy.

You can't really, unless you want to become your own auto mechanic. Which you may have to do if you expect to get what you want. Or pay the man, and get half that.
I guess we should fix

Umm, wait.
and see if I miss any more oil. And get the

Makes no difference unless compared to original specs.
About the O2 sensor;

Not yet, no. See if you can find a rebuild man, but get customer's who have used him before you decide to do so. I just went through all this very crap you are talking about, and I spent 4K before I got to the rebuild. Fixing shit on the outside will not fix the inside stuff, but who can do it? Its a dying art. Its not cost effective anymore. It will be in a year or two after deflation straigtens everything out again. You can get gas 350's for a dime a dozen now, gets some horsey's in it with a cam if you want. Now I don't know if this will swap in, w/the tranny but don't believe what everybody says on this either. Every mechanic I ever talked to in the last 20 years is a bullshit artist. You get the bullshit detectors out if you talk to enough of them. and they all accuse the other of lying. Unless perhaps they happen to work together, but even then its debateable. These guys have went by the wayside in our throwaway society.
Its just something to look into. You may not have to go with a 454, and get as much power, with better mileage. Depends on what you pull, our tranny, and lots of other things I don't yet know any thing about, etc..
Hatt
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After reading the replies to your questions. I have some points to ask. Do you know if the ECM has been replaced? The spedo cal is in the ECM ( I think for 87) It sounds like the prev owner changed the ECM to try to fix the MIL condition. Just a thought. get the numbers off the top of the ECM and check it. You may have a bad ground connection somewhere, or just a bad connection. O2 sensors last a while. Oil leak , rear seal. Not really a big deal. With 135k on it, do you know what use the prior owner subjected it to? Heavy towing? stop and go? If it was a heavy service then I'd opt for a New power plant, (maybe trans too) if the Body, interior, and under carraige are in very good shape. Was it ever in an accident?
Cheers Martin

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But not for an 88? There is no speedo cal in my 88. They tell me that didn't come till digital speedos and nothing in those 88 ECM's concerning those driven by a chain of mechanical gearing, cables and the use of magnets in the speedo at the dash to translate the vehicle speed for your eyes.
It sounds

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I wasnt sure, and your correct. It a cable driven speedo. Perhaps the previous owner had a junk yard tranny put in and never put the right speedo gear in.
Martin

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replies in-line

I'm assuming you mean that at 80 it reads 60, not 40
anyway, the speedometer drive and driven gears can be changed to fix this
you will need to remove driveshaft and take off tail housing to see what gears you have (tooth counts)
let me know what you have, I'll send you the proper ones

at 7000 ft, I've seen a lot of tow vehicles do this, especially up a long grade
the ECM is basing fuel rate on your starting altitude, and as you climb, the mixture becomes richer because the air thins out (3% per 1000 ft)

I see you've changed the O2 sensor twice. get the fuel pressure checked, make sure it's in specification

rear seal needs replaced, which will necessitate dropping transmission

lots of engines are going strong at 135k
these 'mechanics' sound like parts changers to me

your check engine light should be out and stay out (if you authorize the work recommended)
you should be informed what was done (or needs to be done) to get to that point
pay via credit card, if it doesn't pan out, call the c c company and dispute the charge

listen: if it tows 3 k at 7000 ft, it's pretty damned healthy in my book

check fuel pressure
get actual compression figures
oil is cheap, a quart in 1000 miles is not too bad, just keep it full
you cat converter is probably OK, if it runs like you said it does.......... as I recall these have 2 converters, and I've seen the rear one plug up on a couple Sub's.........but it was totally gutless when it did
G
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Back in September, I wrote:

This is an interim update. We still haven't solved all problems, but I think we are much closer to doing so. Some problems we discovered were due to spark plug wires. The first replacement set DH installed melted (a big block engine will do that, if you don't know to buy wires that will hold up to the heat). Then, the second "idiot mechanic" who looked at the engine neglected to re-attach one spark plug wire. I knew the engine was "off" when I got it back but I did not see why; DH saw the unattached wire as soon as I got the truck home from the shop.
Taking the throttle body apart, DH found extreme wear, to the point that the valves tended to stick and when closed could not prevent flow. That alone could explain most problems with the engine, and also explained the chronically "sticky" gas pedal. DH replaced the TB core and all gazillion gaskets; soon after, the truck started to stall when coming to a stop or near stop, and would not start again easily. Taking the TB apart again, we found the new gaskets were leaking. So, DH installed a second new set of gaskets. Now, for the first time since we bought the truck one year ago, the engine runs very smooth and idles slow. The service engine soon (SES) light still comes on as soon as the engine reaches normal running temperature, but now that may be due to a fouled O2 sensor. (The only code ever pulled off the computer is the 02 sensor complaining about a lean fuel mix; reading the sensor directly shows it was seeing alternately too rich and too lean fuel mixes, that mix way out of whack.) The current sensor is only a few months old, but the constant fuel flooding from the worn-out TB may have fouled it already. So, the next step is a new O2 sensor. If that doesn't do it, then a visit to a good (non-idiot) mechanic with diagnostic equipment to monitor readouts while the engine runs.
By the way, we also discovered that a previous owner removed the engine thermostat, which DH promptly replaced, grumbling about "yahoos". When we first bought the truck, the engine could not reach its normal running temperature; the missing thermostat was the reason why. Did some idiot remove it in an attempt to "fix" the chronic SES light and "lean fuel mix" error code from the O2 sensor?
Old problems remaining from September:
1. The speedometer and odometer both are inaccurate, by the same amount. This is still true, and the problem has to be the wrong speed/odometer gearing inside the transmission. Leave it alone until the transmission needs work for another reason; meanwhile, take extra care not to speed.
4. Engine oil is now dripping from the back of the engine, where it joins the transmission. Still dripping, but seems to be slower; keep an eye on it and plan to fix it reasonably soon.
New problem:
1. Cruise control died. Don't really need it, so fix it later.     Una
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On Sep 18 2003 (yes, that long ago) Una wrote:

That's a code 44, FWIW.

I guess it was more than they wanted or were able to take on, but they chose not to say so. Because they were not up front with me, they will get no more of my business.

This shop at least took a stab at the problem but they did not get far with it. Instead they tried swap-parts-until-it-goes- away, beginning with just about the most expensive part. Pass.
More than a year later, I found Shop #3, and Shop #3 fixed the SES code 44. A previous owner had the transmission replaced, in which job the wiring harness got pinched. So the computer was getting garbage data from the O2 sensor. The fix: patch the wiring harness. Cost: $180.
Of course, to *find* the source of the problem took hours of work, during which many other problems were found and fixed (mostly leaks: vacuum lines, gaskets, fuel injector), so the total cost came to $1800, but that is money well spent! Shop #3's compression test showed a nominal 140 (outstanding!) on all cylinders. So I don't need that $6,000 new engine block.
This truck suffers rubber rot (no surprise given its age and the climate here in New Mexico) so a lot of money is going into replacing the gazillion hoses and tubes under the hood, as well as all door seals...and the tires...and and and. But still it is a good deal, financially. New, a 3/4 ton Suburban with the functional extras this one has would cost $40,000. And because depreciation has run its course, I feel comfortable driving it where few people would risk driving an expensive newer truck.
    Una
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