Low idle when cold
#1
Low idle when cold
My 97 idles low (5-700 rpm) when I first start it in the morning. If I put it in reverse and hit the brakes it stalls. If I wait a minute the idle goes up enough to not stall in reverse.
Problem is the idle is already set correctly. Once the engine is warmed up a bit, idle is normal 750-800 with AC on in Drive.
I've replaced the overflow valve thinking it might be an idle fuel pressure issue, but there was no change.
Lift pump was replaced a few years ago.
Is there something that is supposed to boost the idle up when cold, like the KSB?
I usually give it a little pedal when cranking to help it start instantly. If I dont, it cranks over maybe 5-6 cranks before starting, instead of 1 crank like my first gen.
What else can I check?
Problem is the idle is already set correctly. Once the engine is warmed up a bit, idle is normal 750-800 with AC on in Drive.
I've replaced the overflow valve thinking it might be an idle fuel pressure issue, but there was no change.
Lift pump was replaced a few years ago.
Is there something that is supposed to boost the idle up when cold, like the KSB?
I usually give it a little pedal when cranking to help it start instantly. If I dont, it cranks over maybe 5-6 cranks before starting, instead of 1 crank like my first gen.
What else can I check?
#2
Registered User
sounds normal to me
my old 12v as well as my current 95 idle lower for a minute or so, then they are fine... mine are manuals tho so id tinker with the fuel to get them going without stalling
my old 12v as well as my current 95 idle lower for a minute or so, then they are fine... mine are manuals tho so id tinker with the fuel to get them going without stalling
#4
Registered User
Mine drives me nuts as well, Idle was set to 800 when warm in drive but idles at 400 when cold, and even worse it idles at 300 when pulling heavy loads- stalls often when on the road for a while, if I set the idle at 800 at that point it then idles at 1200 the next day its driven.
#5
I know many others have this same problem, but that doesn't make it "normal".
I didnt buy this new, but I would be willing to bet that it didnt stall when the first owner put it in reverse.
I was hoping somebody has solved the issue.
I will clean the prefilter and see if that helps.
I didnt buy this new, but I would be willing to bet that it didnt stall when the first owner put it in reverse.
I was hoping somebody has solved the issue.
I will clean the prefilter and see if that helps.
#6
Registered User
Low idle when starting a cold diesel with no electronic control and large rotating mass seems reasonable if no throttle is applied. I found that 5W40 synthetic diesel oil helps it ramp up to 850 RPM quicker. The OP says his idle increases as the engine warms up. OK, good enough.
My engine starts on the first revolution with or without a little throttle. However, I want the oil pump to push more oil than at 600 RPM low idle at startup, so I immediately hold the throttle at 1000 RPM for at least a minute. Then it will idle at 850. This requires a very light touch on the pedal and feeds enough fuel to counter poor cold combustion, overcome initial friction, and quickly pump up oil pressure to lubricate the bearings. Computer controlled engines (as my Lexus) do this automatically and return to standard idle in a minute or so.
Who else follows this routine? Who advises against, and why?
I still get 25 MPG and don't need to add oil between changes.
My engine starts on the first revolution with or without a little throttle. However, I want the oil pump to push more oil than at 600 RPM low idle at startup, so I immediately hold the throttle at 1000 RPM for at least a minute. Then it will idle at 850. This requires a very light touch on the pedal and feeds enough fuel to counter poor cold combustion, overcome initial friction, and quickly pump up oil pressure to lubricate the bearings. Computer controlled engines (as my Lexus) do this automatically and return to standard idle in a minute or so.
Who else follows this routine? Who advises against, and why?
I still get 25 MPG and don't need to add oil between changes.
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roadhammer
3rd Gen High Performance and Accessories (5.9L Only)
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