Popping from exhaust

[Chunkychops]

Started the car up yesterday and there was a popping noise coming from the exhaust while idling, a bit like backfiring but not as loud. I took the breather tube off from manifold and it stopped. I made sure the tube was not blocked and replaced it only for the noise to start again. Ive had a look on here but cant find anything relating to this. Any ideas?

[Chunkychops]

Im told the vacuum/retard unit on the bottom of the distributor might be faulty which is causing the pop through the exhaust. With the tube to the top of the manifold disconnected it seems to run ok, no popping. Is it ok to leave it disconnected or will there be any adverse effects? Should I blank anything off?

[FI Spyder]

Not sure how your emission run in the UK for your year of car. It sounds like if you take an intake manifold hose off it's OK. When you do this you are introducing air into the intake which is not going through the carburetors. If you are running rich the extra (non carburetor air)is leaning it back out so it is not so rich. A rich mixture will tend to pop in the exhaust as it ignites outside of the combustion chamber (in the exhaust).

The distributor vacuum diaghram on older cars (pre emission) would advance the ignition at high vacuum (high speed). On emission cars this was reversed. While still commonly (mistakenly) called a advance diaphram, it retarded the spark on high vacuum (in over run condition) to help decrease the emissions. On a pre emission car it would be detrimental to remove this hose as you would not get the spark advance the engine was designed for. On an emissions car there would be no performance degrade as you would be removing the spark retard and would only adversely affect the emissions.

That said I'm not familiar with you car/year. Perhaps a UK person can confirm.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

[Workshop Help]

Which spark plug(s) are running rich?

Mildred Hargis

[Chunkychops]

Thanks for the replies. Its a 1981 standard 2.0 and now its not running atall. I started it up earlier and it was ticking over ok (without the vacuum tube attached) then, there was a noise (I think from the dizzy area) and then it cut out and now wont start atall although it is turning over.

This car has fought me all the way and I spend more time with my ead under the bonnet than actually driving it. Any ideas anyone? Will check the plugs first off.

[andyf]

From your first couple of posts, checking the plugs first is the best course of action, you will soon tell if it is running rich by the state of them.
The noise thing is impossible to comment on without some more info - what sort of noise was it, did it last for a period of time or sudden?
One final question, does it turn over quicker than normal? If so, don`t try it again your timing chain might have snapped (this would be a very rare occurence so probably no need to worry, just thought I`d throw it in there).


1980 Persian Aqua DHC

[sonscar]

Guess I was unlucky,mine snapped,certainly did turn over more quickly and indeed did make a strange noise just before failure.Another failing I have had is the springy contact on the top of the rotor arm snapped off,and I have had the points heel wear away closing the gap which caused misfiring.Steve..

[Chunkychops]

Well I checked for a spark, no spark, so took the dizzy cap off and removed the rotor arm (its an electronic ignition, no points).
And there seems to be the problem, broken bits of black plastic underneath the metal base plate things that the rotor arm screws onto, one piece with a bolt still through it.
I dont know what this plastic part is but wahtever it is it has shattered. I cant find the part on Rimmer bros diagrams so Im assuming I need to get a whole new dizzy assembly?

Would I need to get one with electronic ignition or will a standard one do?

[Workshop Help]

My friend, apparently your problem has been found. You need another electronic ignition. The new issue is what kind do you want? The two aftermarket systems on this side of the ditch are the Pertronix or the Allison/Crane units. They are sold on your side of the ditch with different names.

I suggest you do some research to choose the one of your choice. Is it possible for you to provide a photo of the distributor?

Mildred Hargis

[Chunkychops]

Thanks Mildred, after a bit of research found this. The dizzy is an AC Delco so hopefully this will do the job. Its still in the car atm so I cant take a photo. The ones Rimmer Bros have are nearly £200.

http://www.ebay.co.uk/itm/Triumph-TR7-A ... 2a14dca104

[Workshop Help]

The item you listed on ebay resembles a Pertronix unit. It is not necessary to replace the entire distributor unless the housing or metal components are broke.

Why can't you take a photo of the distributor in the car? That would be a big help.

Mildred Hargis

[saabfast]

To fit that one you have to remove the distributor and strip it down, fine if you have a miniature spanner and hands (or the special tool bent spanner). Otherwise there is also the Pertronix Mildred noted. This is sold in the UK as the Aldon Ignitor but is cheaper from Retro Rockets who are US company but keep a stock in a UK warehouse so it is actually shipped from here (although paid in $). It is still more expensive than the Accuspark but can be fitted from the top without removing the distributor. I have had one for the past 3 years or so, car starts first time, runs smoother and I have never had to go near points again! They seem to have changed the website name:

http://www.vintageperformance.com/retrorockets/



Alan
Saab 9000 Stg 1 (now passed to son for his family car)
Saab 9000 2.3 FPT Auto (now gone that others might live)
Saab 9000 2.3 LPT Auto (sold on, wish I had it back)
Saab 9-5 2.3 Vector Auto Estate
'81 TR7 DHC

[Chunkychops]

Im trying to upload some pics but it wont let me. How do I do it?

[Workshop Help]

Set up an account with Photobucket.com. Upload your photos from your computer. Once you have chosen the photo in your 'Library', click it to bring it to the "links to share' box on the right. Next, click on the IMG selection where you will see a 'copied' come up briefly.

This holds the photo ready to be transferred to the post you are making. When you are ready to place the photo in your post, click on the icon, fourth from the right. Then, right click next to the,'[img] [img]'. Finally, delete the un-necessary verbage around the actual photo information. You will have to practice a few times to get the photo at the desired 4x6 size.

Yes, I know it's a bit awkward, but just get used to it.

Mildred Hargis

[Chunkychops]

Ok cheers, will get on it.