Loud clunk on start up
04-17-2019, 10:25 AM
#47
Not recently. It runs great once started. I'm sensing fuel issues inducing backfires is the right track. I'll try to pull the fpr vac line but of course I'll be terrified to start it because there's a good chance it will grendade the starter again. Can't get a core on a starter that's in 4 pieces! I suppose if it's all dried out it should start at least once with confidence, then check fuel. Maybe this happened because I was trying to start it up after the winter and it was slow to get going which made fuel leak through much worse then normal; grenading starter. I will try to see the condition of fuel in intake.
04-17-2019, 01:03 PM
#48
Fuel pressure Damper missing?
I say leaky injector because we also had hot restart issues last fall before putting the car up for winter. It would fire up nice stone cold but the rest of the day restarts required far more cranking then it should, so I thought maybe an injector was leaking down causing flooding/richness that took the car a bit to over come on restarts, but this residual fuel would dissipate overnight. I did the injector test last year and did NOT see anything amiss. Now you mention the FPD and FPR. We replaced the FPR early in the game but the dampener was bad and we bypassed it (as is fairly common I found out). So it's been running without one for quite a while. I'll look into testing the regulator's vac line for fuel and possibly restoring the dampener (but they are stupid pricey).
I'm not sure this is related to the starter kickback and subsequent destruction though.
If the starter is generating an electric field that triggers the sensor and tries to fire the car "early" (and "backwards") this kicks against the starter which is still trying to spin the engine correctly, you get violence and mahyem; busted starters. This makes sense to me but using the right bell housing, correct starter, good grounds, shielded sensors "should" elimnate that UNLESS extra fuel hanging out allows the "backfire" where as without this fuel it would not backfire so readily.
If this makes sense I will look hard at fuel leaking in somewhere. That's the plan at the moment; another new starter and fuel leak possibilities from regulator. The dampener not being involved should probably not be an issue, I don't think, or if so I can plumb one back in, although I'm not too keen on all that work unless it's highly suspect.
I will look hard at the regulator and leak through first. As I recall from previous work it makes and holds good pressure while running but tended to loose it a bit faster than it should, dropping in pressure after 20 minutes or so which is a bit too fast as I recall (and prompted the injector test).
Do we think extra fuel exacerbates the tendency to backfire and destroy starters?
Thanks for the input.
I'm leaning toward keeping this car personally. I really like it. I'm pretty sure mamma will have a cow though.
I'm not sure this is related to the starter kickback and subsequent destruction though.
If the starter is generating an electric field that triggers the sensor and tries to fire the car "early" (and "backwards") this kicks against the starter which is still trying to spin the engine correctly, you get violence and mahyem; busted starters. This makes sense to me but using the right bell housing, correct starter, good grounds, shielded sensors "should" elimnate that UNLESS extra fuel hanging out allows the "backfire" where as without this fuel it would not backfire so readily.
If this makes sense I will look hard at fuel leaking in somewhere. That's the plan at the moment; another new starter and fuel leak possibilities from regulator. The dampener not being involved should probably not be an issue, I don't think, or if so I can plumb one back in, although I'm not too keen on all that work unless it's highly suspect.
I will look hard at the regulator and leak through first. As I recall from previous work it makes and holds good pressure while running but tended to loose it a bit faster than it should, dropping in pressure after 20 minutes or so which is a bit too fast as I recall (and prompted the injector test).
Do we think extra fuel exacerbates the tendency to backfire and destroy starters?
Thanks for the input.
I'm leaning toward keeping this car personally. I really like it. I'm pretty sure mamma will have a cow though.
I could start my car dry with no bucking and it wouldn’t run but if I kept trying it would buck and sounded like metal something bang. So that’s fixed now and never had it again. Good luck.
04-17-2019, 02:45 PM
#49
Well, I would agree accept that my research shows many run without the dampener. If it's not in the mix it can't fail! Putting back in would cost a lot of money so I'm holding off on that one. I'm reading up on fuel pressure regulator failures, Clarks says usually the pressure goes high on the rail but ours is not, although it does go down too fast and injectors don't "appear" to be leaking down so I'm tempted to replace it but I will resist pending further investigation. I'm thinking of looking for fuel in the intake and checking the vacuum line for gas, still researching that one. It seems to me there has to be another problem making the starter grenade worse. It just shouldn't be doing this over and over.
Research turned
, sure matches symptoms.
Research turned
Last edited by jvandyke; 04-17-2019 at 03:45 PM.
04-29-2019, 06:21 PM
#51
you need a new fuel pressure regulator
You need a new regulator. There should be no gas there. I put a beck/arnley aftermarket one on mine sixty bucks and it worked. You probably have gas in the bottom of your intake manifold like I did too. Car will run like crap in that condition and cause all kinds of funky things.
04-29-2019, 06:33 PM
#52
That's what I thought but I did a lot of fuel line testing and the FPR passed, the injectors don't leak, same issue, different thread: https://rennlist.com/forums/924-931-...l#post15791372
