efi High Idle At Normal Operating Temperature

[bnam]

Chenu,

A mityvac is good for testing vacuum to a specific level.  But to test for leaks, you can just put a hose and suck out the air to see if you are able to get a vacuum or if air is leaking thru.

 

If you have air leaks here, it could be the cause of the low idle when warm.

 

Byas

[jgerock]

The crankcase vent tube routes air into the center of the air cleaner and a tiny bit into the throttle body. This air is unfiltered so it accumulates in the throttle body and intake plenum. If there is a pooling of oil in the bottom of the horizontal plenum, then most likely there is an engine condition problem.

[ck_74tii]

I have riden it for over a week and this is how she consistently behaves. idles at ~1600 rpm when cold after starting, eventually when the car warm up the idle holds at 1100 rpm. Interestingly there is a transition phase in between runnign at 1600 rpm and 1100 rpm that lasts for about 2 min where the idle goes down very low to 400 rpm or so, i tap on the throttle to keep it going lest I stall.

 

Does this behavior give some clue as to whats happening? I would liek to adjust the idel screw to lower rpm but do not want to try untill i have an idea of whats going on.

 

BTW I have replaced all the vacuum lines. I have the hose comming from the front of the manifold (that goes into the valve on top of air filter) plugged. I have ordered a new crankshaft breather hose and plan to soak the valve in cleaner. Has anyone tried removing the nut on it?

 

 

Carl - I noticed there is one section of on one of the hard plastic tubes that have gone thin, I will post pictures when I get to work on it over the weekend.

[bnam]

Have you checked if the valve diaphragm is leaking?  Put a hose on the small inlet and suck on it, it should hold a vacuum.  Try the same on your vacuum advance can.

[OriginalOwner]

+1 bnam.

 

 That's how mine operates: when it's cold, high idle rpm.  Then when the engine gets to "normal" temperature, the "normal" idle sets in.  So far so good ...... I guess.

 

 But that drop-down to 400 rpm, I'm no particular help as to why that happens.  I will however make a huge guess:  it could be that little screw adjuster inside the tuna can.  My engine responds to 1/4 turn movements of that adjuster, and low idle and/or idle surging has been one of the symptoms it is time to mess with it.

 

 And just to say it:  there are 2 screw adjuster thingies.  The little one inside the tuna can, I'm pretty certain it is for CO adjustment.  The other adjuster goes through the front of the tuna can, and is the actual idle adjuster.

 

 So it could be time to take a few deep breaths and make some adjustments.  Keep a detailed logbook of what you do so you can re-adjust backward to where you started.  (translation:  I wish I had kept logbooks of all the adjustments I made 30+ years ago).

 

I recommend Google'ing around the internet in general for "2002tii" and see what you can find & learn.  I just found this website with some interesting info for fuel injection .....

http://www.bimmers.com/02/faq/engine.html#fuel_injection  

 

 

Cheers,

 

Carl

[ck_74tii]

Carl - u suggest I tinker with idle screw outside of can first or with CO screw on inside. I am thinking u meant the outer screw but thought I check.

My guess is that the low idle is due to removal of vaccum line to valve on air filter.

Byas - I will check out the narrow tube vacuum over weekend.

If I were to remove throttle body can I mark the location of rod from tuna can to rotation post and reinstall it. Are there any other things to worry about. I.was thinking of.cleaning TB when I.install crankcase breather hose.

cheenu

[OriginalOwner]

Yes, start with the outside adjuster screw, see what happens.

 

Cheers,

 

Carl

[jgerock]

Just did a cursory check of high idle on a friend's 74tii (July 74).  First thing after reviewing this thread is the hose connections.

 

From the vacuum valve on the air cleaner, the large hose goes to the large fitting on the front side of the intake plenum, small hose goes to the smaller fitting on the plenum. Small white colored hose from throttle body plenum is connected to the vacuum canister on the distributor.  Is that correct?

 

Car in question does not have a plastic fitting on the crankcase breather return hose to connect to the throttle body vacuum port. 

 

Also noticed the make-up air hose from the warm up regulator up to the plenum was cracked. 

 

Hope the owner is watching this thread - the vacuum valve needs to be checked (among other things we discussed).

 

 

[randall2v]

7 minutes ago, jgerock said:

Just did a cursory check of high idle on a friend's 74tii (July 74).  First thing after reviewing this thread is the hose connections.

 

From the vacuum valve on the air cleaner, the large hose goes to the large fitting on the front side of the intake plenum, small hose goes to the smaller fitting on the plenum. Small white colored hose from throttle body plenum is connected to the vacuum canister on the distributor.  Is that correct?

 

Car in question does not have a plastic fitting on the crankcase breather return hose to connect to the throttle body vacuum port. 

 

Also noticed the make-up air hose from the warm up regulator up to the plenum was cracked. 

 

Hope the owner is watching this thread - the vacuum valve needs to be checked (among other things we discussed).

 

 

watching very carefully Jim

[jgerock]

7 minutes ago, randall2v said:

watching very carefully Jim

Now that we have established a "connection", here are two pics of the engine bay.

Next issue is the tachometer isn't working.  Car has Pertronix so the old condensor wire is hanging free near the distributor.

There is a black wire at the negative terminal on the coil (which I think is the tach lead wire).

There is an extra black wire that isn't connected (see blue colored butt splice connector).

Since I'm not well versed in the 74tii, is there a different connection for the tachometer?  The black wire IS connected to the back of the gauge cluster.

Edited July 3, 2016 by jgerock

[RyanEsca]

I'm having a high idle issue on my 74tii only when warmed up too. Stays around 1500rpm, not too much info on this issue from what I can find. Cold start is good and idles at 1100rpm.

You can see how my deceleration valve is plumbed. I changed all vacuum hoses except the KF to Plenum, which seemed to be ok. I do have the throttle body vacuum line going into the crank case breather hose.

I did notice the fuel enrichment arm doesn't fully bottom out when warm as well. The warmup regulator does stop sucking in air once warm. I've been hesitant to touch anything since the last time it was tuned by ProBimmer before it sat for 4 years (started it once a month during hibernation).

[CaptainT]

Hi Everyone

 

I have just joined after having been a "follower" for some time.

 

Intro: I have a 2002tii lux 1975 (Brenda by name) that I have owned since 1980. A Getrag 235/5 CR gearbox and LSD have been fitted from new. The car is UK spec so there are some differences to the US spec.

 

With regard to this thread, I have recently posted twice on the forum.bmw2002.co.uk concerning similar subjects that may be of interest:

1. Intermittent Flashing Ignition Light.

2. Tii Set-up Info

The car was fitted with a Powerspark electronic ignition in February 2016. Prior to that, the tickover had been around 1300 warm and after was 1000. A couple of months ago I started having start problems, hot and cold, which indicated a cylinder flooding. I could start the car and get it to fire on all four by flooring the throttle. Tickover had returned to around 12/1300. The first thing I did (see 1.) was carry out the thermotime/cold start valve and timer box checks. This cured the start problems, both hot and cold, which indicated a bad contact somewhere as nothing was physically changed.

 

The tickover was still high so I decided to play with the "tuna can". This is detailed in 2. above. The one thing to come out of that (and as found in the linked thread on this site) is that the universal instruction to use a 4mm drill bit to line up the cam did not work. There is a reference to the illustration in the Haynes Manual which clearly shows the cam halfway across the hole. In my case, the cam was around one third of the way across when I first looked. I used a 3mm drill bit when resetting. Not having a CO meter, I used the method found here: 

As I stated, it was not easy. The original mixture setting was totally lost after much turning back and forth but at the end of it I do have a stable set up and the car pulls strongly in all gears through the range. I believe the car is running rich, both on tickover and throughout the range. Playing with that might come later!

 

Of interest, before all this started, the car would start from cold at around 1300 rpm but by the time I reached my first stop one mile down the road would be at 1800 rpm. The next stop, four miles further, would see a reduction to the standard 1300.

 

After all that, I took the car for its MOT (passed - as usual) and asked for them to measure the CO. Unfortunately, I was not there so the readings were taken at 1990 rpm for some reason. The CO reading was 5.36%. The reading at tickover should be 2-3% up to a max of 4.5% (BMW Workshop Manual). The CO reading is apparently variable throughout the range and can vary with load as well as RPM. The engineer who has much BMW knowledge, advised me it was fine with those figures and as all feels well and Brenda is happy to leave well alone!

 

Hope the above is of some help to those struggling with their tickover, etc.

 

TY

 

PS On to the taco issue. My condenser had two wires going into one connection. After fitting the Powerspark I taped off the connector and the tacho worked fine until a couple of days ago when one wire pulled out. The tacho stopped. I reconnected and all is fine again. Not sure about the black wire by the coil. Mine has a red from the Powerspark and blue /purple from the dis. If the wire is just resting against the coil pole I can only suggest taping it up and seeing if that brings the tacho back to life.

 

 

 

Edited July 9, 2016 by CaptainT

[RyanEsca]

On 7/5/2016 at 8:54 AM, RyanEsca said:

 

I'm having a high idle issue on my 74tii only when warmed up too. Stays around 1500rpm, not too much info on this issue from what I can find. Cold start is good and idles at 1100rpm.

 

You can see how my deceleration valve is plumbed. I changed all vacuum hoses except the KF to Plenum, which seemed to be ok. I do have the throttle body vacuum line going into the crank case breather hose.

 

I did notice the fuel enrichment arm doesn't fully bottom out when warm as well. The warmup regulator does stop sucking in air once warm. I've been hesitant to touch anything since the last time it was tuned by ProBimmer before it sat for 4 years (started it once a month during hibernation).

 

 

 

Well after some more work I noticed the throttle body was a bit dirty and wasn't allowing the butterfly to return all the way back to resting position. I cleaned the throttle body as much as I could while on the car and it seems to be idling just perfect now @1100rpm when cold and warm. I'm going to order up gaskets and other misc parts so I can pull the throttle body, clean it properly and refresh some of the hardware while I'm in there.