Engine and Transmission Tech

tips, technology, tools and techniques related to vehicle driveline components

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en
ian jenkins
Mississauga Ont canada
(67 posts)

Registered:
12/27/2010 11:06AM

Main British Car:
77 tr7

rover 14cux engine miss
Posted by: en
Date: October 17, 2011 02:45PM

Hi
has anyone had this happen:
I had a miss between 1500 and 2000 rpm.
My TPS isn't putting out a linear change to throttle position.
I drove it with the TPS disconnected and guess what?
Engine ran great. I was checking air/fuel ratio and it was proper, even under wide open throttle(around 13 to 1]
Seems to go against logic?
ian


cgill
Chris Gill
Salmon Arm, British Columbia
(129 posts)

Registered:
08/13/2009 12:06AM

Main British Car:
1979 MGB roadster Buick 300 stroker with EFI

authors avatar
Re: rover 14cux engine miss
Posted by: cgill
Date: November 02, 2011 12:01AM

Hey Ian;

I have the exact same issue!! When the engine isn't under load I get a slight miss between 1500 to 2500 rpm. Under load there is no miss and the engine pulls really strong up to and over 4000 rpm. I have done an extensive search for vacuum leaks and haven't found any.

Where is the tps located? I would like to see if that makes a difference to how mine is running.


en
ian jenkins
Mississauga Ont canada
(67 posts)

Registered:
12/27/2010 11:06AM

Main British Car:
77 tr7

Re: rover 14cux engine miss
Posted by: en
Date: November 02, 2011 08:44AM

The Throttle Position Sensor is located on the end of the throttle shaft, opposite the side with the throttle linkage.
It is usually held on by 2 slot head screws. It has a 3 pin electrical connector
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cgill
Chris Gill
Salmon Arm, British Columbia
(129 posts)

Registered:
08/13/2009 12:06AM

Main British Car:
1979 MGB roadster Buick 300 stroker with EFI

authors avatar
Re: rover 14cux engine miss
Posted by: cgill
Date: November 02, 2011 12:28PM

Ah yes. I know what you are talking about now.

So your car ran better without it plugged in? What about replacing the sensor to see if that helps?


cgill
Chris Gill
Salmon Arm, British Columbia
(129 posts)

Registered:
08/13/2009 12:06AM

Main British Car:
1979 MGB roadster Buick 300 stroker with EFI

authors avatar
Re: rover 14cux engine miss
Posted by: cgill
Date: November 04, 2011 06:00PM

Hey Ian,

I spoke to my buddy who is a ford mechanic last night and explained what you found with unplugging the TPS. He said that EFI systems have a 'backup program" for lack of a better word, that causes the ECU to richen the mixture to the point that the car will run quite without the TPS plugged in. I wonder if that is what is happening with yours.


en
ian jenkins
Mississauga Ont canada
(67 posts)

Registered:
12/27/2010 11:06AM

Main British Car:
77 tr7

Re: rover 14cux engine miss
Posted by: en
Date: November 04, 2011 07:29PM

That would make sense, thank you


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