Missfire

[maverick218]

Hi, can anyone help. I have a Ford Maverick 2.7 gls 1997 swb. I have just completed a major service all fluids and filters but i still find that when you rev engine in Neutral the engine missfires and splutters before obtaining revs. My mav has allways done this and most garages are saying this is a bit of a glitch in the ecu mapping and is typical of this model. Is there anyone else who has fixed this. I wondered if it could be the injector senser. Any help would be appreciated

 

[Toolbox]

Many TDIs do this when free revving, also emit a puff of white smoke with the misfire.
My advice would be, if your motor is ok when driving then don’t worry about it, you could end up spending a lot of money and getting no were :doh

 

[maverick218]

Many TDIs do this when free revving, also emit a puff of white smoke with the misfire.
My advice would be, if your motor is ok when driving then don’t worry about it, you could end up spending a lot of money and getting no were :doh

Hi, thanks for that , but it is definitely getting worse and time goes on and to be honest i dont know how it keeps on going through mot's. Its really smoking and spluttering on take up of revs in neutral. I tried dissconecting No 1 fuel injector sensor but this makes no differance at all............and i mean NO DIFFERENCE so i'm thinking it could be this. Ford will only sell sensor c/w injector £218. Is there a simple test i can carry out ie resistance/volts etc. Am i correct in thinking that this sends a signal to pump for advance/retard timing???? Oh and being that i am a new member just gota say great forums loads of bits i have encountered and hope i can help others to.

 

[Toolbox]

You can test the resistance through the sensor it should be approximately 105 ohms.
If yours test out ok then you can try swapping the wire around in the plug and reconnecting it, by pulling out the coloured tab in the plug the wires can be withdrawn and swapped with out the need for cutting and rejoining the wires. This was an early Nissan fix to overcome a misfire termed by Nissan as bunny hoping. This was subsequently replaced by adding a resistor in to one of the MAF wires and then replaced again by a moded ECU.
The sensor is for the ecu to determine the exact time of injection, to enable it to adjust the pump timing.
I have wondered in the past if the problem is due to low delivery fuel pressure with in the injection pump that is needed to work the advance / retard valve, the pressure and delivery of fuel is maintained by a vain pump within the injection pump.

Oh nearly forgot welcome to the club

 

[maverick218]

You can test the resistance through the sensor it should be approximately 105 ohms.
If yours test out ok then you can try swapping the wire around in the plug and reconnecting it, by pulling out the coloured tab in the plug the wires can be withdrawn and swapped with out the need for cutting and rejoining the wires. This was an early Nissan fix to overcome a misfire termed by Nissan as bunny hoping. This was subsequently replaced by adding a resistor in to one of the MAF wires and then replaced again by a moded ECU.
The sensor is for the ecu to determine the exact time of injection, to enable it to adjust the pump timing.
I have wondered in the past if the problem is due to low delivery fuel pressure with in the injection pump that is needed to work the advance / retard valve, the pressure and delivery of fuel is maintained by a vain pump within the injection pump.

Oh nearly forgot welcome to the club

Hi again Jeremy, in the darkness of the nightjust been down to motor and tried injector sensor wires. I dissconnected plug and senser side has no resistance while loom (pressumably going down to pup/ecu is showing 1.1. If it is supposed to be 105 ohms then i think mines duff. Do you no of anybody in club who has replaced and if so, do you really have to buy the whole injector ? Cheers Mark

 

[Toolbox]

A couple have replaced them in the past and it is correct that you need to buy the whole injector as this is not a serviceable part and should not be taken apart.
When you say you have no resistance do you mean you have continuity or an open line.
£218 seems a good price for a new one, you could always try a second hand one.

Testing down the wires away from the sensor should be avoided with the ECU in circuit.

 

[maverick218]

A couple have replaced them in the past and it is correct that you need to buy the whole injector as this is not a serviceable part and should not be taken apart.
When you say you have no resistance do you mean you have continuity or an open line.
£218 seems a good price for a new one, you could always try a second hand one.

Testing down the wires away from the sensor should be avoided with the ECU in circuit.

with the meter connected to the senser wires the meter shows no reading ie open line £218 from ford £186y from Nissan

 

[Toolbox]

I would have thought your engine check light (MIL) would have been on with it being open circuit.

Most peculiar.:nenau

 

[maverick218]

I would have thought your engine check light (MIL) would have been on with it being open circuit.

Most peculiar.:nenau

Whats this "as one door closes another opens"

 

[maverick218]

Whats this "as one door closes another opens"

Jeremy can you confirm that it is 105 ohms and not mega ohms my meter reads nothing even on x10. Tried my brothers vehicle which is the same as mine (but incidently runs fine) and this also reads nothing on meter when connected to his senser .Regards Mark

 

[Toolbox]

Mark,

Yes 105, have checked mine in the past with my Fluke meter (auto ranging) ok.

Have a look at the manual below page EC430

http://www.sferamydlo.com.pl/Zbyszek/Nissan/R20/ec.pdf

If you think the sensor is your problem, why not swap ithe injector with your brothers.