Turned key 5-25 times then it starts!

[ronnyrtaylor]

Hello! I'm new to this forum. I have a problem. My 1984 Chevy Suburban C20 6.2 diesel - used to be a military vehicle, I was told. Anyway, lately I started to have this problem: when I put key in ignition, turn it on then after glow light goes put (about 4-5 seconds) and I turned it to "start" - nothing. Tried for the second time. Nope. So on the third attempt, after the glow light goes off, I kept turning the key several times (5 to 25 most of times) then it will start. It has been like that for about a month. Did a research. Bought a new ignition lock cyl...no better - same result! Read about it somewhere else online saying it could be ignition switch, starter, solenoid, bad battery, bad battery connection, bad battery cables and so on. I hate taking my Suburban to a local garage...knew they would charge me millions. I am capable of fixing/repairing basic problems - brakes, fuel pump and others. But this problem is bugging me. Which one should I go for and hope it'll fixed. Switch? Solenoid? Which? Will appreciate any kind of guide where I can see and fix it by myself. Thank you very much.

[DmaxMaverick]

Welcome aboard!

Well, the lock cylinder you replaced is not indicated by your symptoms. If the key turns and the glow cycle happens, the lock cylinder is fine. A broken lock cylinder will either not turn, or just spin in the hole, often without the key. In that area, the ignition switch is a much more likely suspect. However, before you start throwing parts at it, do some simple diagnostics. You'll need a test light or VOM (Volt/ohm meter), and perhaps a helper. Connect a VOM or test light to the "start" pole on the starter solenoid (and connect the ground probe to chassis). Turn the key to "Start". If you see battery voltage (or the light) at the pole, and it doesn't start, it's either a bad connection at the solenoid, or the solenoid itself. If you don't get battery voltage, it's either the ignition switch, or connecting wires or connector(s) between. This is assuming the main Batt+ and ground cables are in good condition and well connected.

A poor connection or a failed main battery cable can also cause the problem. A poor conductor can carry a light load, such as lighting and the glow cycle, but may break contact once a heavier load, such as the solenoid and starter, is engaged. Test this with the VOM or test light. Connect the VOM/Light to an accessory circuit, such as headlamps (while they're on), and turn the key to "Start". You can also watch the headlamps, but that requires a helper. If it's breaking contact, the voltage (or light/headlamps) will drop when the heavy load engages. It will often reconnect, but not always immediately. If no voltage change is noted, then the heavy load is not being connected (key-start power isn't reaching the solenoid, or the solenoid is failed open). If a slight dip in voltage/light is noted and the starter doesn't engage, the solenoid is likely getting power, but is not engaging the starter (stuck plunger, or poor internal contact). Any continuous solenoid clicking indicates low battery voltage, or poor connections.

[ronnyrtaylor]

Good morning. Alright, I'll go do what you suggest for me to check on the problem. Anyway, a friend told me that I might want to check on glow plug timer, too. Shouild I? Thank you very much.

[DmaxMaverick]

It's a good idea to check the glow plug relay, if you're having glow plug relay issues. Working or not, the glow plug system has no effect on cranking the engine. A failed glow plug system may prevent a start, but the engine should still crank. If the glow plug lamp is showing, the plugs are getting power (this doesn't guarantee the plugs actually work, so testing them may be in order if it cranks, smokes, and doesn't start).

[ronnyrtaylor]

Alright...where can I find glow plug relay? I love my Suburban and wanted to learn more about it. Thanks.

[DmaxMaverick]

The GP relay (solenoid switch) for 82-84 is mounted to the driver/left side fender. 85-93 glow plug controller is mounted above the left side rear valve cover, and they are different (85+ being the better system, and is easily fitted to previous rigs, if it comes to that).

[Kennedy]

Ign slider switch is a god possibility, also Neutral safety switch. Test as recommended and be sure that the Ign slider just hasn't gone out of adjustment.

[ronnyrtaylor]

Howdy! I finally got back to my Suburban and did what all your suggestion and see if it did fixed. It gets better BUT once in a while I had to turned key twice (all silence and no crank) before I got it started. So I went ahead and tested my two batteries. Results seem odd TO me. Maybe it's normal to you. If not, please tell me what's wrong.


I used digital multimeter tester. With engine not running - 13.30 and SLOWLY increases to 13.65+. With engine running and headlight & A?C off, it reads at 12.88 steadily. With AC running full, 13.02 then SLOWLY goes down to 12.80-. Headlights on and AC running high, it reads 12.70 to 12.54. What yall think? Thank you.

[DmaxMaverick]

That is curious. At idle, the voltage should never be below key-off voltage. Typically, it should be between 13.6V and 15V any time the engine is running. I suggest testing again, at several points of running, such as, immediately after a start, and at several minute intervals while continuing to run (5, 10, 15, 20, or more if readings continue to vary). If the swings are wild (minimums to maximums), suspect poor grounds and/or cable-terminal issues. You should also check battery voltage of individual batteries (engine/key off), disconnected from one another and the chassis. Significant variations between them may explain the voltage drop and/or swings. One bad battery of the connected pair may indicate acceptable static voltage, but can play havoc with the voltage regulator while running, which in turn, can cause failures of a good battery, regulator, and/or the alternator.

[JohnC]

Yes, I would load test each battery (remove the ground from each one in turn so they are isolated). If they don't test about the same they will be fighting all day long. (But, I don't think this has anything to do with how many times you have to turn the key...)