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Discussion Starter #1
When engine is cold, regardless if its 25 or 75 outside, it usually takes at least 6 attempts before it fires up. While engine is cranking it begins to throw grayish smok out of the exhaust the entire time and when it does fire up its smokes like crazy for about 5 mins then dissipates and goes away. When engine is warm it runs great, no issues whatsoever. I can shut the engine off and it will fire right back up when engine is still hot. Engine hasn't used any coolant or oil either, engine has 257,000 on it
 

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Hello & welcome
First thing I would do is check the glowplugs. Mine was doing the same, Turns out I only had 3 glowplugs functioning.
 

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Discussion Starter #3
I changed 6 out of 8 of them. 2 I couldn't get to and after changing them it didn't make a difference at all and it was about 65 degrees outside so I wouldn't think it would be the glow plugs would it?
 

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92 cheverolet Scottsdale 6.5 turbo diesel
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each plug draws 15 amps, this pulls the dash battery volt meter down in to the 9-10volt range during activation, if you do not see that good chance they are not activated, a hole saw to the inner fender well gets to the tough 2 plugs. there is a mod using a fender mount Ford starter solenoid to extend the on times for cold starts using the new ac delco60G plugs on this site someplace the 92/93's need it.
 

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Discussion Starter #5
Yea voltage drops when plugs or activated then goes back up to around 12-14 volt when they cycle off.
 

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Discussion Starter #6
It's almost acting like it's drawing in air somewhere/fuel trickling back into cylinders. Even after I shut it off after driving it for awhile and let it sit for 20 mins i still have to crank it a few times even when the temperature is warm outside
 

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92 cheverolet Scottsdale 6.5 turbo diesel
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the db2 injector pump was not designed for low sulfur diesel! you must add an additive. put clear vinal tubing on pump and injector return lines to monitor air intrusion. hook up a garden sprayer and spray on injector pump if hot and no start condition, cold water works but not as well. Stanadyne additive is best and Walmart 2cycle oil is cheapest Couple of ounces per tank is enough. the new glow plugs need more time to deliver an ideal start! Consider the ford solenoid mod it is cheap.
 

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1995 GMC Suburban
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Did you check the fuel filter?
Not sure if there is a Lift Pump on a 92? but if it is, then you need to check it.
 

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I had same issue with my 1993 6.5 turbo. Using this forum I learned that there are two fuel pumps. A primary, bolted to the lower frame that's below the drivers side.
A secondary fuel pump that is attached directly to the fuel injection system. Located on the intake manifold.
The primary pump provides fuel to the secondary. If the primary fails the secondary will still pump fuel
But, secondary is not designed for this and excessive fuel is used. Adding this strains this pump, if it fails you'll need at least $1500 to fix.
Two ways to check, each very easy. First, start truck, let run for 2 mins then stop. You should hear the primary pump "clicking". If not, this pump is not working.
Second, attach fuel pressure gauge to the "T" valve prime point. Start engine, open valve. If vacuum the primary pump isn't working.
Two points define what is likely wrong. Primary pump is bad or the OPS (oil pressure sensor) switch is bad.
With engine off:
To check primary pump, remove the plastic cover on the firewall behind the AC canister. You should see a fuse for pump. Using your fingers pop the fuse and wires off firewall. Then look to the right and you'll see terminals. Take the pump fuse/wire and touch fuse contact to terminal. If your hear "clicking" from under frame then the primary pump does work.
Fix:
These engines have a weird sensor that is to shut down fuel pumping if in an accident. But these are common to fail.
O'Reilys has this part, Oil pressure sensor. Plus takes special socket to install, which they also have. Costs about $40, for both.
To replace the OPS get ready for sore fingers and lying on top of the motor.
Pop AL cover off and towards the very back of motor and just right of center you can see the OPS. It's down at back of intake manifold
Replace this and should get primary working again.
One point: with primary working you can hear it running.
 
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