mikespain835 Posted September 20, 2018 Report Share Posted September 20, 2018 Hi All,I realise that I am asking about a TR5 in the TR6 forum but there seems a lot more info about the metering unit here. I'm trying to get a TR5 to accelerate from idle instead of bogging down.It seems to be over fueling at idle. It has cp throttle bodies with air bleed screw and push on fuel return pipe. Ignition timing set at 11 degrees btdc at 850 rpm Checked fuel pressure at metering unit gives 100psi I have 6 inch hg vacuum at the manifold and the 6 inlet ports are all within 1/2 a unit of flow (in this case kg/hr) showing 2 to 21/2 and have tested at part throttle -again all showing more or less equal flow. I changed the throttle spindles (which rectified the play and adjusted the butterflies to be best seating possible. This greatly improved the idle(which was all over the place) giving me a stable idle that can be adjusted down to 650 rpm but still very very rich I have checked the mixture control unit and it has got blue springs fitted ,should'nt they be silver or red.? thus leaning the mixture more? I have trolled through many posts but non seem to give any info about the effect the different springs have. any help or comments would be very much appreciated thanks Mike (malaga spain) Quote Link to post Share on other sites
DaveN Posted September 20, 2018 Report Share Posted September 20, 2018 Er.... is the diaphragm ok? Also make sure that the fuel cavity spill return line is clear. They can block at the small ‘rubber’ hose under the l/h wheel arch. Quote Link to post Share on other sites
TR5tar Posted September 20, 2018 Report Share Posted September 20, 2018 Hi Mike, Sorry to hear of your issues. If you want to drop me an email, we can have a chat, as I've experienced similar. dfcummings@aol.com Cheers, Darren Quote Link to post Share on other sites
Mike C Posted September 20, 2018 Report Share Posted September 20, 2018 (edited) Is your 6" Hg at idle? Seems a bit low. I have a TR5 cam in a bored 2.7 litre TR6 engine and my idle vacuum is generally around 10" Hg. Many TR6 engines have a much higher idle vacuum than this. BowerPower in Sydney developed a fuelling curve for this engine. At 6"Hg vacuum it's getting fed 27% more fuel than at 10"Hg. There was no new spring fitted when the MU was recalibrated but I don't know whether a PO had fitted a non standard spring at sometime in the past. Edited September 20, 2018 by Mike C Quote Link to post Share on other sites
John L Posted September 20, 2018 Report Share Posted September 20, 2018 The blue springs are for the saloon car, not sure why, (I think more inlet vacuum) but the TR5 springs should be both red. With 7" of vacuum. What does the fuel pressure do when you try to accelerate?, I would increase it a little to 105psi. to cover the drop at acceleration. Have you checked that the diaphragm on the MU holds vacuum? Do you know what the MU unit is timed up at?, #6 port at the MU should just be opening at 10 degrees before tdc. John Quote Link to post Share on other sites
Peter Cobbold Posted September 20, 2018 Report Share Posted September 20, 2018 (edited) Mike, The timing marks might have slipped - the rubber in the torsion damper distorts. I'd set the tickover by turning the disy a feww mm to and fro slowlty until you get the best rpm. Over-retarded spsrks will cause bogging. Peter Edited September 20, 2018 by Peter Cobbold Quote Link to post Share on other sites
mikespain835 Posted September 20, 2018 Author Report Share Posted September 20, 2018 (edited) Thanks for the quick replies.I will check if the diaphragm holds vacuum and that the pump is timed correctly. The metering unit looks as though it has been overhauled recently as it is very clean and there is clean yellow anti tamper paint on the screws. I forgot to say that the engine was rebuilt etc in 2017.Also a bosch pump kit was fitted along with a rebuilt long PRV -non adjustable Edited September 20, 2018 by mikespain835 Quote Link to post Share on other sites
roy53 Posted September 20, 2018 Report Share Posted September 20, 2018 I would double check the metering unit timing . Roy Quote Link to post Share on other sites
barkerwilliams Posted September 20, 2018 Report Share Posted September 20, 2018 Mike, Every time mine has been lumpy pulling away until it gets to about 2,000 revs it is the butterfly balancing that has cured it. My issues have been that at tickover the car is running on two cylinders with a good mixture, the other four cylinders the butterflies have been tight shut but the injection still gives them a slug of fuel on each cycle so they just get way, way over rich with dirty plugs just 'oribble. When the throttle opens it takes quite a few cycles to blow the cylinders and plugs clean when the engine can start to run nicely and pull properly. When balanced the engine still runs a little rich, as it is designed to do, but all cylinders are singing from the same hymn sheet and when the throttle opens they all respond together. My car runs at 6" to 7" vacuum which I believe is correct for a CP PI .Alan Quote Link to post Share on other sites
john.r.davies Posted September 20, 2018 Report Share Posted September 20, 2018 John, I had the same symptoms, due to the choke lever being stuck open, ever so slightly. The cause was a kinked choke cable Simply ensuring the lever was all the way back cured it. John Quote Link to post Share on other sites
Ashley Posted September 21, 2018 Report Share Posted September 21, 2018 Hi Mike. I was recently called out to look at a car that was suffering with the same problem. My friend had just finished setting up the car but was not happy with it’s pick up from idle. He had balanced the butterflies with an air flow meter and the engine running at idle. ( He considered the butterfly adjustment to be at it’s most sensitive with the lowest rpm.) I suggested me rebalanced the butterflies with the rpm at 1500 as per the brown book. This worked for us and might hopefully solve your problem. I assume the brown book states 1500rpm as this is a typical low power setting that the car will be asked to accelerate from on the road, and therefore it is more important that the butterflies are accurate at this power rather than idle. All the best, Ashley Quote Link to post Share on other sites
astontr6 Posted September 22, 2018 Report Share Posted September 22, 2018 On 9/20/2018 at 12:20 PM, mikespain835 said: Hi All,I realise that I am asking about a TR5 in the TR6 forum but there seems a lot more info about the metering unit here. I'm trying to get a TR5 to accelerate from idle instead of bogging down.It seems to be over fueling at idle. It has cp throttle bodies with air bleed screw and push on fuel return pipe. Ignition timing set at 11 degrees btdc at 850 rpm Checked fuel pressure at metering unit gives 100psi I have 6 inch hg vacuum at the manifold and the 6 inlet ports are all within 1/2 a unit of flow (in this case kg/hr) showing 2 to 21/2 and have tested at part throttle -again all showing more or less equal flow. I changed the throttle spindles (which rectified the play and adjusted the butterflies to be best seating possible. This greatly improved the idle(which was all over the place) giving me a stable idle that can be adjusted down to 650 rpm but still very very rich I have checked the mixture control unit and it has got blue springs fitted ,should'nt they be silver or red.? thus leaning the mixture more? I have trolled through many posts but non seem to give any info about the effect the different springs have. any help or comments would be very much appreciated thanks Mike (malaga spain) Hi Mike, Your Hg looks low to me? What sate of tune is your engine? Do you have a standard cam for your TR5? If not in my experience the MU often needs to be re calibrated as the engine will run too rich. Also you need to check for vacuum leaks, the servo unit and the rubber balance pipes between the manifolds are good starting points, as is the manifold pipe to the M/U. Lastly have you done a compression check on a hot engine? I am not an expert on the TR5 but if I remember correctly the TR5 has a differently calibrated M/U to a CP TR6? Bruce. Quote Link to post Share on other sites
Mike C Posted September 22, 2018 Report Share Posted September 22, 2018 (edited) If you still want to have a go at adjusting the different springs etc- Lee Janssen prepared this MU adjustment guide maybe 10 years ago: His site is: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&ved=2ahUKEwiYgNvyss7dAhVIUt4KHaPoDlsQFjAFegQICRAB&url=http%3A%2F%2Fwww.tiggersavage.com%2Ftr6_overview.htm&usg=AOvVaw3zx6NlJkHJFMGB8_Piq-ZV The relevant part of the site is: http://www.tiggersavage.com/pi_overview.htm Edited September 22, 2018 by Mike C Web site location didn't copy. Quote Link to post Share on other sites
stuart Posted September 22, 2018 Report Share Posted September 22, 2018 Direct link to that site Mike http://www.tiggersavage.com/pi_overview.htm Stuart. Quote Link to post Share on other sites
Mike C Posted September 22, 2018 Report Share Posted September 22, 2018 Thanks Stuart. From my collection of things that I might try someday. Quote Link to post Share on other sites
mikespain835 Posted September 22, 2018 Author Report Share Posted September 22, 2018 Thanks everyone for the input,I will be looking at all these points when I can get back to it next week.I will keep you all informed of progress - again many thanks Quote Link to post Share on other sites
mikespain835 Posted September 26, 2018 Author Report Share Posted September 26, 2018 Hi again right- The tube to the atmospheric pressure side of the control unit is clear Checked for vacuum leaks all good and no leak from control unit diaphragm. checked over fueling lever is fully returning and it has gap between cam and lever. checked metering unit timing-set as per brown book for cp engine,just see the opening at top of No 6 port. Tried adjusting the ignition timing not much change reset the throttle bodies at 1500 revs. Although a very slight improvement it is stil nowhere near right or driveable. what I have noticed is when cold it runs a bit better and as it warms up it gets worse and really smells of fuel from exhaust and plugs are sooted up. I feel that what Mike C says is relevant as there are blue springs fitted. I have been searching for some red springs but to no avail from the usual suppliers, will send an E-mail to malcolm at prestige injection,anyone got any ideas where I could get some,also any more ideas as to anything else that could cause the problem? Quote Link to post Share on other sites
Peter Cobbold Posted September 26, 2018 Report Share Posted September 26, 2018 Did the MU work OK before the engine rebuild or is it an unknown? If the moving-stop balance srping is lacking or weak it will run rich even at correct fuel pressure. Number 46 Quote Link to post Share on other sites
mikespain835 Posted September 26, 2018 Author Report Share Posted September 26, 2018 HI Peter, I'm afraid it is unknown,however the metering unit does look prestine as if it is a recon unit, when I removed the adaptor for No 6 outlet the o ring was supple and no signs of age ,and all the connections are sqeaky clean.All I know is that the engine was reconditioned last year and has been hardly driven since. Quote Link to post Share on other sites
John L Posted September 26, 2018 Report Share Posted September 26, 2018 I'm sure you will have to have the MU recalibrated if you get some red springs, but if you want to be adventurous, take off the black cap on the MU, mark the position of the screws/rings, undo only the largest lower ring, and turn the whole set anticlockwise, perhaps a 1/4 of a turn at a time and restart, but put the black cap back on and this will make sure to hold the vacuum. Screwing anti clockwise will weaken the mixture, clock wise will enrich the mixture. Doing it this way changes all the settings at the same time, if it doesn't make an improvement put it back to where you started, and have the unit calibrated correctly. Have you tried Neil Ferguson for the springs, sometimes he's on here? Quote Link to post Share on other sites
Peter Cobbold Posted September 26, 2018 Report Share Posted September 26, 2018 1 hour ago, mikespain835 said: HI Peter, I'm afraid it is unknown,however the metering unit does look prestine as if it is a recon unit, when I removed the adaptor for No 6 outlet the o ring was supple and no signs of age ,and all the connections are sqeaky clean.All I know is that the engine was reconditioned last year and has been hardly driven since. Hi Mike, I wonder if storage has cused the moving-stop to seize ...rusted with old ethanol fuel in it ? The m-s might be stuck where it slides into the MU housing so you could try spraying WD40 after removing the rectangular plastic cover. Peter Quote Link to post Share on other sites
mikespain835 Posted October 20, 2018 Author Report Share Posted October 20, 2018 Hi again---problem solved. I removed the injectors and put them on a cleaning rig I have made (basically a plastic deposit to a bosch pump and filter through an adjustable letby valve to a return pipe tee'd into feed pipe with pressure gauge) anyway fitted the injectors one by one and 4 out of the 6 had leak by and more like jets of fuel rather than a nice cone. After flushing them through I managed to get them clean and a good conical spray.Refitted them and after bleeding the injectors it ran quite well.After changing the blue springs to silver or plain springs it roared !went for a test drive and great response all through the revs.Job Done! I first thought that the rough running was down to worn throttle spindles,after changing them and changing to ball and socket throttle rods it improved but nowhere near enough.The biggest improvement was cleaning the injectors and the icing on the cake was changing the springs. Thanks to everybody for your input and help ,it does help to discuss these problems as it makes one think of all the variables to cure a problem thanks again-Mike Quote Link to post Share on other sites
astontr6 Posted October 20, 2018 Report Share Posted October 20, 2018 1 hour ago, mikespain835 said: Hi again---problem solved. I removed the injectors and put them on a cleaning rig I have made (basically a plastic deposit to a bosch pump and filter through an adjustable letby valve to a return pipe tee'd into feed pipe with pressure gauge) anyway fitted the injectors one by one and 4 out of the 6 had leak by and more like jets of fuel rather than a nice cone. After flushing them through I managed to get them clean and a good conical spray.Refitted them and after bleeding the injectors it ran quite well.After changing the blue springs to silver or plain springs it roared !went for a test drive and great response all through the revs.Job Done! I first thought that the rough running was down to worn throttle spindles,after changing them and changing to ball and socket throttle rods it improved but nowhere near enough.The biggest improvement was cleaning the injectors and the icing on the cake was changing the springs. Thanks to everybody for your input and help ,it does help to discuss these problems as it makes one think of all the variables to cure a problem thanks again-Mike Hi Mike ! Did you actually find out what was causing the injectors on 4 & 6 not to spray properly? Was it bits of 'O' ring rubber? Bruce. Quote Link to post Share on other sites
mikespain835 Posted October 22, 2018 Author Report Share Posted October 22, 2018 Hi ,it was actually 4 out of the six injectors but no sign of any rubber just gummed up with old fuel Quote Link to post Share on other sites
Mike C Posted October 22, 2018 Report Share Posted October 22, 2018 I used to drain the old fuel out in spring and replace it. This year I just added Stabil for winter and the engine started perfectly after the usual long lay up initial crank to refill the injector lines. Quote Link to post Share on other sites
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