baffledLS

Hi,

I truly hope the collective wisdom here can guide me in the right direction.


I'm fixing a 93 Ls 400 for a friend of mine. It happened to have the premium package for that year. Unfortunately, the r/s rear air strut was leaking. I swapped in regular struts from his other Ls 400.

Yet, on to my main problem. This vehicle is getting the converters hot. Here's the grocery list so far that has been changed. Coils, wires, caps and rotors. Plugs. Car starts easily, timing doesn't seemed to have jumped. Pulled wires indvidually while vehicle is running to check for spark.

The craziest part of all of this, plugs 1,7, 4,6 are clean but smell of gas. Plugs 3,5, 2,8 are fouled out? I'm at a total loss on what to do next. Swapped igniters to no avail. O2 sensors are fouled out from running so rich.

What is possibly my next move?

Thanks

j2b4o

Iirc these cars get clogged converters and they get very hot(glowing in some cases). But there has to be some issue causing the bad converter problem. The plug situation is a head scratcher for me so I'm sorry I can't help u there.

PureDrifter

iTrader: (10)

lol the converter isnt the problem, it's a symptom. the car's running pig rich and the fuel is igniting in the cats, and will destroy them inside and out if you try to run it like that (may be dead already).

you need to figure out your spark/fuel issue first.

baffledLS

There is something definitely going on with the fuel system. The plugs sem to be getting fire but it's like some injectors are hanging open..... I totally lost on this, plus wore out from trying to figure it out the only thing left to do is start swapping injectors around from the other car......

LexterLS40

can you diagnose the car ?

cobalt91

Have you checked the fuel pressure? Sounds like maybe a faulty fuel pressure regulator.

baffledLS

I haven't swapped the regulator. I may try that.

Yet, on the drivers side of the fuel rail there must be some sort of fuel dampener that looked like another regulator that had a screw in the center of it. On the car that has the premium package, the screw was backed all the way out. I said to myself this isn't right and swapped in the one from the othe car with no change in performance.

The fuel regulator doesn't smell of gas at the vacuum line, so I've left it alone at the moment. Again it's like only certain cylinders are affected. 1-7 -4-6, the plugs are clean as a whistle, no combustion but smell of gas?! The othe cylinders are black/sooty looking.....

baffledLS

Well,

I swapped fuel pumps and fuel regulators to no avail. The only thingn left is the whole fuel rail with injectors. If this doesn't solve it, I'm done with it.

I've even tried the other pcm from the other car, no change at all.

This is ridicoulos

PureDrifter

iTrader: (10)

if you ruled out fuel as the problem in those cylinders (which are on 2 separate banks) then you need to rule out spark issues...

fixmiester

Any chance the fouled cylinders are sucking coolant from a bad manifold seal, or crack? That plug fouling may be from antifreeze. Once fouled, then they would smell of gas, and the cats catch it from there.

baffledLS

After putting in a fresh set of plugs, the same ones get fouled out. I've never seen anything like this. 3-5-2-8. Myabe the intake is the culprit. Yet upper or lower?

fixmiester

I would suspect the intake manifold; have you noticed a loss of coolant?

baffledLS

I can't per se' because I can't keep the car running long enough without possibly ruining the converters.

This is a car my friend bought to retire his 300,000 mile 93. This one has 130,000 with issues also.

The lesser of two evils........

baffledLS

Yet, the plugs aren't coolant fouled, they are fuel fouled out.

His 300,000 mile 93 developed a coolant leak. I couldn't pinpoint but I knew it was possibly the intake. I told him not to drive it because it was going to get worse. Did he listen? Of course not.

I eventually saw the starter valley starting to fill up with coolant. I stated don't drive this thing, it's going to leave you stranded. He was lucky enough to get stranded at his front door. When I looked at it again the starter was practically submerged in coolant. That finished off the starter. Of course the plugs got coolant fouled out along with the oxygen sensors. They have this yellowish/ white look to them. So, I know the "newer" LS isn't coolant fouled, it's fuel.

There also seems to be some type of exhaust leak on the right hand side of the vehicle. It's seems to sound like it's coming from behind the cylinder head by the firewall.


Who knows...........

baffledLS

Well,

I've learned a few things over the past couple of hours.

The exhaust leak behing the r/side cylinder head is probably the egr pipe, which seems to be quite common on these cars. I've also learned that a malfunctioning egr could be causing my problems, along with a vacuum leak like someone stated earlier. Yet, I don't here any hissing.

I plan to spray some carb cleaner along the intake manifold to see if the idle picks up. Yet, the car starts so smooth when it does.

The guy I'm dealing with is a piece of work. Weak battery, no gas in the car, no money to pay?! Why do I try to help these type of people when they can't help themselves is beyond me.

Maybe, I just feel sorry for them, maybe I'm just crazy...........