5L V8 Stalls during normal driving

[jon_vs]

My 5L V8 Caprice drives well, starts without problem. However, while driving sometimes the engine just stops - the engine warning light comes on followed by the rest of the dash lights. I wait about 15 to 20 seconds or sometimes more, turn on the ignition - I hear the fuel pump prime and most often it starts (sometimes it needs a second crank) - idles normally, runs normally so off we go again. I may not have the problem again until the next time I use the car.

I have checked the error codes and only get "12" – telling me that everything is OK. Within the past 50,000 klms, I have replaced the coil, ignition control unit, hall sensor, leads, distributor cap, fuel pump - all this was to chase and fix an earlier problem (the hall sensor). The problem is intermittent but it is becoming more regular.

The car always starts from cold and hot. When I had the previous problems with the Hall Sensor it was (always) more of a starting problem than a running problem.

 

[Troy5L]

are all the hoses hooked up? u might have a leakin vaccum hose..

or even, turn the car on and when its idiling tap the MAP sensor, if the revs bounce when u tap it then its fault and might be causin u some problems...

maybe go over the coil, ICU, hall sensor, leads n dizzy cap and see if everything is ok...if u still cant find the prob i guess droppin into a mechanics and seeing if they can find the problem...good luck man

 

[Dinwoodie]

Hey mate this seems to be a common problem happening with 5.0L's around now, i've spent hundreds on fixing the solution to mine (i was having the exact same problem as you) and after spending a heap of coin it came back to a $60 hall efect sensor in the dizzy, hope this helps and saves you some effort, peace

 

[jon_vs]

Hi Troy5L
Thanks for your thoughts. I have checked the vac pipes - all seems well. I have tapped the MAP sensor with no noticeable effect on the revs. Disconnecting the MAPS vac pipe certainly produces an effect. I checked out the electrical components as you suggested but could not find any “obvious” problem. Unfortunately the stalling problem is such an intermittent one. It is going to be hard for any mechanic to find unless he has had a previous similar experience.

 

[jon_vs]

Hi Dinwoodie,
Thanks for your reply. The last time i had a starting problem I also spent heaps in time and $, and yes it was the hall effect sensor. However, that time it produced very different symptoms to what I am experiencing now ( they were intermittent, not starting and then sometime after minutes, hours - what ever "it" felt at the time, the engine would start as if there was never a problem. The engine would never "stop" once it was running.) Now I am not having any problems starting, but heaps of problems stopping!

 

[BlackVXGTS]

Did you replace the coil? In my experience they just stop working altogether but it might be worth a try.

 

[jon_vs]

Hi BlackVXGTS - I checked back over last 70K or so - the coil has been replaced.
Here's an UPDATE - I have spoken to 4 mechanics, the first not a clue but willing to quote on it, the next two passed the buck and the fourth (also an auto electrician) recons it could be the ICU rather than the HES (in his experience), so he has suggested to replace the ICU first. Hmmmmm. The car performed faultlessly yesterday (must realise that I'm onto it!). At the end of a run I touched the ICU and it was hugely HOT (easily >70 C). Is this normal?

 

[hako]

Maybe try replacing the fuel pump relay....or at least swap with another on the relay block. Also check the fusible links - make sure they are connected tight. I don't know about the ECU getting hot though I'd imagine they would get rather warm just like a PC.
Good Luck.

 

[vnss5ltr]

i would just leave it for a little bit. as much as you can bare. i have had similar problems and they can just be a result of circumstance. give it a few days, see if it clears up, if not find a serious mechanic. i love mechanics who have no clue, defeats the purpose

 

[jon_vs]

Hi Hako,
Thanks - I have already tried swapping the relays to no effect and have also checked the fusible links - nothing there either. Meanwhile, Repco provide an exchange ICU for $255 and an exchange (new) HES for $105. Where the ICU is a breeze to replace, the HES is way more complicated to get to - who was the engineer who designed the placement of that one? I had a Jag once and its workshop manual said to remove the engine, first raise the bonnet (!!) I guess the Holden manual might say to remove the distributor, first remove the engine !!