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Stalls at idle

T

Taza

New member
Engine 2007 Volvo Engine 5.7Gi EFI

Engine Stalls at Idle.
I Have cleaned the flame arrester
Fitted a new OEM IAC Valve
Fitted the e-clip to the fuel pressure regulator
Checked fuel pressure low pressure pump 18psi (manual says it should be 8psi ?)OK at all revs
Checked high pressure fuel pump 52psi OK at al revs
Fitted new fuel filter
New spark plugs
New leads,dizzy & rotor

No fault codes on Rinda Tool

If I adjut the RPM to 850rpm it runs ok and doesn't cut out

any help appreciated
 
Hi

all connections are fine, I can operate the IAC valve from the Rinda Scan Tool, increments of 100rpm,so i know its operating OK
 
Not sure how you adjust the throttle butterfly on those but just going by my jeep there should be a anti diesel adjustment that holds the butterfly slightly open so the engine does not stall when you throttle down quickly. When the TPS senses the butterfly is being opened the computer closes the IAC valve fully. Run the engine around 1500 RPM and unplug the IAC motor then disconnect the throttle cable and adjust the engine idle to around 700 RPM with the throttle butterfly. Then just plug the IAC motor back in and the computer should control engine idle. Another possibility is the throttle body just needs to be cleaned at the butterfly Just put some gas on a rag and with a screwdriver clean the bore of the TB. Once you get it idling good then adjust the cable to fit.
 
Cheers Kimcrwbr1

so when the butterfly is fully closed the IAC valve should be open slightly ? The only way I can increase the rpm is adjusting the throttle cable

From cold start the engine will run at 600rpm for about 5mins then just stall,if I adjust the throttle cable so it idles at 800rpm it will run ok and not stall.
 
Hi bud

I have checked the PVC valve and it looks and feels OK the ball is rattling around.

but now you have said its part of the maintenance plan will buy a new one
 
A vacuum guage can point you in the right direction if it is mechanical it will show up with manifold vacuum pressure. At engine idle it should hold steady at 20 inches.
 
Hi Bud

I have never performed a vacuum test, could you explain how to do it, and where to put the test gauge.

thanks for all your help
 
how do I get it back in adjustment, what should the readings be on my Rinda scan tool at idle and at different revs
 
Did the diacomm show the requested idle speed? Clean the throttle body and iac passage with sea foam or a throttle body cleaner available from any parts house, sounds like the passage is plugged up causing iac to stick. Also check to make sure butterfly is clean. You should be able to t off the fuel psi hose with no ill affects to anything.
 
Clarification, should be able to t off fuel pressure regulator vacuum line. Was asking about requested idle speed because you said you can change idle speed with the scan tool, indicates that the circuit is working. Have seen many injected engines idle at specified speed with a dead hole, just not very smooth. The rinda scan tool will allow small idle speed changes upon request. Possible that you may have a bad tps or a crank sensor out and ecm not receiving correct inputs. Check for correct reference voltage at all sensors and a smooth ohms test on tps sensor. Last but not least, have dealt with this before, a bad ecm. If every pin test shows good I would look at finding a known good ecm donor to swap out. Good hunting and keep us informed
 
It is best to use a analog (needle sweep) ohm meter to test the TPS you can see any dead spots in the pot it should have a nice clean sweep up and down with throttle movement.
 
I am never a fan of throwing parts at a problem, but I can tell you that when I had a similar issue, replacing the points with the pertronix solved my issue. It was 100ish total and now the engine starts perfectly every time. I will never own a motor w/o pertronix again. Truly.
 
after searching the internet and reading about all the different sensors and what could happen if they fail I came across this article, so I have ordered a new crankshaft sensor.

The most common failure for one of these sensors is when the engine is idling it will just stall. This is because the pulse width is at its widest gap because of the slower engine speed. Heat will also cause the sensor to fail because of the thin wire winding which will expand with heat and short out to one another changing the sensors resistance which will cause the sensor to stop giving a signal to the main computer. Once this happens the pulse generation to the injector and ignition systems will stop the engine from running.

A failing crankshaft sensor is famous for working when the engine is cold and then to stop working when the engine heats up. When you let the engine cool off the sensor will start working again. Testing this sensor's intermittent failure can be difficult due to its ability to start working again. Though you can test the sensors resistance using a voltmeter the true way to test the sensor is to use an oscilloscope when the sensor is hot

will keep you posted
 
Are you talking about the sensor in the distributor? I know gm sometimes called that a crank sensor. They also had a few engines with an actual sensor at front of engine that was a crank sensor. Either way I believe your on the right track. Could you put a spark tester on coil wire to see if your losing spark at idle?
 
Taza - Did you ever find what caused this issue??

I have a 2006 Volvo Penta 5.7 Gxi and it will stall and quit when coming down from a higher RPM into idle after warm. No chance to restart until cooled off, it just turns over. Seems to be the same issue you have.
 
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