33 engine problem - Alfa Romeo Forum
You are currently unregistered, register for more features.    
 
Thread Tools
(Post Link) post #1 of 17 Old 13-02-08 Thread Starter
Status: Married
AO Member
 
Iain.Oglethorpe's Avatar
 
Join Date: Feb 2008
Location: United Kingdom
County: Hampshire
Posts: 932
Garage
Help 33 engine problem

Hi all, I 'll cut to the chase , my mk2 33 with AH motorsport race engine started to develop a problem on sat night and this morning. Basically I am driving quite normally and the engine cuts out...its not a fueling issue and im fairly certain its not electrical , the car dies and i wait for a minute and start the engine again and i get a massive misfire and the she runs fine again. I checked all the fuses , fuel pump , jets on the 45mm carbs , spark plugs , oil and water levels . The only thing I think it might be is the coil pack might be playing up as it doesnt run a dizzy. I have give the car a 8mile quick blast tonight to try and replicate the problem but nothing untoward accept a slight mis fire when running a fraction over tick over and a pinking noise when de accelerating from high revs ?????? Any Ideas Guys.

Phat 33.
Iain.Oglethorpe is offline  
Sponsored Links
Advertisement
 
Status: Spingo La mia Alfa nella Notte
AO Member
 
suds's Avatar
 
Join Date: Mar 2005
Location: United Kingdom
County: Merseyside
Posts: 577
Re: 33 engine problem

sound something with the timing you have said you dont have a dizzy what have you got emerald megasuirt edis ?
suds is offline  
Status: -
AO Silver Member
 
Greek's Avatar
 
Join Date: Jul 2006
Location: Greece
County: -
Posts: 2,986
Re: 33 engine problem

How about humidity? Maybe there is some in the sparg plugs cables and when the engine heats up it creates vapors that causes that problem....
Greek is offline  
Status: -
AO Platinum Member
 
David C's Avatar
 
Join Date: Aug 2003
Location: London, England
Posts: 29,957
Re: 33 engine problem

If you are running an ignition ECU, check the TDC sensor.
David C is offline  
(Post Link) post #5 of 17 Old 14-02-08 Thread Starter
Status: Married
AO Member
 
Iain.Oglethorpe's Avatar
 
Join Date: Feb 2008
Location: United Kingdom
County: Hampshire
Posts: 932
Garage
Re: 33 engine problem

I was looking at the sensor , but dont know of any way of checking it other than a swap out.......although today I pulled all the fuses out and found a loose 16 amp which is on the same circuit as the rear de-mister i think the ecu is on the same circuit which explains the stopping and startng issue and the mis-fire on start up I hope.
Iain.Oglethorpe is offline  
(Post Link) post #6 of 17 Old 14-02-08 Thread Starter
Status: Married
AO Member
 
Iain.Oglethorpe's Avatar
 
Join Date: Feb 2008
Location: United Kingdom
County: Hampshire
Posts: 932
Garage
Re: 33 engine problem

yep....again its what was reccomended by AHM, I wonder if I could get the program for me laptop to see what the sensor is doing.
Iain.Oglethorpe is offline  
(Post Link) post #7 of 17 Old 17-02-08 Thread Starter
Status: Married
AO Member
 
Iain.Oglethorpe's Avatar
 
Join Date: Feb 2008
Location: United Kingdom
County: Hampshire
Posts: 932
Garage
Cry Like A Baby Re: 33 engine problem

Well the problem has partially been solved but their is yet more problems , I changed the Facet Redtop fuel pump as this packed up on sat morning which has stopped the car dying on me when driving but the mis-fire still appears at about 1500-2500rpm then disappears above 3000rpm sometimes it stops the car revving at all and it sound like its on the limiter yet its at 4000rpm (rev limit on the car is 8750rpm), has anyone had a cam belt slip and if so what was the outcome? or had a ecu glitch?. Any advice please.
Iain.Oglethorpe is offline  
Status: Car in bits again...
AO Silver Member
 
Spacenut's Avatar
 
Join Date: Feb 2007
Location: Hampshire, UK
Posts: 1,566

Member car:

Nova T33/1.5

Re: 33 engine problem

The misfiring sounds like it is either fuel or ignition-related. If the cam belts slipped a tooth you might expect some rough running (probably dropped valves in your current state of tune!), but I can't believe it is that. The ignition timing sensor would be my favourite suspect at the moment. Is it an inductive proximity sensor or magnet-triggered type? Either way the clearance between the sensor head and the timing cog is critical. It may be that it is generating a weak trigger pulse.

Fuel is obviously the other possible culprit. I had similar problems with my engine with blocked carburettor jets. I guess you are running a fuel pressure regulator with the Facet Red Top, as Webers/Dellortos do not like high delivery pressure.

Why did the pump fail? I only ask because a friend of mine suffered a fuel pump failure followed by running problems and when we stripped the carbs we found shredded parts of the pump diapgram clogging up all the jets!

Good luck with the diagnosis - it sounds like you've got a really nice engine there

Lauren

Alfanauts are GO!!!
Spacenut is offline  
(Post Link) post #9 of 17 Old 18-02-08 Thread Starter
Status: Married
AO Member
 
Iain.Oglethorpe's Avatar
 
Join Date: Feb 2008
Location: United Kingdom
County: Hampshire
Posts: 932
Garage
Hmmm Re: 33 engine problem

Cheers Lauren, yep i swapped the pump out on sat as it kept intermittenly stopping and i have a fuel king pressure regulater then to an in line filter then off to one bank of 45mm twin webber and then out to the other set of carbs , the in line filter was replaced last week when the problem started and i have since cleaned the idle jets twice as they clogged up, i think your right about the main jets being also clogged. The old fuel pump filter was clogged with a small amount of particals the only issue i have is cleaning the main jets , about 17 years ago i attempted to strip down a twin choke carb that was fitted on my old renault fuego and the end result was buying a new carb at cost and then having to get the car tuned. Any pointers as how to go about cleaning the main jets would be greatly received. Oh and as for the sensor i swapped the lightened fly wheel for a standard 16v one about 7 weeks ago after the ring gear slipped for the 3rd time on an outing to donnie so the problem could be partly to blame on that?.
Iain.Oglethorpe is offline  
Status: Sprint locked away...
AO Member
Sud/Sprint/33 Lounge Winner 09
 
Join Date: Oct 2001
Location: United Kingdom
County: Cambridgeshire
Posts: 349
Garage
Re: 33 engine problem

What have you set the fuel pressure to with the regulator?
Greg is offline  
(Post Link) post #11 of 17 Old 18-02-08 Thread Starter
Status: Married
AO Member
 
Iain.Oglethorpe's Avatar
 
Join Date: Feb 2008
Location: United Kingdom
County: Hampshire
Posts: 932
Garage
Re: 33 engine problem

Hi Greg , im sure its not the fuel flow rate as the engine ticks over fine runs to 1500rpm and the mis fire happens until you reach over 3000rpm which convinces me that pressure is not the problem more as to a main jet..... oh and i should have said it only mis-fires on one cylinder.
Iain.Oglethorpe is offline  
kevjtd
Status: - Update
Guest
 
Posts: n/a
Re: 33 engine problem

the carbs aren't too bad to strip the top down, nothing to bite you like some carbs that have linkages everywhere. i had a similar problem with my old sprint, it was ok'ish on full throttle but on a balanced throttle or trying to tick-over it was very lumpy. turned out to have a piece of gasket sealer stuck in one of the jets, can't remember how many jets there are but the best thing to do is just take one out at a time and give it a good clean with an air-line or carb cleaner. may be barking up the wrong tree but worth checking.
 
kevjtd
Status: - Update
Guest
 
Posts: n/a
Re: 33 engine problem

Quote:
Originally Posted by Iain.Oglethorpe View Post
Hi Greg , im sure its not the fuel flow rate as the engine ticks over fine runs to 1500rpm and the mis fire happens until you reach over 3000rpm which convinces me that pressure is not the problem more as to a main jet..... oh and i should have said it only mis-fires on one cylinder.
miss-fires on one cylinder, done a compression test? does the spark plug on that cylinder look a different colour to the rest? oily deposits?crack in the insulater around the electrode? have you swapped plugs from one cylinder to another to see if the miss-fire follows the plug? sorry if it all seems like basic stuff, just trying to think of something you might not have considered.
 
(Post Link) post #14 of 17 Old 18-02-08 Thread Starter
Status: Married
AO Member
 
Iain.Oglethorpe's Avatar
 
Join Date: Feb 2008
Location: United Kingdom
County: Hampshire
Posts: 932
Garage
Re: 33 engine problem

plugs look fine, but i admit i havent tried swapping them around yet, and they all fire ok as you would expect.....oh well more back ache tomorrow eve, their is a down side to lowering cars .
Iain.Oglethorpe is offline  
kevjtd
Status: - Update
Guest
 
Posts: n/a
Re: 33 engine problem

all good fun, that's what you have to keep telling yourself
 
Status: Sprint locked away...
AO Member
Sud/Sprint/33 Lounge Winner 09
 
Join Date: Oct 2001
Location: United Kingdom
County: Cambridgeshire
Posts: 349
Garage
Re: 33 engine problem

The first thing you need to do is set the fuel pressure properly - you want 3-4psi - if you run more than about 5psi into the carb you start to push fuel past the needle for the float even when the float chamber is full and end up flooding the carb.
If its not misfiring over 3000rpm then its definately not a main jet, besides they are hard to block anyway due to the size of them - near impossible if the carbs were clean in the first place and you are running a good inline filter. Have you checked the accelerator pump jets? These are even smaller than an idle jet. To check you need to look down each venturi and open the carb to full throttle and look for a squirt of fuel going straight down the venturi - do this with the engine off and one at a time. Are you running Dellorto or Weber?
Greg is offline  
Status: Car in bits again...
AO Silver Member
 
Spacenut's Avatar
 
Join Date: Feb 2007
Location: Hampshire, UK
Posts: 1,566

Member car:

Nova T33/1.5

Re: 33 engine problem

I had a shard of fibreglass mat in one of my jets, which presumably affected the airflow irrespective of the engine speed. It got in through the air cleaner rather than the fuel inlet. My carbs are standard Weber 36 IDF's, no problem to strip down, but I removed them from the engine just in case I dropped a jet down into the inlet manifold (I've seen it happen - not to me fortunately).

I guess if you are using the starter ring gear to sense the crank position then changing the flywheel will make a small difference to the timing (probably less than a degree though), as the ring gear is typically a shrink-fit onto the flywheel - I don't believe there is any registration or location device - there's no need for one in a conventional application. The sensor distance from the ring gear will be important though, you want minimum running clearance for this type of proximity sensor. Perhaps if the ring gear is a bit mangled up that might affect the pulse train as well.

I set my Filter King to 2 psi, it creeps up a bit when the engine is hot. Dellortos in particular seem to be very sensitive to fuel pressure. The specification for the mechanical fuel pump used on the boxer reads something like 3 psi at 6000 rpm! At idle that may drop considerably

Lauren
Spacenut is offline  
Reply

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

Tags
engine , problem

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