L-jet AFM replaced, but the car won't stay running. (SOLVED) Options

[zach914v8]

Clark brother, I am seriously glad you got this thing going. Good work man.

[jim_hoyland]

Great news ! What does the 20 tooth AFM adjustment do ? And what are you looking at to judge its right ?

[malcolm2]

Great news ! What does the 20 tooth AFM adjustment do ? And what are you looking at to judge its right ?

My engine has been converted to a 1911 cc from the 1756 cc (1.8). The original AFM was setup for the 1756 so to get the 1911 to run properly it has to be re-adjusted by changing the spring tension. The spring is wound up inside a big toothed wheel. So you move teeth to adjust.

Since my backfire bent my AFM i had to get a new one. So the AFM was not my problem, but i could not adjust it til i got the car to run.

I used an Air/Fuel gauge to measure the changes and fine tuned the amount of fuel the AFM tells the fuel injection sys to give the engine.

[jim_hoyland]

Interesting; after upgrading recently to 2L and installing the Vanagon TB, I had wondered whether any correction is needed. It runs good and AFRs were within range

[timothy_nd28]

Adjusting the airflow meter is something that I would not recommend as they are calibrated from the factory. In most all cases, you can simply plug and play a new AFM straight out of the box with no issues. However, not so much in Clark's situation.

Clark had a air/fuel gauge (an awesome tool) which painted a picture on how the engine was doing.

At the beginning, his engine was running 18.0:1 air to fuel mixture, which is very lean. His meter seems to be pegged at 18.0:1 throughout the entire RPM range.
Feeling confident that he rectified all vacuum leaks by use of his ingenious vacuum leak detector, I felt we could proceed with making adjustments.

We also needed to make sure something screwy wasn't going on with his ECU, so I had him plug his spare cylinder head temperature sensor into a glass of ice while the body of the sensor was jumper-ed to the negative battery post. After rerunning the test, the air/fuel meter changed slightly from super lean, to not so much lean. This was encouraging and proved that the ECU does work and altered the air to fuel mixture in regards to temperature.

At this point, we made baby step adjustments to the AFM. The big clock spring controls the tension to the AFM's flap. Relieving spring tension will make the car run richer. Fine tuning is still needed because the air/fuel meter seems to be fidgety and doesn't seem to have the resolution for a finer tuning. 20 teeth seems like a bunch, but I have a feeling with a new gauge, the final answer may be closer to around 14-16 gear teeth (CCW from the original position).

[jim_hoyland]

Thanks for the explanation-

[KELTY360]

(IMG:style_emoticons/default/smilie_pokal.gif) (IMG:style_emoticons/default/smilie_pokal.gif) (IMG:style_emoticons/default/smilie_pokal.gif)

A tribute to persistence and ingenuity. Congratulations!

[Rob-O]

Wow, very nice! Glad you found that leak.

Where did you get the A/F kit? How much?

[malcolm2]

Wow, very nice! Glad you found that leak.

Where did you get the A/F kit? How much?

I borrowed it from a friend. It has a pipe that goes in the exhaust with the sensor on it and a cig lighter plug for power. I am not 100% confident in it. I plan on looking for one to buy. Might even install it in an extra spot on the dash.

[Porschef]

Throttle body gasket was one of my leaks. Glad you found it! (IMG:style_emoticons/default/beerchug.gif) (IMG:style_emoticons/default/cheer.gif)

[malcolm2]

The leak was so bad that the car would not run. Making it difficult to use the starting fluid method. That ho-made smoker was perfect. After i fixed the TB leak i saw some tiny streams in a few places.

So i have a few more leaks to get. But I am gonna drive today. She has been on jack stands since before Christmas waiting on me to get to her.

[Rob-O]

Well, I hope that's the last of the major troubles for awhile. Between the 914 and the Volvo, you've had your hands full!

[ndfrigi]

wow big thanks again for various members here especially "the Ljet man" Tim who is always there to help us. He did helped me before and he really did help me go through various steps to fix my electrical issue on my 75 1.8 Ljet. I may be asking his help soon on my minor backfire if this can damage my AFM flaps.

Good to hear your car is running now!

[malcolm2]

wow big thanks again for various members here especially "the Ljet man" Tim who is always there to help us. He did helped me before and he really did help me go through various steps to fix my electrical issue on my 75 1.8 Ljet. I may be asking his help soon on my minor backfire if this can damage my AFM flaps.

Good to hear your car is running now!

Yep, i now believe the backfire will do damage. It was a low, different sounding backfire. They call it an internal backfire.

So, i suggest you buy a spare afm and tune it in. And you make a smoke machine and use it a couple times a year or when ever you change any induction part.

[ndfrigi]

wow big thanks again for various members here especially "the Ljet man" Tim who is always there to help us. He did helped me before and he really did help me go through various steps to fix my electrical issue on my 75 1.8 Ljet. I may be asking his help soon on my minor backfire if this can damage my AFM flaps.

Good to hear your car is running now!

Yep, i now believe the backfire will do damage. It was a low, different sounding backfire. They call it an internal backfire.

So, i suggest you buy a spare afm and tune it in. And you make a smoke machine and use it a couple times a year or when ever you change any induction part.

currently, my car runs well on all gears and 800 to 900 rpm on idle when it is in normal running temp. No hesitation when I accelerate. I get the small backfire when I slow down only. Usually just before I downshift.

[pete000]

I have been playing with a AFM on my L-Jet and am a bit skeptical of the 02 sensors at the tail pipe. I think the readings can very there. I am planning welding in a bung and getting the 02 sensor further inside the exhaust.

My car seems lean at idle. There are a few videos on youtube showing the procedure of the two ways to change the mixture on the flapper box.

Keep posting your results.