Group --

I'm not only new to the forum, but new to diesel's in general -- please excuse any stoopididy here.

The Glowplug light in my 89 suburban 6.2l comes on during a cold start only about 20% of the time. Multiple reinsertions of the key won't get it to come up, and I have to crank the engine for 5-7 seconds before it will fire, and then there is a fair amount of white smoke. When the light (and I assume, the Plugs themselves) are working, the engine turns over instantly, with much reduced or no smoking.

The plug light generally then comes up when the engine has has some run time during the day, or when the temp is such that they are not needed.

Would this indicate a temperature sensor going bad, or that the plugs themselves are headed south, or?

Any input would be appreciated. Thanks!

Jonathan

Sounds like the Glow plug sensor

along with the glow plug sensor there is a two prong glow plug temp inhibitor sensor that can cut the power to the glow plug sensor and the glow plug or sensor won't come on. i wired past mine. its been so long ago i cannot tell you where it is located. it is screwed into the head i think on the rear of the passanger side head or on some i think it is up by the injection pump screwed into the coolant cross over tube. some one here will elaberate or do a search on glow plugs

Not all that popular around here, but I just swtiched the glow plugs to the more stout version and went the manual glow plug route. Very straight forward.

Welcome to the forum! Don't worry about working on a diesel... They are really simpler than a gas engine.

Not all that popular around here, but I just swtiched the glow plugs to the more stout version and went the manual glow plug route. Very straight forward.


Hey, the manual plugs are popular, they are just not as "idiot-proof" as the standard setup...

The Glowplug light in my 89 suburban 6.2l comes on during a cold start only about 20% of the time. Multiple reinsertions of the key won't get it to come up, and I have to crank the engine for 5-7 seconds before it will fire, and then there is a fair amount of white smoke. When the light (and I assume, the Plugs themselves) are working, the engine turns over instantly, with much reduced or no smoking.


Could be a number of things. Could be the glow plug inhibit switch (quite likely), in which case you just cut the wires to the switch, strip them, twist them together, and, if you are in a good mood, solder and shrinkwrap the connection.

Could be the controller, in which case you replace the controller.

Could be a loose or dirty connection, which is the hardest to find. To find it you've got to inspect the entire wiring harness for the glow plugs and all of the associated connections.

I'd start the investigation by looking at the inhibit switch.

Good luck!

its been so long ago i cannot tell you where it is located. it is screwed into the head i think on the rear of the passanger side head

HI good memory about that ,it is the one on the top of the head near the firewall


If it not solve your probleme add a manual button ,cheaper and more reliable than the controller .

Ed

i have nothing against the manual conversion other than my rigs get borrowed out to familiy and friends when they need a rig to get by with and i like keeping them stock. i did rewire my 84 to a 85 style glow plug controler because every two years my old one would go bad. my brothers 84 has probabley 10 years on it with out a problem, go figure. i changed mine over to the 85 and later style a couple of years ago and still going strong.

Thanks everyone! I'll report on my results!

Jonathan

Group --

Hello again, I'm back.

The issue with the glowplugs had self resolved with (much) colder weather that hit early in the northern CO high country, and apparently the temp sensor on the Plugs had no problem interpreting 20 degree nights as needing glowplug participation. So, I blew off fixing this (then) nonproblem to address other more pressing issues, like work.

However, I'm now in Phoenix for the winter, and as the nights are now in the 50's, I can't get 'er to energize the plugs in the am, and have to Plug in and leave the hood open to the sun till midday to get the relay to kick in and turn the light on.

I investigated the other advice you all provided here (thanks), and found that the vehicle, despite being an '89, does not have the temp sensor configuration described (the sparkpluglike unit that goes in the block at the rear of the right head. It's not there, physically -- no hole in the block. The vehicle is Canadian (with Km speedo scale, even), and apparently, the next year iteration of multicontroller is being used here -- part number 12496078. I think this is the two bolt pronged, five small lead, sealed unit that goes on the mount behind the manifold intake.

I went through all my grounds and conections yesterday as per the Haynes manual suggestion, and still no startie/glowplug light this am. But, I think I don't want to go replace this $130 controller if this going to be ongoing issue -- I'd rather go the manual cutout route. Another recent thread that (now closed) just gave detailed instruction on how to do this with the block sensor/controller configuration, I'm wondering if anyone has done this cutout with the multiple controller/non-block sensor system described above?

Gracias amigos

Jonathan

You should post a picture of the controller... It is hard to tell form your post what kind of system you have.

Any of the systems used on these trucks can be wired to function manually... :)

Group --
Hello again, I'm back.
I investigated the other advice you all provided here (thanks), and found that the vehicle, despite being an '89, does not have the temp sensor configuration described (the sparkpluglike unit that goes in the block at the rear of the right head. It's not there, physically -- no hole in the block. The vehicle is Canadian (with Km speedo scale, even), and apparently, the next year iteration of multicontroller is being used here -- part number 12496078. I think this is the two bolt pronged, five small lead, sealed unit that goes on the mount behind the manifold intake.
Jonathan

The glow-plug inhibitor switch can be in various places depending on year and/or application of a 6.2. Many have it in the head, but with some it's in the aluminum thermostat housing. I just went through this with my son's 87 Suburban with a 89 GMC Suburban engine.He was visiting here in NY from Colorado and his switch went bad. So, we went up on the hill to look for one in my 6.2 graveyard (I've got over a dozen 6.2 trucks, vans, buses, Blazers, Burb, etc.). We finally found one - but it was bad also. So, for $13 we bought a new one at Partsamerica. I've been using the GM switches for my Isuzu diesels also - but for a slightly different reason. With the 6.2s - the sensor is supposed to let the glow-plugs operate below a certain temp. With the Isuzu, the same senor allows a solenoid to energize a fast-idle device when it's below a certain temp. Same job - but different purpose.
In regard to installing a manual setup - I have them on all my 6.2s as a "backup" along with the original system intact - and the manual button is sort of hidden. I don't want someone borrowing my truck and holding down on the manual button for 10 minutes. I will say though, that since AC Delco gave up selling their own crappy plugs and started reboxing the German Beru plugs instead - glow-plug life is MUCH better.
Switch # was either TSU135 or Sorenson TSU177 - I forget which.

OK, thanks.

Here's a photo of the engine compartment with the air cleaner removed.

I'm trying to ID the marked components, relative to the decription being given by ag4gt on this other thread concerning bypassing the glowplugs:

http://www.dieselplace.com/forum/showthread.php?t=34618

I'm thinking that "aa" is where the sensor should be (and is not), A or more likely B is the controller, and C is the relay?

Jonathan

Check ebay. I just bought a new in box cotroller for around $50 US. (now it just needs to show up)

Garald

First, let's straighten a few things out. "A" is the combination glow plug controller/relay. It is the same as the '84-'87 style. "B" is the cruise control stuff. I don't know what "C" is.

I don't have time to finish writing this post... I'll finish it later... :eek:

OK, thanks.

Here's a photo of the engine compartment with the air cleaner removed.

I'm trying to ID the marked components, relative to the decription being given by ag4gt on this other thread concerning bypassing the glowplugs:

http://www.dieselplace.com/forum/showthread.php?t=34618

I'm thinking that "aa" is where the sensor should be (and is not), A or more likely B is the controller, and C is the relay?

Jonathan

AA is where the sensor - a.k.a. "glow plug inhibitor switch" goes in some versions of the 6.2. It would thread into the metal block-off plate on the water-port. Same port on the other head is where our photo shows A - which is the combination glow-plug and controller and in one unit. The older 6.2 have the controller and relay as two separate units. Keep in mind though, that there are at least three different locations used for the inhibitor switch - AA in your photo, or in front in the water-crossover manifold, or directly into the cylinder head in the same hole as the opposite head uses for the coolant temperature switch sending unit.
B - is the cruise-control vacuum servo.

AA is where the sensor - a.k.a. "glow plug inhibitor switch" goes in some versions of the 6.2. It would thread into the metal block-off plate on the water-port. Same port on the other head is where our photo shows A - which is the combination glow-plug and controller and in one unit. The older 6.2 have the controller and relay as two separate units. Keep in mind though, that there are at least three different locations used for the inhibitor switch - AA in your photo, or in front in the water-crossover manifold, or directly into the cylinder head in the same hole as the opposite head uses for the coolant temperature switch sending unit.
B - is the cruise-control vacuum servo.

:exactly:

Oh-Tay!

This is helpful -- as not only are the components given multiple names ("sensor" vs. "switch", etc), but the manuals don't give clear initial descriptions or illustrations of the parts in question, despite having photos of more complex processes. This is a failing for the uninitiated, and I'm sure it's an oversight born of familiarity.

I'll bet you guys see the same process over and over here. Thanks for the clarification, now I am getting a clearer idea of what's involved,

Jonathan

Group --

I seem to have come to resolution on this issue, but not entirely through the use of the advice given, which I appreciate.

Basically, while the controller unit was immediately evident, the sensor was not, in any of the suggested locations. I suspect the controller is a next generation multi unit for 1990 and up. Again, as the vehicle is Canadian, there may be some difference in configuration.

I simply disconnected the grounds on both batteries, and connected the two main studs to ring clamps attached to doubled 16 gauge wire running to a 20 amp momentary paddle switch under the dash. I checked for any activation of the controller when reconnecting the batteries, as suggested. Now, the plugs (with the indicator light) come on manually when I hit the switch, and the controller still seems to be doing it's job of cycling the plugs during warm up.

This am, the rig did not want to start unassisted in 60 degree temps, but I cycled the switch for six seconds and hit the starter -- instant ignition!

Thanks! Now I can go back to the boonies with my Trailer in confidence.

Group --

I investigated the other advice you all provided here (thanks), and found that the vehicle, despite being an '89, does not have the temp sensor configuration described (the sparkpluglike unit that goes in the block at the rear of the right head. It's not there, physically -- no hole in the block. The vehicle is Canadian (with Km speedo scale, even), and apparently, the next year iteration of multicontroller is being used here -- part number 12496078. I think this is the two bolt pronged, five small lead, sealed unit that goes on the mount behind the manifold intake.
I went through all my grounds and conections yesterday as per the
Jonathan

You're probably looking in the wrong place. GM puts the inhibitor sensor in at least three different locations- depends on the year and/or the vehicle it goes in. My son was just here visiting from CO - and he put a 88 GMC Suburban 6.2 into my older 87 Chevy Suburban (with blown 6.2). The engines had different locations for the sensor.

It can be in the cylinderhead - using the same hole as the other head uses for the temp sensor, or it can be in front in the water-crossover manifold, or it can be in top-back of the passenger-side cylinder head - installed in a coolant block-off plate - just as the controller is on the other side.

Yep, manual glow plugs switches make things pretty simple... Less stuff to fail, that's for sure.

Glad you got it working! :)

Just make sure you used heavy enough wires on the switch if you are not using the relay to carry all the current... The glow plugs draw more than 100 amps... :eek:

Also, just so you know in the future, your glow plug setup is the late '80s setup. It is the standard one that was put on all civilian trucks of that era. The Canadian trucks had the same glow plug setup (my truck was built in Canada, coincidentally).

Yep, manual glow plugs switches make things pretty simple... Less stuff to fail, that's for sure.


Also, just so you know in the future, your glow plug setup is the late '80s setup. It is the standard one that was put on all civilian trucks of that era. The Canadian trucks had the same glow plug setup (my truck was built in Canada, coincidentally).

Is yours just "built in Canada" or is it a Canadian version? I ask because I have one that is a Canadian version - not just built there - and it drives me nuts. Speedometer major markings in KMs, oil pressure in KPa, etc. I will never get used to, or like, the metric system. I've been cursing it since Ford introduced it into the US with the Pinto - and used color-coded bolt heads to indicate if SAE, USS, or Metric.

Mine was built in Canada for sale in the U.S. so it has all the U.S. gauges (although the fuel gauge is the only one that works right now ):h)...

I never liked the metric stuff either, although I am getting used to it now... For a little while I was into Japanese motorcycles which are all metric, and lately I've been working on more metric cars than standard cars, so I am getting pretty comfortable with the metric system (although I will never be as comfortable with it as I am with standard measurements).

The cars I really dislike working on are the ones that have a mix of metric and standard bolts... You never know whether the wrench you are looking for is standard or metric. :rolleyes:

The trucks built for sale in Canada were pretty much the same other than the gauges... I always liked the look of the metric speedometer because it goes over 100... ):h

Is yours just "built in Canada" or is it a Canadian version? I ask because I have one that is a Canadian version - not just built there - and it drives me nuts. Speedometer major markings in KMs, oil pressure in KPa, etc. I will never get used to, or like, the metric system. I've been cursing it since Ford introduced it into the US with the Pinto - and used color-coded bolt heads to indicate if SAE, USS, or Metric.

It's got the speedo in Km's -- so's this is a real Canuckian version, eh?
Interesting that Diesels would be popular there, and the fact that it's a 1500, not 4wd, considering the cold and snow they have in all regions. In Colorado these days, you apparently need 4wd for all aspects of life, even if you live in downtown Denver.

I however, am on a permanent snowbird schedule, and am out of there by Halloween these last few years. Towing a 25' Airstream I really am appreciating the fuel efficiency of a diesel rig. :ro)

I can vouch for the 4x4 3/4 and 1 tonne versions being much more popular in Canada. at least in my area anyway. I never leave the house in the winter without my chains(just in case) and at least 400lbs in the back. We have a number of high passes that would be similair to those found in Colorado for winter conditions.

It's got the speedo in Km's -- so's this is a real Canuckian version, eh?
Interesting that Diesels would be popular there, and the fact that it's a 1500, not 4wd, considering the cold and snow they have in all regions. In Colorado these days, you apparently need 4wd for all aspects of life, even if you live in downtown Denver.

I however, am on a permanent snowbird schedule, and am out of there by Halloween these last few years. Towing a 25' Airstream I really am appreciating the fuel efficiency of a diesel rig. :ro)

Where I live - a 2WD is useless - even sometimes in summer weather. I live on top of a mountain and the road is very steep and dirt. When we get heavy rain -many 2WDs cannot make it. But, I must admit- in the dead of winter - when the wind puts deep snow drifts on our road even when it isn't snowing - and it gets glazed with ice - our 4WD Subarus are much safer to drive than any K5 Blazer, truck, or Suburban. I've tried just about every type of tire there is - and the big vehicles can really take spin - often more or a problem when trying to stop -then when trying to go. Many times, to get down my road with a heavy 6.2 vehicle - I don't dare use my brakes until I get to the bottom. Only safe way down is to put it in 4WD, low gear, low-range - and whenever it can't hold itself back - hit the accelerator a bit. I have three plow trucks - all K5 6.2 diesels - and two have chains on all four wheels all winter. With the chains - I never have a problem - but a rig with full chains is awful to drive once you get onto a plowed road.

In reference to Canada - I drive through usually two round-trips a year - from central New York - to the UP in Michigan. We take the upper Canada route past Lake Nippissing and camp in a provincial park. There is also an area that looks like a barren lunar landscape named Sudberry. I see 6.2 diesels all over the place - much more than in my area of central New York. And - especially 1/2 ton pickups and G series vans.
This year - we had a problem coming back and had to take an alternative route. That's what I get for driving my Ford instead of a GM. MY 94 F250 with 7.3 IDI turbo-diesel sprung a huge transmission leak and I got stuck in London, Ontario - what a mess! I met an old guy - resident Canuk - at the transmission shop. He owned many diesels - said he had over a dozen - and I told him about my two-dozen. We both like our 6.2s - funny thing was - he was there with HIS Ford also - same trans. and same problem. We got talking about prices - and he was shocked when I told him how little I often pay for diesel trucks. According to him - used prices are MUCH higher where he lives - even with the exchange rate. In fact - when comparing my 94 F250 4WD ex-cab 7.3 turbo-diesel - to his 93 - I told him I bought it recently for $3300 and it was a rust-free Colorado truck - he just about called me a liar. When I told him that I often buy K5s with 6.2s in the $500-$800 price range I thought he was going to punch me . Well, not really - but he DID regard me as a chronic liar.

as far as gauges go when my brother and i and his ranch boss at the time bought our 84 6.2s all together , my brother came with gas gauges in the oil , water holes fuel gauge also said unleaded gas.. dealer proptley changed the fuel gauge but none of the rest. and i have seen subaru's go into places i couldn't get as long as ground clearence wasn't an issue.

Where I live - a 2WD is useless - even sometimes in summer weather. I live on top of a mountain and the road is very steep and dirt. When we get heavy rain -many 2WDs cannot make it. But, I must admit- in the dead of winter - when the wind puts deep snow drifts on our road even when it isn't snowing - and it gets glazed with ice - our 4WD Subarus are much safer to drive than any K5 Blazer, truck, or Suburban. I've tried just about every type of tire there is - and the big vehicles can really take spin - often more or a problem when trying to stop -then when trying to go. Many times, to get down my road with a heavy 6.2 vehicle - I don't dare use my brakes until I get to the bottom. Only safe way down is to put it in 4WD, low gear, low-range - and whenever it can't hold itself back - hit the accelerator a bit. I have three plow trucks - all K5 6.2 diesels - and two have chains on all four wheels all winter. With the chains - I never have a problem - but a rig with full chains is awful to drive once you get onto a plowed road.

In reference to Canada - I drive through usually two round-trips a year - from central New York - to the UP in Michigan. We take the upper Canada route past Lake Nippissing and camp in a provincial park. There is also an area that looks like a barren lunar landscape named Sudberry. I see 6.2 diesels all over the place - much more than in my area of central New York. And - especially 1/2 ton pickups and G series vans.
This year - we had a problem coming back and had to take an alternative route. That's what I get for driving my Ford instead of a GM. MY 94 F250 with 7.3 IDI turbo-diesel sprung a huge transmission leak and I got stuck in London, Ontario - what a mess! I met an old guy - resident Canuk - at the transmission shop. He owned many diesels - said he had over a dozen - and I told him about my two-dozen. We both like our 6.2s - funny thing was - he was there with HIS Ford also - same trans. and same problem. We got talking about prices - and he was shocked when I told him how little I often pay for diesel trucks. According to him - used prices are MUCH higher where he lives - even with the exchange rate. In fact - when comparing my 94 F250 4WD ex-cab 7.3 turbo-diesel - to his 93 - I told him I bought it recently for $3300 and it was a rust-free Colorado truck - he just about called me a liar. When I told him that I often buy K5s with 6.2s in the $500-$800 price range I thought he was going to punch me . Well, not really - but he DID regard me as a chronic liar.

Have you tried studded tires. Seem to make a big difference in my experience. I do agree on the Subaru's. Those things will track through almost anything as long as they have the clearance.

Also I can vouch for almost all things automotive costing much more in Canada. For one of us to buy a 6.2 K5 for $500-$800 it would have to have 500 000Km on it and be completely rusted out(probably not even running). The price for a reman 6.2 is around $5000 Canadian. Even my master rebuild kit was $1600 Cad. I don't understand it myself. It isn't like our dollar is worth that much less anymore. Somewhere around 10% now.

Have you tried studded tires. Seem to make a big difference in my experience.

Yes - I used studs for years but finally gave up on them. Problem #1 is the studs fly out in short order. One winter of frequent 75 MPH highway driving and half are gone. The other problem is - wet roads. 30 years ago - in my area - salt use was moderate. So, in the dead of winter, some roads would stay snowpacked for days, sometimes weeks. Even the Interstate. No more. Even a hint of snow or ice and the salt is dumped by the tons. So, much winter driving is on wet salty roads - and with studs - the tires skid something awful on wet pavement. So now - I reluctantly use the so-called "studless" snow tires with special rubber compounds. I did not trust them at first, but I am now quite impressed with them. If I lived in an area where less salt was used - I would do things differently.
None of that, by the way, applies to my older 4WD Subaru wagon. That thing holds the road with just about any kind of tire. Maybe because it's light? But, Subaru does not make a 4WD anymore and good ones are getting scarce. Mine is a 93 - I bought it down south three years ago. So, three local salty winters and it's just about had it. I suspect by next year, it will break in half. I already have over a dozen parked in my field that met the same fate. My wife - in winter drives an AWD Subaru - quite different setup than mine. I don't like AWD - it's on all the time - but as I said - I cannot find rust-free 4WDs anymore.

They hardly use any salt at all in my area anymore. Guess that's what happens when the highway maintenance contracts always go the the lowest bidder. It's okay by me though. I'd rather skip the rust and drive a little slower.

Well.

I sold my 94 Subaru AWD wagon to get into the 6.2 to tow my trailer.
I've had three, and it was far and away the best vehicle I've had -- zero maintainance in thee years, perfect handling in all conditions.

American engineering, by contrast, seems to assume a level of ongoing maintainance and investment. I've had to put about $1,000 into my 94 Burb with an initial purchase price of $3400. But when you gotta pull something, there's really not a Japanese option -- at least for under $40k.