Jump to content

OK, I need some help, VR6 engine experts chime in please.


Recommended Posts

2.9 ABV lump, 1994, coil pack, OBD1, just fitted it in a 2.0 8v Corrado.

It's got all new chains and guides, mk4 head gasket, 268 cams, 6lb fidanza flywheel, gas flowed head, waisted exhaust valves, turn2 crank pulley, sh1t home made exhaust with the 8v lamda probe which is blowing at the moment. new blue temp sensor, AMD chip, and some other shit that I've probably forgot.

anyway, the problem is that it runs lumpy as hell under 3000rpm and sound like a WRX. at first I thought this was down to the lightened flywheel and not having the VGI on at the moment, but after reading up in it a bit I now think it's running wrong.I also feels pretty flat up top and isn't eager to pull at all. It won't pull from 3000rpm in top without jerking like mad.

I checked the cam timing many many times beofre I put the manifold on, so I don't think that's out, although Vince said they have been known to jump a tooth on initial start up when they've been dry of oil for a while.

I have a spare MAF but I haven't tried it yet. and I will fix the exhaust shortly too.

I've VAG-COM'd it, no errors, but my mate said the cam timing seems quite retarded.

Experts only please reply, no silly answers please. All help appreciated.

I'm going to run VAG-Com on it again tonight and refer to my VAG manual and check all the sensors are reading correctly. It'll take ages, but I need to eliminate them all before I have to pull the manifold off and check the timin again.

Link to post
Share on other sites

After my head gasket was replaced my engine ran like shite.

The diagnostic tool showed a fault with the cam position sensor which would have made sense as its a common problem apparently. Took it to a bosch specialist to check all electronics and they said it was all fine.

Mechanic that did the head gasket was stumped, as he swore he put the engine back together properly. Anyway he agreed to take it apart as i was getting pissed off, and he had got the cam timing one tooth out. He said he'd aligned TDC by rocking the thing back and forward, the 'old fashioned way', rather than align it properly with the mark on the clutch.

Dont know if this is any use, but thats my story :)

Link to post
Share on other sites

Phat,

You have a Turn2 front pulley and a Fidanza flywheel fitted yes?

So...... How did you find TDC then?

I'm presuming that the Turn2 doesnt have the little TDC notch and that the Fidenza doesnt have a TDC marker line either.... which would mean you'd used another method of locating TDC.

If so, did you use the "clutch cover plate pointer via the inspection hole in the bell-housing" method??

cos there are two pointers (on standard clutches anyway) and its been known that people can pick the wrong one.....

Its just a thought.

Its also a thought that if the Fidanza did have a TDC marker, then it could concievably be off? Or even that the rotational position of the clutch cover is not in the exact same position as a stock flywheel, if you did use the cover pointer method....

Jules

EDIT: added stock clutch qualifier.... 8o)

[ Edited Thu May 13 2004, 07:09PM ]

Link to post
Share on other sites

The flywheel and the pulley both have the correct timing marks on them. I checked the timing last night, it was bang on. so that left me kind of stuck. I took all the plugs out to check. 1-5 were slightly red, which is normal for optimax users apparently, but number 6 looked like it'd never been used. this made me panic, as I was thinking straight away there was no compression in number 6, but after a mate told me to check the injectors I found the fault.

I unplugged them all, and tested them individually by poking them in a cup and putting 12v on them direct off the battery. number 6 wasn't opening at all. so I fitted a different one which works. I'll have it running in about an hour I reckon.

no wonder it felt lumpy and a bit flat!!

I'l eager to find out how it'll go on all 6 if it performs like that on 5!!!

cheers for all the suggestions.

Link to post
Share on other sites

good stuff - nice when you find something like this, buried deep in the engine....! ;)

I suppose the poor MPG you were seeing was a symptom of a dead injector (could have been anything though.... !ill ) - the ECU would have been widening the injector pulse widths on the remaining 5 good injectors to make up a good Lambda signal..... the probe would have been seeing too much air I guess.

Jules

Link to post
Share on other sites
×
×
  • Create New...