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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 21628
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Engine will run fine but will not tick over

Resolved Question:

Engine will run fine but will not tick over
Submitted: 1 year ago.
Category: Car
Expert:  Matt replied 1 year ago.
Hello you don't say what model and engine size and fuel type this is ?
Customer: replied 1 year ago.
It's a 3.2 dispel engine on a shogun I have changed sensors on injection pump and now the engine will not idle at all. It's got worst.
Expert:  Matt replied 1 year ago.
Hello OkI'd start by replacing the fuel filter if you haven't already as even if slightly blocked it can effect the running
Customer: replied 1 year ago.
Have changed filter at the same time as changing sensors.
After starting and running engine at 2000 rpm for 10 mins the car will now idle in neutral ok but will cut out as soon as you put it in gear.
Expert:  Matt replied 1 year ago.
OK if it won't take any load then its very likely a lack of fuelI'd suggest getting a fuel injection specialist to measure fuel pressure at the injection rail as this will show if the main pump is in good conditionalso if this model has an MAF meter on the intake try disconnecting to see if this helps at all
Customer: replied 1 year ago.
The car runs and pulls fine when it is above 1000 rpm if pump was faulty wouldn't it cause problem at all speeds.
No change when MAF disconnected
Expert:  Matt replied 1 year ago.
Hellothanks for the extra informationyes if the pump was struggling then you would have a lack of power throughout the rev rangeas the issue is only effecting idle and low speed then check the connections to the EGR valve, if either the vacuum pipe of electrical connection are damaged / corroded then the EGR can be on all time which certainly will hurt performance. Its also possible that its a fault with the EGR valve so its worth removing the valve and cleaning it out with brakecleaner, if it looks particularly clogged then replace it.
Customer: replied 1 year ago.
ERG connections are ok and vallve is clean, any other ideas.
Expert:  Matt replied 1 year ago.
Hello Ok the next thing to try is setting the TPS (throttle position sensor) on the pump this should be set to read 0.7V with no pressure on the throttle
Customer: replied 1 year ago.
How is this adjusted?
Expert:  Matt replied 1 year ago.
the position sensor is held with a few screws, just loosen them so you can turn the sensor and then use a voltmeter onto the 3 wires to locate the low voltage signal that will be about 1V
then adjust the sensor position whilst measuring the voltage to give you 0.7V
Customer: replied 1 year ago.
I have ordered a new TPS and will fit it and set up as you state.
If this does not work is there anything else I could try.
Today I tied back the acceleaotor peddle so it runn at 1200 rpm and car does not cut out when put in drive.
Don't know if that helps with any diagnosis but would be good to have something else to try if it does not work.
I can then sign this conversation off. Many thanks for your help.
Expert:  Matt replied 1 year ago.
hello Bill if that doesn't help it would be worth measuring the TPS output across its range - just open it manually and measure the resistance on the meterit needs to change smoothly and steadily with no sudden jumps, if it does do this then replace the sensor
Expert:  Matt replied 1 year ago.

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