CEL/poor idle...p1222 code...

[BMWManiac]

Car was running perfect until I removed my intake manifold to get it done by Renewed Finishes.

Reinstalled a spare intake manifold, all intake gaskets. The spare manifold had a TB/TPS already mounted.

Whenever I start the car, the idle jumps up to 2k and slowly comes down, and then the motor struggles to idle. Then every few seconds, the idle jumps up and slowly returns. If I go for a drive, the car runs just fine. CEL will randomly come on/off, but mostly comes on when driving less than 10mph.

I swapped in a new TB gasket, no change. Put my TPS on the TB and no change. I've checked the vac line that goes to the intake manifold/fuel purge solenoid, vac line to ICV, Vac line that runs to the brake booster, vac line that goes to the valve cover.....

I think it is a vac leak, but there are only so many places to check....sprayed WD40 at the injectors, all around the engine and can't see to find indication of a vac leak.

Any ideas before I bring it to someone to smoke it?

[jlevie]

This sounds very much like an intake leak and a P1222 code practically confirms that. A smoke test will tell where the leak is.

Did you use new seals on the oil return tube when you swapped manifolds? If not that would be a likely candidate.

[BMWManiac]

I definitely did not use new seals...I only saw one seal at the bottom of it....is there a seal between the manifold and the tube itself?

Found it...so I remember there being a washer, but I didn't see any gasket...wonder if it was in the block. I will replace that one

[jlevie]

There is an o-ring at both ends of the tube. They can hardly ever be successfully reused.

[BMWManiac]

Appreciate it....both gaskets order and will be replaced. I shall report back in a couple days! Thanks!

[BMWManiac]

Just an update. Installed both o rings on the oil return tube so i think that solved my vac leak issue. However, the idle is still high...no more surging though. Had a buddy adjust the throttle/cruise cables and that made it better, even adjusted the screw. However, idle has returned to being above 1k. I think the issue is the TPS...it works, but I installed it facing the throttle opening (parallel). I noted there was room for adjustment of the screws. Should the TPS be angled slightly to the firewall or radiator?

[Bretts85E30]

U have to physically set it using an ohm meter the Bentley manual has all the info ull need adjust it

[derty30]

my car does pretty much the same thing it idles around 500 or 600 and it bounces almost sounds like it is about to stall... i havent checked for vacuum leaks just yet, hopefully its a quick fix!!

[Bretts85E30]

yeah i did I head and harness swap and still having an idling issue similar to this lol
but its super low almost like it wants to stall.

[BMWManiac]

I replaced one more vac line and put my original throttle body back on....it is 'better' and the idle is just about perfect, but it doesn't feel dialed in and the CEL will come on randomly at idle...even when idle seems fine. I am 99% sure it is my TPS and I have to continue to adjust it. I hear the 'click', I just have to continue to mess with it and get my ohm meter out.

[BMWManiac]

I used an ohm meter to adjust my TPS....I think it is no longer the issue. When I start the car, the car wants to die almost immediately when cold. After the car is warmed up, the car idles rock solid at maybe 650/700 rpm, but I can feel slight, what I would call, "rumbles" in my seat to let me know something is not exactly perfect.....then the CEL comes on. I give it gas, the CEL turns off immediately.

I'm going back to the vac leak theory.

[JCarp90]

I used an ohm meter to adjust my TPS....I think it is no longer the issue. When I start the car, the car wants to die almost immediately when cold. After the car is warmed up, the car idles rock solid at maybe 650/700 rpm, but I can feel slight, what I would call, "rumbles" in my seat to let me know something is not exactly perfect.....then the CEL comes on. I give it gas, the CEL turns off immediately.

I'm going back to the vac leak theory.

Mine does the same thing. Oh, bitches.

[BMWManiac]

I think I've found my leak(s). I sprayed carb cleaner where the injectors meet the intake manifold and the engine speed definitely increased. Removed the injectors, and noticed that all the lower injector o-rings were brittle and very hard. Great, I had some spair injector o-rings! Replaced/reinstalled the injectors....

No change!!!! I again sprayed carb cleaner and I again noticed the engine idle speed increased....what next? RTV around the injector where it goes in the manifold?!

[Balleristic31]

Check for a crack in the manifold

[BMWManiac]

Check for a crack in the manifold

Thankfully, I have my newly refinished intake/valve cover from RF to install...just wanted to wait until I did my turbo build and replaced the headgasket