Vacuum Lines all New: Running Rich, replaced all hoses so engine is very tight Options

[Brian Mifsud]

I recently replaced all of the vacuum/ fuel/ miscl hoses in my '76 2.0 with new Genuine German hoses including the stuff at the fuel tank. Intake runner to Intake manifold "hoses" were also replaced so ALL the engine's rubber is new and tight. I carefully followed the guide on Pelican so I'm pretty certain everything is plumbed correctly. I adjusted the valves before I resinstalled the engine, and have about 1/2 and hour of running time on it subsequently. After careful adjusting my timing (was at 20 degrees BTDC @ 3500RPM, now is 27) I started down Brad Anders' list.

Idle DOES respond to adjustment on the throttle body, but DOES not respond to ECU IDLE mixture adjustments.

Throttle lags on acceleration.

Car is running "stinky" rich... wisps of black smoke when throttle is goosed.

Cold Start valve has been disabled by disconnecting supply line.

I suppose I could always go back and check my work and readjust the valves to make sure they aren't too tight as I habitually tend to adjust on that side of the "tolerance".

Anyhow, in order of priority, I'm guessing the following is the best bang for buck in trying to pin down the "running rich" issue, tell me if you agree:

1) Readjust valves
2) Check fuel pressure
3) Remove Head Temp sensor and check resistance in ice bath, then room temp, then boiling water.
4) Ring out harness to make sure head temp sensor is being "listened to" by ECU..
5) Suggestions???

[Rand]

The temp sensor on the plenum is plugged in, and the MPS is connected properly (and holds a vacuum)? You've probably covered those, but just checkin' the first ideas I had.
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[Brian Mifsud]

The temp sensor on the plenum is plugged in, and the MPS is connected properly (and holds a vacuum)? You've probably covered those, but just checkin' the first ideas I had.
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I'm guessing that these should be checked after adjusting valves in terms of likely "suspects"?

Thanks

[Rand]

I would check these first just because it will only take a couple minutes and they can definitely cause your symptoms.

[Brian Mifsud]

Understood.

Thanks for advice

[TravisNeff]

check the CHT (at the head), once cold and once warm. I had one that was fine until the engine was at temp - then shorted out. It was bad enough to leave me on the road stranded. Luckily my buddies saved my bacon and towed me home.

[Rand]

Good luck Brian. Keep us posted.

How did it run before replacing all the hoses? If the "rich" symptom only showed up after the hose replacements, then double-checking the hose routing/connections might be the first priority.

[Brian Mifsud]

check the CHT (at the head), once cold and once warm. I had one that was fine until the engine was at temp - then shorted out. It was bad enough to leave me on the road stranded. Luckily my buddies saved my bacon and towed me home.

CHT? Cylinder Head Temperature Sensor?

[TravisNeff]

Ayup, also known as TS2 (temp sensor #2)

[Brian Mifsud]

Good luck Brian. Keep us posted.

How did it run before replacing all the hoses? If the "rich" symptom only showed up after the hose replacements, then double-checking the hose routing/connections might be the first priority.

It's been a few years, but I test drove the engine in Mike Mueller's car and don't remember and throttle lag or smoke. Like every assumption.. I'll go through all my hose routing from scratch... can't hurt.

Thanks for advice.

[TravisNeff]

Also!

You wrote "I recently replaced all of the vacuum/ fuel/ miscl hoses in my '76 2.0 with new Genuine German hoses including the stuff at the fuel tank. "

Make sure you don't have a kinked return line to your tank, that will make your fuel pressure go through the roof.

[Bleyseng]

Also!

You wrote "I recently replaced all of the vacuum/ fuel/ miscl hoses in my '76 2.0 with new Genuine German hoses including the stuff at the fuel tank. "

Make sure you don't have a kinked return line to your tank, that will make your fuel pressure go through the roof.

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and check the CHT and MPS holding a vacuum of 15hg for 5 minutes

[Brian Mifsud]

Also!

You wrote "I recently replaced all of the vacuum/ fuel/ miscl hoses in my '76 2.0 with new Genuine German hoses including the stuff at the fuel tank. "

Make sure you don't have a kinked return line to your tank, that will make your fuel pressure go through the roof.

oooohhh.... that sounds nasty.... and here I thought I was thinking ahead by making sure there was plenty of slack in the new high pressure hoses at the tank so I could easily pull the tank without needing to disconnect... hope it didn't backfire on me...

[pbanders]

There's a bunch of stuff on my web site about rich running. The top reasons for rich running that spring to mind are:

1. Leaky, wrong, or maladjusted MPS
2. Open head temp sensor (either bad sensor or broken wire in sensor or harness)
3. High fuel pressure (malajusted or blocked return line)
4. Leaky cold start valve (spewing gas into the plenum)
5. Wrong parts (wrong ECU, MPS, CHT, injectors, etc.)

[Bleyseng]

Hey Brad,

Its good to see ya posting here. Hope you're doing good and you're healthly too.

[pbanders]

Hey Brad,

Its good to see ya posting here. Hope you're doing good and you're healthly too.

Geoff, thanks, I post here from time to time, it seems like 914Club has a lot more traffic these days than PP's board.

Health is fine. My 914's getting a long-overdue rebuild right now, should be done in a month or so. Very stock rebuild, I'm going for reliability and smoothness. Can't wait to have a motor that has some compression and manifold vacuum again - I think my ring gap was about 1/4"!!

[pbanders]

Here are a couple of pics of my engine rebuild that's underway:

http://members.rennlist.com/pbanders/more_..._Engine_Rebuild

Yeah, I know, looks like every other T4 that ever got built up. But that's the way I like it.

[Bleyseng]

looks good!

Stock cam, haha sick of the Web73?

I went with Rabies version of the Web73 in my recent refresh of mine. Yup, it was a chore to tune the Djet but it runs sweet now.

[pbanders]

looks good!

Stock cam, haha sick of the Web73?

I went with Rabies version of the Web73 in my recent refresh of mine. Yup, it was a chore to tune the Djet but it runs sweet now.

When we ripped it apart, turns out the cam was stock, not a Webcam 73. Tuning the FI should be easy. I have a brand-new 043 MPS that I used to setup another good MPS I have to identical injection durations across the full vac range. We're going to start with that one and see if any tweeking is needed. I'm trying to hold on to the new MPS for as long as I can - considering that they're $1000+ these days!

Did you observe the cooler running that Jake says comes with that cam? I think he was saying it was 30 deg. F cooler than the stock cam. I never did get him to tell us what was specifically different (lift, duration, ovelap, etc.) with his cam over the 73 or the stock.

[Bleyseng]

On mine its about 20F cooler (oil temps)but I also upped the compression to 9to1. (IMG:style_emoticons/default/biggrin.gif) On 90F days it would hit 260F sometimes running hard at AXing. Now 240F is the warmest its been running hard on 95F days so its an improvement. Driving around town/freeway its about 210F.

The difference is 2 degrees more of exhaust duration I think which is to cool off heads more as I have observed on both my 914 and Westy. The Westy runs 250-300F head temps now which is waay down from stock before.

Yes, I have a NOS 043 and a Clean OEM 037 that I use to calibrate the Wavetek before setting any MPS I work on.

Boy the MPS I use now is in the .80, 1.35, 1.76 range for this motor to get a AFR of 13.6 to1 at PL and 12.5 to 1 at WOT. idles ok too.
NO, leaning out at higher rpms -5000 to 6500 using a LM1 to track it. Should have Mythbusters prove the ole wife's tale false about Djet leaning out at 5000 and above.