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Topic: 3126 Caterpillar Cold Start (Read 462 times) previous topic - next topic

3126 Caterpillar Cold Start

When I was putting the wire harness back on our 3126 Caterpillar, I found a wire labeled "Wait to start". Could not find any reference to it on the FT wire diagrams, never found a place that it hooks to.

This wire does not produce, either a ground, or power when the dash " wait to start" is on. After studying the Cat engine diagrams, then looking at the heater plenum on top the engine, I saw that the solenoid for the power to the heater grid was there. Everything was in tact, except the power side wire that went to a Caterpillar plug was factory capped off, with a Cat factory cap. This told me that in no way was the intake heater ever working.

Obviously it was never hooked up by FT since new.
Our coach was a Texas coach, then a California coach, so no one probably ever noticed. Living in the northwest, I did find it hard to start in extreme weather.

I ran a ground wire back, from a momentary switch at the dash, using one of the extra wire's in the harness to the solenoid ground side. Then hooked a small 30 amp auto breaker and powered it from the plenum hot wire right on top the engine, simple fix. I just hold it, while the "wait to start" cycles.

If you have a 3126 cat, it would be interesting to see if yours is hooked up.

Chris
Chris and Tammy White  CDA Idaho
Previous owners 1997 U295 36' 3126 Cat 300 HP Build # 4998
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: 3126 Caterpillar Cold Start

Reply #1 –
Chris,

Use the voltmeter on the "engine side" of the intake manifold heater solenoid when someone turn the key to the first position (not turning over the engine).  The intake manifold heater is important to starting your engine (actually most all modern diesel engines).
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: 3126 Caterpillar Cold Start

Reply #2 –
Quote from: wolfe10 –
Chris,

Use the voltmeter on the "engine side" of the intake manifold heater solenoid when someone turn the key to the first position (not turning over the engine).  The intake manifold heater is important to starting your engine (actually most all modern diesel engines).

Correct Brett,that would be the way to test the system. One can even feel the heater to see if it's getting warm.
But in my situation, there was a ground to the solenoid. It was grounded to block,but no power wire on the positive side of of the solenoid. It was a short 12" wire, but never hooked up, factory capped off. Not even a power wire in the area.
I will post a picture later
Chris
Chris and Tammy White  CDA Idaho
Previous owners 1997 U295 36' 3126 Cat 300 HP Build # 4998
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: 3126 Caterpillar Cold Start

Reply #3 –
Quote from: gracerace –
Correct Brett,that would be the way to test the system. One can even feel the heater to see if it's getting warm.
But in my situation, there was a ground to the solenoid. It was grounded to block,but no power wire on the positive side of of the solenoid. It was a short 12" wire, but never hooked up, factory capped off. Not even a power wire in the area.
I will post a picture later
Chris

Here is a picture of the stubbed off factory plug. The wire comes out, goes around 12" to the positive side of the  heater solenoid.
Chris and Tammy White  CDA Idaho
Previous owners 1997 U295 36' 3126 Cat 300 HP Build # 4998
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: 3126 Caterpillar Cold Start

Reply #4 –
Quote from: gracerace –
Here is a picture of the stubbed off factory plug. The wire comes out, goes around 12" to the positive side of the  heater solenoid.

I wonder if I have one on my 3176B ?
Hans & Marjet
1995 U300 "Ben" (#4719)
3176B Cat,4060HD,Jake
SKP#139131
Motorcade#17579
2006 Honda Element (towed)