Alfa Romeo Owners Club of Australia Forum

Technical => 900 Series (Alfasud, Alfasud Sprint, 33) => Topic started by: 33racer on May 21, 2012, 07:09:06 PM

Title: Alfa 33 16v not starting
Post by: 33racer on May 21, 2012, 07:09:06 PM
Hi guys

Ive recently built a 1.6 16v motor for my race 33 but im having trouble to get it started its got spark and fuel getting to it. and it combusts the fuel every now and then but usually as a big flame out the exhaust pipe. Does anyone know what is wrong or how to fix it. ive also tried changing the timing but nothing. also atm im just using the standard motronic ecu.

Any help appreciated

Regards
Steve
Title: Re: Alfa 33 16v not starting
Post by: colcol on May 21, 2012, 08:40:09 PM
I was told when i was an apprentice,[shortly after the invention of electricity], that there are 3 reasons a car will not start, 1. no spark, 2. no petrol, 3. no compression, you say you have spark, and there is fuel, how about compression?, do a compression test, [i know that is difficult in a 16 valver], and see how it looks, also check your timing belts are timed right, they can be timed ok, so the valves don't hit the pistons, but they can be 180 degrees out, as i found out once, it would fire, but not run properly, also, have everything at Top Dead Centre, and see if you look like you are getting spark, just take off ignition lead, and bump it over by hand, to make sure you are getting a spark around Top Dead Centre, by removing spark plug and shorting out to see for spark, Colin.
Title: Re: Alfa 33 16v not starting
Post by: Frank Musco on May 21, 2012, 11:40:17 PM
Steve

I second the distributor being 180 out. Cross the leads opposite to each other and it should start if that's the problem.

Was the car running well before you built the race engine?

I'm very interested in what you've built. Should get some very scary high revs out off it! I've considered building a de-stroked 1700...one day...

good luck.
Title: Re: Alfa 33 16v not starting
Post by: colcol on May 22, 2012, 07:45:51 PM
Also make sure your starter motor is kicking the engine over at a fair rate of knots, if it cranks too slow it will be hard to start, as Frank said, try bringing the no1 piston to Top Dead Centre, and seeing where the rotor is pointing, it should be to no 1 or 180 degrees opposite, remove distributor and turn the distributor 180 degrees, and see if it will start, if i remember rightly, the 16 valver doesn't have a hall effect triggering setup in the distributor like the early 8 valve 33's, but is triggered by a crank sensor, is that correct?, Colin.
Title: Re: Alfa 33 16v not starting
Post by: colcol on May 24, 2012, 08:25:36 PM
A big flame out the tailpipe indicates timing, belts or distributor being out, i know cause i have been there myself, Colin.
Title: Re: Alfa 33 16v not starting
Post by: 33racer on May 25, 2012, 04:39:27 PM
Thanks for all the help. Ok the timing was 180 degrees out and i do have plenty of compression but now its trying to start but it just wont stay started.
Title: Re: Alfa 33 16v not starting
Post by: 33racer on May 25, 2012, 05:16:28 PM
OK i got it working now it was the rotor in the dissy was really worn and it was making it spark all the time.

Thanks for all the help.

Regards
Steve
Title: Re: Alfa 33 16v not starting
Post by: Alfapride on May 29, 2012, 11:23:31 AM
can an ECU be disassembled and rebuilt or is it a sealed unit??
Title: Re: Alfa 33 16v not starting
Post by: colcol on May 29, 2012, 08:11:41 PM
There are people that rebuild ECU's, Google it, and see what you come up with, get a price on a new one or change over one first, someone might have NOS sitting around, Colin.
Title: Re: Alfa 33 16v not starting
Post by: Alfapride on May 29, 2012, 11:06:25 PM
thanks Col, depending on whats in them I might have a go myself, I can solder and replace parts in electronics pretty easily.
Title: Re: Alfa 33 16v not starting
Post by: festy on June 08, 2012, 11:08:11 AM
The ECUs in these are pretty simple devices compared to "modern" ECUs - two 2-layer PCBs with a mixture of PTH and SMD components. Almost all semis are PTH, only some of the resistors and caps are SMD.
The problem will be that it uses a few custom Bosch ICs, so you can't get generic replacement parts for some of them.
What's wrong with your ECU though?