at two spots in the rpm range, the tach will jump down and back up when i'm accelerating. its kinda like the CAS isnt reading anything for a split second. this only happens at two spots in the rpm range; between 2500-3000 and between 4500-5000. its kinda of strange and no variables (like throttle position, vacuum, boost, etc.) seem to change it.

can anyone offer any help?

 

Have you tried a datalog to see if there is anything funky happening? like an RPM spike, or an abnormal injector duty % or even a hickup in the ignition timing? ive sometimes run into faulty grounds on the coils, or even bad plugs or plug wires that have caused behaviours like this.

 

What are your gains set at?

 

ign gain set at 2. i tried raising it up, but no effect.

after talking to a couple people, i have come to the conclusion that it may be the fact that i dont think i have the CAS wire shielding grounded. anyone else have any ideas?

 

With the CAS wire shielding not being grounded, wouldn't the problem be more consistent? It seems like the condition for interference would exist all the time with the shielding not grounded. I don't know, maybe I'm thinking about it wrong.

 

well, its very consistent, just only in those 2 rpm ranges...

 

The sheilding is grounded @ one end inside the harness, you don't ground it at both ends.

Does the engine falter when this is happening?

If you hold the RPM's right at that range where it happens with no load in neutral, will it constantly do it? Ignition settings correct? offset/teeth count etc?

 

if i hold the rpms in the area, the tach will drop randomly and it will do the grounding out thing just as it does when i'm driving

at which end is it grounded vito?

 

you arent supposed to ground it @ the CAS, the sheilding gets grounded to the rest of the grounds in hte harness, you can confirm this by checking continuity with a multimeter between the sheilding @ the CAS end of the harness and the ground of the car. If theres no continuity then maybe there is a harness issue and it's not grounded properly, if there is continuity it's grounded and the problem is somewhere else.

You didnt have this problem before with the last motor, so look at what has been changed since then, go back over everything.

 

Hmm..

I grounded both ends...

Ruh oh?

 

it isnt grounded at both ends.

 

Guys, the additional ground wire on the haltech harness with the round terminal is precisely the shield gound for the entire harness, this ground is only done at the ECU side of the harness, dont ground any of the shields at the connectors/sensor's end.

If you do additional shielding, make sure its grounded on the ECU side only.

 

ok i am confused now.

 

i redid all 3 grounds and they are all great. problem is still there...

 

i just got back from grounding the CAS shielding. no avail.

need more ideas


also double checked the wiring to the CAS, all colors are correct:
HALTECH: CAS:
yellow-----------> red
green-----------> green
red--------------> white
blue-------------> white/black

 

did you double check the settings in the ignition setup?

 

yes they are all correct.

 

help. the datalogs show 0 rpms during this hesitation.

 

have you tried a different cas? confirmed good connections on all the cas wires? I know you checked that the colors were all going to the right place, what about the quality of the connection?

It sounds to me like it might be interference, did you rewire the haltech? Where is the CAS bundle being routed? near the ignition wires or anything else you can imagine being problematic? Can you try routing it differently?

 

no im gonna try a different CAS tonight. it really just seems like there is a split second in those RPMS where it doesnt see a signal at all.. its weird.

 

Sounds somewhat similar to my problem. Just sent my e6x in to see if that was the problem and it checked out okay, so thats..not it. My problem, however, is that it just doesn't want to pick up rpm's at all. Let us know what you find out.

 

Where are your CAS lead wires routed??? Do they run along the spark plug wires? Ignition Wires? Alternator Charging lead?

Where exactly do you have the haltech grounded to, and what else is grounded on that point?????

 

no they run right along the block, back along the firewall. away from anything that could cause interferance (spark plug wires or alternator wire, etc)

 

regrounded CAS side of wiring. problem still persists.

going to swap CAS's tonight.

 

hope it works out