Cold Blooded PVR V6

[Corrida]

Hi Everyone,

 

I have had my 87, 780 for almost three years and she has always had this one constant problem. I do not know if other 780’s with the PVR V6 engine have this issue. I have filed through forums through many websites and no one else has mentioned this problem. She has a very cold-blooded engine, very cold indeed. I have to idle the engine for 15 minutes before she runs properly.  Sometimes when I set off, the engine spits and sends a steady vibration which rocks the car. Then almost by magic she smooths out and feels right/powerful. When the engine is warmed up the car is very quick and buttery smooth however, if I sit at a red-light, the engine starts to idle poorly, making the RPM needle dance between 15oo-500 RPMs. Sometimes she can stall or just make the famous idiot lights faintly come on. I am finding that using a fuel cleaner (Royal Purple) can help tremendously and pretty much solves the problem temporarily. I use 87 octane level because of the V6, should I be using something else? I’ve replaced, fuel filter/pump, wires, plugs, and the exhaust system.

What am I missing?

 

 

Thank you

Keep ’em Rolling.

[christopher]

I am of the opinion that the PVR V6 ran on magic and prayers.  The one PVR V6 780 I had would run perfect one day and then not start for a day then start and then may die for half a day then run for 20 mins then die for 3 weeks. you get the idea. There seemed to be no logic whatsoever to the way these things were wired.

[Johan VlagsmaParticipant]

Hi Sean,

Have you checked the basics? I would probably start by checking the entire intake side for air leaks, torn hoses, poor fitting clamps etc. but also all gaskets in the intake right to the block. Idle rpm hunting is an indicator for air leaks. Especially look for hoses that are normally tight but eg when bending have a leak, this gives the occasional problems like you mention

Johan

PS have converted your car so the specs are right: http://780coupe.com/ownership/sean-corbin-none/

[Corrida]

Thank you Christopher and Johan for replying. The note on RPM hunting is very helpful and I will pay close attention to the intake side.  She has 135,000 miles and I wonder how high these engines go in milage.

 

Thank you for your time.

 

PS Thank you Johan for changing the specs.

[Lager]

Hi!

I would also check the distributor cap, rotator, spark plugs and spark plug wires.

[dn010Participant]

Late to post but I wonder if this has been solved? I did not see anyone mention the MAF sensor; they get dirty, they go bad and can cause all sorts of problems. Also you can check the wiring to, and the actual coolant temp sensors- if it runs better when hot it may be an issue with that.

I’ve worked on a variety of PRV engines for over 15 years now, I’ve seen them click past 200,000 miles. I find them to be extremely reliable – never have I once been stranded by a PRV powered car. If you start with the regular maintenance items and take care of them, they will last a very long time.

[Corrida]

Thanks dn010,

I have yet to check the MAF sensor and I am not sure why, through checking the wires, plugs, vacuum hoses etc, I must have glazed over it somehow. Now that it is summer I no longer need to run the engine for 15 min, I just turn her on and go (very convenient). In the spring I used a fuel line cleaner called Royal Purple and boy what a difference.  The main thing that I find with my engine is that either burns too much fuel at times or the idle is a little bit off while I’m stationary at a traffic light.  Sense using the product Royal Purple my PVR is running wonderfully but she does still have a rough idle at times when  stationary.

[errcl65Participant]

I am looking for maintenace checklist for the B280F (V6 PRV) to keep it at “Stage 0”.

Is there a Green book outlining this?   When (time/mileage) things should be checked/renewed?

 

[dn010Participant]

I will check my literature, I am almost positive I have something regarding maintenance intervals.

[dn010Participant]

Corrida –

Consuming too much fuel can be a result of a dirty MAF, it is telling the computer X amount of air is entering the engine and compensate by injecting more or less fuel when the actual amount of air entering is Y and now you’ve got a bad air/fuel ratio. If you go to a parts store you can buy MAF cleaner, it is a spray which you can remove the MAF and use spray the cleaner on it to try cleaning it up. Sometimes it works, sometimes you just need to replace the sensor. However, if you find the fuel system cleaner to work, that would indicate you’ve got one or more injectors that are either dirty or clogged and the cleaner is working to clear this up.

[dn010Participant]

Here is a shot of maintenance schedule, you’ll be following the 87-89 Models column on the right.

[BertoneParticipant]

Hi,

My car (V6 PRV B280F) also vibrates a lot when standing still and idling.

The revs stays constant at 900 rpms according to the dash. The engine runs ok once on the road.

Ive changed:

Rotor and distributor cap

Engine oil and filter

Gas filter

Air filter

Sprayed clean the EGR with zero residue spray

Cleaned idle valve and throttle body

Complete ATF flush

Checked intake hose for leaks…no leaks

What else is there to do do get a smooth non-vibrating engine idle?

 

[errcl65Participant]

Did you clean the MAF ?     Your list didn’t mention new plugs.   Pull the plugs, check the tips and gap.

Could be bad gas as well or water settling in the bottom of the tank.   Do you get a lot of water

in the exhaust?    How full is your tank when this happens?    If you run less than 1/2 tank and

have rough idle, it could be bad in tank fuel pump.

[dn010Participant]

I agree to clean the MAF with specific MAF cleaner. If you mean your engine is idling at 900 RPMs, that is pretty high.

[BertoneParticipant]

Changed to new sparkplugs also..forgott to add them in the lista above.

[dn010Participant]

Try to clean the Mass Air Flow sensor. These are hot-wire sensors so make sure it dries out before reinstalling and running it and try it again. Make sure your spark plug wires are tight and in good condition. Check the condition of the terminals and wires at the coil. If none of these help I’d start looking at injectors and fuel pressure regulator.

[BertoneParticipant]

Yes, I cleaned the MAF with special spray but no change…

900 or 850 rpms…not sure since I can only read it via the dash. But the rpms are steady (not moving up and down)..

Yes, water was dripping out from the exhaust joints after the catalytic converter when i dove it for a 20 Km spin yesterday (first “long” drive since 2008) !!!

The car has been standing un-driven for 8-10 years.

Tank is only half full…filled with 30 liters of new gas the other day so perhaps there is still 10 liters of  old gas now mixed with 30 liters of new gas…

Why is water dripping??

Thanks for your help !

[BertoneParticipant]

The car seems a little bit low on idle revs: 750 rpms according to the gauge when warm.
Will investigate if I can increase revs with just a little bit.

I think it should be 900-850 rpms for a B280F.

 

[errcl65Participant]

That water from the exhaust is from the water in the gas tank that is getting cleared out.

Stick some more HEAT or 99% isopropyl alcohol in the tank and drive it.

[dn010Participant]

The RPM is not low. Idle speed on the B280F should be 750. The instructions in the book say to set the basic idle speed to 700 with the CIS test point grounded and once you remove the ground it *should* increase to 750.

[BertoneParticipant]

Ok, thanks…just located the CIS test port (white/red cable) and the adjusting knob (under the throtthebody) in the engine bay.

Will do this tomorrow once I drive the car since it needs to be warm before doing it. I’ll report the results. Cheers.

[Author]

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