TR6 PI - running very rich

[Tim D.]

Hi,

Agree regarding setting up related to actually engine spec.

Neil F. set up mine and it was 95% right.. then ran the car on the AFR and just needed a slight tweak to the off idle mixture to give perfection..

Setting up de novo with no idea of starting settings would have been pretty much impossible using the AFR method. Too many related factors in the MU..

Cheers

Tim

[john.r.davies]

Morten,

a non-hardening sealant would deal with the injector issue.

 

EG LocTite MR5922 http://www.loctite.co.uk/2838_UKE_HTML.htm?nodeid=8797721034753

John

Edited July 12, 2017 by john.r.davies

[MortenHoyseth]

@BlueTR3A-5EKT: compression is excellent, they are equal and compression is high (don't exactly recall the number, 11-12ish on my device). So seems - so far - nothing has been damaged by the extra fuel.

@AstonTR6: I've got a CP manifold. Just to make things more complicated, the engine is a 2.5PI from '71, fitted in a '73 US car - rebuild in the 80s. So no guarantee that the manifold is original to the engine. The dizzy has been rebuild to work with this engine, and it works great now. The MU - well, I do not know if this was the one that came with the engine back in '71. I'm not aware of any MU differences over the production period except from the return pipe connection (push or screw), but obviously the internal setup might differ. However the MU was professionally rebuild 3y back, for this engine spec.
Regarding vacuum - it read about 5inHg. From what I've learned somewhat low.

@Tim D: very promissing, looking forward to have Neil checked the MU

@John.r.davies: Excellent tip, I'll give it a try.

Cheers

Morten

[astontr6]

@BlueTR3A-5EKT: compression is excellent, they are equal and compression is high (don't exactly recall the number, 11-12ish on my device). So seems - so far - nothing has been damaged by the extra fuel.

 

@AstonTR6: I've got a CP manifold. Just to make things more complicated, the engine is a 2.5PI from '71, fitted in a '73 US car - rebuild in the 80s. So no guarantee that the manifold is original to the engine. The dizzy has been rebuild to work with this engine, and it works great now. The MU - well, I do not know if this was the one that came with the engine back in '71. I'm not aware of any MU differences over the production period except from the return pipe connection (push or screw), but obviously the internal setup might differ. However the MU was professionally rebuild 3y back, for this engine spec.

Regarding vacuum - it read about 5inHg. From what I've learned somewhat low.

 

@Tim D: very promissing, looking forward to have Neil checked the MU

 

@John.r.davies: Excellent tip, I'll give it a try.

 

Cheers

Morten

Morten,

 

The figure of 5 is far too low! It s/b in the region of at least 10 minimum for pre-emission TR's and for pre-emission saloons it s/b 12 and14 for all emission engines, that is post 1973.This test data is as per BL May 1978. I believe that is where your problem lies? Your next route s/b a compression check? Was the vacuum check done from the servo spigot with the servo pipe disconnected? Air Leaks could also be part of the problem as already asked?

A general comment: These days people in general do not pay much attention to the manifold vacuum on Triumph PI engines, in the 1970s BL garages zeroed in on this, as their first port of call for PI fault diagnostic testing, due to Cyl. Head problems with this engine.

 

Bruce.

[Mike C]

Steve Weblin has collected a lot of useful Lucas PI and electrical information on his Lucas website.

 

Point 9 of Lucas Fault Diagnosis Card 1 included in the PI library might be of use:

 

http://vitessesteve.co.uk/LucasStuff/Lucas_Petrol_Injection_Manuals.htm

 

Calls up 7-8 inches of vacuum with a standard TR6 cam. Might be a bit less if your cam is a bit wilder.

Edited July 13, 2017 by Mike C

[astontr6]

Steve Weblin has collected a lot of useful Lucas PI and electrical information on his Lucas website.

 

Point 9 of Lucas Fault Diagnosis Card 1 included in the PI library might be of use:

 

http://vitessesteve.co.uk/LucasStuff/Lucas_Petrol_Injection_Manuals.htm

 

Calls up 7-8 inches of vacuum with a standard TR6 cam. Might be a bit less if your cam is a bit wilder.

Hi Mike,

Your vacuum figure is not as per my British Leyland Eng. data? One of the Forum contributors had his TR5 rolling road tested at IWE and his car was at 10Hg, which is exactly in line with my quoted figures?

 

Bruce.

[Mike C]

Hi Bruce

 

For most of us the original Triumph/ British Leyland/ Lucas parameters as detailed in Steve's collection of Lucas manuals are only a starting point. My vehicle had various owners modifying/fiddling with it for 28 years before I purchased it, they made many modifications which Triumph never intended, especially during the years in which a TR6 was considered to be an expendable hot rod.( I've learnt over the years with my TR6 to use the age old principle-"if it works don't fix it").

 

The 7-8 inches of vacuum for the TR6 comes from the Lucas Primary Check cards which were used to maintain these cars when they were still relatively new. This series of mechanic's check cards got me out of trouble over the years. Nothing wrong with 10 inches Hg , Lucas specified 10-12 inches Hg for the saloon 2.5 PI engine.

 

My engine was around 5-7 inches Hg last time I measured it, but I can't confirm I have an original TR6 cam fitted , and it took a lot of damping on the gauge's connection tube to get a stable reading.

 

Regards,

 

Mike C

[astontr6]

Hi Bruce

 

For most of us the original Triumph/ British Leyland/ Lucas parameters as detailed in Steve's collection of Lucas manuals are only a starting point. My vehicle had various owners modifying/fiddling with it for 28 years before I purchased it, they made many modifications which Triumph never intended, especially during the years in which a TR6 was considered to be an expendable hot rod.( I've learnt over the years with my TR6 to use the age old principle-"if it works don't fix it").

 

The 7-8 inches of vacuum for the TR6 comes from the Lucas Primary Check cards which were used to maintain these cars when they were still relatively new. This series of mechanic's check cards got me out of trouble over the years. Nothing wrong with 10 inches Hg , Lucas specified 10-12 inches Hg for the saloon 2.5 PI engine.

 

My engine was around 5-7 inches Hg last time I measured it, but I can't confirm I have an original TR6 cam fitted , and it took a lot of damping on the gauge's connection tube to get a stable reading.

 

Regards,

 

Mike C

Hi Mike,

 

If the needle on the vacuum gauge is jumping about it is a probable sign that that there are other things wrong with your engine, i.e. air leaks- worn butterflies/spindles, valve guide ware and inconsistent or low compression between cylinders. Did you do your vacuum check with your servo pipe disconnected and use that spigot for your vacuum gauge only. This is what my Crypton Gauge instruction say, to do? for consistent readings!

 

Bruce.

[MortenHoyseth]

My vacuum gauge needle is certainly jumping about. I blanked off the servo hose and measured on the hose to the MU. Have not tried like you describe, Bruce. However, I do not understand that the vacuum should be constant?

[Mike C]

I normally clamp the line to the gauge until the needle settles down with a small G clamp- here's a video a bloke posted of testing the vacuum of a TR6 with a clamp on the line (the clamp is just visible)-

 

https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=video&cd=2&cad=rja&uact=8&ved=0ahUKEwj9m-WMxY3VAhVHTLwKHQ-FCo8QtwIIJTAB&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DSiDOp-KgNTo&usg=AFQjCNGLymN1O01djrzzbz8bqR3yHTUQdw

[MortenHoyseth]

Excellent Mike, I'll test it out - thanks!

[MortenHoyseth]

Dear all - case closed ! Finally - after 1,5y of problems after rebuild, the TR6PI now runs like charm. First test drive yesterday - first in 4 years. A truly religious moment to me.

This last problem, with it running very rich, was that the datum linkage had become detached (thanks Neil for your help on this!). After that was fixed, no more black smoke and a good idle. Still it had problems reving and ignition was far too advanced (but had to, to make it run). No vaccum leaks found, but it was as simple as putting in new spark plugs and setting gap to 30 thou. Goes like a charm!!

Oh, my - I've totally forgot what it is like to drive a working TR6 - heaven

So this concludes all the post-rebuild issues over the last year. Major issues have been:

1. MU unit - datum linkage, earlier destroyed threads with alu parts (rebuild after that)
2. PRV - new unit produced over 140 psi -> rich running stage 1 -> fuel in oil sump -> changed dizzy pedestal gaskets
3. Distributor locked in max advance, making ignition waaaay off.
4. Injectors faulty
5. Electrical issues - engine kept running after ignition key was off/removed -> feedback voltage from alternator via relays -> alternator produced enough voltage/current to keep the engine go -> diode/switch added, rather than removing the relay.
6. Low voltage at coil -> bad electrical work by me
7. Issues with electrical distributor kit -> back to gaps and points.

That's what I can remember. The problem has been the issues combined, to sort it out one at a time. To me it has been frustrating, but finally there. Thanks for all help
I'll be out driving now.

[ianhoward]

Hi Morton

 

Pleased to learn you have it sorted! Enjoy!

 

Cheers

Ian

[Steves_TR6]

Excellent detective work Morten, glad you can now enjoy the full TR6 experience.

 

I think my 6 has saved me a lot of money, it's so much fun ive not needed to buy any more cars !

 

Steve

[barkerwilliams]

Morten,

 

You now have a years worth of driving to catch up with. I hope you enjoy it.

 

 

Alan

[Gary Flinn]

Morten

 

I can relate to your problems after having similar trouble with the Fuel & Injection systems on my 5 last year.

 

Enjoy the car now, they really are a joy to drive

 

Gary