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Hi all, this is on the '89. I've had this constant problem with it running rich for a long time now. Today my girlfriend said that she saw a little puff of black smoke out my exhaust and sometimes I get a sulfur smell (not nearly as badly as I used to though and I've been told thats just from a new cat converter getting "broken in"). I'm getting about 14-15 mpg in town and about 20-25 on the highway. Here are my specs:

-about 70k miles on the engine and around 155k on the transmission
-Flowmaster muffler about 8k miles ago
-High flow cat converter about 15k miles ago
-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
-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
-Rebuilt ECM/PROM compliments Delphi that I got off Ebay with a lot of T Type parts
-Adjustable vacuum modulator (a little on the soft side right now)
-"fresh" rubber on the vacuum lines
-No squaling or clunking from the engine... maybe a bit slow on throttle response though
-very slight damage to MAF screen... I have extras as of a couple weeks ago but I didn't think it would hurt it that much
-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 but the IAC has not

The only things I can think of are a bad TPS that isn't throwing a code, bad IAC valve, bad EGR valve (I've swapped in spares with no changes though) a bad evap canister (do they go bad??), faulty ECM (I have spares but swaps in the past don't seem to make a difference), bad transmission (no overdrive or something?), or the plugs are just too much overkill.

So... help in the right direction would be great. As you can see, I'm pulling my hair out trying to get this figured out with swapping in spare parts and whatnot.

My first thought would be MAF. But normally you'd get a 34. Hmmm. Or a 21 for TPS....but that would give you idle problems, cold starts would be around 2k rpms...throw a scan tool on it and see what you've got for an o2 reading as well...

What is the code on the MAF?

MAF is code 34. TPS is 21 and/or 22. I'm getting neither code right now and I have a known good MAF on the car now.

I don't have access to a scan tool but I seem to recall that theres a way to get a cable that will hook into a laptop that can access live data from OBD1 ECM's. Would something like that work?

I don't know if there are different ones or not, but you mentioned the MAF was replaced. The MAF on my has a number AFH50M-02G on it if you want to verify it. You might also want to verify the ECM you put in it from Ebay. I think it has a setting for the gearing on the tranny iirc.

The MAF's do have different numbers but I don't think anyone on LeSabreT have ever had issues with the being different.

The ECM came out of another T Type which should have had the correct 2.97 gearing. My current transmission is 2.97 so it should work but I've got a spare that I can swap in just to see what happens.

Good ideas so far... keep em coming

I had a different one on my 89 from a 91 I think it was and it ran a little strange. The 89 code, which has now been posted, should be verified as this could be an issue....proper calibration keeps it in spec...but it won't throw a code.

Good point. I'm pretty sure the MAF came off another T Type so it should be of the correct vintage but I could check it. The motor is a '90 BTW but I figure as long as the ECM is an '89 that all should be good. I'll see about digging up the original ECM too.

Just an update. Heres a list of what I've eliminated as possible issues:

-IAC (swapped over from the '88 and no change)
-EGR (put some hi-temp silicone on the gasket to make sure I'm not getting a leak)

Next up is the ECM. It still runs rough and still smells like rotten eggs after I gun it. If the ECM doesn't do it, then I'm starting to suspect a faulty TPS. Does that seem like good logic?

Hey guys. I yanked the rebuilt ECM out and got the original ECM sitting side by side. Some questions:

1. Were T Type ECM's different from regular LeSabre ECM's programming (T's had 2.97 gears where most others had 2.84)?
2. What is the correct number for the T Type (Or Vin C PROM chips in general)?
3. Where, exactly, is this number located? I know its on the chip, but whereabouts?

Help is much appreciated

Edit: Found the numbers:

Original ECM: ATYL 8061
Rebuilt ECM: ANBH 2522
88 T Type ECM: AJSA9248

Edit 2: Wait a sec... stupid me! I have a second T Type... why don't I just yank its ECM instead??
Edit 3: Added the '88. Hmm... which one to choose...

Eric, you might also look to the fuel rail and injectors, My wife's 90 had rust in the pipe, and an injector (don't know which one) would bleed pressure down after shutoff and make starting rich and difficult. Found one on ebay with injectors, changed the O rings and even at 206k, starts now with just a flick of the key.

ECM is easier to swap and see, and zero cost for you but its worth a look if that fails to fix

Swapped the ECM and went for a test drive. The car seems to like this other ECM just fine but I still get the sulphur smell.

Speaking of issues on the fuel rail, I was thinking about swapping the fuel pressure regulator from the '88 onto the '89.

What gets me is that everything on the motor itself only has around 70k miles on it. What are the odds of having an injector fail with low miles?

Edit: Just went out and fiddled with the FPR. I removed the vacuum line and didn't smell gas. Started 'er up and still didn't smell gas. Sprayed some WD40 in and no change in RPM's. Slipped the hose back on and the car started idling like it has been: rough. Its not super rough by any means but still... its enough that its not burning fuel as it should.

What next? TPS?

I'm still pulling my hair on this one. The car seems to run great when I first swap (reset) the ECM but after its had a learn cycle the acceleration gets poor and I start getting the sulphur smell. Also, the idle seems to be smoother after an ECM reset but after a few minutes its right back to running rough again.

Suggestions? This issue is really driving me nuts.

I don't see your TPS having anything to do with this.

FPR possibly. MAF definitely.

I'll have to dig up all my spare MAFs then and see what happens when I start swapping them in then.

Swapped out the MAF with a known good one but no luck... same exact problems.

What next? FPR?

Edit: I swapped in a FPR from my '88 (which was running quite smooth) and it seemed to help the idle some. I think I'm going to go ahead and buy a new one and swap it in and see what happens.

Sorry for all the replies in a row but I just want people to see that theres a new post with new information

Just got back in from playing with a fuel pressure tester. Not sure how accurate the info is since the unit is a US General from Harbor Freight.

Anyway, 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 are clear that I have issues with fuel. 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?

Alibi wrote:Sorry for all the replies in a row but I just want people to see that theres a new post with new information

Just got back in from playing with a fuel pressure tester. Not sure how accurate the info is since the unit is a US General from Harbor Freight.

Anyway, 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 are clear that I have issues with fuel. 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?

It should hold pressure at about 40-47psi with the key on engine off
about 37-43 psi (i looked it up today and i dont remember exact) at idle

There are 2 problems you could have but i guarentte(sp) you one of these is your problem IF your sensors are reading correctly.
leaking injector(s)
Bad FPR

To test the fuel injectors you can buy a fuel injector tester but its not going to help you if you cant hold residual pressure. the otherway you can test them is to pull the fuel rail and injectors out of the manifold (leave the injectors in the fuel rail) and turn the key to on. If any are leaking then those must be replaced.

To test the FPR you must start the car put the fuel pressure tester on the schrader valve then pull the vacuum line off of the FPR the pressure should spike and hold alot higher than normal. You may also have a hole in the diaphram of the FPR which would leak gas and get sucked into the intake through the vacuum hose you should be able to tell this by pulling the vacuum hose off to test for the pressure spike.

Now you didnt say anything about any of the sensors that affect fuel except the MAF. you didnt mention anything about the ECT, IAT or MAP sensor. All of those have to do with fuel. Your computer will not go into closed loop operation if it thinks the coolant temp is too low. If your not in closed loop then the computer ignores all signals sent from the o2 sensor this could make you run rich.

If your IAT is reading that the air is alot colder than it really is that could make your car run rich although probably not as bad as you say it is. I would still check the resistance. To make sure its the right resistance for the temp its at.

Your MAP sensor senses atmospheric pressure when you turn the key to on. It also senses load and manifold vacuum. Now if there was a vacuum leak in the vacuum hose going to the MAP then it will probably give you a higher reading than what it should be. The MAP sensor voltage should follow the TPS pretty closely.

So what you really should do is get a scantool hooked up and watch the voltages and signals of all ur sensors while you are driving. You are still going to need to take care of the fuel system not holding residual pressure which from the sound of it appears to be your fuel pump. If your fuel pump was still good and just your filter was clogged then you would still meet specs for the residual pressure. It might take longer to build that pressure but it would do it. Seeing as how you are not holding any pressure it could very easily be your fuel pump or leaking injectors. But with your rich condition i would say injectors since a wornout pump would cause a lean condition. restrictions would cause lean, leaks cause rich.

I have a new fuel filter and FPR sitting at home... I just haven't had time to swap them in. After that I was planning on buying an ALDL cable and hooking it up to my lappy to see what I'm getting from the sensors but its all about time right now.

I've never thought of checking for a leaky injector by yanking the rail and injectors so I may do that sooner or later too.

The IAT is fairly new (couple thousand miles maybe) and is located right after the cone air filter. Stock, the IAT is also located right after the filter so I assume this is fine.

The CTS has around 70k miles on it so I'm assuming its good.

Where is the MAP on the Vin C? I've never needed to track one down before...

I have recently found a very small leak in my radiator thats enough to keep it from building up much pressure in the system so I 'm wondering if air bubbles are causing some problems...

I wouldnt assume anything. I have bought NEW sensors and you would think that they would work but they dont always.

I might be getting my engines mixed up i have been so busy looking up stuff for so many different engines at school that its starting to blur. I will double check the MAP sensor.

the fuel pump has a check valve in it, if that goes bad, it will loose all fuel pressure when it is turned off. I had it happen on my Park Avenue, It made for hard starts.