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Strange problem - TR7V8

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Vegas_M
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Strange problem - TR7V8

Postby Vegas_M » 31 Jul 2020 06:53

Hi all,
Been quite a while since I last posted.

I have a 1980 TR7 soft top with a 3.9L-V8 transplant, electronic ignition and a GM 1-wire alternator. Been running fine for about 10-12 years. However....

Recently, she started having problems. She will start and idle fine with choke when cold and for a short while without when warm. Within a few minutes of driving, the turn signals stop flashing and the engine won't idle. If I keep the rev's up, she stays running. If I let her cool down for an hour, sometimes whatever is wrong resets and she is fine again for a short while, but sometimes it doesn't reset. If I disconnect the battery and reconnect, whatever is wrong is reset and the cycle starts again.

Even when the signals won't flash the 4-way flashers work (Yes I know there are separate flasher units), headlights work and will pop up. Fuses all look fine, but I changed all of them to be sure. I'm sure it can't be coil or dissy 'cause that wouldn't affect the signals, would it? I've examined the wiring and short of pulling the dash (again), I can't find and shorts.

All thoughts and suggestions welcome. Help! :oops:
Martin Rothman
BC, Canada

stevie_a
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Re: Strange problem - TR7V8

Postby stevie_a » 31 Jul 2020 07:11

1. if you don't use the turn signals does the fault not happen ?
2. Are you using the standard flasher unit?

If fault only happening if you use the indicators and you are using standard flasher unit, my first go to would change to modern flasher unit, same wires just add an earth.

Just don't understand why this would effect the running but Triumph wiring anything is possible
If it's not broke don't fix it.



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busheytrader
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Re: Strange problem - TR7V8

Postby busheytrader » 31 Jul 2020 11:43

Hi,

Dodgy indicators / turn signals, as per Stevie, changing to a modern flasher unit is a good idea anyway for a consistent rate.

Dodgy idle - are you running a carb or fuel injection? Which electronic ignition are you using? If it's the OPUS type distributor you're lucky it's lasted this long.

Why are these happening together, I'm not aware of anything common between them apart from cleaning up earth / ground connections? On my DHC there's a common earth point below the dash on the passenger side that's needed cleaning several times? Otherwise could just be a coincidence.

Adam
Last edited by busheytrader on 01 Aug 2020 09:21, edited 1 time in total.
Image

TR7 V8 DHC Jaguar Solent Blue. 9.35cr Range Rover V8, Holley 390cfm, JWR Dual Port, 214 Cam, Lumention, Tubular Manifolds, S/S Single Pipe Exh, 3.08 Rear, 200lb Spax & PolyBushes all round, Anti- Dive, Strut-Top Roller Bearings, Capri Vented Discs & Calipers, Braided Hoses, 4 Speed Rear Cylinders, Uprated Master Cylinder & Servo, AT 14" 5 Spokes or Maestro Turbo 15" Alloys, Cruise Lights, S/S Heater Pipes, Replacement Fuel Tank. No Door Stickers. Mine since July 1986, V8 from 1990 courtesy of S&S V8 conversion kit (built not bought) and big brake kit.

Beans
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Re: Strange problem - TR7V8

Postby Beans » 31 Jul 2020 18:26

Sounds like a general bad electrical main connection (= probably corroded earth points)
Image
1976 TR7 FHC (currently being restored ...)
1980 TR7 DHC (my first car, a.k.a. Kermette)
1981 TR7 FHC (Sprint engined a.k.a. 't Kreng)

http://www.tr7beans.blogspot.com/

stevie_a
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Re: Strange problem - TR7V8

Postby stevie_a » 31 Jul 2020 20:45

This is the main earth that Adam is talking about

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If it's not broke don't fix it.



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kstrutt1
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Re: Strange problem - TR7V8

Postby kstrutt1 » 31 Jul 2020 21:51

Mine used to do all sorts of strange things which it turned out was down to where the large spade terminals push into the main battery cable, after several unsucsesfull goes at cleaning / closing them up replacing them with eye terminaĺs permanantly resolved it.

Other thing it did was the nut on the starter solenoid battery cable came loose, on my V8 conversion the alternator main battery cable also connects here, strangely it started fine but alternator charging was all over the place.

Vegas_M
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Re: Strange problem - TR7V8

Postby Vegas_M » 04 Aug 2020 06:18

Well.... My grounds are all nice and clean now. The fuel pump rebuilt. Fuel filter replaced. Wires checked everywhere for shorts - none found. Battery checked - 12.7V. Alternator checked 13.8V at fast idle. She still runs like sh*t.

OK, time to take the Edelbrock 1404 apart for a look see. Damn.................. Both float bowls loaded with slimy gelatin. I guess either I got a bad batch of fuel, or when I put her away last fall, either I didn't add the fuel preservative to the fuel and/or didn't pull the pump fuse and run it till the carb was dry. Anyhow, the carb is now cleaned and re-tuned. I drained the existing fuel (still good for the lawn mower) and refilled with premium. The car is running great again. I'm not sure why it was running good for two months this year, until it started to bung up. I'm going to keep an eye on it though. I had the gas tank professionally sealed when I did the V8 conversion, 15 or so years ago, so it might be the sealant in the gas tank starting to come off as a gel. Not sure how it would get past three fuel filters (Pre & post pump & sight glass filter at carb), but you never know.

Oh, and the signal flasher I replaced. Actually, it was intermittently faulty and had nothing to do with the poor running issue. Just showed up at the same time. Typical :evil:

Thanks for all your suggestions. I guess she just decided I needed to give her some attention. :oops:

M.

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Martin Rothman
BC, Canada

busheytrader
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Re: Strange problem - TR7V8

Postby busheytrader » 04 Aug 2020 12:28

Glad to hear it's sorted.

If I don't run mine for a couple of weeks the fuel usually evaporates from the Holley carbs fuel bowls altogether. I let the electric pump fill them up before starting. I've seen many American engine tuners moan about the volatility of contemporary fuel causing this.

I removed a fuel tank from a Mini Cooper that had stood for 10 years. That had a thick stinky gel at the bottom of it.

Beans
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Re: Strange problem - TR7V8

Postby Beans » 05 Aug 2020 20:31

I never had problems with the modern fuels.
Maybe the additives caused the problems?
Image
1976 TR7 FHC (currently being restored ...)
1980 TR7 DHC (my first car, a.k.a. Kermette)
1981 TR7 FHC (Sprint engined a.k.a. 't Kreng)

http://www.tr7beans.blogspot.com/

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