Issue with accelerating past 40 mph...hiccups NEED HELP!

CBradio · Post by **CBradio** » Thu Jul 24, 2014 11:42 am

Sounds like an ignition issue to me

Could be you have a broken or worn spring in the mechanical advance of your distributor

Or maybe its the electronic ignition - is it difficult to try with points just to rule the electronic module out?

I am pretty much having the same issue, BUT I noticed it goes away when I either disconnect vacuum advance (you dont have that on your distributor) or retard the timing a bit. This suggests to me that for some reason Im getting too much advance.... My mechanical advance springs look okay however, although they dont quite match. Unlike yourself, Im not sure whether Im just timing the car overall too advanced. I dont get the stutter if I retard my timing, but then the car doesnt really move until like 2500 RPMS..

You have the advantage of having had your car running without incident, so Im going to assume your timing is correct.
Im assuming also nothing else really changed (vacuum leak?)

If I had to guess, and I could be totally wrong:

1. Your electronic points are conking out (try to swap points in and see what happens)
2. You have a broken or worn spring in your distributor or weights are stuck in an "out" position (are you up to opening up to take a look?)

GripGreg · Post by **GripGreg** » Thu Jul 24, 2014 1:25 pm

By 'kicking down', do you mean hesitating & choking?
Have you cleaned your fuel injectors?
As you know, it takes more fuel to get in the upper rev range.
And, your distributor is brand new,,,or is it used?
Greg

KenB · Post by **KenB** » Thu Jul 24, 2014 1:51 pm

This could be a lot of things but I would want to rule out distributor and electronic ignition box on the right inner fender. If you've got a spare of either to swap in and test for diagnosis, do it.

I had a 318i with L-Jet once and experienced this kind of phenomenon twice--once it was the distributor and once it was the electronic ignition. The only way I could figure it out was by swapping in parts someone lent me.

But that was my situation, doesn't mean it's yours too.

Good luck with it.

KenB

CBradio · Post by **CBradio** » Thu Jul 24, 2014 2:07 pm

I think Nikki has a 530i points distributor with a pertronix item inside....

Also, Nikki..... greg asks a good question: what do you mean by kickdown?

For me, its like this..... if I HOLD the pedal down at 3000 RPM, the RPMS will "hiccup" - they will drop down to ~2700 or so, then climb back up to 3000 RPM, then hiccup back down to 2700, then back to 3000 ..... etc. If I give more gas and get past the 3000 range, all seems well.

Is this the kickdown you are describing {albeit at a different RPM}?

shebuilt · Post by **shebuilt** » Fri Jul 25, 2014 5:40 am

Sadly this keeps me up at night.

Ok kept original distributor and coil. Swapped and same issue.

Exactly what you are describing cb. I hold down accelerator and it hits about 2500 to 3500 rpm and seems to surge or miss or likes its having a hard time breathing but it goes back to same rpm just won't increase. If I push it past it will do it just mis at higher rpms.

Now a friend is suggesting injectors? Its pretty low miles but anything is possible.

CBradio · Post by **CBradio** » Fri Jul 25, 2014 1:03 pm

Oh I know the feeling!

I guess it could be the injectors.
I just changed my injectors! I would recommend not touching your injectors just yet.

I think if anything, it could be the injector connectors or resistors?

When you swapped distributors, were you using points?

I converted to 528i ignition....

Im trying to figure out why it does this. I also get plain missing at higher RPMS.

Im certain its not fuel system related for me because if I unplug the vacuum advance or retard the timing a bit, it stops. Im timed now at 22 BTDC at 1200 RPM because if I run it at spec 2100 RPM the car gets too hot and doesnt have any low end power.

shebuilt · Post by **shebuilt** » Fri Jul 25, 2014 6:23 pm

The one I swapped does have points. The other is as you stated earlier - petronix. Also have two coils and swapped. Same thing.

Just purrs at low rpms and starts right up but rev him past 2500 or 3000 or try to pass a slow driver on 405 and thats not gonna happen!

one friend says injectors another says timing? Can't believe timing out of the blue but heck who knows.

Really don't want to take it to the shop - not a fan of being charged an arm and a leg.

CB what do you think your issue is?

bizz · Post by **bizz** » Fri Jul 25, 2014 6:58 pm

I'm going to mention injectors again - only because the old 520i I had presented the same symptoms, the PO mentioned that he had to remove/clean the injectors in the past to remedy the same issue. Sure enough once I got the injectors out, one of them was quite blocked.

GripGreg · Post by **GripGreg** » Fri Jul 25, 2014 7:06 pm

NIKKI
That doesn't sound like fuel injector issues to me.
What I was really asking was, when was the last time you added a top quality injector cleaner to your gas?
What's the answer?
I do that 3 or 4 times a year. If I remember!!

AND, I use nothing but Arco Premium!!! 91 octane.
Greg

Ps.. Aha! I might retract my statement, after readig Bizz's post!!!! Wishie, Washie, huh??

shebuilt · Post by **shebuilt** » Fri Jul 25, 2014 11:24 pm

Hey Greg...I put sea foam in and it didn't do a thing.

I haven't removed the injectors.

CBradio · Post by **CBradio** » Sat Jul 26, 2014 1:28 am

Maybe worn spot on afm track?

Have a friend you can swap with for a minute?
Combo relay too- those can get bad solder joints.

Im not quite sure we have the same issue- I have no problems passing anybody. I feel like mine is a timing or ignition issue...
Not sure yet what exactly.

Also, Do you have a fuel pressure guage installed?

jkycia · Post by **jkycia** » Sun Jul 27, 2014 8:13 pm

How did you conclude that this is not due to your fuel pump?
Did you replace the pump. As I said earlier I think I had very similar symptoms
on one of my cars (it started stalling when I was pushing it on the highway,
I had to drive 50 mph. As long as I kept in exactly at 50 to 53 MPH, it was fine. This was in illinois, so no hills. In the city it was fine). I puzzled over it and basically was stuck with the problem. It seemed to have improved when I changed the fuel filter but came back.
Finally it stopped running all together and I found out that the pump had failed. When I replaced the pump, the problem was gone. There are alot of people on here that are more way more knowledgeable than me but I would say, bad gas would eventually be flushed out and so would go away with new clean gas. I don't think it is the injectors. I can't see how that could give you sharp trouble at a certain high RPM or speed. You could be losing fuel pressure when you are giving it a lot of gas (pump is weak or line is somehow blocked). It could be the distributor settings. I don't have experience with that so much.

jkycia · Post by **jkycia** » Sun Jul 27, 2014 10:06 pm

... what about the problem being from bad spark plug cables?

Mike W. · Post by **Mike W.** » Mon Jul 28, 2014 8:36 pm

Easy stuff first, it's not the intank pump, 530s didn't have one. I doubt it's injectors, the usual problems are leaking, either internally or externally, but working fairly well when running.

It does sound like ignition, although substitution seems to have eliminated it, with the spark plug cables as a possible exception. Spray them with water with it running and see what happens. Not so much it gets down to the plugs, but the cables. Make sure all the FI and body grounds are good, that stuff can drive you nuts. AFMs are a possibility although a lot more get changed or worked on than give problems. Could be combo relay too, but probably not.

shebuilt · Post by **shebuilt** » Tue Jul 29, 2014 9:17 am

thanks again all for the ideas. Since i have the fuel pump i will try that...won't hurt (just the $100 bucks on the Bosch did!).

The wires plugs cap rotor were put on earlier this year and i bought those performance wires on special at bav auto (red wires)...

I will check the connections and ground.

So Mike you are leaning towards me trying to find a AFM? whats the combo relay?

Again scratching my head when it is in park and I rev it - chokes off or fights to stay revving at about 3000k RPM and of course driving same thing.

There is a weak brittle wire coming off the coil that is barely there...green on positive side with another - I by passed it with a thick gauge wire and it didn't change the symptom so I thought to eliminate this. It follows in to the plug on the fuse box with other wires.