NSW Corvettes
General Discussion Area => Corvette Related Chat => Topic started by: jimandemma on March 19, 2017, 05:51:31 PM
-
Hi guys and gals,
seem to have a problem with the engine cutting out at idle after about around 2o seconds of running and when driven, intermittent coffing and spluttering then stalls when you come to a stop. I originally thought it may be a blocked fuel filter, but after inspection, appears fine. Fuel pump all good also. When it does cut out at idle, it's instant, so doesn't appear to be fuel related. Car has been running like a clock with no evidence of a problem before this started. Could this be an electrical problem, maybe the distributor? I can't see any arcing around the cap or from any of the plug leads. Any help or advice would be greatly appreciated.
Cheers, Jim
-
Hot wire the engine to start , that will by pass all the electrics then you will know where to start to look.
isolate the problem to engine bay .
Bfit
-
not sure how to hot wire to start BFIT
-
When you say "checked the fuel filter" - on my 78 350 Quadrjet there is a small inline filter on/in the carby body where the fuel pipe enters. You need to remove fuel line (use two spanners) from memory it is paper, I assume your 75 would be the same, maybe "bfit or sirfixalot" could comment. Also check "bowl" for water. Not unusual for tanks to fill with water, fuel floats on top. Sorry if I'm preaching to the converted, sometimes little items can be over looked. Good luck.
-
When you say points, I assume it is a basic points systm (no electronics) check points, if in doubt I allways change leads, cap, CAPACITOR and points. That leaves nothing to chance and will ensure long life. Oh! Nearly forgot - the Ole COIL v8's can be notorious for crossfire, start the car in the pitch dark and look for cross fire at the plug, leads and cap and coil. Be aware you can (on some cars) see the plugs fireing down in the cylinder.
-
Vettech, took fuel line off this morning from carb (Holley 650) but no fuel filter there. Re-assembled, started motor, all good now. Not sure what the hell is going on, but running fine now.
Jim
-
Welcome to the mysterious world of the Corvette.
-
Ummmmmm. That is the worse fix, did you pump any fuel out of the line when it was off?. I hate intermittent faults which clear with no know cause being found.
Hate to say it - but it may come back. Sorry but I'll look forward to hearing about this again here on the forum. Ever the pessimiss. Happy cruising.
-
Mmm vapour lock on a cold day unusual.
Did u take the fitting out of the carby to look for the filter
-
Pumped fuel out of the line, no problem there. Found no filter at the carb when the fitting was off. Haven't driven the car yet, but is idling fine now without cutting out and back to easy starts. No idea what it was, but went away as quickly as it came.
-
Maybe some blockage which came out with the fuel. Would not need to be very big. Well I hope that is that. Happy Cruising.
I know the Quaddy has the filter, not sure on the Holley !?!?!?!?....
-
Maybe some blockage which came out with the fuel. Would not need to be very big. Well I hope that is that. Happy Cruising.
I know the Quaddy has the filter, not sure on the Holley !?!?!?!?....
every Holley I have word on has a sintered bronze filter.
something like this
https://eb9239d2b3c1bda1d53d-6b4eb896915f5ae433f1eefb2b932a4d.ssl.cf1.rackcdn.com/230107.jpg
It's in there to hopefully keep the crap out of the needle valve. But some people do leave them out
with the idea it will flow more fuel.
questionable at best that idea. When one want to flow more fuel its best to go up a size in needle and seat.
Time will tell if the problem will crop it head up again
Bfit
-
Well, it did crop up again today. I think I know the problem. The last week I have been jacking one side up (LHS) to check the brakes, this is when the cutting out started when back on the ground. When I checked the fuel line on the carb the other day, the caar had been on the ground for a day or so and started and ran fine. Yesterday I jacked the car up one side at a time to put it on jack stands to bleed the brakes. Started to cut out again, so I'm now thinking the float in the carb is sticking at an angle when 1 side of the car is jacked high enough causing it to cut out after 15 to 20 seconds. Thoughts?
-
Which type of bowl does the carby have , side pivot or centre pivot.
Any thing is possible
Bfit
-
Put a gauge on the fuel line. Had the same symptoms a few years back. Turned out to be a dicky valve in the pump. Should be between 2 and 5 psi.
-
Todays update. Fitted a 7PSI Carter electric pump and new filter, Holley fuel pressure regulator and fuel pressure gauge at the Carb. STILL cuts out after about 20 - 30 seconds with trouble starting again. I have fuel pressure at the Carb of 6 PSI but engine sounds like it is slightly missing. By chance, checked the battery and was only 10.7 volts. I currently have the battery on charge to see if it holds voltage, could this be the problem? If not, I have new leads and a complete new HEI dizzy to replace the current factory HEI dizzy.
-
With a bad battery, can too low of a voltage while running, load the alternator enough to cause a stall?
Jim
-
It you have more than 10.5 volts while cranking it should run.
What's your vacuum like
Is this an automatic.
Bfit
-
Hei ignition is not a lover of low voltage 10.5 v is way too low i'd investigate why it is that low car will run on alternator without battery. Voltage when running should be about 13 volts
-
Car is automatic.
Not sure on vacuum yet
Haven't checked alternator output yet as car doesn't run long enough.
I'll check battery in the morning and go from there whether it is stuffed. If not, alternator next I suppose.
-
Battery can't be too bad if it keeps starting car
-
Get a can of Aerostart (you can also use wd40, hair spray, undie arm spray as last resort) start her up, when she faulters, give a light spray into intake, if she picks up and runs on the spray, and then faulters when you stop the spray - its a fuel problem. If it faulters on spray then it could be electrical.
If you are running original points (kettering sytem) check gaps and points condition (no pits or holes, splats).
Check capacitor, no cap = no ignition. Best way to check is - get a new one, I dont know many in the club who would have a metre to check caps.
when spraying etc, keep all your bits away from intake esp face, eyes etc
If its starting, then battery will be good enough, for the alternator to stall a motor it would require a near dead short, and "the smoke" would be a good indicator.
I love a good suduko.
( I once had an English car, the cap was screwed onto the moving base plate in the dizzy, came loose, & as it rattled around the ignition splatted on and off. I could not find it as I did not appreciate the importance of the cap, I end up making up & fitting CDI and only then did I see the loose cap.)
-
OK, battery was fine but put a new one in anyway - still the same. Alternator charging fine
Put on new leads - still the same. Pulled a lead, plugged in a spark plug and have spark though not bright.
Put on a new HEI distributor cap with coil and rotor from new dizzy - ran great for about 5 seconds then died. Refused to start, so pulled a lead, plugged in a spark plug and have no spark??
Starting to run out of options. Can't find a capacitor near the dizzy.
Only thing left is this relay or whatever it is in the picture that has the power wire from the distributor going to it as well as other wires.
-
Ok, memory not good so I'll go out and awaked the chickens and mice and get my Hei dizzy out and refresh - at least now you know its Electrical. Back soon.
-
Attached to the heater box bottom of pic
-
Checked the inline fuse which is fine
-
OK, battery was fine but put a new one in anyway - still the same. Alternator charging fine
Put on new leads - still the same. Pulled a lead, plugged in a spark plug and have spark though not bright.
Put on a new HEI distributor cap with coil and rotor from new dizzy - ran great for about 5 seconds then died. Refused to start, so pulled a lead, plugged in a spark plug and have no spark??
Starting to run out of options. Can't find a capacitor near the dizzy.
Only thing left is this relay or whatever it is in the picture that has the power wire from the distributor going to it as well as other wires.
That looks like the horn relay
Bfit
-
Attached to the heater box bottom of pic
HORN RELAY on the other side near booster
Bfit
-
Checked the inline fuse which is fine
There is an inline fusable link near the starter.
As I rembember it it comes into play as you let go of the key in the start procedure
Worth looking at
Hot wire the engine and see if it runs
Bfit
-
Ok I'd forgotten how heavy these are. It's got a Accel HEI Cap with Super Coil and leads, the coil provides the HT directly via cap and leads to the plugs. On the outside there is a 5pin connector, one is power, three are from a connector wired into the base. The three wires come from the Electronic Module screwed into the base, it has another connector which wires to the Hall Effect Module (under rotor) which is the electronic equivalent of the old points. On the base plate should be a Capacitor.
The following could be suspect.
1. Capacitor.
2. Hall effect pick up.
3. Ignition module
4. Main HT Coil
Also the 12v supply could be intermittent. I cant think what the fifth (5) wire is - maybe Tacho ???
Get a metre to see if the 12v to the dizzy fails. We need to isolate each bit untill we get it.
-
That relay maybe for the fan on "MAX" speed.
-
How bout replacing the dizzy, have a new one here considering all these bits are on the inside.
Never replaced one before, can I just remove the old one noting rotor direction and put in the new one in the same direction?
-
Before, I'd get it going, checking the 12v when it faulters, else you may go to the trouble only for the new one to fail as well due to faulty supply.
-
OK, will check the 12V supply tomorrow morning. If it is, where from there?
-
Well if its the 12v supply, it becomes a wire and or module chase. My knowledge is 78 up, not sure on 75 if they have relay, anti theft or similar things in the circuit.
-
no worries, we'll find out first and go from there. Bloody frustrating!!
-
Have power to distributor and started this morning but again, cuts out.
Noticed dirty fuel pooling in the manifold this morning.
-
Picture 2
-
picture 3
-
Suspect leak on RHS of carb
-
Oily carb adjustment screw LHS
-
The relay in question is high speed fan relay for ac. Dissy should have a pink wire which has 12v in run & start position & also white wire which is output from dissy to tacho. These should be two individual plugs into dissy for these wires. There should be no wire going to relay from dissy. Remove the pink wire & run a wire with spade connector from dissy terminal to battery + on alternator then try to start engine
-
yeah, was wrong on relay. Will try the wire to alternator in the morning.
-
All fixed. Ended up being the module in the distributor. Thanks guys.
Jim
-
I hope you bought a half decent one I put a chinese one in my 79 gave up on me going down the coast, was doing 100k on freeway then nothing. Did you use heat sink paste under module?
-
Yes Sirfixalot, good advise, you need that heat sink paste.
-
Bought a Proflow distributor from VPW so nicked all the bits off that. Yes, plenty of heat sink paste under the module.
-
You are troubling me now. Why buy and xfer ALL parts if you had the culpit module.
Why not swap over complete Dizzies or just the module.
A new complete dizzy is NEW, has no bearing (bush) wear, or pinion wear etc good for twenty years.
Anyway - happy cruising hope to see you around.
-
Changing out a distributer , can be a bit of a chalange for someone who has not done one before.
Bfit
-
Yes - but help is only a call away.
-
Was going to install the new dizzy, but due to lack of experience, wanted it to be the last thing I'd do. Honestly thought it was the fuel pump and changed that, then maybe the leads or coil so changed them, then was told by an associate he had the same problem with the dizzy module so changed that and all fixed. Will eventually change the distributor when I get a hand down the track, but at least the car is back to normal and driveable now.
-
I'm at Clarence Town, I can probably help with that if you like, just send us a pm.