Author Topic: Hard Starting Cold  (Read 359 times)

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Offline willsonrick

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Hard Starting Cold
« on: February 27, 2019, 12:25:49 PM »
In my 98 Safari with a 3126B. If I let it sit for more than 3 days, it starts but, burps white smoke and idles rough for a few minutes. if I go to fast idle it will smooth out. Go back to idle it surges.

If I let it go for  a week or longer It take 30-40 seconds to start and belches a huge cloud of white smoke.
Also noted, it seems to have a lot more black soot on the exhaust and does blow a bit when accelerating.

I have followed the advice on this forum and others.

Did the bubble test at the fuel pressure regulator.  Replaced Racor 490 with the new 790 with electric prime. Replaced fuel line to the pump.

Thought I had it whipped.  No Joy. It starts ok after 1 or 2 days but, 3+ white smoke, runnuing ragged at slow speed again.
 
Replaced the fuel pressure regulator with CAT part.   No Help.

I am not in a place where I can run the bubble test again now. But,  It seems if all the fixes put in worked, that the system is slowly leaking by somewhere..

I am kind of at a loss as to where to go next. 

Real question is, can I get by working this way until I get home and have access to mechanic and shop or am I in real trouble?  It seems to work well when underway.

Rick Willson
Rick Willson, 1998 Safari Sahara Model 3006, 3126 300 hp

Offline Brett Wolfe

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Re: Hard Starting Cold
« Reply #1 on: February 27, 2019, 02:08:45 PM »
Rick,

By pressure regulator, I assume you mean the one in the back of the head that the return line connects to. 

Don't know if you have the Caterpillar manual primer pump.  If you do, before trying to start next time, pump it.  If easy to pump, pressure has bled off.  If it is firm within a stroke or two no problem.

Have you verified that the INTAKE MANIFOLD HEATER is functioning.  There is a relay on  top of the engine that activates it.  When you turn the key to the first position, the intake manifold heater should come on.  When it does, voltage on the chassis battery and on the dash gauge should drop below 12 VDC, as that heater takes a lot of amps.  If not working, it makes starting a lot harder.

Offline David.e.atherton

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Re: Hard Starting Cold
« Reply #2 on: February 27, 2019, 04:51:39 PM »
 Rick, your problem is startup of your engine and smoking is normal until engine get
to warm up to operation temperature. You are experiencing with your engine ECM is
still in the ( Cold Mode ), the engine will do real strange noises and exhaust smoke is
white in color. Damage by increasing engine rpm’s with cold oil under extreme high
pressure is asking for real problems. In most cases depending on how cold it is, the
engine operation will not straighten out and have real low power for about  15 to 35 minutes.
Your return fuel pressure regulator will  fall under different area you are trying to figure.
Last your engineTemperature Regular has been updated because problems with the
old style regulator keep engine in the cold mode.all the time and many missed diagnostic
troubleshooting the low power problem.  Ask Dave, Dave Atherton Retired Cat Mechanic

Offline willsonrick

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Re: Hard Starting Cold
« Reply #3 on: February 28, 2019, 05:56:08 AM »
I did replace the fuel Pressure regulator(sorry for the imprecise info).

The inlet air heater checks out also.   I might add that the temp here is 80 degrees.  I don't have the manual prime pump.

This has been ongoing since I overheated due to a water leak in the heater hose.  I pulled it over before shutdown but the engine did derate just before pulling over. 

I don't know about the cold mode issue.   It has been 80 degrees or above nearly every start. After starting the first time  in a day, I can shut it off immediately, and then restart and all is normal.  If I get to someone who has a CAT E reader will they be able to confirm one way or another? 

I have no expertise(except advice from fellow RV ers) to base this on , but, I suspect a leaking Fuel injector.  Having said that I , like Dave Atherton, would like to avoid spending money on parts until the real problem has been ID'd.

Thank for the advice and directions.

Rick Willson


Rick Willson, 1998 Safari Sahara Model 3006, 3126 300 hp

Offline David.e.atherton

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Re: Hard Starting Cold
« Reply #4 on: February 28, 2019, 06:49:56 AM »
Rick, ok what I’m getting from this last post . You had a over heating issues but can you go into
more detail, can you take me step by step from startup. Than driving down the road what goes
on until it runs ok or not than the next startup. This is very important and let’s not throw parts
at your problem with all this guessing. Any coolant loss, is the engine oil level raising, is there
Lot of blowby after start and running. What color is your smoke at different times running.
Do you have ny lights on dash or lights come on than off. Does engine jerk at climbing grades
is so what rpms. I can assist you but need all information from the start. Need your complete
Engine Serial Number first thing. Ask Dave, Dave Atherton Retired  Cat Mechanic

Offline willsonrick

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Re: Hard Starting Cold
« Reply #5 on: February 28, 2019, 12:11:03 PM »
OK Dave  here goes

:Engine Serial  7AS15350            3126B

Let me start by saying I had a  1996 Safari with the same 3126B engine.  Aside from a few easly fixed problems it gave me no touble for 2 years.  Never really had to work on it.

That said this 1998 Safari is 5 feet shorter but weighs about the same. It has always seemed less strong than the 1996. Part due to the fact of gear ratios.  The 98 runs  about 1700 RPM at sixty vs 2050RPM for the 1996.

Back to the current issue.

The coach has about 90,000 miles and has run without flaw in the 3 years I've had it until this issue. Regular maintenance has been performed since I got it.

Coming back from the rally in OK the coach ran normally for the first 50 miles.  Water temps  indicated moving between 190 and under depending on hills. 

The temps started getting slightly higher and dropping down slower as we  kept going.   Finally after a few miles of this, the temps started easing up past 190.  I down shifted to 5 th to keep RPMs up on hills.  No help.  Said a couple curse words, started looking for a spot  to pull over.  Going uphill next time engine - derated.  Engine Light  Pulled over, Let idle for a couple of minutes. Ran out to the back and saw antifreeze all over the toad. Shut down engine.  Found leak in heater hose above exhaust manifold. Did not have proper repair parts or tools so wrapped a piece of instabond tape over the hole put baker on it and tie wrapped it.   

It took a little over an hour to get this accomplished. Proceeded to refill radiator very slowly. Put in 1 pint at a time.  Started engine before adding water.  Proceeded onward ,got coupler and hose clamps and replaced the field repair with a proper one.

Coach acted exactly like normal until next morning.  That's when the hard starting began.

Would not start until starter was run for about 30-40 seconds. White smoke coming out of exhaust the entire time. When it started to run on its own, it was really ragged sound and white diesel smelling smoke billowed for 10-15 second then disappeared when the engine smoothed out.

Next stop, same thing. same symptoms.

Next stop, same thing.
Made it home to SC.
Started to get advice about inlet air system from other forum and ended up at air leak into fuel system.
Called you and then did the Fuel pressure regulator hose test and  ID'd a leak. Traced that down to Racor filter.  Jumpered it out with coupler.  Ran it a few times like that and it seemed ok. It seemed ok if I started it every day. Let it sit for 4 days, went back to same problem.Replaced the Racor 490 with the new 790 with electric prime and the fuel line from the filter to the pump.

Came down to Florida.  Starting daily, no issues 3 or more days, hard start.

Replaced the Fuel pressure regulator. Used a CAT one. 

Same problem, can't sit for more than 3 days or problem reoccurs.

There appears to be no coolant loss after 1000mile.  No oil level Rise either.

White smoke only happens on the first start of the day. After that almost no smoke visible though the exhaust pipe seems to have more soot on it than I think normal. Black Smoke comes out if I floor it when almost warm, but not quite up to temp.

After the first start of the day, Driving there is no jerking, No alarms light or gauges are different than before.  No active are indicated.
Blow-by appears to be the same as before.

Using the diagnostic flash codes I got  39, 51,  15
Ijust got these I don't know when they are from but there are alrm or check engine lights.

That's the story, I hope you can help.

Thanks in advance.
Rick Willson






Rick Willson, 1998 Safari Sahara Model 3006, 3126 300 hp

Offline David.e.atherton

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Re: Hard Starting Cold
« Reply #6 on: February 28, 2019, 03:45:36 PM »
Richard, your flash codes if correct takes us to your problem.  Let’s start with flash code # 15,
Injection Actuation Pressure Sensor Erratic. Flash code # 39, Injection Actuation Pressure
System. Flash code # 51, Intermittent Battery Power to the ECM.

What I would like you to do, when engine has been sitting like when hard starting happens
and remove wire to the injection Actuation  Pressure Sensor ( location first sensor along
bottom of valve cover from front or fan side of engine above Heui pump.) this is a triangle
Shaped plug with 3 wires going to the IAP sensor. Note: engine cold do not try to start until
wire has been disconnected from sensor. What you looking for if engine will start and run,
If the engine starts than your problem is faulty IAP sensor. Let’s start here first and also very
possible dirty or shorted connection.  Ask Dave, Dave Atherton Retired Cat Mechanic

Offline willsonrick

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Re: Hard Starting Cold
« Reply #7 on: March 01, 2019, 06:32:42 AM »
Thanks.
Give me a 3-4 days to let it sit and I will get back on it.

Rick
Rick Willson, 1998 Safari Sahara Model 3006, 3126 300 hp

Offline willsonrick

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Re: Hard Starting Cold
« Reply #8 on: March 05, 2019, 07:34:42 AM »
Dave,

Ok, Started rig after 5 days,  Disconnected the IAP sensor before starting.

Got white smoke and ran ragged for about 10 seconds before smoothing out. 

Let it run for a few minutes and it seemed to run normally. 

Redid the flash codes,   got a 39 and a 51 .  The 15 has disappeared.

I am ready for whats next. Thanks in advance for helping

Rick
Rick Willson, 1998 Safari Sahara Model 3006, 3126 300 hp

Offline David.e.atherton

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Re: Hard Starting Cold
« Reply #9 on: March 06, 2019, 02:31:16 PM »
Rick what you have just found your problem with the engine start with the injection Actuation
Pressure Sensor.  Sensor needs replacement ( off hand part number should be for replacement
Caterpillar number 161 - 1704 ). Yes engine, it ran rough at idle at first than ran smooth and
What all this tells you Sensor is bad, if Sensor was good there would be no engine start.
 The other flash codes will go away after new sensor is installed. Ask Dave, Dave Atherton
Retired Cat Mechanic

Offline willsonrick

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Re: Hard Starting Cold
« Reply #10 on: March 07, 2019, 05:59:52 AM »
Thanks Dave,

Glad you confirmed that. I was wondering about the rough start and then smoothing out.  I really appreciate you walking me through this.

Thanks again

Rick
Rick Willson, 1998 Safari Sahara Model 3006, 3126 300 hp