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V8 5.0 litre stalling.

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So, it's a 1992 VQ statesman, but it has a VS 5.0 litre (not that it makes much difference.). The problem is that the car stalls after warming up. When you first start it up it idles fine but on the rare occasion will go up and down between 700-1200 (1k revs usually being a steady cold start idle). If the idles being fine the car after being driven for 5-10 minutes will start playing up. (Auto tranny) After being driven and you start coming to a stop, (usually gearing down from 3-2 or 2-1) the cars revs will just plummet to a stall (sometimes can be saved by feathering the accelerator leading to flying through the corner aha.). After it stalls the car usually takes a minute or 5 of cooling down then it will merrily start like nothing happened but then the accelerator needs to be kept on slightly otherwise it will stall from what seems like low revs. I've replaced the ignition module, (before I did it would take hours until it would start again so I'm guessing it half fixed the problem... Or fixed one of many problems ha.) before I replaced my friend suggested pouring cold water in front of the engine to cool the CAS, it started after doing it them a few days later I found out that V8's don't have CAS only the V6's do, so I thought that was a bit odd. The Ignition Leads and Coil were replaced and the dizzy was retimed 7 odd months ago. I will be replacing the Distributor tomorrow hopefully (invade it being the Hall effect, so ill update that.). I've read many things throughout different threads, starting from vacuum leaks, faulty/dirty throttle body, MAP sensor, IAC etc etc, seems like many things can cause something like this. Dealing with the whole fuel to air ratio with spark etc.). What hoses must I check for the vacuum leak? And I do have a slight rocker cover oil leak, bottom 2 alen key bolts are missing. Any small things I clean or any DIY checks I can do to various parts? I did the fault code check and it read 15 but then I took out the 'engine' relay fuse (i think it's called, front small fuse box adjacent to the battery) and now it's reading '12' satisfactory running, so I may have reset it, it's been driven after that so I might re-check it.

Sorry for the long read, I just want to be specific to keep any mis-diagnosing at a minimum, cheers.
 

VR38

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I would be doing a fuel pressure test.

i had a fuel pump that would give similar symptoms.
 
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Note: Code 15 / coolant temperature sensor circuit (high voltage) is showing up.

Cheers, I will try and do that today.

Also I've let the car warm up in park this morning and after a few minutes it will vary idle revs as said before. Before I replaced the ignition module the air box would be hissing but that's come to almost a complete stop (vacuum leak maybe?)
 

Circlotron

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Maybe the hissing was the IAC open wide to try and maintain the idle.
On mine you can hear it quite plainly.
Is on gas though so the setup may be somewhat different.
 
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Yeah possibly, still yet to get to the IAC to check it. It's odd because I never heard it before that. It's fuel injected.

*update* So bought a new PCV valve (only because I had to replace the hoses connected to it due to deterioration like a mo'fo and because it was cheap)

I have to wait till this arvo to install it and the dizzy though. Which brings me to my next question, how to remove the complete dizzy? I've removed the basics like the leads, cap, wire connector. I've got a general idea on how to remove the rest starting with the rotor and what not but I'm stumped as to how I rotate the engine so the TDC mark lines up and all. Any idea on how to rotate the crankshaft pulley to meet up with the TDC without starting the car? *Dont have any right tools to be turning the centre nut on crankshaft* any other ways?
 
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50LTRv8

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To remove the dizzy, there is a clamp you need to loosen at the base of the dizzy and you will be able to remove it. I had to get a special tool, it looks like an L shape with a ring spanner on one end and a rachet end on the other.

You rotate the engine by finding the bolt in the middle of the main belt pully on the end of the crank, remove the spark plugs to make it easier (removes compression). Make sure your at the right stroke when you get to TDC on cyl 1 (both valves will be closed).

The tool you could use would be a rachet with a small extension and a socket, and I know, it is tight for space.

Also when the engine is running and your using a timing light on it, remember to bridge the pins on the diag socket to get the correct timing.
 
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Ok cheers, hopefully my mate mechanic has the tool otherwise, where would I buy it from?

I was hoping there was an easier way than that because I don't have a big enough socket haha.
That will give me a good reason to check the condition of the spark plugs at least.

Ill leave the timing to the mechanic lol. I'm only an amateur. Are you talking about the diagnostic connector on top of the passenger side kick panel?
 
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Yeah the dizzy was easy as, didn't need the tool at all. But the new dizzy was from the later model engine with the rectangular square connector for the cords. Only problem now is there is no spark, will I have to replace the connector from the harness with the later model one? That's the only reason why I can see that there is no spark now.
 
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It was the distributor that made it stall (hall effect sensor) most likely. It still lacks power though, seems to be making high revs and not going no where. I know it's a heavy car but it ain't a tank, so I expect something is wrong ha.
 
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