Anyone know what this is?

Guest · Post by **Guest** » Wed May 16, 2007 3:11 pm

Just went out for a short trip in my 71 2.2 (mfi). It was the first trip of the day and only about 3 miles. When I was nearing home all of a sudden the car choked up and wouldn't rev and it started to backfire very loudly. Got out the car popped the lid and reved it and there were plumes of black smoke coming out of the exhaust. It would idle, but as soon as you rev it goes flat and backfires. I'm thinking it's something to do with the cold start solenoid. Anyone have any ideas, also how I can disable the solenoid top get the car home?

Thanks in advance

Adam

Nick Moss · Post by **Nick Moss** » Wed May 16, 2007 4:16 pm

it sounds like the 25 mm cold start pipe from the left heat exchanger to the pump has become disconnected somewhere.

Guest · Post by **Guest** » Wed May 16, 2007 5:09 pm

Thanks for the reply.
Would that be the pump that sits on top of the fuel filter that has a wire as well as a pipe going to it?

hot66 · Post by **hot66** » Wed May 16, 2007 6:19 pm

the hose runs from the rear of the left heat exchanger past the rocker cover & up into the engine bay on the left side .... it finishes at the thermostat on the large MFI fuel pump

Guest · Post by **Guest** » Wed May 16, 2007 6:41 pm

Thanks for the help guys. I'll check it out.

Guest · Post by **Guest** » Thu May 17, 2007 10:50 am

Well, I had a look at the pipe from the heat exchanger to the pump and that seems all secure and fine. Anyone have any other ideas. I'm wondering how I can test the cold start solenoid?

Guest · Post by **Guest** » Thu May 17, 2007 12:49 pm

I've done some more investigating; took the feed from the cold start solenoid off and apart from a single squirt at start it's not pumping fuel in. Took air filter off and checked for obstructions, nothing I can see. However, I have noticed the tacho is behaving erratically and jumping all over the place while the cars running. I've a feeling this is driven off the coil, so I'm wondering if perhaps the coil is breaking down. The car idles OK but as soon as you try to increase revs the engine is vibrating and jumping all over the place goes flat, backfires and dark smoke coming out of the exhaust, though it will idle.

Any thoughts?

hot66 · Post by **hot66** » Thu May 17, 2007 1:10 pm

have you checked the points / timing ? Is the ignition advnacing ?

Is the car still running a stock CDI box?

Guest · Post by **Guest** » Thu May 17, 2007 1:19 pm

Just checked the points, however I'm unable to check the timing a my timing light broke the other day. I'll have to borrow one and check.

Guest · Post by **Guest** » Thu May 17, 2007 2:16 pm

Bearing in mine what's been said about the timing advance, I took the distributor out to have a look if the weights were advancing. The wafer that sits under the weights has broken up and twisted around. I fished the broken bits and the remaing piece out. I put the distributor back in and fired it up. Still the same, but if I manually advance the timing as I slowly increase the revs I can get the car to rev, but it's very hit and miss. Naturally the wafer is there for a reason, does anyone know what the reason is and would the car behave as it is with the wafer broken and removed. The faulty distributor is numbered 0 231 159 006. I have a spare (porsche) distributor, however the number ) 231 169 009 and the shaft is a larger diamiter by 3mm. Does anyone know if I have it turned down I can use it?

Guest · Post by **Guest** » Sat May 19, 2007 11:58 am

After talking to a local Porchse mechanic who sometimes does work for me, he told me to take the thermostat housing off and check that the rod with the bi-matal washers on isn't binding up. I took the housing off and pulled out the rod with the washers on. The washers were a bit dirty, but didn't appear to be binding. I have to admit that looking at this set-up I couldn't really work out how it works. I'm assuming that when hot air flows from the heat exchanger some of the washers buckle and push the rod in thereby turning the cold start enrichment off. Can anyone confirm?

Guest · Post by **Guest** » Sat May 19, 2007 4:01 pm

Ran the car and removed the thermostat cover and as I released the cover and took the tension off the spring the car stalls. If I push the rod with the washers on in I can start the car and it idles, release pressure on the rod and it dies. So, I'm assuming it's working. I'm guessing in colder weather some of the washers bend and pull the rod back thereby enriching the fuel system, not in as I originally thought. Someone please correct me if I'm wrong. I'm now begining to think it's ignition related, as the tacho is still going crazy. When the car is idling the tacho is bouncing up and down. The CDi unit is whistling as usual with the ignition on.

Guest · Post by **Guest** » Sun May 20, 2007 6:09 pm

OK, so I swapped over the CDi unit and the coil from my 72 car put it on the 71 car and it fires up and runs OK. I then fit the CDi and coil from the 71 car to the 72 car and it fires up and runs OK. Go figure, I guess I must have had a bad connection or something.
Thanks for the help guys.

hot66 · Post by **hot66** » Sun May 20, 2007 7:37 pm

glad you've got it sorted. Always difficult to diagnose from a far