348 Leaking from driver side catalytic converter after super major.

I recently performed a super major on my 1990 TS but I am now having issues with the car running very rich. My main issue is bank 5-8. It is running so rich that the it is leaking fuel through the exhaust gasket prior to reaching the cat converter. It actually left a puddle on the floor that is how much was pouring out. I shut the car off before it started to get hot so i don’t start a fire. I have done the following so far:

1. Adjusted the MAF to baseline 383. It runs but backfires and smells very rich. Adjusted higher and it goes away but then smokes with a rich smell. I lower it and smoke goes away but back to backfire and rich smell.

2. I Replaced both FPRs and ignition coils. I also checked the resistance on all 8 wires (6 ohms). I placed an in-line spark plug tester in each cylinder to test the wires and they are firing consistently.

3. Replaced all fuel injectors with 4 spray mist pattern injectors. They are rebuilt but designed for this car so I can’t imagine that it would be injecting more than what the vehicle was designed for.

4. Replaced o2 sensors. Removed the o2 sensor on 5-8 because it was fouled I don’t want to reconnect until I resolve the issue. I also have 2 new CATs but don’t want to install until issue is resolved.

5. I have no CELs displayed. Well the adaptive lambda adaptation code came on (1211) but once I removed it and replaced the o2 sensor it went away after a reset.

6. The spark plug on cylinder 7 was fouled I switched wires. No change. I also swapped ECUs but made no difference.

Bank 1-4 is not leaking although it still emits a rich odor as well. My next move is replacing the coolant temp sensors but there are no codes indicating that there is an issue.

I am at a loss....hopefully someone has an idea on what to do next.


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What's a super major?

 

Swap out the injector in #7. It's stuck open. Maybe a piece of crap in it.

 

LOL just as he subsequently explains it.

 

put the original injectors back.

 

Really? So the belts/tensioners aren't part of the major? I must have missed that in his explanation.

 

So you are saying petrol is leaking from the exhaust system onto the floor?? I very much doubt only 1 spark plug is fouled. There is a fundamental problem there. Start by checking the firing order..

 

As I understand it, a super major is major as you know it, except full (cam timing/valve shim) and then some.. like oil pump tensioners/update, front pump bearing, maybe clutch and throw out, wires, coils, check valves, sensors basically a super major or more than major in another vernacular.

 

Or maybe it's the Google translator. I've noticed recently that many of these new members, who are asking for tech advice, don't have anything in their profiles. In my opinion, their part of the world should be included (e.g. Central Europe or a specific country) because of the car's configuration and the members' access to resources.

 

Yep, translation from Canadian Albertese is a problem for Google, eh?

 

Didn't see where he said Canadian. So how would you say "Super Major" in French?

Super - French to English = Great

 

OOPS. I read Alberta instead of Alberto. But at any rate, translations from Chicagoan may be difficult too!

 

Lol on the super major. My apologies on my profile data not being updated. I thought I updated it but I just went into my profile now and took care of it. My part of the world is in the heartland of America. What I meant by a “super major” was a lot more work completed than what is normally involved in a typical Major (valve adjustment, cam timing, fuel pump gasket replacement,“suspect bearings replaced” etc.) I see some understood but others did not my bad. I am new to this forum but have been working on Porsches (water cooled and air cooled) and BMWs for over 20 years and with that said this car is actually a bit easier (by a small margin) and a lot more fun to work on. The engine bay is spacious. I love to work on this car and enjoy the smell of the engine compartment when I open it. Well maybe not right now. I choke when I open it now....but that will soon be fixed (with assistance of the fine gentlemen on this forum) I know I still have a lot to learn about this car.....but with the help of everyone on this forum I believe I can accomplish anything.

Now back to the issue at hand....I think plugzit and Yelcab are spot on in the injector replacement/ faults. I will replace all injectors with the original ones and report back.

 

Ernie did a hell of a lot more but didn't call it a super major

 

He sure did do a lot more. I followed his excellent DIY when I did mine. Without it....it would of taken me a lot longer and I would have made some mistakes that I am sure of. Reading his DIY on the major is one of the reasons I bought the car. He proved it could be done at home in your garage with jack stands. If I recall correctly he called it a “major major” I shall strike super major from the record.


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I'd start with what's been mentioned here already:

1. Firing order (maybe a crossed plug wire)?
2. #7 Injector (stuck open)
3. Re-evaluate the 4 spray mist pattern injectors

(O/T) If: "Super" (French to English) = "Great". Then: A greater version of the major; "Greater" (English to French) = "Plus Grand". So yeah, a Super Major is gonna cost ya at least $1000 more.

 

Yes Ernie is a legend here. He has given a lot of people the encouragement and confidence to do the work themselves that they otherwise would never even consider attempting (myself included)

 

I had the exact same problem .... it was the crankshaft.

 

Swapping the injectors worked! It ran great for 20 minutes. The 4 spray pattern injectors was too much even though it was advertised for this particular make and model. Now I have to replace the CAT converters...



View attachment 2610924

 

Not sure what that has to do with it? Pretend he said a major then extra stuff as Merriam-webster defines "super" as "over and above : higher in quantity, quality, or degree than : more than ".

Lavenknight - Glad to hear about the injectors I was googling for people with those 4 hole updated injectors to see if they flowed the same I was skeptical there is 3 more holes after all, so thanks for the update!

 

Glad to hear you got it solved. The 348/355 section has some of the best DIYers I've ever seen (Bruce and Ernie included).

 

Here is a picture of the original injector and the 4 spray mist injector. I was assured the net quantity would be the same (4 smaller injects of fuel = 1 larger one) but that was of course not the case... a lesson learned.



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The thing about sharing lessons learned is to help prevent the next person from making the same mistake.

Thanks!

 

Glad you got it sorted.

 

The 4 spray injectors still have one pintle (needle) like the original one and the 4 holes are only on the pintle cap. The problem you had was either due to the "4 spray" injectors having very high flow or because they are just faulty.

Here's a table of possible replacement injectors for the 348. Other than the Porsche injectors 0-280-150-730 (which are identical to the original 348's 0-280-150-731), a very close replacement is the one highlighted green.
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