Hestitency (sp?) under load.
Discussion
Apart from me pump not running the other day, which may be the culprit, I get the odd hesitant running. Almost like lack of fuel. Happens at various speeds. Sometimes after a jolt from the road but only for a second max probably a fraction or so. That led me to checking connections. Sure wedg1e has mentioned checking the ECU for dry joints? Anyhow, checked with a magnifying glass and no dry joint either side of the board that I can see. Fuel pump terminal lucar's loose and tightened up. Still doing it. There was a chattering fuel relay and that has been replaced with the connections checked but still doing it, not sure how the relay is activated but there is a dent in the body. Fuse board checked and appear to be OK. New fuel filter should be here monday to try that for a partial blockage. Coil connections checked as have leads and earths.
So, anything I have missed anything I can check and is straight forward to do?
So, anything I have missed anything I can check and is straight forward to do?
rev-erend said:
Jeff - why not check the basics like fuel pressure and fuel stall tests before getting into dry joints !
You seem to joining the 'every problem must be complicated' bandwaggon ..
It could just be a worn out pump.
Sure its not a complicated problem. Everything I have done is easy and quick to try/check etc so far. Dry joints are bread and butter fault finding for me. The filter has been on for a while now so probably not a bad idea anyway. But fuel pressure, now that is getting outside my tool box. Where can I get a pressure gauge and what is the stall test?You seem to joining the 'every problem must be complicated' bandwaggon ..
It could just be a worn out pump.
Edited by rev-erend on Friday 29th June 14:38
Ta.
PS, pump is the last thing to get changed at the price if I can help it.
Take two wires out to the fuel pump and connect up a small bulb across the pump so you can see when it is running. Since you probably won't be able to connect the original wires and the additional ones to the same terminals on the pump that leaves a point of failure at the pump where the bulb may show there's power on the wire but it isn't reaching the pump. You can address that by making sure that the connections at the pump itself are all sound.
This test light will enable to to prove or disprove your theory that the pump is dropping out for some reason. There are lots of possible causes for problems in the pump supply, and this test will give you a chance to rule them out at a stroke.
This test light will enable to to prove or disprove your theory that the pump is dropping out for some reason. There are lots of possible causes for problems in the pump supply, and this test will give you a chance to rule them out at a stroke.
Try a new / different HT lead from coil to distributor. I had a similar problem once and it was just that. Discovered it after changing just about everything else at great time, expense and frustration. The problem only showed up when driving with a few revs on, and bumps / jolts made it worse. I thought I had previously eliminated any lead problem as I had sparks at the plugs but it appeared it was only breaking down under load.
GreenV8S said:
Take two wires out to the fuel pump and connect up a small bulb across the pump so you can see when it is running. Since you probably won't be able to connect the original wires and the additional ones to the same terminals on the pump that leaves a point of failure at the pump where the bulb may show there's power on the wire but it isn't reaching the pump. You can address that by making sure that the connections at the pump itself are all sound.
This test light will enable to to prove or disprove your theory that the pump is dropping out for some reason. There are lots of possible causes for problems in the pump supply, and this test will give you a chance to rule them out at a stroke.
Ah.Didn't think of that. Fit it, run up the local bumpy road and see if the light out tallies with the hesitancy.This test light will enable to to prove or disprove your theory that the pump is dropping out for some reason. There are lots of possible causes for problems in the pump supply, and this test will give you a chance to rule them out at a stroke.
Thank, looks like a Sunday job now.
GreenV8S said:
Take two wires out to the fuel pump and connect up a small bulb across the pump
Even simpler - get an old blown fuse, solder a couple of wires to it and stick it in the fuel pump fuse socket, then connect an ammeter to it.When you get your problem, check the ammeter for the usual reading.
Just a quickie (that's all I can manage these days 
)... just because yer solder joints LOOK sound, doesn't mean they are. ISTR it was Dexy's ECU I had under the magnifier, could find no fault but an ECU swap proved his was at fault.
Resoldered both boards from end to end and the problem resolved itself.
)... just because yer solder joints LOOK sound, doesn't mean they are. ISTR it was Dexy's ECU I had under the magnifier, could find no fault but an ECU swap proved his was at fault.Resoldered both boards from end to end and the problem resolved itself.
Wedg1e said:
Just a quickie (that's all I can manage these days )... just because yer solder joints LOOK sound, doesn't mean they are. ISTR it was Dexy's ECU I had under the magnifier, could find no fault but an ECU swap proved his was at fault.
Resoldered both boards from end to end and the problem resolved itself.
I have come across joints were the hole is filled with solder but the shape of the fill and the way it has formed around the pin indicates that it has not bonded to the pin of the component?)... just because yer solder joints LOOK sound, doesn't mean they are. ISTR it was Dexy's ECU I had under the magnifier, could find no fault but an ECU swap proved his was at fault.Resoldered both boards from end to end and the problem resolved itself.
Right, try king lead although quite new (I know, easy and no harm in trying). Bulb across the pump and see what happens. Take it from there. I will try them one at a time.
Adam, nice idea for the fuse but at the pump I think that pretty much try's everything to the terminals? It is also quite quick and not long enough to stop and check. I would have to find me needle multimeter to see s deflection. Never liked trying to spot these on a digital. I will keep it in mind though. Thanks.
Edited to add.... bother. Piggy back lucars have vanished and I only have a gas soldering iron and am not lighting that up under the tanks so its off to the usual suspects to get some bits. Also have an idea, wire in a bulb holder to somewhere convenient under the dash and if there is a suspect problem in future, just chuck a bulb in to try it.
Adam, nice idea for the fuse but at the pump I think that pretty much try's everything to the terminals? It is also quite quick and not long enough to stop and check. I would have to find me needle multimeter to see s deflection. Never liked trying to spot these on a digital. I will keep it in mind though. Thanks.
Edited to add.... bother. Piggy back lucars have vanished and I only have a gas soldering iron and am not lighting that up under the tanks so its off to the usual suspects to get some bits. Also have an idea, wire in a bulb holder to somewhere convenient under the dash and if there is a suspect problem in future, just chuck a bulb in to try it.
Edited by jmorgan on Sunday 1st July 14:31
Right. Problem gone. Chattering relay or the king lead. I need to put one of them back to prove it. Sods law though its gone away to sneak back when I least expect it.
Anyhow, work went mad and I ended up not chasing the leads to the pump. Still a handy thing to have I think but seeing as its petrol I think my gas iron is out of the question to double up a lamp wire (rather than use piggy back lucars). So, what is the flash point of petrol vapor? I am assuming its safe to solder with an electric iron under the tank? Might be able to pull them back into the car.
Anyhow, work went mad and I ended up not chasing the leads to the pump. Still a handy thing to have I think but seeing as its petrol I think my gas iron is out of the question to double up a lamp wire (rather than use piggy back lucars). So, what is the flash point of petrol vapor? I am assuming its safe to solder with an electric iron under the tank? Might be able to pull them back into the car.
jmorgan said:
So, what is the flash point of petrol vapor? I am assuming its safe to solder with an electric iron under the tank? Might be able to pull them back into the car.
Petrol is actually pretty safe stuff to work around as long as you don't have any sparks or incandescent heat sources. Liquid petrol boils below its flash point so if you pour petrol on a hot exhaust etc it will simply boil off. Oil and hydraulic fluids are far more dangerous from that point of view since they will spontaneously ignite on a hot surface. Having said all that, the petrol should be *inside* the tank and if you have petrol vapour hanging around the outside there's something very wrong!Gassing Station | Wedges | Top of Page | What's New | My Stuff