Engine M13A - performance issues diagnostics - Revision history

Bosanek: Added a chapter about throttle body

2020-03-31T11:04:46Z

Added a chapter about throttle body

Bosanek: New chapter on engine coolant, and more info about testing the viscous fan

2020-03-31T10:42:31Z

New chapter on engine coolant, and more info about testing the viscous fan

Bosanek: New chapter on engine heating issues

2020-03-30T11:09:33Z

New chapter on engine heating issues

Bosanek: Removed the embryo note

2020-03-28T08:14:47Z

Removed the embryo note

Bosanek: Added a new chapter

2020-03-27T21:05:38Z

Added a new chapter

Bosanek: Added more chapters

2020-03-27T20:26:34Z

Added more chapters

Bosanek: Added a chapter on crankshaft and camshaft sensors

2020-03-25T12:39:17Z

Added a chapter on crankshaft and camshaft sensors

Bosanek: Brand new article on performance issues and diagnostics in M13A engine

2020-03-25T12:26:07Z

Brand new article on performance issues and diagnostics in M13A engine

New page

{{intro-notes}}
{{embryo-note}}

== Introduction ==
{{Gen3|}}

The purpose of this article is to mention all performance issues which a Suzuki M13A engine might develop, and then possible causes and diagnostic methods to determine the exact or at least the most probable cause.

Examples of performance issues are:
* stuttering,
* loss of power,
* uneven RPMs when idling or when throttle is applied,
* excessive fuel consumption,
* not able to start,
* overheating under normal load,
* etc.

== Some issues and solutions ==

=== Exhaust Gas Recirculation (EGR) valve ===

An EGR valve helps reduce harmful emissions by introducing a small amount of exhaust gas, below the throttle plate, into the intake manifold. This has the effect of cooling the combustion chambers, as the incoming exhaust displaces part of the oxygen in the combustion chamber and takes up volume, even though it does not support combustion.

* A faulty EGR valve can cause rough idle and poor acceleration.
* If EGR is on during idle, stumble and even stalling will likely result.
* If EGR is on during hard acceleration, low power (from reduced air/fuel volume) is the result.
* If the engine stumbles or stalls at idle or lacks power under load, EGR may be staying on and not shutting off.
** On the other hand, if the engine is pinking at cruise, EGR may not be turning on to cool down combustion chamber temperatures.

=== Idle Air Control Valve (IAC) ===

IAC is connected to the engine's primary air intake valve (the Throttle Body, or TB) and is responsible for making minor adjustments to engine airflow. While the IAC valve's effect is fairly minimal while the TB valve is open, many engines rely on the IAC for idle or low-speed operation. IAC valve mechanisms can become dirty and clogged.

==== Start-and-stall ===

The engine will catch and run for a second or two, stutter and die.
* If "blipping" the throttle prolongs engine failure, but doesn't prevent it = IAC
* If "blipping" the throttle results in immediate stalling = fuel-related failure

==== Deceleration failure ====

Lifting your foot off the accelerator, the engine's TB valve completely shuts. In the case of a malfunctioning IAC, it will starve the engine of air = stalling either while decelerating or after coming to a stop.

==== Weather factors ====

A very cold engine needs more fuel than a warm engine, which is important to know while diagnosing the problem. An obstructed or stuck-shut IAC will result in a rich air-fuel ratio at idle, so the engine will start very easily while cold and then die suddenly after a slight puff of black tail-pipe smoke. A stuck-open IAC might start fine while warm and may continue to run if the engine reaches high-enough RPM.

==== Intermittent Stalling ====

An intermittent stalling condition is one in which the vehicle might start fine, act as though it's going to die, idle smoothly and then die completely. Alternatively, the vehicle may run fine most of the time, but stall periodically and then restart with a bit of difficulty. Intermittent stalling almost always indicates a dirty or clogged IAC.

==== Dependency on temperature sensor ====

The temperature sensor tells the ECU it is at running temperature and the ECU adjusts the IAC. If the temperature sensor gives erroneous information, the IAC will fluctuate.

First case is disconnect the IAC plug, and if it settles at around 1400 RPM, you can more or less guarantee it's the temperature sensor.

{{Edited}}

[[Category:Engine - gen3]]

@@ Line 36: / Line 36: @@
 * If the engine stumbles or stalls at idle or lacks power under load, EGR may be staying on and not shutting off.
 ** On the other hand, if the engine is pinking at cruise, EGR may not be turning on to cool down combustion chamber temperatures.
@@ Line 229: / Line 238: @@
-==== Old or wrong enegine coolant =====
+==== Old or wrong enegine coolant ====

@@ Line 145: / Line 145: @@
-* Going through water (especially muddy water) can muck up the engine coolant heat exchanger (wrongly called "radiator") and cause it not to cool effectively, making the engine more likely to overheat.
+* Going through water (especially muddy water) can muck up the exterior of the engine coolant heat exchanger (wrongly called "radiator") and cause it not to cool effectively, making the engine more likely to overheat.
 ** If the heat exchanger is visibly full of debris and muck, then it should be carefully cleaned. This is best done by draining the engine coolant from the system and removing the heat exchanger from the vehicle.
@@ Line 152: / Line 155: @@
-* The engagement mechanism (viscous hub) of the viscous fan (the big fan in front of the engine coolant heat exchanger) can become worn, causing the fan not to lock up and spin as fast as it should. This then severely hampers heat exchanger's performance.
+* The engagement mechanism (viscous hub / clutch) of the viscous fan (the big fan in front of the engine coolant heat exchanger) can become worn, causing the fan not to lock up and spin as fast as it should. This then severely hampers heat exchanger's performance.
-** If the fan is your prime suspect, you can temporarily mechanically lock it (so that it always spins) with zip ties or something and see if your issue(s) disappears or not.
+** If the fan is your prime suspect, you can temporarily mechanically lock it (so that it always spins) with "zip ties" or something and see if your issue(s) disappears or not.
 ** If you remove the fan from the vehicle, '''make sure''' that you do not place it in a horizontal position.
-*** Reason: With used viscous fans, that position might ruin the viscous set up in its hub, decreasing its mechanical resistance.
+*** Reason: With used viscous fans, that position might ruin the viscous set up in its hub / clutch, decreasing its mechanical resistance.
-** A replacement viscous hub for this fan is available in the [https://www.bigjimny.com/store/fan-viscous-hub.html BigJimny store].
+** A replacement viscous hub / clutch for this fan is available in the [https://www.bigjimny.com/store/fan-viscous-hub.html BigJimny store].
-Additional notes on how to check if the viscous coupling unit / hub of the fan is working properly:
+Additional notes on how to check if the viscous coupling unit / hub / clutch of the fan is working properly:
 * With a cold engine, grab the fan blades and see if there is side to side play or a rattle.
 ** If there is, the viscous hub is worn.
@@ Line 168: / Line 172: @@
 ** When you first drive off, the fan should roar like a vacuum cleaner when you rev the engine from cold. Then the noise should disappear when hot.
 *** No idea why this happens, as it is the exact opposite of what you would expect. Possibly the fluid has to warm up before it can start working properly.
@@ Line 180: / Line 191: @@
 *** A non-faulty Jimny thermostat activates at the temperature of around 83 degrees C, so boiling water will trigger it.
 *** Note: If a thermostat is removed from the engine, you will need a new gasket to put it back in. At this point you may as well replace it with a new thermostat, since they are quite cheap and come with a new gasket.
@@ Line 215: / Line 229: @@
 {{Edited}}
 [[Category:Engine - gen3]]

← Older revision		Revision as of 08:14, 28 March 2020
Line 1:		Line 1:
	{{intro-notes}}		{{intro-notes}}
−	~~{{embryo-note}}~~
−

	== Introduction ==		== Introduction ==

← Older revision		Revision as of 21:05, 27 March 2020
Line 19:		Line 19:

	== Some issues and solutions ==		== Some issues and solutions ==
		+
		+
		+	=== Generic solutions ===
		+
		+
		+	Try pulling apart every connector in the engine bay that you can find and spray it with contact cleaner, fill with petroleum jelly and re-connect. This fixes a remarkable number of problems.

← Older revision		Revision as of 20:26, 27 March 2020
Line 91:		Line 91:

	The crankshaft sensor rarely gives a fault code on a computerized vehicle diagnostics, because the ECU usually thinks that the engine has just stalled and doesn't log anything.		The crankshaft sensor rarely gives a fault code on a computerized vehicle diagnostics, because the ECU usually thinks that the engine has just stalled and doesn't log anything.
		+
		+
		+	=== Mass air flow rate issues ===
		+
		+
		+	The engine needs a constant feed of air in order to burn fuel and to make explosions in its cylinders which make it run.
		+
		+	The feed of air is determined as a mass air flow (MAF) rate, usually expressed in grams/second or lb/min etc.
		+
		+
		+	However, a MAF sensor does not exist "per se". Instead, the MAF is calculated based on individual readings from several different sensors. Those sensors are usually:
		+	* IAT (Intake Air Temperature);
		+	* MAP (Mass Air Pressure);
		+	* TP (Throttle Position);
		+
		+
		+	If either of these sensors are bad, the ECU will not mix the fuel and air properly, which usually leads to one of the following problems:
		+	* Engine stalling;
		+	* Uneven engine RPMs when idling (RPMs go up then down and so on);
		+	* Too rich fuel mix (raw fuel smells from the exhaust);
		+
		+
		+	However, the ECU will have a default / "failsafe" parameter "mapping", which it will use if it detects a failed sensor. Therefore, if you are having one fot he above mentioned issues, you can try diagnosing the cause by unplugging one of the above mentioned sensors in turn.
		+
		+	For example, if the engine RPMs are uneven when the engine is idling, when you unplug the sensor that's sending bad signals, the idle RPMs should stabilize. It might still behave improperly (for example idle "fast" - on high RPMs), but idle RPMs should be '''stable'''. If this kind of change happens, you have found the bad sensor.
		+
		+
		+	=== O2 ("Lambda") sensors ===
		+
		+
		+	Jimnys with M13A engine have two such sensors, which are quite expensive.
		+
		+	These are feedback sensors which inform the ECU about the composition of the exhaust fumes, so that the engine can adjust the fuel/air mixture accordingly.
		+
		+
		+	A typical issue which a bad O2 sensor causes is significantly to drastically increased fuel consumption, usually accompanied by reduced power. However, they can cause other issues as well (someone should contribute to this chapter).

@@ Line 39: / Line 39: @@
 IAC is connected to the engine's primary air intake valve (the Throttle Body, or TB) and is responsible for making minor adjustments to engine airflow. While the IAC valve's effect is fairly minimal while the TB valve is open, many engines rely on the IAC for idle or low-speed operation. IAC valve mechanisms can become dirty and clogged.
-==== Start-and-stall ===
+==== Start-and-stall ====
@@ Line 70: / Line 70: @@
 First case is disconnect the IAC plug, and if it settles at around 1400 RPM, you can more or less guarantee it's the temperature sensor.