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No throttle response on cold startup

Ibrahim

New Member
Joined
Mar 4, 2016
Messages
9
Country Flag
pakistan
Hi all,
My 1998 100 series 1 HD-FTE auto diesel Land cruiser has a problem that even the 'experts' haven't seen. Perhaps someone out there has:
Generally and randomly, when cold starting, the engine fires instantly, but rather than idling at its normal 800 rpm, it idles at 500 rpm. When you press the throttle nothing happens- no rev rise. Nothing. If you shift into any gear nothing happens, no movement to suggest it has engaged at all. After repetitive pressing of the throttle (while testing out all the newly invented curses you have conjured up) and after about 30-60 seconds, the throttle starts to respond, minutely at first but improving press by press until it is responding normally. When you shift into a gear now it responds normally too, and away you go. All subsequent warm starts are normal.

I have checked it on computer testing and the ECU shows no faults.

Any thoughts ?

Regards

Ibrahim


 
How about a blocked fuel filter or some restriction to the fuel flow, I think you have an in tank filter too, possibilly a vacuum in the tank try it without the fuel cap on???
Also an air leak in the system letting the fuel to run back slightly, taking a while to self bleed the system on start up, check all the fuel lines and unions, are there any non reurn valves?
Maybe give the hand prime pump a few pluses before starting from cold and see if this helps??
All of the above probably would not show up on a diagnostics scan so I would check out these first.
Lastly the foot throttle sensor maybe faulty, I have opened mine and cleaned it with electrical contact spray see if this improves things, but I still feel it is fuel feed related.
Hope this helps?
Welcome to the forum!
 
Hello Sir

Thank you so much for reply.
I have recently installed the fuel filter but still the problem hasn't solved.
I have tried giving the hand prime pump pulses before the startup but still no luck.
I will try it without the fuel cap on to see if this works and lastly if that doesn't work I will try to check the foot throttle sensor.
I hope that this will help.
Thank you again for your prompt reply.

Bestest Regards
 
Do you pump the primer until it's too hard to pump anymore?


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Yes I pump the primer until its too hard to pump anymore but still no luck. I've tried this several times.
 
Most likely either the pedal-sensor, as mentioned above here, or the throttle position sensor. Both are known to fail, needing cleaning. Both of them feed their info to the engine ecu, which decides how much to open the throttle. (Aka "Fly by wire")
 
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Also check the "throttle body" housing the butterfly. If this 'fly does not open you will only idle. It could be bunged up or have corroded connectors on the plug/socket.
 
Were you able to solve the problem? On my LC100, I have the same error. Even the replacement of the fuel pump did not help.
 
Most likely either the pedal-sensor, as mentioned above here, or the throttle position sensor. Both are known to fail, needing cleaning. Both of them feed their info to the engine ecu, which decides how much to open the throttle. (Aka "Fly by wire")

Yep I'd bet on that too, they have been known to play up if they get dusty, a good blow out should help no end.
 
The gas pedal has been changed unchanged. Throttle's position does not have this vehicle.
 
Looking at his profile he's not been on here since June 2016
 
Hi guys. I know this is a old post. Having the same issue and can not seem to find the fault! Has anyone had some luck with this issue.

No one seems to have an answer.

Thank you in advance
 
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