VP losing power whilst driving

[mbvp73]

Hi there,

First time on Just Commodores so I hope Im in the right place to post my question and that someone might be able to help me.

I have a '92 VP Commodore wagon with the 3.8 V6. Up until 6 months ago my car was running fine. It then developed some unusual behaviour. This is what is happening...

1/ Whenever its a hot day or ive been doing some sustained high speed driving, my car starts to jolt and buck like a rodeo horse (silly analogy I know but thats what it feels like!), lose power to the point or nearly stalling then it will continue on its way. This happens with the AC on or off.

2/ As well as this, sometimes the car will cut out suddenly, even whilst I am driving. This has happened at times where it hasnt been a hot day.

3/ On hot days or a long sustained highway drives, when I stop the car and try to restart within a few minutes, it won't start. But give it 10 minutes and it starts like nothing has happened.

4/ Whilst cleaning the car yesterday, I noticed green coolant leaking down in the driver footwell. I'd say that the heater core might have a leak, but is there some other explanation? I had a service a month ago and they did a cooling system pressure test and found no leaks but I think they may have missed the interior leak. Are heater core replacements big bucks to fix? Coolant loss is minimal but I fear it could get worse.

In regards to the power loss, my guess is that the fuel pump could be on its way out but maybe someone out there might know better than I.

If anyone could give me some ideas as to what the hell is happening it would be much appreciated.

Thanks

mbvp73

[JD]

check your codes see if its picked up anything.

[mbvp73]

JD, I hope this gets back to you!!

Thanks for replying by the way

I told my mechanic who did my last service (Which included an injector clean) what was happening and he actually said he would check the codes (I gather that is hooking something up to the engine management computer or something similar) and he found nothing irregular. In fact he said it was great.

Been looking at some very similar posts to the one I just put on and they say it could be a coil thing or a fuel pump problem. I forgot to say in my initial post that the fuel pump, when the car starts in the morning, does that humming noise when the key is in the 'ON' position. When the car is hot, playing up and I try and start, and the key is on the 'ON' position, it sounds as though the fuel pump is gurgling, not 'humming', so to speak. Vacuum leak? Dirty pump? Apparently the VP fuel pump have a gauze filter in them. And once that is clogged you need to remove and clean it. Does anyone know about this?

Does anyone know if fuel pump replacements are 1/ a big job and 2/ expensive?

Thanks JD

mbvp73

[Sp0tteh]

to get the fuel pump done by someone else your looking at around 200-300 do it yor self for 80 odd. gl

[PaRaDoX]

ok, i went throught this, they replaced the Coils, Ecu, Fuel pump and CAS

it was the DFI modeul which is a part of the coil packs.. it wont return a error code...

see if you can borrow someones coils to test, as i bet you thats the problem, mine had the exact same symptoms.. dont buy new parts, borrow parts and see if it still does it

[lazza44]

CAS for the starting problem i reckon

[Matt_vp]

most probably fuel pump or cas, when it wont start when its hot try pouring cold water over your cas then try to start it if it starts it is the cas.
Matt

[pandaman]

CAS for the starting problem i reckon

Quite possibly a correct diagnosis. mbvp73, next time the bugger won't start when it's hot, chuck some cold water over the crank angle sensor, (do a search of this forum to find out where it's located, I can't remember exactly) If that's the problem, the cold water should cool it off and the bugger should start.

Coolant in the drivers side footwell? Dang man, I reckon you're right, heater core is probably on the way out. It's a bastard of a job as you've gotta remove the dash, and in a car this old plastic trim never goes back in place easily. If you're confident with mechanical stuff it's not a hard job, just bloody tedious apparently. (Never had to do one myself thank the lord) If the leak is very small it could have been missed in the pressure test, and may not be worth worrying about just yet, especially if the cooling system is still doing it's job.

The surging is the really interesting thing, paradox reckons dfi module, he could be right. But given that you're having cutout problems and the fuel pump sounds funny, my money would be on fuel filter first off. That's a VERY easy job. Grab yourself a new fuel filter, (Ryco brand is the shiznit and fuel filters are cheap anyway) depressurise the fuel system, and replace the filter. (it's right next to the tank) I love this job because all ya need is a flathead screwdriver and maybe a pair of safety glasses to avoid fuel in the eyes. Oh and maybe a jack and a chassis stand if your beast is a bit low.

Good hunting bro.
Neil

[vq_statss]

hey myn was jolting i changed the ignition rely underdash and my key emobiliser in glove box was loose so i put it down to one of them the rely was burnt lookin on the prongs.....just a hint for ya

[peter65]

Hi there - looks to me like you have 2 problems.
1. the "bucking bronco" sounds like it might be a a fuel problem to me - esp if its under load as the engine startves of fuel. to fix it, start with the cheap (read: simple) DIY stuff - check all fuel line clamps from the tank, thru the fuel filter (near the tank under the car) and along the line to the fuel rail via the pressure regulator (ita a the rear of the motor, on the drivers side). Check all connections are tight (trim the rubber pipe by 1cm or so and reconnect any sus ones) and you can also replace the fuel filter (~$12 if i recall correctly) while you are at it.

2. The coolant leak. i have had a few minor leaks on my 300kkm vp. Again, try tracing the heater hoses under the dash and tightening the clamps as req'd. You may need to remove the hose, trim 1cm or so off the end and reconnect as the hoses perish and can weep.

Note: if you have lost a lot of coolant, you may need to drain, flush and refill the cooling system (you should do this every 2yrs or so anyway as part of routine maintenance on your car). Do this after you have found your leak! Try not to mix different brands of coolants - they arent compatible!

sorry for all the words - pm me if you want more! cheers and good luck.

[mischf]

Check your alternator voltage, should be about 14V no higher. My VN started cutting out after pulling off the freeway and slowing down, new voltage regulator fixed that ($50). Definately try tightening hose connections to your heater core, they're probably just loose, and put some stop leak in there. Theres a good one in a grey bottle, with pellets in it, got heaps of glue in there, forgotten the brand think it starts with a G. And yeah CAS will be rooted.

[mbvp73]

To all who replied

Thanks heaps for the advice. Im a bit busy today but when I get time I will read thru your replies in more detail and note down everything that you all said could be wrong with my VP and take it to a mechanic to check out.

Whoever thought up this Commodore forum is a genius. This is brilliant!

All the best to all of you VN VP driving dudes and dudettes

mbvp73