Damp fish of an engine on S4 Spider - Alfa Romeo Forum
You are currently unregistered, register for more features.    
 
Thread Tools
(Post Link) post #1 of 6 Old 20-08-07 Thread Starter
Status: -
 
Join Date: Jun 2007
Posts: 17
Damp fish of an engine on S4 Spider

Hi there

I wonder if anyone can help. I recently had a full service done on my S4 spider 2L. Ordinarily the unit is pretty free revving and will pull to a "red line" of 6200rpm without much fuss. When it came back from the garage it felt quite gutless and the car would really struggle to get beyond 4000rpm. The engine is completely stock. I took it back to the garage and asked them if they had done anything to the fuel mix / timing as they did say the CO was a bit high and they leaned it back a bit. Other than that nothing. New plugs, filters, oil etc. After it came back the second time there was a marginal imporovement but it was screaming around 5000rpm and there is a very noticeable drop off in power. The garage thought this may be valve bounce and suggested they take the head off and investigate further.

I'm reluctant to let them do this as its one of those situations where the car was running fine before the service and MOT and now after its come back from them it feels really flat. Upside however is that the car is a lot more economical on fuel now!

I also noticed that whilst on a recent long distance run on the motorway the car would struggle to get to 4000 rpm in fifth and when it did there was a more noticeable vibration from the prop shaft.

The car is a late model 1993 (L reg) car and it doesn't have a Cat on it. Its done in the region of 90,000 kms.

I'm not in the habit of thrashing my bella but the engine was previously a really satisfyingly punchy unit and now its a bit of a damp fish!

Grateful for any advice or insights

A
ajmassey is offline  
Sponsored Links
Advertisement
 
Status: -
 
Join Date: May 2006
Posts: 37
Re: Damp fish of an engine on S4 Spider

I wonder whether they have altered the timing and the vibration at higher revs is a misfire rather that propshaft ?
davey is offline  
jpa
Status: -
AO Member
 
Join Date: Feb 2007
Location: Otley
Posts: 22
Re: Damp fish of an engine on S4 Spider

Not sure how much bearing this might have on it running that badly, but what spark plugs have they put in? Might be worth checking if they are correct type for the engine.
jpa is offline  
Status: -
AO Member
 
Cosmo's Avatar
 
Join Date: Jul 2006
Location: Surrey, England
Posts: 480
Re: Damp fish of an engine on S4 Spider

Quote:
Originally Posted by ajmassey View Post
I took it back to the garage and asked them if they had done anything to the fuel mix / timing as they did say the CO was a bit high and they leaned it back a bit.

...the car was running fine before the service and MOT and now after its come back from them it feels really flat. Upside however is that the car is a lot more economical on fuel now!
You have to conclude that it is all quite a coincidence huh? Get them to richen up the mixture again and see if that puts you back to where you were before. Otherwise it could be something relatively simple such as knocking a sensor lead off or introducing a vacuum leak.
Cosmo is offline  
Status: Wyrd is Life
AO Gold Member
 
Stori's Avatar
 
Join Date: Nov 2002
County: -
Posts: 11,591
Re: Damp fish of an engine on S4 Spider

From your post, I am assuming that you know little about the ingnition/fuel system in your car?
Firstly I would find a 'dealer' who was more competent. To suggest that the problem is related to valve bounce (caused by valve springs becoming 'weak' ) indicates that this dealer is staffed by incompetents (aka revenue raisers)... Valve springs on a road car do not loose their properties overnight!
Assuming adjustable, I would suspect the ignition timing is a prime suspect. I know you can produce a car that will not really rev out by adjusting the ignition timing inapropriately.
NB Normaly adjusting the idle mixture will not affect top end performance . I would suspect that you cannot change fuel mixture on this car, except at idle speeds?

Normally, I would first check that all the ignition/fuel components changed are as specified, then I would check all leads are fitted correctly, then check the ignition timing, followed by checking for any air leaks into inlet system
Obviously if this does not find the problem then there are other components faulty that are causing the problem . This would depend on sensors/ MAF? etc fitted to your car which I know nothing about.




Last edited by Stori; 20-08-07 at 23:55.
Stori is offline  
(Post Link) post #6 of 6 Old 21-08-07 Thread Starter
Status: -
 
Join Date: Jun 2007
Posts: 17
Re: Damp fish of an engine on S4 Spider

Thanks for all your advice on this, I will make necessary checks and feedback.

regards

a
ajmassey is offline  
Reply

Go Back   Alfa Romeo Forum > Supported Alfa Romeo Models > Technical & Vehicle Assistance > Engines (TS, JTS, JTD & V6)

Tags
damp , engine , fish , spider

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome