View Full Version : cold start problems with tweaked pump
12-11-2002, 09:55 PM
I've got a little '92 D250 that's become a bit of a nusiance lately. <br>When the temps are in the 40s to 50s it's a real pain to start. White smoke and the usual bucking and kicking are my reward for turning the key. This morning, the heater didn't kick in and the truck wouldn't start without pumping the throttle. <br>My pump pressure has been turned one revolution and I think the extra fuel may be part of the problem. <br>I've noticed the problem with pre- and post- start. The last time I was pulling through the mountains, the intake heater wasn't cycling and the engine was too cold for proper burn. <br>If the temps drop into the 30s then the heater cycles but the engine is happier if I cycle it twice. <br><br>Whaddya think folks? This is getting annoying. <br>Could it be one intake heater is out or is it the fuel pressure?
12-11-2002, 11:40 PM
when I turned up my 93 it did have a little harder time to start but it is not that bad. Heck it is still easyer than my 94
12-11-2002, 11:46 PM
The fuel heater may be part of it. <br>The intake heater will cycle pre and post start up. I have no idea if both of them are working or if it's just one. <br>It's pretty frustrating. The heater is iffy in the mornings. After driving it for 20 minutes to work and letting it sit for 5 hours, the heater won't cycle and it's a coughing and smoking POS. After work, same thing. If I don't go to lunch, the heater will cycle and it starts ok. Sometimes I have to let it cycle twice. <br><br>What gets me is that it's really not that cold yet. We're talking temps in the 40s in the morning.
12-12-2002, 01:39 AM
I'm thinking your problem sounds like the KSB solenoid is not working properly. With cold/cool temps the KSB solenoid will increase internal pump pressures to max. This results in timing advance. Once the engine starts to warm, the KSB drops out and your internal pressure drops back to 4bar and normal timing. 1st Gens like timing around 14.5 to 15* advance. That setting alone will cause/fix alot of white/bluish smoke problems at cold/cool starts.
You should have a wait to start light that indicates the manifold heater is cycling, that will go out after 5-25 seconds depending on outside temps. Once the engine is started the heater will cycle on/off, on/off till the intake temps reach about 90*F.
The most common failure on this circuit is the temp sensor on the intake manifold (there are only two). The one closest to the intake horn is the charge air temp sensor, and the one closest to the firewall is the KSB temp sensor.
On the 92 the voltage to the KSB is 12vdc when triggered.
Hope that helps.
12-12-2002, 04:54 PM
If the KSB temp sensor has failed, will there be any other signs?
I ran the codes and it came up empty. I ordered the other air temp sensor from my buddy but I haven't installed it. Maybe I can swap it for the KSB sensor.
I don't always get a wait to start light. There's no signal to turn on the heater so the truck tries without it.
I'm not a newbie to these things but I've had very few problems in 222,000+ miles.
12-12-2002, 11:59 PM
No, I don't think you can swap the sensors. They each have a different trigger temp.
You should always get the WTS light with key on. Even when warm, the light will trigger on as a self-diagnostic, then go out.
You can test the KSB itself if you like. Remove the spade connector on the KSB.
Start the truck, and supply 12vdc to the spade connector on the KSB directly from the battery, alternate from contact/no contact. If you detect a subtle change in engine sound, idle, smoke, speed .. then your KSB is functioning. The next thing to confirm is the sensor function. This has to be done on a cool/cold morning.... Lift hood pull the connector off the KSB and attach a dc voltmeter. Turn on the key and see if you get a signal from the sensor. No signal = a roached sensor.
That is were I'd start with your symptoms, then go from there.
BTW here is a link to some VE pump pictures I've got on another site...
12-13-2002, 01:25 AM
Like Bushy said, the KSB sensor is actually a temperature switch and can be checked by using an ohm meter, a candle and a glass of ice-water. The switch should audibly open and close by going from hot to cold. I tested mine and it worked, just not at the right temperatures.
The intake sensor is a resistive device that changes resistance with temperature and is hard to diagnose. The resistance will be a certain value at certain temperatures as with most IAT's on gas engines.
My feeling is that your timing is off (too retarded) and your intake heater system is malfunctioning as you stated. Even if your heater doesn't work, once the truck does start, there shouldn't be large amounts of white smoke until its far below 0. Like near -30. As soon as you get the grid heaters fixed, have the pump timed.
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