'89 Running Rich

[Alibi]

Hi all, been a while since I posted but I've got a problem that stumping me pretty good. First, some specs:

-1989 Buick LeSabre T Type with a little over 200k on the chassis
-Vin C motor with about 70k miles on it
-2.79 ratio transmission with about 150k miles on it

Here are my symptoms:

-Sulphur smell after a quick acceleration
-Rich gas smell on startup
-Occasional puff of smoke
-Slow acceleration
-Idles at around 550-650 RPMs but its rough-smooth-rough-smooth-rough-rough-rough after the motor warms up
-Car seems to have better throttle response after resetting the ECM but the problem comes back after its had enough time for a learning cycle

Here are some facts and parts that I've eliminated:

-Flowmaster muffler about 8k miles ago
-High flow cat converter about 15k miles ago (CarSound Magnaflow)
-Belden wires wrapped in loom
-Type II ignition swap (blue on the underside of the coils)
-NGK Iridium plugs (overkill I know now but not at the time I got them)
-NTK (division of NGK) O2 sensor, less than 10k miles on it
-FWI with K&N filter (system worked great on my '88)
-JB welded cam magnet from a code 41 about 10k miles ago
-No codes/SES light
-Correct ECM programmed for 2.79 trans and it is known to be good
-Adjustable vacuum modulator
-"fresh" rubber on the vacuum lines
-No squaling or clunking from the engine
-very slight damage to MAF screen but it has a known good MAF sensor
-I have cleaned the intake recently but the first time 20k miles back or so I did it I used carb cleaner (d'oh!) and since then the MAF has been replaced
-IAC has been swapped out with a known good one
-I don't smell fuel in the FPR and the idle doesn't change when I spray WD40 into it (checking for a pinhole leak)

I think the next step is to check the TPS but otherwise I'm stumped. As far as I can tell it should be running right but its not.

Suggestions would be greatly appreciated as I'm going nuts trying to fix this

[maxwedge]

A full scan will look at fuel trims to verify arich condition and what the pcm is trying to do about it, also look at the fuel press.

[Alibi]

Originally Posted by maxwedge

A full scan will look at fuel trims to verify arich condition and what the pcm is trying to do about it, also look at the fuel press.

I don't have access to a scanner. Is it feasable to get a cable to connect to the OBD1 port and then to a laptop? If so, any suggestions on where to source one?

Otherwise, other sources that I'm finding are suggesting a bad fuel pressure regulator. I swapped in one from my other VIN C motor car (that runs very well) and it seemed to help some but not 100%.

Any other suggestions?

[maxwedge]

Not up to speed on the cable/laptop link. But today to fix a modern efi car, a scanner is basic equipment, without it a lot of guess work is in the future for any driveability /emissions issue.

[HotZ28]

Originally Posted by Alibi

I don't have access to a scanner. Is it feasable to get a cable to connect to the OBD1 port and then to a laptop? If so, any suggestions on where to source one? Any other suggestions?

http://www.aldlcable.com/

[Alibi]

Originally Posted by HotZ28

http://www.aldlcable.com/

Aha! I remembered such a thing existed, I just couldn't remember exactly where/what. I think this would be $60 well invested.

On a side note, I decided to check my fuel pressure:

Fuel pump has around 70k miles. The fuel pump is supposed to be around 40PSI at idle but I don't know how accurate the guage is that I got from Harbor Freight.

Heres the pressure readings:

Engine off for about an hour: 0 PSI
Turn Ignition to "on": Jump to 10 psi but slowly drops back down to zero in about 15-20 seconds
On Startup: Jumps to 35-40 PSI
At Idle: Stays right at 35 PSI (A tad on the low side, eh?)
On idle roughness/burps: Pressure drops 1-3 PSI when the idle goes bad...
Bumping the Throttle: Goes down to 32-33 and then jumps back up to 35-36 after its been goosed a bit

At this point I could see fuel starting to build up behind the lens of the pressure tester.... what the heck?? So I killed the motor and its sitting outside now.

However, I think these results may suggest that I have issues with fuel delivery to my injectors. The filter has around 20k miles on it so I think I'm going to try to change that ASAP. I dropped by O'Reily and they have a FPR for around $80 where autozone has one for $30. Will I be OK getting the AZ unit or should I wait?

Ultimately, it could be my fuel pump going out. The pump is original to the engine which has around 70k miles on it which to me seems a bit low for a factory pump.

Thoughts, suggestions on which route I should go in first?

[HotZ28]

Originally Posted by Alibi

At this point I could see fuel starting to build up behind the lens of the pressure tester.... what the heck?? So I killed the motor and its sitting outside now.

If you have fuel inside the lens of the gage, you have a bad gage. Try another gage before changing parts!

[Alibi]

I figured as much... I'll take the gauge back this afternoon and grab a fuel filter while I'm at it as I know it needs that for sure at least.