Speedometer broke and check engine light

[sheppardpat47]

Hello everyone

I was driving to France, when I left, my speedometer didn't worked and was stuck to 105km/h (neither the trip or odometer works), after hitting the top of the dash, the needle is at 0km/h

That's a broken cable probably, but what's very weird is that the ECU is throwing a check engine light. When accelerating, it stays on, when getting off the gas, it turns off. I have no idea why.

Is it related to the speedometer?

I also have sometime small "fuel cuts" when driving, it's very rare but it can happen, it's generally once while driving on the highway and last about half a second.

Maybe bad fuel pump? I have no idea... So weird!

Car start and run fine. Still has plenty of power.

[banpei]

It's not related to the speedometer itself as that's a separate unit.

Which one of the lights is illuminated?

The third on the left is the catalytic converter overheating warning, and the second on the right is the check engine light illuminated by the ECU. If it's the latter, when you start the car, this is illuminated by the low oil pressure as the engine isn't turning and the ECU doesn't receive a signal. What reading for the oil pressure do you have on your gauge under accelleration? Does it suddenly drop?
It could be a faulty oil pressure sensor giving a too low reading but also a loose connection within your gauge cluster as the light is controlled by whether there is oil pressure or not. I would also check the oil level in your engine out of precaution.

[Ivan141]

If the check engine light is coming on, you might be able to pull a diagnostic code, that would be the first thing to try.
As far as the fuel cuts go, that doesnt sound like a problem I hear often. I had a fuelpump on the way out 20 years ago (lol)
it would cut out intermittantly (back then usually on the highway) for a few secs, sometimes even 10-15s and then come back to life.
It did that for about a week before it died though.
There are 2 relays responsible for keeping the fuel pump powered on:
-EFI main (controlled by ignition)
-Circuit opening relay (controlled by ignition on startup and by ECU while running).
It would be more difficult to diagnose these though.. you could jerry rig an LED connected to the COR output pin to spot if the power is being cut when the fuel pump
cuts out.

[sheppardpat47]

(Today 07:54 AM)banpei Wrote:  It's not related to the speedometer itself as that's a separate unit.

Which one of the lights is illuminated?
The third on the left is the catalytic converter overheating warning, and the second on the right is the check engine light illuminated by the ECU. If it's the latter, when you start the car, this is illuminated by the low oil pressure as the engine isn't turning and the ECU doesn't receive a signal. What reading for the oil pressure do you have on your gauge under accelleration? Does it suddenly drop?
It could be a faulty oil pressure sensor giving a too low reading but also a loose connection within your gauge cluster as the light is controlled by whether there is oil pressure or not. I would also check the oil level in your engine out of precaution.

Only the check engine light illuminates, only when driving on highway (under load) when I let go the gas, it doesn't illuminate. Oil pressure is perfect as well as temperature



I have absolutely no idea, I think it might be fuel too lean because of fuel pressure dropping? I don't know. The thing is, the car runs fine, drives fine, but I was fed up so I just took it back to my garage as the weather is dreadful in Belgium today.

(Today 08:31 AM)Ivan141 Wrote:  If the check engine light is coming on, you might be able to pull a diagnostic code, that would be the first thing to try.
As far as the fuel cuts go, that doesnt sound like a problem I hear often. I had a fuelpump on the way out 20 years ago (lol)
it would cut out intermittantly (back then usually on the highway) for a few secs, sometimes even 10-15s and then come back to life.
It did that for about a week before it died though.
There are 2 relays responsible for keeping the fuel pump powered on:
-EFI main (controlled by ignition)
-Circuit opening relay (controlled by ignition on startup and by ECU while running).
It would be more difficult to diagnose these though.. you could jerry rig an LED connected to the COR output pin to spot if the power is being cut when the fuel pump
cuts out.

The thing is, the fuel cut is only on the highway (driving 120kph, so 4500rpm, which I mainly do)
This car mainly see highway driving, and I don't hesitate to rev it to 8000rpm when leaving rest areas to get back to speed lol
I think for me the best hypothesis is the car doesn't get enough fuel on highway, when pressing the gas the throttle let more air and the fuel pump can't keep up, thus the O2 sensor is like "uhhhh...problem, need more expensive juice" thus throwing a code, once the gas pedal is released, O2 sensor see less air, so no problem anymore.

I think it might be that, but like, guh... Another 250€ to spend on Flo's

Here is a video (captions work because I was yapping in French, obviously)

[banpei]

I would say you check the ECU fault code by Ivan's suggestion. Download the 4AGE manual or the diagnostics manual (if you didn't do that already). In the 4AGE manual, the diagnostics section is on page 81.

[sheppardpat47]

(Today 08:39 PM)banpei Wrote:  I would say you check the ECU fault code by Ivan's suggestion. Download the 4AGE manual or the diagnostics manual (if you didn't do that already). In the 4AGE manual, the diagnostics section is on page 81.

Thanks, I'll do that tomorrow before going to the arcade. My garage is near it. I brought a paperclip with me, who knows...