3 replies to this topic

[rubdub]

Hey guys,

 

Last time I had MPI in the garage the mechanic ran a diagnostic on it for me. We got these readings:

 

5 Ambient Air Temperature Sensor Short Circuit to Ground 

25 Ambient Air Temperature Sensor

13 Oil Temperature Sensor Circuit Voltage Too High

23 Oil Temperature Sensor

 

For the past few months my fan has been quite erratic, runs almost constantly(although not as frequent recently), will come usually within a minute of starting engine even from cold. Also have been having rough starts from cold (a friend of mine thinks that could be the fuel pump though), erratic idling sometimes will go up to 1500 rpms and then back down again.

 

I have since bought a new air temperature & oil temp sensor for Minispares and planning on fitting them later this week.

 

has anyone else had these readings, or similar symptoms and been resolved by changing air and oil temp sensors? Any advice on fitting them, i.e does oil have to be drained first?

 

Cheers guys 

 

 

[tmsmini]

Are you sure they ran the correct diagnostic version?

It sounds more like a coolant temp sensor issue than anything else. There was a service notice about the connectors for the temp sensor, perhaps it was never done.

Cleaning and the use of some contact cleaner may help temporarily. A check and clean of all the sensor connections as a precaution would not hurt.

 

I believe the ambient air is a calculated value from other sensor values in the SPi and there is no ambient air sensor in the MPi and that value is not used.

The oil temp sensor does not feed the ECU with MEMS 2J used in the MPi.

 

Perhaps the "air temperature" sensor you purchased is 

Sensor for Inlet Air Temperature

Green

Air temp sensor with green plastic top, fitted in top of manifold on MPi, Also known as IAT sensor 10001

 

If you have erratic idling I would look at this:

Air Control Valve on Inlet Manifold 1996 on MPI also known as stepping motor--idle air control valve (IACV) Bolts on the side of the injection body housing to control engine idle speed and air flow from cold start up. The blue socket loom cap fits this unit.

 

MLZ100090

 

It may need cleaning and a check of the sealing surface with the O rings

Edited by tmsmini, 04 October 2016 - 05:58 PM.

[Steve220]

Sounds like he ran an OBD2 software on a car not capable of giving proper readings.

If the fan is running almost constantly I'd be looking at the coolant sensor. Unplug it before you start the car from cold again and see if it does the same thing.

As an FYI, the mpi engine does not use the oil temp feed. The signal does not go to the ecu but directly to the gauge on the dash. It also only has an inlet air temperature, not an ambient air temp sensor.

[rubdub]

Cheers lads, gave the idle air control valve a clean and it's definitely running smoother, and lost its sluggishness. Will see over the coming days how the cold starts are now.

 

Will have a look at the coolant sensor later today hopefully.

 

The oil temp gauge isn't working anyway so going to change that sensor anyway I think.

 

Thanks again!