1993 Chevrolet Blazer running thread

[TechnoLoGs]

Originally Posted By: css9450
Originally Posted By: TechnoLoGs
Codes 12 and 44.


Finally we are getting somewhere. This should have been done like 300 posts ago.

Not familiar with the difference between 2.8 and 4.3 Blazers, but I'll volunteer that at least on the 2.8s, the O2 sensor is reached from behind the passenger's side wheelwell. You'll have to jack it up and place jackstands. But its very easy. Plenty of room for the normal O2-sensor sockets they sell at the parts store.

Watch a few Youtube videos first for pointers.


May I ask what is up with "Universal 02 sensor" vs 3 and 4-wire leads? I want to get the somewhat expensive $70 Denso one.

Now, that said.. if I can jam a ratchet on there and get it off. And then wire it back up (hardest part for me.) As this is what cheap/fast shop will do. Is that fine ?

I have ramps........................................... But the shop wants to do it and seems to want to do it for free, and use smoke machine to see if leaks... but if 02 sensor, may not have to do leaks test.. though I must drive like this until first/only day off: Tuesday.

 

[PF52]

Originally Posted By: TechnoLoGs

May I ask what is up with "Universal 02 sensor" vs 3 and 4-wire leads? I want to get the somewhat expensive $70 Denso one.



Get the AC Delco one. You don't want to fool around splicing your old harness connector onto a universal sensor.

The extra wires are for ground and for the heating element in the O2 sensor (although to be honest, I would have assumed the 93s still had an unheated sensor, but no big deal).

 

[yonyon]

Definitely go with one that fits and plugs in without any extra complications. If you buy the semi-universal "fits nothing" sensor this will turn into another great saga complete with gnashing of teeth and rending of garments and whatnot.

 

[Astro14]

There are two reasonable choices:

1. Diagnose this.

2. Drive it until it blows up.

Stop buying parts, you're only guessing! And wasting your money. You must have a lot more money than I have...I can't afford to buy parts and chemicals the way you do!

 

[yonyon]

Astro14, he clearly has decided against driving it until it blows up. That may happen anyway, but it's not what he wants to do. This leaves diagnosing the problem then, doesn't it?

He hasn't got a gas analyser, a scan tool, a compression tester, or even a a simple DVOM. This means diagnosis must be hired out or done using the limited resources available. There is a lot to be said for hiring out the diagnostics, but given the quality of mechanics Techno Log has chosen in the past it's pretty much a wash whether he does it himself or hires a dancing llama to do it for him.

One of the resources he has available is the OBD system. That system is pretty much worthless without a known good oxygen sensor.

 

[JHZR2]

Originally Posted By: yonyon
12 is nothing. 44 is a lean code. Your gas readings show low oxygen/rich condition. Suspect faulty oxygen sensor.


Concur as suspect - but what about a vacuum leak or a leak somewhere in the intake??

 

[OVERKILL]

Originally Posted By: yonyon
12 is nothing. 44 is a lean code. Your gas readings show low oxygen/rich condition. Suspect faulty oxygen sensor.


Bingo. The ECM thinks it is lean? His emissions test shows the opposite. Probably a baffed O2 as you've noted yonyon

 

[yonyon]

Originally Posted By: JHZR2
Originally Posted By: yonyon
12 is nothing. 44 is a lean code. Your gas readings show low oxygen/rich condition. Suspect faulty oxygen sensor.


Concur as suspect - but what about a vacuum leak or a leak somewhere in the intake??


For a vacuum leak to cause this it would have to be medium to large and located downstream of the plenum chamber. An exhaust leak would have to be upstream of the catalytic converter and fairly large unless it's within 2 to 3 inches of the O2 sensor. A misfire or mechanical engine problem would be more likely than either of those but should present a noticable vibration.

 

[TechnoLoGs]

Originally Posted By: JHZR2
Originally Posted By: yonyon
12 is nothing. 44 is a lean code. Your gas readings show low oxygen/rich condition. Suspect faulty oxygen sensor.


Concur as suspect - but what about a vacuum leak or a leak somewhere in the intake??


Originally Posted By: OVERKILL
Originally Posted By: yonyon
12 is nothing. 44 is a lean code. Your gas readings show low oxygen/rich condition. Suspect faulty oxygen sensor.


These things are still possible, as it did stall out this morning (a first!) and sometimes still runs perfect. I still need to "go junkyarding" (hard, I work a lot and will have to try to find time to check a local place to see what they have when I have money) but I think I need to get the:

1. Radiator support/fan shroud
2. New intake plenum, the one that got partly chewed by the fan blade and is now taped up...
3. Fan shroud has where some hoses go, and don't right now.

Should i let the shop use their "smoke machine" to see for leaks? I ran a LOT of water through the engine brake booster. Maybe my exhaust is OK......... Just that sensor.. ?

Just speculating here. But I got up under there with the screwdriver, found my ALDL, freed it, paperclipped it, and found the code. Code 44. I also was surprised to see it say "lean" when we smelled exhaust at idle; and though I can feel air on my feet when the car is in motion, (?) I smell less exhaust.. I think..

I see a Denso "Oxygen sensor - OE style; Upstream; 4 Lead Sensor; O.E. Quality Replacement Sensor - 1 YR REPLACEMENT IF DEFECTIVE" for $57.99 at Advance.

Bingo. The ECM thinks it is lean? His emissions test shows the opposite. Probably a baffed O2 as you've noted yonyon

These things are still possible, as it did stall out this morning (a first!) and sometimes still runs perfect. I still need to "go junkyarding" (hard, I work a lot and will have to try to find time to check a local place to see what they have when I have money) but I think I need to get the:

1. Radiator support/fan shroud
2. New intake plenum, the one that got partly chewed by the fan blade and is now taped up...
3. Fan shroud has where some hoses go, and don't right now.

Should i let the shop use their "smoke machine" to see for leaks? I ran a LOT of water through the engine brake booster. Maybe my exhaust is OK......... Just that sensor.. ?

Just speculating here. But I got up under there with the screwdriver, found my ALDL, freed it, paperclipped it, and found the code. Code 44. I also was surprised to see it say "lean" when we smelled exhaust at idle; and though I can feel air on my feet when the car is in motion, (?) I smell less exhaust.. I think..

I see a Denso "Oxygen sensor - OE style; Upstream; 4 Lead Sensor; O.E. Quality Replacement Sensor - 1 YR REPLACEMENT IF DEFECTIVE" for $57.99 at Advance.

Oh, and I have an iPhone 4 (soon) to video/take pics to Youtube, in a few weeks. The S3 I bought (for $50) is still activated to someone's account.

It is ok. I only have one day off next week, so Sprint As You Go will be my service on a $100 iPhone 4. Good enough for me, I will accept that.

 

[TechnoLoGs]

Originally Posted By: yonyon
Originally Posted By: JHZR2
Originally Posted By: yonyon
12 is nothing. 44 is a lean code. Your gas readings show low oxygen/rich condition. Suspect faulty oxygen sensor.


Concur as suspect - but what about a vacuum leak or a leak somewhere in the intake??


For a vacuum leak to cause this it would have to be medium to large and located downstream of the plenum chamber. An exhaust leak would have to be upstream of the catalytic converter and fairly large unless it's within 2 to 3 inches of the O2 sensor. A misfire or mechanical engine problem would be more likely than either of those but should present a noticable vibration.


Do you feel I should have my timing inspected? Because I don't think the other shop wants to be bothered with it, so it may hafta stay lik eit is for awhile, especially since I don't get how the car can run with the distributor cap off... Plus, it's tucked way up at top of engine on the GM. You kinda have to lay on the engine to get to it (loose or off) and wow, another tight squeeze. This shop, They just want to change parts. (meaning, the 02 sensor, when I get it! They let people bring them the part, then they change it. They sometimes get it from a place but sometimes it costs.)

The truck has intermittent "wants to diesel or run-on" upon shutdown, sometimes doesn't at all (shuts off as it should) and sometimes makes a sort of attempt to combust after shutdown. I can't figure out why, except that it does not full-on diesel/run-on. (Though that too points to timing, IIRC.)

I know it is a simple thing but it may be just involved enough, plus the marks I can't see [censored] css9450 and cmorr have stated, for me to do, this simple thing. And I don't trust Advance to rush it, they check battery states 2 minutes after a car shuts off and call it accurate...

 

[yonyon]

Originally Posted By: TechnoLoGs

2. New intake plenum, the one that got partly chewed by the fan blade and is now taped up...


That's a fresh air duct, not the plenum. Air flows from the duct through the throttle body, then plenum, and after that the intake manifold on it's way to the engine.

 

[yonyon]

Originally Posted By: TechnoLoGs

Do you feel I should have my timing inspected? Because I don't think the other shop wants to be bothered with it, so it may hafta stay lik eit is for awhile, especially since I don't get how the car can run with the distributor cap off...


You've indicated there's good reason to suspect the base timing may be off. Get it checked. If the shop you're working with doesn't want to do that, cmorr seems to have a recommendation for a nearby shop that could help you a lot.

The timing is not checked with the cap off. Everything is connected and operating as a normal warm idle condition except for one wire that normally carries the signal from the ECM to the ICM commanding the advance. The wire gets unplugged, the whole distributor as a unit gets turned, then the wire gets plugged back in.

 

[TechnoLoGs]

Dumb question: Timing could make it "run with a miss" and sometimes want to run-on/diesel and sometimes shut off fine, likewise with running, right?

I an describe when check engine light will come on: Any speed over 60MPH, more or less. Then, eventually, when at lights, it will go back off.

Now, with leaving ALDL jumpered, will it blink the code then I am going 70MPH? Just before I see the SES light come on, the RPMs race up and I feel a "push" of sorts, as I don't press harder on the gas pedal, but I feel it and then, BOOM! SES light.. Then I give it throttle about 5 minutes later and it goes off and the light comes on again in town then shuts off again when at a light, sometimes 2 minutes sometimes 10. That is what it does...

 

[TechnoLoGs]

Originally Posted By: yonyon
Originally Posted By: TechnoLoGs

Do you feel I should have my timing inspected? Because I don't think the other shop wants to be bothered with it, so it may hafta stay lik eit is for awhile, especially since I don't get how the car can run with the distributor cap off...


You've indicated there's good reason to suspect the base timing may be off. Get it checked. If the shop you're working with doesn't want to do that, cmorr seems to have a recommendation for a nearby shop that could help you a lot.

The timing is not checked with the cap off. Everything is connected and operating as a normal warm idle condition except for one wire that normally carries the signal from the ECM to the ICM commanding the advance. The wire gets unplugged, the whole distributor as a unit gets turned, then the wire gets plugged back in.


Yes, I would have to drive to PA to go to cmorr's shop but at this point it is not outside the realm of possibility. I will have to Google Maps it. They can check timing.. not adjust?

That, or I need to see if my co-worker's shop in NJ can do it, or wants to. Describes an "honest mechanic" so I am not sure if I should run from that...

Address
3055 W Chester Pike
Broomall, PA 19008
610-353-7900

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=3136441#Post3136441

^^ Though "Chester Pike".. If that is anywhere near Norristown's Germantown Pike or Ridge Pike then it may not be so far...
**Edit: It's by Upper Darby.. OK, I see it. Two hours out. I would call first but.. Ok I see a general picture forming.

 

[TechnoLoGs]

I am soo happy the Blazer runs and drives as it is while I go see what is what with what!

I think that means the engine has promise.. ?

 

[cmorr]

Originally Posted By: TechnoLoGs

Yes, I would have to drive to PA to go to cmorr's shop but at this point it is not outside the realm of possibility. I will have to Google Maps it. They can check timing.. not adjust?


The place I recommended is the the Keystone AAA Diagnostic Center. This is owned and operated by the Keystone AAA as a diagnostic center only. because they don't make repairs they have no conflict of interest, they are well rated and have the equipment. You would leave with a detailed breakdown of your car's health and recommended repairs. You could book a follow-up with them to ensure repairs done elsewhere were performed properly. I used them to diagnose a fuel related issue that stumped a large Phila BMW dealer. I also used them for my sisters Honda that had a bizarre intermittent stalling issue

 

[eljefino]

Dieseling and running on pretty much stopped when they stopped making carburetors.

This means you have something letting fuel in after you turn off the ignition.

A leaky fuel injector is on this short list.

Though I guess you can do it also if you are running real hot from bad timing.

Go somewhere competent already for an hour diagnosis! Just bring it to a random garage near DD's and have them look at it while you work.

 

[Gabe]

Originally Posted By: yonyon
You've indicated there's good reason to suspect the base timing may be off. Get it checked. If the shop you're working with doesn't want to do that, cmorr seems to have a recommendation for a nearby shop that could help you a lot.


I don't think the timing can be checked.

In '93, GM used some electronic advance timing system. In order to set the timing, the computer - brown wire on the firewall - was disconnected and the timing set to line up with the marks. When the wire was reconnected, the timing was relearned.

 

[AVB]

Originally Posted By: Gabe
Originally Posted By: yonyon
You've indicated there's good reason to suspect the base timing may be off. Get it checked. If the shop you're working with doesn't want to do that, cmorr seems to have a recommendation for a nearby shop that could help you a lot.


I don't think the timing can be checked.

In '93, GM used some electronic advance timing system. In order to set the timing, the computer - brown wire on the firewall - was disconnected and the timing set to line up with the marks. When the wire was reconnected, the timing was relearned.


It still needs to be set to 0° with the wire disconnected.

Code 44 makes sense because a defective 02 sensor can make the pcm think the engine is running leans so it will compensate causing the rich condition that caused you to fail the inspection.

 

[RF Overlord]

Originally Posted By: TechnoLoGs
I also was surprised to see it say "lean" when we smelled exhaust at idle;

Originally Posted By: AVB
a defective 02 sensor can make the pcm think the engine is running leans so it will compensate causing the rich condition that caused you to fail the inspection.

^what AVB said^^^

It's also possible when they put in the new motor they somehow damaged the O2 sensor wiring...check that before you waste $70 on a new sensor.