Engine Grounding
 

Hi guys...
After getting my engine re-installed I noticed the famous 3000 rpm hesitation to be worse with the Street ported engine.

I've been grounding everything like downpipe/negative battery/ect.
I noticed a 7/16 bolt hole in the intermediate housing?????
That's beside the engine block coolant drain. My main engine ground is attached to the front housing. My question is: Would
adding another ground to the empty bolt hole w/4 gauge wire to the frame help eliminate the 3000 hesitation when the engine is cold? thanks for the replies.... jack

Grounding
 

www.pettitracing.com provides a free grounding kit.

You may want to check with them.
(954)735-0100:confused:

it might, it might not. try moving the current location of the ground to a different hole. clean the contact area. add another ground. check the one at your cat back/main cat junction.

i'm dealing with the same thing, and i've added 4 braided 4 guage grounds in various places and 4 other random grounds.
the hesitation is better, but not cleared up.

either way, for $4, it's worth a try!

where have you put your added grounds??

im having some bucking problems when my headlights are on and some people suggested that i have a bad ground or lack of..i want to add more grounds to see if the problem will go away and since its the cheapest option so far..

First thing, before adding more grounds, check and clean your current grounds.

besides the battery, where else are the ground locations??

i did search but they didnt specify where the stock points are..

Just the few I can think of right now:

1. One on the US driver's side of the engine (since people can ground it in difference places, you'll just have to look)
2. Passenger rear side of the UIM
3. Under the car on the exhaust

ok the passenger rear side of the uim is grounded properly (or so i think it is but it looks normal), the engine ground i cant find it (spent 30 minutes looking for a wire lol) and there is no ground on my exhaust at all..

will it make sense to just ground one of the hangers or maybe one of the flanges of the exhaust to the body? or how is it supposed to be done?

that prob explains why my car acts funny with the headlights on??

what ecu are you using?
J

the stock ecu

car started acting funny recently..since 2 weeks ago was the first time i had to use headlights in about 5 months lol since i hardly drive this car and when i do, its in the daytime..

The exhaust system ground is part of the O2 sensor circuit, so it could affect the O2 sensor reading and, therefore, idle mixture.

damn i forgot abou the o2 ground..so um why would it only affect the car with the headlights on??

but you make alot of sense cause my a/f gauge (yes the pos non wideband one lol) shows lean all the time, maybe once in a while, it will show stoich or sometimes show nothing at all like its not working (but only for a few seconds)..but then when i turned the headlights on, it showed rich and stayed lit up moving around like it was normal continuously..

where is the o2 sensor grounded to? the dp?

Yes.

The headlights just cause more current flow and slightly lower voltage in the system. The FD electrical system is very touchy (all the posts about 3K hesitation and grounding), so I'm not very surprised that it would be affected this way.

IIRC, the stock ground runs from the DP/main-cat flange to the body.

you may want to run a 4 ga. ground from a bolt on the side of the front rotorhousing to the a/c compressor bracket, that helped my hesitation because when the trailing plugs kick in, it is the closest point to dump the current.

The headlight current flows through the ground to the firewall. Check it with your hand when the headlamps are on. If it gets warm, it has resistance. I added a braid ground strap in parallel with this one. I suspect the "plug in" on this ground is the culpret to many grounding problems. Not sure why it requires a push-on feature - do we change our engines that often? ;)

thanks for the input guys

im gonna start off with my o2 sensor first since that was the last thing that was touched before the problem (well not right before but the only that was touched before the problem)..and since the a/f gauge is the only thing that acts funny with or without the headlights on and basically whenever electrical load is being put on the engine, it acts funny, im assuming thats the problem..

im gonna see if maybe theres a loose connection or maybe i need to clean the ground to it..

^ or you could just get a pfc and not have to deal with hesitation issues anymore

I think I'm having the same problems as you ulost2my7 when I turn on my headlights my idle goes up a bit. I turn off my headlights it goes back down where it was.

You are running a ported motor with a stock ecu. Thats not really a good risk to take. I wouldnt boost it too much because if the port is good it'll be very lean. Get a PFC and have it tuned.
John

well in my case, it has something to do with my a/f gauge..if i turn the fans on, my gauge will stay in lean..if i turn on the headlights with the fans on, it will go to stoich, if i hit the brake with those headlights/fans on, it will go to lean, let go of the brake, it will go back to stoich..now i turn off the fans and leave the headlights on, it will go to rich, step on the brake, it will go to stoich..

so its def something electrical with this gauge or something..i have to check to see if maybe its grounded right..if anything, im just gonna take off this gauge since its pretty much useless..

and the headlight thing actually affected my driving..it will idle fine but when driving, during low rpms 1500-3000k, the car will jerk and buck to a point to where you have to stop cause its not driveable..

If you really want to get a "good" signal from the O2 sensor, get some tinned copper braid and a suitable stainless hose clamp. Clamp the braid to the O2 sensor body, route it up to the firewall and install a crimp connector on the end of it and attach to the firewall ground point. Be careful how you route it as the braid will get quite warm, and could melt through any electrical cables it touches for the first 18" or so.

This will ensure you have as good a ground on the O2 sensor as possible.

Hate to spend your money for you, but the PFC WILL fix the jerking/hesitation issue - it did for mine. It's a new car now, the way it should have been in 1993!

That's a heckofa good idea. I think I'll do that just because it should be that way, even though I'm not having bucking/hesitation!

thats a great idea but this never happened to me before when i had these gauges..it was only that one time 5 months ago where i touched it, then found out recently that it affected my electrical system somehow that when i turn on my headlights, the car will jerk when driving..

im pretty sure the pfc will cure it but maybe not since this problem wasnt there before..

^The problem wasn't there before for many others either. I think the real problem is the stock ecu not being able to correctly interpret inputs and therefore is telling the car to do some wierd crap.

The PFC is good for more than just getting rid of the hesitation. IMO it was well worth the 1200 I paid for it plus commander.

maybe, if thats the case, our electrical system is weird as hell..i mean it was working fine before, then i touched it and then all hell broke loose..

and i am getting a pfc eventually but right now i have to solve the problem cause its getting to that time where its gonna get dark early and i cant even drive the car with the headlights on..