3.5 v8 dies after 10 mins

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
Any news did su guy help...
Good morning all. Right SU carb man been. A little bit rich so retuned it so now runs clean more than enough for modern day emissions not that I have to worry about that, he said he had never heard such a quiet sweet rover v8 however nothing to do with cutting out god dam it!
So not spark
Not fuel starvation
With the exhaust wrap and now made heat shields certainly not excess heat.
The only thing I can think of is my home made loom I’m not sure if it makes any difference but I have got relays for fuel pump or ignition they are both direct feed?
I’m thinking unplug everything bar what the engine needs to run and see what happens and other suggestions always appreciated.
Can anyone confirm what I can get away with ....just feed to coil and feed to starter motor?
 
1B00763C-5086-4BAF-A0DA-5E1594D23B9A.jpeg
2259D439-AEEF-4603-9199-2362E4B20012.jpeg
Must say love the embossed aluminum
 
You will need a supply to fuel pump too. And if your not charging I am not sure how long the battery would last, quite a while if fully charged I would think.

Have you checked all the vacuum lines too,

Those heat shields look nice:)

J
 
@kermit_rr

Think you missed what he wants to do, basically hot wire it with minimum wires to eliminate his loom.

Although we all seem to think it’s not electrical it’s something else eliminated.

I would also be tempted to try a hotter grade of plug, as from latest description of problem it was underload and fully warmed up.

J
 
you're right yea. i was reading up the page and got confused haha
it would be fairly simple to do some diags at the point it stops.. a test light on the fuel pump and the low side of the coil will say whether they are still getting current, then pull a plug and crank to check HT side
I can't remember, but have we tried easy start or similar down the carb to see if it starts/coughs etc on that?
 
Agreed, but it seems it starts straight back up again.

All the problems seem to have started after the initial run in period, then started to give it some load/beans and now problems.

J
 
Agreed, but it seems it starts straight back up again.

All the problems seem to have started after the initial run in period, then started to give it some load/beans and now problems.

J
Yes since then for sure and yes I wanted to have the least amount of wires to run the engine to bypass the loom just to eliminate that side as I made the loom. I need to get together the list so....fuel pump...starter...coil...and run the alt to the battery if I did this completely separately and it solved it then I would set about replacing the loom as I’ve tested plugs etc but hadn’t done a power test whilst running on anything to see if the electrical signal stops so that would be worth doing. Can I also add at this point my charge light didn’t come on two days before the carb man was due to arrive so checked the voltage of alt and it was only 11.43 volts and this was the second new alt (from eBay) so I ordered one from Rimmerbro’s hoping that the quality was better (eBay ones both were hard to connect the plug onto the alt connection tabs) fitted the new alt from Rimmerbro’s connection on the back was much better and solved the issue. Next morning yesterday when carb man arrived the alt wasn’t charging again and then in the afternoon when checking under bonnet temps after heat shield install alt was charging again? Does this gave a connection it can’t be all duff alternators hence my thoughts on a dodgy loom.
 
You will need a supply to fuel pump too. And if your not charging I am not sure how long the battery would last, quite a while if fully charged I would think.

Have you checked all the vacuum lines too,

Those heat shields look nice:)

J
Yes made a massive difference to the heat coming off the headman headers and protect the brakes lines from heating up to I would recommend that stuff great to work with
 
my mantra is, if in doubt check the earth cables!!
I had to do this the other day and ran a jump lead as a temporary earth strap to test resolution
Yes next thing on the list then. Today I ran a separate feed to the fuel pump and coil and starter, ok no relays (reading up on relays its more of a safety good practice thing to keep high amps away from switches wet fingers etc probably more of a good idea as it’s a Landy lol) and yes you’ve guessed it still cut out and if anything I would say it run for even shorter periods.
I did try to avoid earthing the chassis and body with the thinking it would help avoid the dreaded electrolytic corrosion and no it didn’t matter how many earthing points I made when cracking the engine over that high draw would track down the weakest earring point so I gave up trying to reinvent the wheel. I then fitted earth strap to chassis to engine and earth hd cable from the Gearbox to the battery I know the connections are good (yes definitely going to recheck the connections) should I add anymore earthing?
Oh and I forgot to add when running all was ok charge light out and charging battery then on restart up the battery was not charging again checking to signal wire on back of alternator no power main two feeding back to battery all ok.
On my new electronic dizzy the coil is not an oil type just made to look like it I checked the positive side and of yes live, put the lamp on the negative side and that was live too is that correct whilst running?
 
Last edited:
Yes coil on other side is the pulse signal. Checked the earths all tight and fuel pump has feed as the pump never stops throughout the cutting out time, being a facet pump you can hear it. I will try a big jump lead from the battery to earth it and some tomorrow.
 
Well strange day I’ve still got the necessary bits hard wired. Connected a hugh jump lead from batt to Gearbox and then started her. Hard to start as cutting out quite quickly, also I tried quick start in the carbs made it die down then pick up. Then I waited for it to cut out to spray into the two carbs when it dies and it made no difference. Switched off and unplugged the jump lead, I then added a clear filter to watch what the fuel was doing on cut out, then restarted waited for it to die which it didn’t so went for a run. The first thing I noticed is it lacked power as the rev’s climbed towards 3.5-4K and a little spluttering so I kept the revs down to 2-3k got about 1/4 mile started to die pulled over checked fuel yes still in the filter restarted straight away got home driving 2k rpm all ok just weak under load.
Turned off restarted without cutting out switched off and left it alone till tonight started no issues, no cutting out took it to temp switched off. Half cooled down restarted no issues so just went up the road still iffy under load so came back left running on drive didn’t die? So the only thing I’m doing tomorrow is a new bulb and holder for the charge light as I think it’s iffy as didn’t charge just now but as I was driving it kicked in other than that I’m back to a few months ago, running but crap under load and then cutting out after a short trip
7B85D443-01CF-40C5-A36D-3F9569BBE2D7.jpeg
 
@kermit_rr

Think you missed what he wants to do, basically hot wire it with minimum wires to eliminate his loom.

Although we all seem to think it’s not electrical it’s something else eliminated.

I would also be tempted to try a hotter grade of plug, as from latest description of problem it was underload and fully warmed up.

J
I will order some and see how I get on
Cheers
 
You seem to have done everything you can yourself and double checked it to no avail...if it was me I would consider dropping it off at a garage and get them to check it out...I'm not questioning your ability just sometimes a fresh pair of eyes makes all the difference.

Rob
 
Need to read all that in the daylight :eek:
Sounds like you have done a bunch of testing and there maybe something in there.

A fresh pair of eyes may help as @Shippers suggested do you have a mate/friendly mech? Is there anybody with a V8 near you on LZ? Got to be.

I really can’t see what we are missing:mad:.

Is the filter on return or feed?

Something is breaking down under load, to me that is spark plugs and work back. Or coil and work other way.

Or a big vac leak under load? Thoughts?

Don’t give up:)

J
 
Back
Top