dblboinger

iTrader: (3)

This weekend I installed a Bonez Hi-flow catalytic converter and Racing Beat Cat-back exhaust. Last night I finally got to take a test drive and found I have a problem. It's very difficult to explain what I was feeling, but here goes...

I had driven the car for about 10 minutes or so and it appeared to be running very well. Then I got on I-5. The acceleration was great but once I got up to highway speed and tried to hold a steady speed the car started "surging". What I mean is every couple of seconds it alternated between feeling like it was going to die and running alright and it kept repeating as long as I triied to maintain a constant speed. If I pushed throttle it would straighten out and ran good until I tried to level off again. I didn't mess with anything under the hood, so I don't think I knocked any connectors off. Anyone got any suggestions of what I could try to remedy this?

Mahjik

iTrader: (1)

Did you reconnect the ground wire which attaches to the exhaust?

bbade

iTrader: (5)

You didn't have cruise control on did you? Might be a problem with the cruise control if you did.

Also, in response to Mahjik I had the ground wire to the exhaust off for over a year with no ill effects, but every FD seems to behave differently with regards to grounding so definitely a good thing to check.

dblboinger

iTrader: (3)

I did not have the cruise on and I did reconnect the ground on the exhaust. I say reconnect because before I did this it was not connected.

Mahjik

iTrader: (1)

So the only thing you did was install the Bonez cat and Racing Beat catback? During that install, you reconnected the ground wire for the exhaust which was not connected when you removed the old exhaust? Do you have a boost gauge installed?

wstrohm

Don't know the emissions control rules in WA, but a new Bonez DP on our '94 failed CA emissions, with new plugs, plug wires, O2 sensor, etc. Finally had to go buy a Mazda OEM cat for $1300+. From the emission readings on the Bonez it looked like the air injection to the cat was not being evenly spread throughout the catalyst.

(A little OT, sorry.)

dblboinger

iTrader: (3)

Exactly. On the boost gauge, I just got one mounted, but not connected yet. Engine was running great before changing the exhaust. My son suggested maybe the ECU "needs time to adjust to the new exhaust." Does the ECU have a "learning curve" like the Power FC? I have a Power FC not installed. that was my next mod, but I've been told not to install the PFC until the car is running perfectly. What say you? Would the PFC maybe give me more info on what might be causing the problem?

dblboinger

iTrader: (3)

Emission are by zip code here...my zip doesn't require testing (YAY!!!) but I'm keeping the stock cat just in case.

Mahjik

iTrader: (1)

The FD uses a MAP based system, so there is no self-learning aside from the idle. When using the PFC, there is a requirement to have the PFC learn the idle but that has no effect for the stock ECU.

The PFC could provide information *if* there is a sensor or similar issue. If it's something more mechanical, the PFC won't provide any more hints than what you already have. I would start by undoing the ground wire and put it back to where it was to see if that changes what's happening. If that doesn't help, try putting the stock cat back in place to see if that makes a difference (i.e. prove or rule out the work you did causing the problem)

dblboinger

iTrader: (3)

Previously I neglected to mention that before the modifications my CEL would come on after about 10 minutes of driving. When I checked the error code it reflected a bad EGR valve. Yesterday, when I went for my test drive, the CEL didn't come on at all. I didn't mention that because I thought maybe replacing the cat cured the problem that was causing the CEL. So this afternoon I removed the ground wire from the exhaust and the car ran great....but the CEL came on again after about 10 minutes of driving. I got to thinking about it and realized that about 10 minutes into the test drive was when the car started acting up yesterday. So one theory is that the bad EGR solenoid is somehow grounding out my ECU and causing the car to run poorly.

But that's not the end of the story...I drove the car for about 2 hours and it ran great. Tons of power and not one instance of missing, until it got dark and I turned on the headlights. The stereo and the AC had both been on nearly the entire time I was driving and not a hint of a problem. When I added the headlights it started again, but not nearly as bad as yesterday. If I turned off the stereo, the AC or the headlights the problem would clear up. It was dark/raining yesterday when I went for my test drive so I had the headlights and the AC on then too, but not the stereo. Once I got on the freeway I turned on the stereo and shortly after the problem started. But like I said it wasn't nearly as bad today, with the exhaust ground removed, as it was yesterday with it on.

My thoughts now are that I may have 2 problems...a bad EGR solenoid and insufficient alternator output. Tomorrow afternoon I will put the ground back on and try it again with all large electrical loads OFF. If it doesn't mis-fire like that then I will add electrical loads until it starts mis-firing.

The alternator thing doesn't really surprise me because I've been concerned about that for a time. I've got about 1800 watts of Alpine in this car and I was concerned the 90 Amp alternator was not enough to feed the stereo and the rest of the car at once, but I hadn't seen any problems up until now. I've already been looking for a high output alternator, but they're hard to find for this vehicle. Unique Audio says they can supply me with a 240 Amp unit that is a direct replacement for my stock unit...but it costs $699 (ouch!). Of course I'll check the battery too, but it's a fairly new Optima Yellow and the voltage doesn't seem to be dropping much, so my guess is the alterator. Stay tuned for the conclusion.

MakoRacing

iTrader: (12)

Thats crazy, my friend passed Cali smog and he had streetport/SMIC/dp/CB ..interestinggggg

Speeder165

iTrader: (7)

I worked in car audio for around 8 years before the turn of the century. 1800 watts is a LOT of juice to be required from ANY factory electrical system. Usually the alternator the factory puts on a car is just enough to handle the existing load that the car can produce with all things working at the same time. Have had 2 vehicles with 1000 watts in them & both had a hard time keeping the battery charged. On one, I installed a Lestek alternator. 175 amp unit. That worked great but the thing was large. Was on a Honda I owned around 1990. Electrical systems in EFI cars are sensitive to voltage changes. You might want to start your car up & run a few things like the stereo for a few minutes & see where the voltage is on your battery. The Optima brand that you have is a good choice to go with, but the alternator may be having a hard time keeping the battery charged. Even if the alternator is working now, it is only a matter of time before a diode goes in it due to stress & then you will need a new one. You may be seeing the signs of an alternator about on its way out now with the problem you are running into. Just a thought.

GoodfellaFD3S

iTrader: (213)

Higher amperage alternator:

https://www.rx7club.com/3rd-generation-rx-7-1993-2002-parts-99/fs-irp-high-output-alternators-820819/page2/

RotorDream

I would recommend installing the PFC if you have the time and a Commander. In my experience it makes diagnosing electrical problems alot easier, unless you like searching through the wiring diagrams and Electrical manuals searching for where to connect the multimeter. I have seen a problem alittle like what you are describing and I moved before he figured out exactly what was causing it. Damn. If I look at it from a non-rotary stand point, the Alternator seems like the likely culprit for your situation. I have installed car audio for years, and 1800W is alot for a 90A alternator.

Look at it this way.
1W =1V x 1A
so in your situation
1800W/13V = 138.5A

Now I know that your not running 1800W all the time, but this is on top of the load the car is already pulling from the Alternator.

Also as Speeder said the factory puts just enough of an alternator to handle the basic loads of the car and a little buffer room.

so in this case
13V x 90A = 1170W

Which means a 90A alternator isn't even enough to power all your audio equipment let alone that and the car.

Just my .02

dblboinger

iTrader: (3)

Speeder165 and RotorDream...I was on this same line of thought as this. I knew I needed a bigger alternator and have in fact been looking for about a month now. I've been looking for a 200+ amp unit though, but thanks to Goodfellas I have contacted IR Performance to see if their 140 amp unit is big enough. I don't know why this wasn't a problem before the minor upgrades I did, but at least now I'm on the right track. Thanks for the input.

Speeder165

iTrader: (7)

I would keep in mind that the bigger the alternator that you have, the better off you will be in the long run for reliability. Large alternators aren`t cheap but are a good investment when you have as large a sound system in your vehicle as you own.

I would get the electrical system "upgraded" & then see how your car behaves. I know in another car that I own here ( 1st gen w/ Haltech FI), with the 1 KW system I have in it, I have to turn down the stereo & knock the heater blower control down a notch or two in the winter time when I come to a light or the car will not idle right & starts smoking in the rear view. When I take off again, all`s well. Well sort of, if you don`t count the dimming headlights at night with the bass notes........puny 60 amp factory alternator. Hehehe!

Take care.

RotorDream

Thats why God invented capacitors haha.

Speeder165

iTrader: (7)

Think I found something in the garage that should work.
I just wish they didn`t weigh 85 LBs each.

RotorDream

hahaha just wrap them in carbon fiber it takes like 75lbs off of them!!!

Upgrayedd

iTrader: (1)

Audie... Have you checked to make sure your MAP sensor vac line is still connected... I've been in several cars that when the bosot was increased from a mod such as yours, or others, the vac line has blown off of the sensor. And it would cause funky issues like that... Hopefully it's an easy fix. My other question is could the car be overboosting and hitting a fuel cut? The text is too small for me to read in this thread (my computer shrunk everything????) so I don't know the answer to this: do you have a boost gauge? If so how much boost are you hitting? And when is your peak boost (rpm)?

RotorDream

Upg
That should help ya!

dblboinger

iTrader: (3)

95% sure it's the alternator. I reconnected the exhaust ground and drove around with all electrical loads turned off for more than an hour and not one problem, but the CEL did eventually come on. The voltage on my turbo timer was reading 14.1 - 14.4vdc. Turned on the headlights - still no problems after 20 minutes, but the voltage was down to 13.9vdc. Turned on the A/C - began feeling slight roughnesss in the way the car was running after about 10 minutes and the voltage was down to 13.6 vdc. Turned on the stereo - within about 3 minutes the same problem came back and the voltage was down to 12.3 - 12.8vdc. Turned everything back off and within a couple minutes the car was running normal again. Turned on just the stereo and found that if I kept the volume relatively low everything was okay, but if I turn it up the problem comes back and the voltage drops. Those big *** amps are just too hungry for that little alternator to feed...gotta go bigger. I found a company this morning that makes a 200 amp alternator with an external rectifier for $499 and it's in a stock alternator shell except for the rectifier which I can mount where the battery use to be. I think that's the avenue I'm going to take.

Speeder165

iTrader: (7)

I think you are definitely headed in the right direction. When I bought the Lestek back in the early 90s, seems like I paid around 450 for it so the price you are paying for the one you are looking at is good.

Wow! On your voltages, Man! They are REALLY dropping a bunch! That poor alternator is going into overtime trying to keep up! You have done well to have had it work & not die up to this point.

dblboinger

iTrader: (3)

I have a friend who use to work at a VLF transmitter site in CA. One time he gave me a tour. The most memorable thing for me was when he took me into this completely empty "room". It was about 12'x12'x8' and it appeared the floor and ceiling were made completely of stainless steel. Turns out, it was a tuning capacitor for the antenna coupler of the VLF transmitter and the ceiling could be raised or lowered to tune for different operating frequencies. Totally blew my mind. He said they have to scrub it down twice a week or they get massive arcing. BTW, the antenna is 100 miles long and is buried in the ocean floor.

RotorDream

Man talk about HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHD radio haha you could probably hear the the hairs growing on the DJs head