Hi,
Have had my tribute for about a week and ran it about 3 times now. Mostly it's been fine but today went across town (20 minutes drive), I then switched the engine off. This is what followed:

• Restarted the engine
• It fired perfectly for about a second
• Then instantly the rev's dropped so low the car cut out.
• Tried to restart it and it wouldn't catch at all.

Starter motor and battery all sounded fine. Left it for around 20 minutes tried again, and she fired up. When sitting at idle tho, the rev's tend to get fairly low, to the point the battery light on the dash illuminates (I guess because the engine isn't generating enough power to charge the battery?). Starting from cold, it's absolutely fine.

Car specs:
2001 Mazda Tribute
4 cylinder 2.0L
Manual transmission
Spark plugs and leads all changed recently before I purchased the vehicle

I have read in other forums about the IAC being a bit dicky, but for the engine to be cranking perfectly and not even be close to firing sounds more like an electrical issue (plugs not delivering a spark?). Is there some sort of sensor that could be preventing the distributor from sending a spark to the plugs? Or would there be a way of ruling out the IAC?

Interestingly, I cannot find a user manual or even an engine diagram or image online for my variant of Tribute engine compartment!!

Any help or guidance would be greatly appreciated.

Brad

 

Sounds like maybe the idle air control valve - possibly the valve sticking.

 

Hi Simonsi,

Yeah I guess that could be the cause. Any suggestions on how I'd rule it out or test it?

 

Its a remove/clean or replace item, I'm not sure where it is on the 2.0 but Youtube might provide a video to show you.

 

Thanks. I think it's located underneath the intake manifold. Annoyingly on the 4 cylinder versions it requires hobbit sized hands and jack stands. The V6 version I believe, it's situated on the top of the block.

So you would suggest just swapping it out anyways? Just wondered if there was a way of testing it before just changing it out....

 

You can have the car scanned, if it is the IAC then there may be an "idle speed out of range" type error indicating the control signals to the IAC did not achieve the idle speed result wanted by the ECU

 

Scanned? Would this be done using an OBD tool?

There are no engine management lights illuminated on the dash to indicate that a fault has been found.....

 

Whether the engine light is lit depends on the fault and whether it is permanent or not, it may well have logged a code but not be displaying the light. And yes a scanner is required (I use a dongle that plugs into the OBD port plus an iPhone app), or some parts stores can scan it for you.

 

Thanks for the video. I had actually seen that. It's similar to my symptoms but my main concern is it not starting once the engine has been switched off. Perhaps the first step is get an OBD reader and see if there are any codes thrown up.

In the mean time, i could try forcing the ECU to relearn the throttle idle setup by disconnecting the battery and reconnecting it.

 

Yeah I'm thinking when cooled off the IAC valve behaves, not sure if it should/could prevent a hot start though. The valve should be simple to clean once removed and rule it out as a cause (or in).

Scanning for codes is your next best move I think