Visit our Twitter feed for more great content
TRExp

TR7 & TR8 Forum

Cold start injector not working - how to fix?

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

Carb-Dave Avatar
Carb-Dave Dave Mundt
Cedar Falls, IA, USA   USA
I'm curious about my cold start injector. Pulled it out and cranked cold engine over. No spray. Checked voltage on harness connector --> ~8.5 volts while cranking. ~4 ohms resistance across the terminals. Fiddled with connector to ensure proper engagement --> still not working. Examined injector - it appears to be full of varnish from old fuel. If plugged, what would be the best homemade method to unplug it? I'll assume that all 8 of the main injectors should also be checked at this point?

This is what my fuel looks like...pumped out of the cold start injector line confused smiley

Carb-Dave (now EFI-Dave)

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

Attachments:
bad fuel.jpeg    39.2 KB
bad fuel.jpeg

darrellwalker Darrell Walker
Vancouver, WA, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
I sent mine out with the rest of my injectors when I had them cleaned, but for a home remedy, I would start with spray carb cleaner. You can also use a 9v battery to pulse the injector once it starts to free up.



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

Carb-Dave Avatar
Carb-Dave Dave Mundt
Cedar Falls, IA, USA   USA
I like the 9v battery idea. But do you think it is enough current to pulse it though?

Carb-Dave (now EFI-Dave)

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
darrellwalker Darrell Walker
Vancouver, WA, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
In reply to # 1593454 by Carb-Dave I like the 9v battery idea. But do you think it is enough current to pulse it though?

Carb-Dave (now EFI-Dave)

It does for the regular injectors. Not sure about the cold start injector.



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

Carb-Dave Avatar
Carb-Dave Dave Mundt
Cedar Falls, IA, USA   USA
In reply to # 1593445 by darrellwalker I sent mine out with the rest of my injectors when I had them cleaned, but for a home remedy, I would start with spray carb cleaner. You can also use a 9v battery to pulse the injector once it starts to free up.

It actually worked and started clicking away with two 9V batteries (2X 500mA) in parallel = ~1 Amp. But still did not pump anything when hooked up to the fuel line..that tells me it might still have an internal blockage. Trying to figure out a way to supply a pressurized solvent and use the 9V batteries until it cleans out.

Carb-Dave (now EFI-Dave)

navydiver Rob Cornick
san diego, CA, USA   USA
1975 Triumph TR7 "The Pumpkin"
1977 Triumph TR7
1978 Triumph TR8
1980 Triumph TR7 "The Plum"    & more
Dave, i bought an injector cleaner of eBay it a plastic manifold that fits into the rubber hose of the injector and adapts to take the nozzle of a can of injector cleaner the other end, to pressurise it, I then used my injector tester to pulse the injector until it worked correctly again. Once its flowing the modern ethanol fuel should take care of the rest. The other way to do it is to connect the injector directly to a fuel pump and run cleaner or acetone through it. the injector needs to see a pressure to work the solenoid only pulls back the needle inside the injector to relieve the pressure. There are a number of other bosch cold start injectors out there which are considerably cheaper than that listed for the TR8 but the fuel inlet is oriented slightly differently not actually a problem unless you're doing a concours restoration.
cheers
Rob



1975 TR7 FHC Ca Spec ACL 4spd
1976 TR7 FHC Ca Spec 4 spd (Temp add)
1977 TR7 FHC ACW 5Spd
1978 TR8 DHC ACT FI development car 5 Spd
1980 TR7 DHC FI Spider 5spd
1980 TR7 DHC FI Spider 5Spd
1980 TR7 DHC FI 5spd
1980 TR7 DHC FI 5 spd
1981 TR7 DHC FI 5 spd

Carb-Dave Avatar
Carb-Dave Dave Mundt
Cedar Falls, IA, USA   USA
In reply to # 1593580 by navydiver the injector needs to see a pressure to work the solenoid only pulls back the needle inside the injector to relieve the pressure.
mmm..something else that might be happening - I might not be getting enough fuel pressure to flow anything out of the injector. This might be part of the problem during the cold starting routine. What fuel line pressure should I be seeing and when would I be seeing it? During ignition 'on' or during cranking?
Thanks,

Carb-Dave (now EFI-Dave)

darrellwalker Darrell Walker
Vancouver, WA, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
In reply to # 1593596 by Carb-Dave
mmm..something else that might be happening - I might not be getting enough fuel pressure to flow anything out of the injector. This might be part of the problem during the cold starting routine. What fuel line pressure should I be seeing and when would I be seeing it? During ignition 'on' or during cranking?
Thanks,

Carb-Dave (now EFI-Dave)

I think the pressure should be around 38 PSI, or maybe 42, less what manifold vacuum. The fuel pump won't switch on until the flapper detect air flow, so you won't see pressure just with the ignition on. You will have to crank the engine. Or press the flap in the AFM to test the pump.



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

navydiver Rob Cornick
san diego, CA, USA   USA
1975 Triumph TR7 "The Pumpkin"
1977 Triumph TR7
1978 Triumph TR8
1980 Triumph TR7 "The Plum"    & more
mines happy at anything above 35psi. You'll only see it with the pump running and it should be continuous though cranking and running. if your not seeing that pressure it could be indicative that the pick up or supply line are equally as blocked with varnish as the injector, common if its been sitting for a long time. Also the fuel regulator on the intake manifold could be shot and not providing sufficient back pressure. I normally check fuel pressure at the take off for the cold start injector, disconnect it at the rail and put the gauge on there and see what you're getting. The fi tank i pulled a few weeks back is factory new on the outside but has a hard layer of varnish on the bottom, the strainer was completed clogged and the pickup was solid, so what looked like a great system was effectively useless. I've learned with the FI cars the first place you start is at the tank. even if it looks clean on the inside the use of modern ethanol heavy fuels will dissolve any varnish thats there and soon clog the filter. I've saved 2 pumps that guys had thrown out by cleaning all the varnish out, the bosch pumps are cooled by the gas so are full all the time when they stand for a long time the gas evaporates just leaving the deposits to clog up and seize the insides. I have a rig using a good pump and 2 filters in series that i use with a gallon of injector cleaner on recirc to flush the blocked pump after leaving it sit in a pot of acetone for a few days. bumping the blocked pump with an on/off switch with a direct 12v supply press it up and once it's running its just a case of leaving it run until it starts no problem. My 8 has there prototype lucas FI system, which i think is slightly different from the production setup in that i get power to the pump when the ignition is on the only thing that stops it is the impact switch in the engine bay.
good luck.
cheers
Rob



1975 TR7 FHC Ca Spec ACL 4spd
1976 TR7 FHC Ca Spec 4 spd (Temp add)
1977 TR7 FHC ACW 5Spd
1978 TR8 DHC ACT FI development car 5 Spd
1980 TR7 DHC FI Spider 5spd
1980 TR7 DHC FI Spider 5Spd
1980 TR7 DHC FI 5spd
1980 TR7 DHC FI 5 spd
1981 TR7 DHC FI 5 spd

Rover827 Avatar
Rover827 Rich Truett
Berkley, MI, USA   USA
1979 Triumph TR7 "Haggis"
1981 Triumph TR8
1982 Triumph TR8
I don't know that these can be fixed.

I brought mine to Kinsler fuel injection in Detroit, one of the nation's top shops for fuel injection work.
https://kinsler.com/Shop/
They couldn't fix it.
If they can't fix it, likely it can't be fixed. Unlike fuel injectors, there are no replacement parts available for it.

Replacements are all over eBay, but they are not cheap.

Carb-Dave Avatar
Carb-Dave Dave Mundt
Cedar Falls, IA, USA   USA
So...what is the best method for draining the tank - given that I can only lift the car off the floor by 18 inches? If the gas looks this bad (see top) and smells even worse, there is no point messing around with the cold start valve..I'm convinced the whole system will need to be drained and flushed.

Carb-Dave (now EFI-Dave)

navydiver Rob Cornick
san diego, CA, USA   USA
1975 Triumph TR7 "The Pumpkin"
1977 Triumph TR7
1978 Triumph TR8
1980 Triumph TR7 "The Plum"    & more
In fairness it’s not worth their while to fix them while they are available. I do them over the period of a week and don’t have an anxious customer breathing down my neck



1975 TR7 FHC Ca Spec ACL 4spd
1976 TR7 FHC Ca Spec 4 spd (Temp add)
1977 TR7 FHC ACW 5Spd
1978 TR8 DHC ACT FI development car 5 Spd
1980 TR7 DHC FI Spider 5spd
1980 TR7 DHC FI Spider 5Spd
1980 TR7 DHC FI 5spd
1980 TR7 DHC FI 5 spd
1981 TR7 DHC FI 5 spd

navydiver Rob Cornick
san diego, CA, USA   USA
1975 Triumph TR7 "The Pumpkin"
1977 Triumph TR7
1978 Triumph TR8
1980 Triumph TR7 "The Plum"    & more
Dave, if you are truly FI Dave, and your pump runs you have the perfect solution, undo the connector in the engine bay to the fuel rail, attach another length of hose and start the pump up by hot wiring the pump with a 12v battery and let the pump suck it dry for you. That way you will flush the pipe work and the pump.
Cheers
Rob



1975 TR7 FHC Ca Spec ACL 4spd
1976 TR7 FHC Ca Spec 4 spd (Temp add)
1977 TR7 FHC ACW 5Spd
1978 TR8 DHC ACT FI development car 5 Spd
1980 TR7 DHC FI Spider 5spd
1980 TR7 DHC FI Spider 5Spd
1980 TR7 DHC FI 5spd
1980 TR7 DHC FI 5 spd
1981 TR7 DHC FI 5 spd

navydiver Rob Cornick
san diego, CA, USA   USA
1975 Triumph TR7 "The Pumpkin"
1977 Triumph TR7
1978 Triumph TR8
1980 Triumph TR7 "The Plum"    & more
Here’s the fuel pickup I took out of the FI tank



1975 TR7 FHC Ca Spec ACL 4spd
1976 TR7 FHC Ca Spec 4 spd (Temp add)
1977 TR7 FHC ACW 5Spd
1978 TR8 DHC ACT FI development car 5 Spd
1980 TR7 DHC FI Spider 5spd
1980 TR7 DHC FI Spider 5Spd
1980 TR7 DHC FI 5spd
1980 TR7 DHC FI 5 spd
1981 TR7 DHC FI 5 spd


Attachments:
208B8225-3EAD-4183-9689-49A3A6493C20.jpeg    35.4 KB
208B8225-3EAD-4183-9689-49A3A6493C20.jpeg

Rover827 Avatar
Rover827 Rich Truett
Berkley, MI, USA   USA
1979 Triumph TR7 "Haggis"
1981 Triumph TR8
1982 Triumph TR8
That plastic filter doesn't show up in anyone's part book, but to replace it, you just order one from a early 1980s Jaguar XJ6.

I found this out by sorting part catalogs and matching it up with the TR8 part.

https://www.ebay.com/itm/JAGUAR-DAIMLER-IN-TANK-FUEL-FILTER-KIT-XJ6-SER-1-2-CBC5649-C26310-C26311/121223438958?hash=item1c397ae26e:g:pBUAAOxy43FRZZJD:rk:6:pf:0

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions




Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster