Author Topic: Engine cuts out when cold  (Read 1578 times)

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Offline themillies

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Engine cuts out when cold
« on: January 18, 2017, 06:02:45 PM »
Hi guys. I need help. This is my third Feroza and I have had it for 12 years. 106,000 genuine kilometres. Extractor and 50mm exhaust. K&N filter. Silicone plug leads and Bosch Platinum plugs. I have swapped the ECU with my spare one and recently replaced the oxygen sensor. Cleaned the auxiliary air valve with carburettor cleaner. Use injector cleaner annually.

At the moment the car is running perfectly apart from PROBLEM 2. Fuel consumption is very good. 11km / litre on the open road. 9.5 to 10 around town.

PROBLEM 1: I notice a slight falter when accelerating. Fuel consumption goes up around 10%.

I check by bridging the ports in the 'check terminal' in the engine bay. 9 flashes on the engine check light indicates Speed Sensor fault. I do the reset procedure and check again. Flashes at 4.5 second intervals - continuously - indicates Normal again. No more problems. A few months later I have to go through the same procedure again.

Speed Sensor is on the speedometer shaft according to a diagram from the workshop manual and it is in the instrument unit. I have swapped the unit with my spare recently and have done 1500km with no further problem (yet).

PROBLEM 2: Start the car from cold. Assume 4 minutes to normal operating temperature. Ventilation fan and aircon off. Idle goes up to 1000rpm and will do this for the first 2 minutes (approx) of driving. Then the 'idle up' no longer functions for the next 2 minutes (approx). When I push the clutch in and take my foot off the accelerator at a traffic light, the revs drop to 500rpm - or drop right off and THE ENGINE CUTS OUT. No misfire, just 'off'. Starts easily on the key or drop the clutch in second if it is still rolling forward.

I compensate for this by keeping the ventilation fan on permanently to 'idle up' about 100rpm. Cuts out less often. ONCE AT NORMAL OPERATING TEMPERATURE EVERYTHING IS FINE. Idles at 800rpm with the ventilation fan on. 700rpm with it off. I would prefer it to be higher but when I adjust the air / fuel idle screw to increase the idle, the ECU soon adjusts back. Idle is smooth without fluctuation.

Any ideas?




Offline themillies

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Re: Engine cuts out when cold
« Reply #1 on: January 19, 2017, 07:04:45 PM »
I have just checked the setting of the Throttle Positioner and the Throttle Position Sensor (with multimeter) and both are set correctly.

Offline themillies

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Re: Engine cuts out when cold
« Reply #2 on: January 22, 2017, 12:50:42 PM »
PROBLEM 2 solved. I looked back over my previous posts for clues. Post 17 - 'A mechanic advised me that the throttle should be fully closed at idle.' (did this back then). I checked again and found that I could still back off the screw about half a turn to fully close the throttle valve (sometimes referred to as the butterfly) in the throttle body.

With no air escaping past the throttle valve, the screw adjustment of the idle is much more responsive. Now I have 900rpm at idle and at normal running temperature. Auxiliaries off (internal fan and aircon) and it does not cut out.

Moral of the story - don't adjust the throttle stop screw. The yellow paint over the screw and lock nut means it is factory set. It is directly linked via the shaft  through the throttle body to the Throttle Position Sensor on the opposite side and any adjustment affects the TPS as well.

Offline themillies

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Re: Engine cuts out when cold
« Reply #3 on: November 05, 2017, 12:24:48 AM »
Nearly a year since I swapped the instrument unit with my spare. No more '9 flashes' caused by the faulty speed sensor. 11.20km / litre on an open road trip through hilly country recently. Still many good years left in the Feroza.

Offline High PSI

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Re: Engine cuts out when cold
« Reply #4 on: November 07, 2017, 10:44:41 PM »
Nearly a year since I swapped the instrument unit with my spare. No more '9 flashes' caused by the faulty speed sensor. 11.20km / litre on an open road trip through hilly country recently. Still many good years left in the Feroza.

Great to hear.  :13: No plans to get rid of mine anytime soon, but getting harder and harder to keep these rigs going with support and parts getting thinner and thinner...

Offline brushhippie

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Re: Engine cuts out when cold
« Reply #5 on: November 08, 2017, 06:28:17 AM »
Glad to hear you worked it out!