3.2 Carrera not running right after mods!

[tony9704]

Is the only way to check air/fuel by way of dyno? Can any shop hook up a computer for a printout that Steve could translate into a new map? (I suppose I could just ask him.)
Also, you guys are freaking me out with all the broken head stud and valve guide stuff!
A bit more history, the top end (including guides) was done 20,000 ago. So I'm hoping the puff of smoke after settling down the idle is just bad combustion.

[88-diamondblue]

Dyno or something like the LM-1 or 2 from Innovate Motorsports to get Steve the AFR's. I used the LM-2 to figure out what my problem was. Cam timing was off due to me timing it wrong. With Steve's expertise and patience the car runs great.

Shouldn't be any issue with the guides since your top end was done such a short time ago. Wasn't trying to scare you just didn't know what had been done to your engine.

[89911]

I didn't ask you but do still have your old chip? If so, replace and see how it runs.

[tony9704]

I do still have my old chip. Wouldn't it run out of sorts with free flowing exhaust and stock chip? I guess it would be worth a try. You guys don't think that running 93 octane in a car chippped for 91 could cause some issues with driveability?

[tshih]

Running 93 octane in place of 91 octane only gives potential power gains and less possiblity of pinging/knocking. The engine should run fine if the chip is stock and you've mod the exhaust. We're talking about smooth running versus rough running not getting maximum power/torque from engine.

[stlrj]

Originally Posted by tony9704

A brief history.....
'88 3.2 with 89,000 mi.
well maintained, doesn't burn a drop of oil
always ran like a new car. I run 93 octane

Than I did this...
Cat bypass, Dansk 1 in- 2out sport muffler, Wong chip (I thought the car would run sweet after these simple, tasteful mods)
Now it runs a little different. It pops when it idles down after revving it, and on deceleration. When I drive it slow, the idle sticks at 2,200 rpms even after you push the clutch in. A quick rev with bring the idle back down perfectly. When I do this rev, a small puff of smoke comes from the tailpipe. The car does not smoke normally at idle or during acceleration. The car at times actually feels like it has less seat of the pants power to me. I would think these mods would be good for 15-20 hp. I should feel that. Either way, the car is simply not running right. I'm guessing AFRs are screwed up but shouldn't the Wong chip have taken care of that? The car has fresh plugs, cap and rotor, fuel filter, air filter. I'm not quite sure where to start. Thanks,
Tony

The first thing I would check is your idle contact and make sure it closes consistently. Also, the tailpipe smoke may be an indication of an over-rich mixture. These chips do not always pass smog due to rich mixture tuning causing many owners to resort to the original chip.


Cheers,

Joe

[BGCarrera32]

So basically you changed 3 things, and then noticed the problem. Start by checking out each of the 3, not chasing everything else under the sun first. The exception would be the throttle linkage, if by chance you jacked the rear of the vehicle up under the engine and caught the linkage, but bending the throttle sounds like a stretch to me unless you had the jack way up under the transmission or something stupid.

You car will be safe going back to the stock chip with your new exhaust and I would start there. Nothing to lose- see what it does and how it behaves. If it goes back to normal- there you go. A more open exhaust with larger tip diameters (or not) may sound raspier/throatier/louder and pop more. Get used to it.

O2 sensors are fuel trim devices that adjust the chip's fuel map slightly one way or the other to optimize power and fuel economy. When you start your car, the 02 sensor is ignored for the first 60 seconds or so anyway. Completely disconnecting it will put the computer in "open loop", which will not hurt anything except a bit of fuel economy and some optimization of the mixture. Not a big deal. Try completely disconnecting it and see where you're at. Euro Carreras of the 80's don't even have 02 sensors...

My experience: continuing to lean the engine out will also cause exhaust popping noises. You need to find a shop with a "wideband 02 sensor" (specifically ask for this on the phone, if they go "huh?" hang up and try elsewhere). This is what the LM-1 and LM-2 are that 88-diamondblue speaks of. This will tell the tech right away where the base mixture setting is and it can be adjusted via the air bleed screw that is hidden underneath the AFM (it is a 3mm hex). Do not dink around with this screw until you have the wideband meter hooked up.

Steve's chips are generally very good ( I have done 3 with him) but they assume you have a properly adjusted, well tuned engine.

Good luck
BG

[ALXinNZ]

Dont panic!, This is but a small issue that will be resolved in due course and be an awesome story to tell and the next P-car meeting.

I have a Steve Wong chip in my car and its awesome!!

Not sure of your year with regards to wiring but I disconnected a brown wire under the seat for the smog restriction. It is just a plug on my car and a seperate wire on the loom into the ecu.......

Regards

Alx

[tony9704]

Thanks for all the great info. I feel like I have a place to start now. Thanks especially to BG for the thourough info!

[dw1]

I have an '87 with the Dansk 1-in-2-out and 93 octane SW chip (and Fabspeed euro-style premuffler). I have none of the problems your reported, and did nothing special when I installed these upgrades. I did, however, install a new O2 sensor (purchased at a local chain auto parts store).

I don't have much to add to the very good previous posts except to point to the DME troubleshooting flowchart in the "tech info center" of this web site.

The obvious stuff are things like vacuum leaks, bad O2 sensor, bad plugs and/or plug wires, etc., are of course the first things to check.

In addition there are some AFM check/calibration instructions at Air Flow Meter (AFM) - from "The 944 Motronic DME" by FR Wilk Yes, this is on a 944, but the instructions still apply.

Searching this board finds a LOTS of info on Motronic troubleshooting.

Good luck!

-Dan
--------------------------------------------------------------
'87 black/black sunroof coupe w. f/r spoilers, fabspeed premuffler, dansk 1-in-2-out, sw chip, euro ride height, bumperette removal, CRD-220, etc.

[tony9704]

Just to update for future troubleshooters- The plug wires looked good and passed the "lights out" test, however, the cars issues sorted right out after changing the wires. (just the wire, not the end connectors) There must've been a faulty one somewhere, causing a stumble- Ben at M+K noticed it. I didn't even realize there was a stumble present, I just thought that was how these cars ran. Also, the problem could've been between the end connectors and the plug wire. You can't see how corroded or worn they are because they are inder the boot. Car runs crazy good now.

[tony9704]

Idle issue was exactly as thought- unrelated. The throttle cable was not letting all the way off. It only happened when it is very hot out. A bit of penetrating oil and the problem cleared.
This would be the first thing I would check with an overactive idle because it was such an easy fix. You dont even have to jack the car up to see and spray. Thanks again guys.

[tony9704]

I'd like to thank Wildcat077 for turning me in the right direction on the idle issue.

[pixxi]

Hi Tony, can you describe specifically the stumble that you mentioned, which was solved with new ignition leads? I have a stumble also with my '87 3.2 right now. Mine was first noticable only rarely, and only when accelerating hard through 2nd gear. Then over a few weeks it became continuously more noticable, even at less throttle and also in other gears. Any thoughts appreciated!
- Brian '87 3.2 Targa

[s5uewf]

You have to reset your CO levels. Before your mods, your car had a more restrictive exhaust system and more conservative timing and fuel map. Introducing these changes likely has altered your engine's baseline CO measurements, which means your air fuel ratio is off. Popping on deceleration could be an indication of the mixture being off, for example.

You should check your CO levels / Air Fuel Ratio.

Also, you may have introduced an exhaust leak when swapping out the exhaust. Listen and check for a leak. One easy thing to check and eliminate as a contributing factor.

Good luck - easy things to adjust and then you wil be all set.

[tony9704]

Hi Brian, Like I had mentioned, I hardley even noticed it at first. Someone else pointed it out. Car started and idles decent and ran out nice. The stumble made the car sound a bit more muscle car at idle . They should however, run smooth and consistent. as a remedy, I did a bit of maintenance- cap and rotor, leads. Mods are going to change things a bit. In my case, a problem that was present was amplified. The leads took care of it though.

[pixxi]

thanks Tony! I will check it out.
Cheers, Brian '87 3.2 Carrera

[pixxi]

Hi folks, thanks for the inputs.

The new wires solved it ! Yay. In love again.

Interestingly, I did not see any sparks initially after several checks in the garage in the dark, until finally spraying somewhat more generously some water mist along the wires - then finally I did see very faint intermittent sparks in the area where the wires run around the top of the fan shroud. :-)

Just for fun, here are some other steps I took prior to detecting and ordering the new wires:

- checked the AFM voltage output consistency using the 9v battery test per the944.com info thread; the process turned out to be quite simple and not very time consuming at all. Was all ok. I didn't open the afm, or clean or move the arm. I simply observed very consistent voltage increase with no drops, when opening the flap verrrryyy gradually.
- checked the O2 sensor voltage output, and it was also ok, ranged approx .1v to .8v per the related threads. The only tricky step was contacting the voltage meter electrodes to the o2 plug. Was glad it determine that it seemed fine.
- Found a vacuum line hanging behind the airbox area, which had disconnected from the y connector behind throttle body. Reconnected that, but did not notice any running change really.

Anyhow, problem solved in the end, thanks Tony.


Brian
'87 Carrera

[dshepp806]

NICE!!!!!

Doyle