Annoying engine problems!

[scc]

Hi there!

Got 2 questions about my manual '98 2.0 GLS. Hope someone outthere can answer them.

1) Recently, I noticed that when travelling at 60 mph the rev's were around 3000rpm (5th gear). I swear I remember it being less. So I cleaned the throttle body and burned a tank of petrol with cleaner. Now its doing 2750rpm for 60mph, is this about right? (Still managing >35 mpg though!)

2) It doesn't end there, the idle speed keeps oscillating between just under ~660rpm to ~700rpm. When the rpm drops, the steering column vibrates shaking the whole cabin. Tried disconnecting the battery, checked engine hoses for leaks etc, but still no good. The vibration gets worse when I turn the cabin fan to max but then recovers. Any ideas?

Many thanks and Merry Christmas to all! :)
Scc

[zedy1]

the maf (air flow sensor)

[Kieran]

Hmmm. The God of GLS power doesn't have his genuine UK service manuals with him at the moment as he is enjoing Christmas Eve at his girlfriends.:) So I may be able to provide more information later about question 2...

1. I have some gear ratio data, so I've calculated the approximate engine RPM in 5th using the following formula:

RPM = (MPH x Gear Ratio x Final Drive Ratio x 88) / Wheel+tyre diameter (feet).

This works out at (60x0.820x3.722x88) / 6.10 = 2641RPM

With an RPM figure of 2750, you're 109RPM or 3.9% out. I'd say this is within acceptable tolerance. Why it was at 3000rpm I've no idea, as your car will be a 5-speed manual (UK Autos are all 4 speed only); so the road speed should directly affect the RPM level... Unless your clutch is slipping?

2.Hmm. Need to have a look at my reference info really, but I'd say that it could be the MAF, or the idle speed sensor playing up?...
Regarding the fans - turning the fans to full will be loading up the alternator and they require more engine power when they're being loaded. I bet if you turned on the fans, the headlamps, fogs and rear window demister (but not the aircon) that your engine might stall...

It could be the alternator on the way out as well, possibly? If the alternator brushes are worn, don't they make the alternator more difficult to spin?... What I'm thinking is that the oscilations are because the ECU settles to idle speed, but the extra alternator resistance almost bogs the engine down untill the ECU catches it and raises the RPM??... and when you switch electrical accessories on, the same thing happens??

I'll post any more ideas I think of when I consult my tome of GLS Power over the next day or two!

And finally... Let me extend a warm welcome from the GLS side of ClubVR-4. I hope you like it here and find the site useful! :grouphug: :welcome:

[Big Ian]

just a thought but might be worth something or maybe not but here go's. is your battery ok i had a similar problem on my last car with the revs dropping more than usual and it was the battery it was dried up in half the cell's also ive heard a bad earth conection can cause things like this to ?? like i say's just a thought.....

[zentac]

2) It doesn't end there, the idle speed keeps oscillating between just under ~660rpm to ~700rpm. When the rpm drops, the steering column vibrates shaking the whole cabin. Tried disconnecting the battery, checked engine hoses for leaks etc, but still no good. The vibration gets worse when I turn the cabin fan to max but then recovers. Any ideas?

Im sure you guys get bored of me quoting FTO stuff all the time but when that happens on the FTO 99% of the time it is the ISC (Idle speed controller) thats faulty. I think the vr4 uses the same one as the FTO as its the same throttle body.

Theres a good article on how to clean it Here (http://www.funky-fto.co.uk/idling.html)

[Kieran]

No! We don't get bored! If the hat fits, wear it!:-D

[scc]

Thanks for the welcome and ideas! I'll let you all know how I get on.

Cheers! (I've been looking for an opportunity to tinker ;))

[scc]

I partly cleaned the MAF by spraying cleaner into the front and back of it. I think there is a thermister hanging down the MAF section when viewed from MAF towards the air-box. This has certainly improved the situation (and the responsiveness :) ).

Currently, I can't fully clean the sensor from the honey-combed covered front without cracking the plastic ridges holding on to the bolt-heads within the air-box. Cracked one already :( . Just wanted to know if anyone has tried to remove and clean the MAF?

[Kieran]

What cleaner did you use?

[zentac]

I should have a spare MAF kicking around somewhere if you bust yours, I bought one with a filter from Japan that I never user. It may be down at my mechanics though.

[KiwiTT]

I noticed that when travelling at 60 mph the rev's were around 3000rpm (5th gear).

My VR-4 does this speed in 2200-2300rpm in 5th.

[Kieran]

The VR-4 auto is geared differently to the UK 2.0 GLS manual though :undecided

[scc]

What cleaner did you use?

I used Wynn's Fuel Injection and Carb Cleaner bought from my local Halfords. I normally use the stuff to clean the throttle body.


I should have a spare MAF kicking around somewhere if you bust yours...

Thanks for the kind offer! I'll certainly bear that in mind. However, I think the MAF is ok at the moment. I'm still going through the current suggestions to fully eliminate the problem.

[scc]

I replaced the stock airfilter with a KN filter and thats made an overall big difference! The idle problem is not as obvious as before except when I try to turn the wheels when the car is stationary - sounds like its time for a service. Does anyone know if better spark plugs will also do the trick? i.e. iridium types?

[Kieran]

Hmm! Everyone Really seems to rate the K&N Panel filters...

Looks like my question about what induction filter to use has been solved :D

Just need to work out a way of improving the cold air feed to the filter. The Mitsubishi item doesn't get much of a 'Ram' effect...