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Markboston

Car dies PI problem

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I would be most grateful for opinions on where to search next for the gremlin that has killed my TR6 (1971).

I bought it five days ago and I ran 150miles back from the dealer fairly well - poor idling and difficulty in revving over 4K. I added injection cleaner to the tank.

The problem is now far worse. The car, when it finally starts, will rev high (over, say 2000) but as soon as the revs drop to 1000 it stalls, no matter how much tickling on the throttle. And is then almost impossible to restart, though it always finally somehow manages.

In the interim, I have replaced all the injectors and the fuel filter, and have put clips on all the manifold branches, representing a considerable a considerable waste of money as the car is not really any better. I live in Eastbourne which seems to be just about as far from any TR specialist as its possible to be.

I am now thinking that the fuel pump may be faulty, but would like to hear some informed advice rather than throwing money on every changeable part I can dislodge. I have no good garage facilities- just a driveway ... many thanks in advance for your collective expertise...

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Hi Mark

 

Not a good start.

 

I'm not that good at these things, but a few steps to start with before someone more knowledgeable comes along!

I had a nightmare with my '6 a few years ago and it was the fuel filler cap - it didn't have a breather hole in it. Opened the cap and it ran like a dream until I could replace the rubber seal with the correct one.

Worth a look. I didn't realise until I stopped for fuel and there was a great 'hiss' as i undid the cap - the air going into the tank.

 

Having said that - not sure why that would make it rev high.

 

Good luck.

 

Roger

Edited by Pogo

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A high idle means too much air leaking into the inletes with closed throttle. Presume you have screwed shut the idle screw? Then the butterflies need to be adjusted. This needs the two screws that secure each to the spindle to be loosened then the position of the 'fly shifted minutelty, to fit precisely in the induction throat. Check with the finest feeler gauge you have, 10 thou or less. The 'fly should grip the feeler to and bottom and sides.

Goodluck, its an art!

John

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Contact the Dealer and get them to sort it out.

 

Unless you bought it on Trade Sale Terms, it shouldn't be your problem. Clearly not fit for purpose.

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Agree with ragtag. Adjusting the butterflies can be challenging if you are not used to it so would make sure you check everything else before embarking on this.

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I don't read it as idling over 2,000 rpm but as the engine will run over 2,000 but not at lower revs.

If this is right -

Nearly all problems are electrical. If the car has points replace the condensor and if no improvement the coil. If it has electronic ignition make sure all the connections are ok and, if you can, have it tested.

Plug leads, plugs and distributor cap are also problem areas.

I carry a spare of all these items in my TRs, they keep you going in the vats majority of situations.

If it isn't electrical, best of luck.

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Hi Mark,

 

Welcome to the forum.

 

I'm sorry to hear of your woes, but hopefully you'll find some help here. If it were me, I think I'd start by talking with the dealer you purchased the car from. If they are one of the TR specific ones, then they'll be more than happy to help you, I'm sure. If they are not TR specialists, then I can see that you might not get far with them. Also, I appreciate that given the distance between you and the dealer and the problems, it'll be difficult to return the car.

 

I'm certainly no expert on the mechanical side of things, but I'm always interested in exploring such issues and to learn. With your particular problem, I'm a bit confused by how you stated the issue. Are you saying that when you start the car, the revs go straight up to above 2000 for a while (with no throttle) and then drop down to 1000 before it stalls? Or, are you saying that when it starts you can rev it above 2000, but as soon as you come off the throttle it drops to 1000 and dies?

 

Cheers, Darren

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I don't read it as idling over 2,000 rpm but as the engine will run over 2,000 but not at lower revs.

If this is right -

Nearly all problems are electrical. If the car has points replace the condensor and if no improvement the coil. If it has electronic ignition make sure all the connections are ok and, if you can, have it tested.

Plug leads, plugs and distributor cap are also problem areas.

I carry a spare of all these items in my TRs, they keep you going in the vats majority of situations.

If it isn't electrical, best of luck.

+1. Definite symptoms of condenser failure.

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Agree that its a air leak problem.

As it got worse during use I would look at the brake booster

 

Second place is the metering unit.

Suck at the hose and look for broken diaphragms.

 

Than all connections with rubber hoses may be wrong.

 

Bolts between manifolds and head should be checked than

Edited by TriumphV8

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Hello Mark, welcome to the forum.

Points gap can close up in a hundred miles or so, if dry of lubricant, and will give exactly that problem:: wont run at low rpm gettting worse as they wear rmore. Friend had a V8 that failed to run below 2000rpm, then failed to start, after 200miles on fresh plastic points fitted dry. Gap the points and smear a smidgeon of grease on them. Then buy a fibre set from Distributor Doctor.

 

Peter

Edited by Peter Cobbold

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So first we must know is it idling at 2000 rpm or not?

That gives exactely the different answers of Peter and me!

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The way I read the original post does not point to an air leak. It won't idle, fair enough, but it also won't rev above 4k. No mention of uncontrolled idle, so not an air leak.

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Hi Mark

I had the same issue regarding the car just dies after a while and found out that there are two types of fuel filler caps one foe injection car and one for carbs the one without the air intake is for carbs as the injection system is seal and needs air intake otherwise you end up with vacuum so car dies through fuel starvation so need to release the cap to allow air in alternative is to make a small cut in the seal to allow air in or replace cap with the correct one with regard to injectors there is a man not far from you Mike bilney lives in cranbrook (07809 061245) he will refurbish all your injectors and will nodoubt help with injection issues you may have.

hope this helps

Bluebob

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Mark,

 

TR6 PI is a great drive sorry you are having troubles.

 

Fuel pump runs at same speed and pressure once the ignition is turned on (before engine is running) or 100mph so yes it could be an issue but easiest way is just to check the pressure (104-106 psi). An engine only running at high revs due to a pump is not one of all the faults I've had or heard of.

 

But attempt any repairs take the car back to the dealer that's the way to get it sorted. Once you attempt to repair the car the dealer can claim the problems are down to the work you have done.

 

Alan

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Hi Mark

 

Sorry to hear about the car. It must be very disappointing after having just bought it. Do you know anything about it's history. If it's been stored for a few years this could throw up a number of problems.

 

From personal experience I always replace things one at a time and then check to see if it's cured the problem or made it worse. It just gives you a reference point.

 

Have you taken the plugs out and checked the conddition and that you have a spark at each plug. If so have you replaced the leads in the right order. That goes with injectors as well. Also you can't always assume that replacement parts work. Have you checked the injectors are spraying correctly. There are plenty of posts on how to do it if you google it. I had a similar problem when I bought my TR6 running roughly and and not revving, it turned out to be one faulty injector.

 

Best of luck

 

Roger

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Definitely check you have a nice cone spray from each injector, and a good spark from each plug. It's also worth checking the timing is right, mine had the distributor fitted badly to the point it came out of the clamp due to the orientation but still turning but the body was free to move!

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Hello Mark

I would check that the choke lever on the metering unit is not sticking on first, not the one you can see, the one below it.

John

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My many thanks indeed for all the most informative and helpful advice, especially including the call and numbers to call, from you most generous and diligent TR owners.

I should perhaps have also stated that the car was owned by a real enthusiast ( unknown to me because bought through a dealer). It’s file shows it was copiously restored - engine and running gear- only 10k miles ago... but that was 20 years ago. The car has I believe sufferered from decrepitudes simply because from judging from its MOT recorded it has been virtually unused for the last decade.

Actually I have been busy carefully checking as far as I am able as many as possible of the points raised from your advices. I hope you will be interested in the findings as follows:

Injectors numbers 1 and 4 spray no fuel from the metering unit, but the remaining four give a nice conical spray. I confirmed that all of the new injectors that I had installed actually worked in themselves. It turns out that the fuel pump fitted to my car is a Bosch, and the live feed had a hot and burned connection which I have temporarily fixed. I could find no obvious foreign bodies in the fuel after examining the filter. I have checked the clearances of the butterflies and as far as I can tell they are close to the port at about a 004 feeler. The car has electronic ignition which I believe bye passes the condenser, which otherwise is untested. There was a distinct hissing noise from the fuel cap when I picked the car up which I think corresponds to the suggested vacuum in the tank, but I have been careful to leave the cap ajar during all recent trials. The spark plugs are new and the distributor cap is recent. It appears to be firmly clamped As mentioned, the motor roars into life on starting and within a few seconds drops dead after a painfully lumpy idle. Therefore, I am sssuming that a big squirt of fuel from the ‘choke’ on initial start can give the engine about as much necessary petrol as an old-school float-chamber’s worth, which, after exhaustion, leaves the engine with 4-pot running and inevitable stoppage. So I am going to fit a new MU. The fuel leads are old and hellish rusty on the unions, and I am going to replace those too while they are accessible. I think it possible that a few hours of use has finally broken down failing circuitry in a car that is simply in need of further maintenance, Many thanks again. Mark.

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Hi Mark

 

Not a great start to TR ownership,

 

In terms of what's wrong there are far more qualified people on here than me but i completley agree with Ragtag and Mhossack.

 

You say you bought the car from a dealer and as already stated unless it was a trade sale they have a legal responsibilty that lasts alot longer than the journey home although i do not know the exact legal obligations and timescales.

 

So you should contact them first, definitely before you touch anything or get anyone else to and ask them to resolve the issues. I would also say you having to take the car back to them is not really acceptable due to the time/cost implications of the journey.

 

Difficult to judge without knowing the cost of the car but i cannot imaging a reputable dealer selling a car on a "retail" basis without a porper road test and checkover as i'm sure they are obliged to do.

 

What would have happend if it were not the engine running badly but the brakes not working on the way hame.

 

 

All the best

 

Cheers

 

Keith

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Hi Mark,

 

I would repeat my advice that you should contact the Dealer. The car is not of merchantable quality/fit for purpose. As the car can't be driven, the dealer is obliged to recover it at his expense or send a mechanic to you, to fix it.

 

However, if you don't want to take this advice or can't for some undisclosed reason then from what you have written please consider the following:

 

If 4 injectors are spraying properly, it seems unlikely that there is anything wrong with the fuel pump or the metering unit. The problem is likely to be between the outlet of the MU to the tip of the injector. This is pretty easy to check. Firstly, you might have an airlock or debris in the injector. Try pulling the pin on the tip of the injector (gently) whilst cranking the engine. (clearly you will need an assistant for this) If this doesn't work, remove the offending injector put the end of the pipe in a jar and crank the engine. Fuel should discharge at reasonable pressure. If it doesn't, disconnect the pipe at the MU end and check for blockage in the pipe. You should be able to blow through it.

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Mark - have a good look inside your fuel tank - I wonder if it's been slosh tank sealed at some point and this is breaking down and causing blockages?

or it might just be rusty.

 

Cheers

Rich

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Sorting the injectors that are not firing is the priority. It is probably just a case of bleeding. Once this is done then you will know more where you are.

Cheers

Tim

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Bleeding the injectors is quick and easy, and sounds like that would cure it. You can feel each injector line for pulsing (make sure they are not touching against another whilst you check) that's the way to find out which needs bleeding

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It shoould still run on 4 cylinders although lumpily. Often an injector will start working when the voltage rises at the pump, after blipping the throttle. Give it some welly after it fires.

Is the battery new and fully charged ? and its earth good.

Peter

Edited by Peter Cobbold

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I am so grateful for all the advice received. Without this I would not have made any progress.

At the moment the car is running again. When it wouldn’t run any more after landing it home last week, it was certainly the case that three injectors were appreciably leaking, which is why I renewed the whole set -tho that may not have been necessary. Next, as I mentioned in my last thank-you post, the MU was supplying only 4 cylinders. I had already hastily bought an exchange before learning that I could have had mine very reasonably reconditioned, or before checking that perhaps the MU outlets only were at fault and (much) more easily changed than the whole MU. So I cannot be sure how failed this unit actually was.

Having installed the injectors and MU ( and new leads which are streel braided, and in my opinion, tailored in size very imperfectly indeed for their intended routing), it was through following the instructions from Mr Raven (AKA) that I managed to squeeze the air out of the system. It is a little difficult to bleed. In fact I would say it was one of the most difficult little bleeders I have encountered.

When the engine roared into life (hurrah), it STILL ticked over like an old dog. Reference was then made to one of my kind respondents who suggested, what I scarcely credited, that the breaker gap, if narrowed, could be causing the symptoms I originally described. Absolutely right! The gap was at about 005. Increasing it to about 020 (will look now up what it should be- points are so shabbily made that wider adjustment not possible) completely cured it. The car now seems fantastic, revs like a lion, ticks over like a lamb, in which condition I hope it will stay. It could be, therefore, that after spending about a grand on bits and leaning over the bonnet for about 30 hours, I could have saved all that trouble by 2 minutes with the feeler gauge. Ack . Looking on the bright side, I am sure that at least my restorations will ensure trouble free wind-in-the-hair (or over the hat) motoring into the sunset.. Thank you all again for your generous support.

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