VN 5L drives like a pig after installing cold air intake. Needs a tune?

[jdodd]

I've just remembered something. Two things actually.

1. I am an idiot.

2. when I put the over-the-radiator CAI on there are two screws which hold it down on top of the radiator.
I must have either over-tightened these, or the plastic CAI was too big for my car, because the shroud was being pushed into the fan blades when I went for a drive.
At the time of installation this didn't occur to me (see point 1 above), but when I took it for a drive the temp guage increased a little more than normal.
So I pulled over and popped the bonnet and with the engine still running (and hence the fan too) I could hear it hitting the plastic. So I immediately took it off and put the standard intake back on.

Could that have stuffed my clutch fan? It makes sense as alot of the time I can hear the fan revving furiously.
Also this would explain why my car is always cool because even on hot summer days it won't go above 1/3.
When the car is completely cold the fan is hard to move by hand, but when the car is hot the fan is easily moved by hand and after spinning it continues to spin for a short distance.
Is this normal or should it be the other way around?
I've heard conflicting answers about this.
Anyway, I'm going to take the fan off and go for a quick test drive.
Also, the clutch fan is connected to the water pump right, so maybe that has a problem.

So does it sound like there's a problem with either the clutch fan or water pump?

hi my vn v8 was gradually getting sluggish and it got really really bad one night. felt like something was holding it back. so i had a listen and could hear a slight grinding noise from the water pump.
so the next night i took it off to replace it and found it was seized up tight and the bearing had let go and the impeller was hitting the timing cover. after replacing it it went like a 5l should.

[4wheelinls1]

How hot did it get? Rough on a hot start and sluggush, how does it crank on start? If it is irregular it may have blown a head gasket.

[raw]

The temp gauge didn't go past half-way. Normally it would sit on just 1/6, so when it approached half-way I got suspicious.

On startup I've noticed a big change too. It used to start smoothly and sound 'bubbly', but now its rough and the sound is a bit like a 'grating' or raspy sound

[jdodd]

yeah it never really got hot, but that did all happen during winter.

[GenReaper]

When the car is completely cold the fan is hard to move by hand, but when the car is hot the fan is easily moved by hand and after spinning it continues to spin for a short distance.
Is this normal or should it be the other way around?
I've heard conflicting answers about this.

Other way around, should freewheel when cold to allow faster warmup.
When hot, bimetal strip makes the fluid coupling get more solid and hard to turn so it pulls air when warm cooling the radiator down.

Take fan belt off and check alternator bearings aint siezed while your there.

[raw]

hi my vn v8 was gradually getting sluggish and it got really really bad one night. felt like something was holding it back. so i had a listen and could hear a slight grinding noise from the water pump.
so the next night i took it off to replace it and found it was seized up tight and the bearing had let go and the impeller was hitting the timing cover. after replacing it it went like a 5l should.

Other way around, should freewheel when cold to allow faster warmup.
When hot, bimetal strip makes the fluid coupling get more solid and hard to turn so it pulls air when warm cooling the radiator down.

Take fan belt off and check alternator bearings aint siezed while your there.

I do have a slight coolant leak cos I have to top up the surge tank every now and then, so it very well could be the water pump,
which makes sense since it is connected to the fan which caused the problem in the first place
While I'm checking the fan and water pump, I'll be able to take a look at the alternator too
I think I'm getting close to the source of the problem now *rubs hands together*

[raw]

Well first of all I can catergorically say the tune is not the answer as I originally hoped, as I recently installed greenfoam's tune and while it made the car smoother, faster and overall better, my problem still exists.

I also found that the ignition coil condenser is only to stop radio interference or something, so I didn't bother changing that.

And I got around to taking off my clutch fan and taking the car for a quick drive. Though this was for interests sake more than anything, as this wouldn't tell me if the clutch fan was playing up since the increase in performance might just be because the fan wasn't on at all! Anyway, car went better (obviously) and sounded much better without that annoying WOOOOSHHHH sound.

But most importantly while I was there I also inspected the water pump and using a bendable mirror and torch I found a leak in the little drain hole, as shown in this thread appropriately named:

stuffed water pump

But could this leakage make the car run slower, sluggish etc.? Or perhaps on the inside the impeller is rooted and holding the engine back? . . . remembering that the clutch fan is directly connected to it

I really hope its well and truly stuffed on the inside, and it fixes my problem so that i get my full moneys worth by killing two birds with one stone (leak, power)

I'll get around to changing the water pump after xmas. I'll keep the hall effect sensor ace up my sleeve for now, and hope that I don't have to bring it out . . .

Merry xmas everyone

[raw]

First of all, I have discovered that I DON"T need a tune, so moderators feel free to move this thread to another place. . . .

I also have a new water pump and clutch hub and both did nothing to solve my problem.

Ok so now I'm down to either the Hall Effect sensor or blown head gasket (I've changed/tested just about every other part in the car)

What are the symptoms of a blown head gasket? I've had this problem for a few years now, so if it was a blown head gasket would the car still be running after all this time? If anything, the car is running slightly better than when it originally happened, but that's probably because I've replaced so many other parts which have partly compensated for it.

[Darren_L]

I'm not so sure about the distributor sensor. If they are faulty they tend to cause a bad missfire or the engine just stops dead. In most of these cases it will throw a trouble code (check engine light will come on)

have you tried borrowing an ignition module ? They can do some wierd things and won't necessarily throw a code. Expensive suckers though, so try to borrow one first if you can and see if it improves things.

[capitalgainz]

if its blown head gasket to a compression test on it even if you suspect it

[VR38]

Don't ever assume part is good or not the cause of your problems, re: condenser, or any other part for that matter, if the problem is not as simple as fuel or spark then test it to be sure.

[raw]

if its blown head gasket to a compression test on it even if you suspect it

I did a bit of research and found this:

Compression Loss
Sometimes a gasket can fail and cause a cylinder to only lose compression. The first indication of the blown head gasket is an audible hissing or tapping sound, which can be difficult to locate, as it sounds like a bad lifter or rocker arm. More severe cases can see a noticeable loss of power from the engine. Depending on the location, you may see the air leak on the engine. The most accurate test for this problem is a compression gauge.

This is interesting because I do have a tapping sound which I've never known where it was coming from.
But my coolant and oil have always been perfect in colour so it's not like they're mixing which would happen if the head gasket was leaking, is this correct?
Remember my temp guage didn't even get to half way, so surely it wasn't hot enough to cause damage?
Anyway, I'll still go ahead and test compression...

I'm not so sure about the distributor sensor. If they are faulty they tend to cause a bad missfire or the engine just stops dead. In most of these cases it will throw a trouble code (check engine light will come on)

What is the fault code for a faulty Hall effect sensor? because I can't find it on any fault code list for a VN V8

have you tried borrowing an ignition module ? They can do some wierd things and won't necessarily throw a code. Expensive suckers though, so try to borrow one first if you can and see if it improves things.

Yeah I meant to try another ignition module but I don't have access to one and sure ain't buying a new one just for a test. But I'll keep trying to source one as it's pretty easy to swap them over

[Darren_L]

What is the fault code for a faulty Hall effect sensor? because I can't find it on any fault code list for a VN V8



Yeah I meant to try another ignition module but I don't have access to one and sure ain't buying a new one just for a test. But I'll keep trying to source one as it's pretty easy to swap them over

46 - No Reference Pulse While Cranking

the correct name for the sensor is the 'distributor reference sensor'. Hall effect is simply the method the sensor uses. It's a binary or on/off type sensor. So it either works or doesn't work. It not like a coolant temp sensor which can give a innacurate reading which can lead to various performance issues.

If the sensor is completely stuffed, the engine won't start at all, because no signal is sent to the ignition module to instruct it to fire the coil - a code 46 will be set. However the sensor can also experience an intermittent failure. Which means it may fail only once whilst cranking the engine. It might mean the engine may just take a second or 2 longer to start, but it will start as soon as the sensor sends the signal. But a code 46 will still be logged in the ECU

And if the sensor is intermittently failing whilst driving, the engine will missfire rather than lose power. Keep in mind if the distributor sensor fails, the coil stops firing.... So it will feel like a missfire, rather than feeling a reduction in performance

[raw]

So it either works or doesn't work. However the sensor can also experience an intermittent failure.

I was also told the inition module either works or doesn't work i.e. the car runs or it doesn't.
And I would have thought 'intermittent running' contradicts this notion of 'works or doesn't work'
My car has ALWAYS started and run. So I'm still not sure whether the hall effect sensor and ignition module is worth testing...

Is the hall effect sensor functionally the same as a Crankshaft position sensor? Because I have researched it and found this:

Sometimes the sensor may become burnt or worn out. The most likely causes of crankshaft position sensor failure are exposure to extreme heat.

This makes sense since my problem came about due to the clutch fan being blocked and causing the temp to rise....

And also this:

A bad crank position sensor can worsen the way the engine idles, the pistons fire, or the acceleration behaviour. If the engine is revved up with a bad or faulty sensor, it may cause misfiring, motor vibration or backfires. Accelerating might be hesitant, and abnormal shaking during engine idle might occur. In the worst case the car may not start.

.....and these are the symptoms I am experiencing.

[delcowizzid]

ignition module or HES in dizzy find a module to try and make sure you have it bolted to somewhere metal while testing they can stuff out and just mess with you some dont just die if its missing a pulse every now and then or miss judging dwell time of the coil it will do allsorts of things

[Darren_L]

I was also told the inition module either works or doesn't work i.e. the car runs or it doesn't.
And I would have thought 'intermittent running' contradicts this notion of 'works or doesn't work'
My car has ALWAYS started and run. So I'm still not sure whether the hall effect sensor and ignition module is worth testing...

Is the hall effect sensor functionally the same as a Crankshaft position sensor? Because I have researched it and found this:

No a distributor reference sensor is not the same as a crank angle sensor. A crank angle sensor determines the specific position of the crank which is used to determine which cylinders fire and for sequential injection engines, it determines which injector pulses. It is usually used in engines without a distributor eg the V6 and LS engines and/or engines with sequential injection (VT 5L) The sensor in your VN distributor simply acts like a set of points. It simply switches on/off for every 45% of crankshaft rotation. The distributor rotor button & cap determine which cylinder fires and as the VN uses batch injection, all injectors pulse at once rather than individually in the case of sequential.

and no, 'intermittent failure' and 'works or doesn't work' isn't a contradiction.
it's a binary/digital sensor - so it has just 2 signals. ON/OFF. There is no variation from those 2 modes. If it fails, it doesn't switch, there is no output which will result in an obvious missfire, rather than reduced performance. In contrast, an out of calibration/faulty analogue sensor such as a coolant temp sensor, may still work, but give an innacurate reading. However, like anything electrical the distributor sensor can experience an intermittent failure. ie it may fail to switch once every 10,000 engine revolutions,

The ignition module is an entirely different kettle of fish. It actually controls the ignition timing during startup, until the engine reaches a specified rpm, afterwhich the ECM switches to EST mode. Whilst in EST mode, the ECM determines ignition advance & dwell via the ignition module. So the module can experience intermittent failures which won't necessarily result in engine missfires (unlike the distributor sensor), however can effect performance due to incorrect ignition advance. I've had 2 ignition modules slowly die over a period of 12 months.

So in a nutshell, what I was originally getting at, is there isn't much point testing the distributor sensor, because it's very unlikely to be the problem. If it were a problem, you would have noticed the engine missfiring. As I suggested, try to borrow an ignition module and see if it fixes the problem (unless the module fails completely ie engine doesn't start or missfires during testing, then the only test you can do is to swap it for a good one and drive it)

[raw]

No a distributor reference sensor is not the same as a crank angle sensor. A crank angle sensor determines the specific position of the crank which is used to determine which cylinders fire and for sequential injection engines, it determines which injector pulses. It is usually used in engines without a distributor eg the V6 and LS engines and/or engines with sequential injection (VT 5L) The sensor in your VN distributor simply acts like a set of points. It simply switches on/off for every 45% of crankshaft rotation. The distributor rotor button & cap determine which cylinder fires and as the VN uses batch injection, all injectors pulse at once rather than individually in the case of sequential.

and no, 'intermittent failure' and 'works or doesn't work' isn't a contradiction.
it's a binary/digital sensor - so it has just 2 signals. ON/OFF. There is no variation from those 2 modes. If it fails, it doesn't switch, there is no output which will result in an obvious missfire, rather than reduced performance. In contrast, an out of calibration/faulty analogue sensor such as a coolant temp sensor, may still work, but give an innacurate reading. However, like anything electrical the distributor sensor can experience an intermittent failure. ie it may fail to switch once every 10,000 engine revolutions,

The ignition module is an entirely different kettle of fish. It actually controls the ignition timing during startup, until the engine reaches a specified rpm, afterwhich the ECM switches to EST mode. Whilst in EST mode, the ECM determines ignition advance & dwell via the ignition module. So the module can experience intermittent failures which won't necessarily result in engine missfires (unlike the distributor sensor), however can effect performance due to incorrect ignition advance. I've had 2 ignition modules slowly die over a period of 12 months.

So in a nutshell, what I was originally getting at, is there isn't much point testing the distributor sensor, because it's very unlikely to be the problem. If it were a problem, you would have noticed the engine missfiring. As I suggested, try to borrow an ignition module and see if it fixes the problem (unless the module fails completely ie engine doesn't start or missfires during testing, then the only test you can do is to swap it for a good one and drive it)

OK thanks for all that info Darren over the last couple of posts.
Just on the ignition module.....I was reading that sometimes excessive heat can create a dry joint or sometimes crack in the resistor.
I've tried once before to open it up and have a look, but after trying to unscrew the 2 screws (see picture below), they just spin and won't come off

[delcowizzid]

even if you undid the screws it wont come out its soldered to the board underneith allmost looks like its cooked

[raw]

even if you undid the screws it wont come out its soldered to the board underneith allmost looks like its cooked

I found that pic on another forum, it's not actually my ign module.
Anyway, I'll find another one to swap over and test, and also test compression and report back
Getting closer to the problem now
Thanks guys

[capitalgainz]

my 32 had a blown hg for years and ran fine, it was only when it built up preasure in the cooling system that the bottom hose fell off and blew the gasket to bits that the coolant and oil mixed, just because ur hg is blown doesnt mean its where the oil and water meet

[VSSS_5L]

Wiser heads would know better but my first thought was vacuum.

[mr j-man]

did u end up finding the problem?? interesting to find out if ya did!

[raw]

Anyway, I'll find another one to swap over and test, and also test compression and report back
Getting closer to the problem now
Thanks guys

Can't believe my last post was back in March! It's so depressing how time flies! And even more depressing is my car is still a pile of junk.
I have since done a compression test and the results were quite consistent, but all readings were VERY low
Seven cylinders were 90-95 PSI, and the other cylinder was a bit higher at about 105 PSI
It's good that they were all consistent, but why all so damn low?
Arrgghh what a headache

[VR38]

Was the throttle wide open?