Glow problem, etc...

[Sceolan]

Hello.

I am having big problems with the glow system on my 89" G30 6,2 Van. Have had the car in for service several times, but the problem is still there. I have ordered a book from this site now, so that I may get an better understanding on how this glow-system shall work.

Some times it glows and start fine, but other times it refuses to glow... Guess there might be a connection problem somewhere... Its for the mostly when the engine is warm, but not warm enough to start without glowing... It just wont glow. I have tried to "manually" override the glowcontroller when the car is warm, but still need a bit glowing, but it wont glow properly then either... The glow indicator-lamp on the dash is slightly visable, very weak light... Why? :(

I'll hope you understand what Im asking for..., my english isnt the best :o

And another question, about my transmission. When should my transmission change from 1 to second, and 2'nd to 3'rd, when Im flat out? (3- speed). Mine is changing from 2'nd to 3'rd at around 50mph, and dont shift down from 3 to 2 before around 35-40mph when I have the pedal to the floor.

Chevy Van owner
Norway

[john8662]

Welcome to the forums!

For the glow problem, the symptoms you're describing sound pretty normal for the '89 model 6.2. They are equipped with the electronic glow controller which is not very modifyable. The controller can work in conjunction with a glow inhibit switch, which is a temperature switch that can force the controller to stay off when the engine temp is warm enough (or so it thinks). This switch should be located on the rear of the engine above cylinder #8 on the cylinder head coolant blockoff plate (back, top of engine), basically on the passenger's side of the engine.

If you find something residing there, remove the connector and "shunt" the connector with a piece of wire, to connect the terminals (to complete the circuit).

Otherwise you'll need to look elsewhere to find out why the engine is hard starting when you get no glow.

For the dim "glow plugs" light, remove the two large connectors on the glow plug controller (remember one is always HOT) and clean the connections on the controller and re-install, try to resolve a bad connection. It could also be a symptom of a failing controller (relay inside).

Check things like your cranking speed of the engine by the starter. If the starter isn't turning the engine over fast enough hot, it will have a hard time starting, this is a big problem with older starters, especially the gear reduction variety (which your year would have come equipped with).

Other things can play into this problem as well, check the above mentioned and report back to us.

For the transmission, I'll let some of our other members take a stab at that one who are more familar with the 3speed TH400 transmission.

Welcome aboard!

J

[DmaxMaverick]

Welcome to the Forums!

Another thing to check when you have glow controller problems, and especially with a weak GP lamp, is grounds. You may have lost one, or needs cleaning. Disconnecting the "temp inhibit switch", as described by John, will force the controller to think it's really cold, all the time.

The TH400.......
Usually when you have shifting issues, it will be vacuum related. There is a vacuum valve on the injection pump, and a vacuum modulator connected at the rear of the tranny. Check all the vacuum lines, and confirm your vacuum pump is up to the task. If the vacuum is ~21" or better at the pump, and at least 15" at the valve and modulator, I'd suspect the modulator is bad. They fail, and it is the most common failure of the 400. The modulator is a cheap item, but is so necessary for proper shifting.

[Sceolan]

Hello again, and thanks for the suggestions.

I must test the glow-system a bit more when I get the time... :) .

But DmaxMaverick, you suspect my modulator to be bad, and that this is a cheap part. Could you tell me where this part is locaded, and how it looks like? :o

[Mr. Bone]

Hello All,

I'm encountering a similar problem with my glow plug relay. Is it better to put a "shunt" in to bypass the temp sensor or buy another temp sens.?? Thanks

[DmaxMaverick]

Sceolan
The module is the only thing at the rear area of the tranny with a vacuum line (or a vac hose nipple if the hose is off) on it. It treads in, pushes in, or pushes in with a clip, depending on year/model of tranny. Looks like a vacuum diaphram actuator. Some are adjustable, so look for a screw head inside the nipple hole.


Mr. Bone
Shunting/jumping is OK for diagnostic or temporary use, but I suggest replacing if your diagnostics show it bad.