Well, this is on my 91 TII with a E6K and this all started out of the
blue. The engine is still being broken in so I have no idea what it
does under boost.

When I am driving the car under light throttle esp under 4000 rpm it
bucks very bad. And every time it hessitates the tach needle will drop
very quickly. Faster than the actually engine rpm could ever drop.

When you are looking at the haltech rpm read out it drops also. So,
that leads me to believe it is some weird problem with the CAS or the
ECU. I have tried swapping CAS and trailing coil with known working
ones and nothing really helped.

I have made sure the the ALT wires are as far away from the CAS wires
as possible. And I am using Magnecore 8.5 wires so I think those are
shielded well.

It seemed to be running a little lean so I enrichened things a little
bit and that did help but the bucking/hessitation is still there.
However, it does explain why teh tach needle drops so fast everytime
it hessitates.

Also, if you try to accelerate...press teh gas down it really bucks. If you are stopped and rev it in neautrl....when you rev it ...it hesitates then revs.

I tried that ferrite rfi filter and that did nothing.

BDC says this is a trigger problem and I def agree. I just dont know where the prob is hidding.

Ideas?
James

 

What are the gain settings? Try turning them to 0 if they are turned up at all.

 

Here is the video of me trying to rev it...
http://media.putfile.com/MOV01906

 

Here are the datalogs of me reving it...and the hessitations while driving it....

https://www.rx7club.com/attachment.p...d=135316&stc=1

 

Both Trigger and Home are 2....copied that from Hitmans setup info....

I will try turning them both to zero.


-------------------------

On the data logs...I never went higher than 4k. However there is one spike to 6800rpm on the hess1 file i think...and two spikes above 10k on the rev datalog file.

James

 

Well, I checked my settings....

Was
Trigger 1
Home 2

I switched them both to 0. The problem is about 95% better. Still there....

What do those settings do?

Here is a good video of me cruising when hessitation/needle drop happens
http://media.putfile.com/Needledrop30

James

 

The gain amplifies the signal from the CAS. I'm not sure of the technical reasoning but usually shows less interference when the gains are set low. ReTed can probably give you the explanation.

You are getting a couple random hits in those datalogs. So there is certainly a bit of noise being picked up. Have you properly grounded the shielding? It should only be grounded at the ECU and not near the CAS.

 

C,

Thanks a million for your advice....you helped me get the car drivable...at least I can put breakin miles on her while I figure this problem!

With the gain on settings of zero....the prob is almost gone. But it still bad at 2000rpmish with light throttle.



One more thing to add to this....
I came back from a two week work strech....put a msd 6a box on the leadings....stated the car...and the problems started. I took the msd out and the problems remained...so I don't know if the msd did something weird when it was fired up....or it was a problem that was waiting to happen.

Yeah, the shielding to the CAS wire bundle is grounded inside the car. But I will check that....maybe the nut came loose.

 

I had similiar break up, except mine happened more so under boost, the cure was to ground the wiring at the CAS...Then the whole forum put its arms up in a tizzy about ground loops and other flux capacitor technobabble... I did it and it works...Max

 

Well, I will give it a try...not gonna hurt anything...

So you grounded the sheilding wiring at the CAS?

Did you play with your gain settings?

James

 

I would ask where are the trigger wires runing through in the engine bay, the alternator is a source for noise, the quality of the spark plug wires will put noise in the trigger too, ive actually swapped sparkplug wires from an old set to a brand new set and the rpms where perfect afterwards.

The most ideal direction to run the trigger wires from the CAS back throught the hole in the firewall is making an "L" straight along the car from the cas, hugging the firewall al the way to the hole, that way they are away from the alternator, and the shielding grounding should actually go on the additional ground wire that is on the harness, what you might want to do is peal back a little of the cover close to the CAS and kinda twirl it around a couple of times at that end and put on some additional covering on those wires just to be sure.

As far as the reason for the gains being set to zero, that is for the E6X which has very sensitive trigger circuits, its strange that you would have noise or RPM bounce with a K, unless you have some serious interferance or noise issues.

 

From my experience the gain settings recommended by the hitman work fine for the 6K, but not the 6X. The three 6X cars we have here all use gains of 0 or 1.

The less amplification you need, the better.

 

Well, but he has an K, and the K just runs nice with gain at 2, so my guess is the electrical system or the spark plug wires, or simply that the CAS needs to be either calibrated, cleaned, adjusted or swapped. Or do you have an MSD box next to the haltech and ignition wires running next to it?

Or, worst case scenario you have it connected reversed.

 

Also worth trying is moving the CAS magnets slightly closer.

 

Thats what i meant with "calibrating and clenaing".

 

 

So, just bend the magnets a lil closer to the spinning shaft?

James

 

Not bending them, just loosen up the screws that moun them, but you should know that there is a minimum and a maximum distance for this, consult the service manual before doing that. And use a filler gauge.

 

Okie, here is what I have tried so far.

I checked out my CAS harness as it ends at the CAS. There is prob about 5 inchs of unshielded wire so I tried the adding a ground wire off the shielding at the cas. I also took some alum. foil and wrapped it there also. Since it was touching the sheilding the foil became grounded.

That helped a little bit.

I also tried bending the magnet a little closer....then I read your last post Claudio...DOH. Anywho...I will try the unscrew the magnet method.

What do the two different gears inside the CAS do? Which one is L and T?

The next thing I am gonna do is install an FD ALT and the relocation bracket...maybe my alt is leaking some rfi.

And I am using Mangecore wires.

It HAS to be rfi from somewhere

So , the problem has come down to this.... If you give it gas at 2300rpm or lower....very light throttle it bucks and the needle drops. Like 5th gear 40mph 2300rpm..and lower will produce the hessitation.

James

 

First off you dont ground the trigger wires at the CAS end, you have a ground already on the wiring harness that you connect to the chassis (not thebatter neg), second, have you tried just swapping out CAS?

 

Okie, today I made the prob worse...like can't really drive it worse.

I relocated my alt with the relocation kit. Thats it I just relocated my alt and the prob is huge now. So, I took the belt off the alternator and ran the car. Same problem. What gives?

Can you take the belt off...and disconnect the alternator then start the car and be ok?

I used an AM radio to go sniffing for EMI. The alternator really was noisey on the radio...but nearly as noisey as my friends 89gxl with an FD alternator.

Here is where I got that idea...
http://www.popularmechanics.com/auto...tml?page=2&c=y

So, is it ok to run with the alt disconnected and no belt?

Doing the AM raido test....you can hear EMI even with the key off. I guess the power wire going to the alt is still hot even with the key off.

I am about to throw this car in the rio grande....

Claudio - I tried taking that extra ground off for the CAS Shielding....didn't help. But I can leave it off.



James

 

Correct me if I am wrong, but wouldnt EMI cause more pickup noise instead of less? EMI (at least in the RF world) will cause more trigger events.

 

Yes, you dont have to ground at the CAS end... anyway, i would think that relocating the alternator to that side of the engine puts it even closer to the CAS, doesnt it? i would just leave it where it goes, and maybe even try a different alternator, its un natural that you should have so much noise, are you sure you have the CAS connected properly to the trigger wires?

 

Moving the alternator and having the problem get worse sounds like a ground-loop problem.
Remember, the alternator grounds through it's *case* and the support brackets.
It could be that brackets are not a good ground???
Cause when you float the ground, the alternator starts spitting out all kinds of RFI / EMI.

Is this those Pineapple Racing brackets?
Aren't they powdercoated?
That might not be a good idea.
If this is the case, try running a FAT ground wire from the alternator case to a good ground spot on the chassis or back to the battery - terminal.


-Ted

 

I did think about that ReTed....yes they are powder coated...

I tried to trouble shoot that by taking my jumper cable and clipping it to the alternator case and then the other end the ground on the battery. No dice...

But the alternator is working great.... 14 v at idle cold. However, the alternator is very old...I have had it since I have had the car in '99. I have an FD alternator and I am going to swap it out as soon as I find a pully.

James