Could use some ideas…

Background: Car sat idle in a garage for six years - 37K miles. Engine was free. 2.0 factory d-jet. I adjusted the valves, installed a new fuel filter, changed the oil & put some gas in it. It fired up but had a very high idle.

Since then, I have done the following:
-New plugs & wires
-New distributor cap, points & condenser (rotor was clean)
-New air filter
-New alternator & voltage regulator - tested good
-All new vacuum lines from AA
-New intake runner gaskets and manifold to head gaskets
-Tested all FI components except the brain. Replaced AAR and MPS with good used
ones, bench tested each before installation. MPS holds 20 in HG and electrical tests
were within limits. Replacement parts are compatible based on this site:
http://members.rennlist.com/pbanders/djetp...tm#troubleshoot
-Tested fuel pressure - dead on factory spec of 2.0 bar
-Dwell well within specs
-Set timing dead on at 27 degrees BTDC with distributor lines plugged and disty at
full advance
- TPS set according to the picture I found on this site
- New plenum to intake runner gasket
- New cold start valve gasket
- Tested PCV Valve
- Plenum inspected – no holes found
- Throttle body removed & thoroughly cleaned

At all ambient temps tested (50-70 degrees F), the car fires right up but stalls almost immediately…this happens twice. Tapping the throttle does not help. On the third start, the car stays running and idle varies between about 800-1200 RPM. After about 10 minutes, it settles in at about 950RPM or so. Besides this, the engine runs great, has plenty of power and pulls hard in all five gears. Is this as good as it gets or am I missing something. Thanks in advance.

Bob

AAR Valve...
What have you dont with that
Cold start injector...what have you done with that?
FI seals...have you replaced them? They cause a vacuum leak and suck in alot of air creating a lean condition in one or more cylinders.

Rich

wut he said!

I had the same problems with an engine that sat for the same amount of time. Everything Rich said & then some...

...b

i had a problem with the idle going back to where i had it adjusted to. i clamped the hose going to the decel valve. (pinched it shut) and my idle went back to where i had it. i left the clamp on their the entire time i drove it, with no more problems. i had a sticky decel valve. you could try to pinch yours and see if it gets better.

good luck

I removed the decel & it was more bedda!

.....b

AAR valve replaced with used, bench tested unit - electrical and heater are good. Cold start injector tested - new gasket installed. Thermo time switch replaced with tested used one. New fuel injector seals installed. Idle can be adjusted with idle air bleed screw.

Anything else you can think of? The car runs fantastic besides the three start problem. I have moved the knob setting on the ECU through every notch. I am about 8 clicks from full counterclockwise position right now.

Thanks.
Bob

Here is a test.

Turn key on to run...turn off.
Do this five times.
Let fuel pump pressurize the system.

Then start it.
Does it stay running now?

It could be a dying fuel pump that drains back when its not running and it takes a few times to pressurize the whole system.

Also, try raising the fuel pressure.

Rich

I will give this a try over the weekend. How is your 914 running after the engine install?

Thanks for the suggestions Rich - how much should I raise the fuel pressure?

Bob

Check the psi by putting a guage in line going to the FI's. 30#'s in what I ran. You might bump it 2 to 3#'s to begin.

....b

Rich:

Performed your test. It had no effect. I raised the fuel pressure to 25 psi - no change. Bumped it up another 5psi to 30 - still the same. Is my fuel pump at fault? Anything else I can check?

Thanks,
Bob

Check Your timming? Oscillation w/ high idle can mean you have a leak where you do not expect it, I do not know what is in Auto Atlanta's vacummn line kit but...

Idle oscillates and/or idle is too high and cannot be adjusted down to 1000 rpm with the air bleed screw Vacuum leak
Timing over-advanced
Check the following areas for a vacuum leak:
1. Intake runner-to-head gasket/spacer
2. Injector seals
3. Intake runner boots
4. Air plenum (e.g. cracks or rust holes)
5. Throttle body gasket
6. Throttle body shaft (worn body or shaft)
7. Distributor vacuum adv/ret cell
8. Auxiliary air regulator (stuck open or leaky)
9. Deceleration valve
10. Manifold pressure sensor
11. Vacuum hose cracks
12. Cold-start valve gasket to plenum

Timing is spot on at 27 degrees BTDC. AA's vacuum line kit included every piece of vacuum line needed to replace all lines.
1. New
2. New
3. New
4. Inspected, no cracks or rust holes found.
5. New
6. Inspected, no excessive play
7. HOW DO I TEST THIS?
8. Replaced with bench tested used unit
9. Tested, will re-test
10. Replaced with bench tested used unit
11. All new vacuum lines & elbows installed
12. New gasket installed

It looks like the only thing I missed on this list is: Distributor vacuum adv/ret cell - how do I test this.

Thanks

Its a vacuum canister.
Remove the one or two vacuum lines that go to it and plug them.
Then if you had a vacuum leak there, it wont be there after you plug the lines.
I cant believe that would cause the three start problem.
It may have an affect if the advance plates are stuck in the full advance position when its cold...then it wont really start right..but it will eventually start...
If you look at the arm that sticks out of the canister it has a little c-clip that attaches to the advance plates.
Remove the c-clip and remove the canister so its not in the way...then see if you can EASILY move the top advance plate...should be really easy and simple to move.


Is this every single cold start time?
If so, put the fuel pressure gauge back inline and leave it overnight.
Turn key on ONCE...read gauge.
Does it show 30#?

It just sounds like you are not running a full fuel system.

Rich

[quote name='r_towle' date='Nov 24 2009, 08:21 PM' post='1242502']
Its a vacuum canister.
Remove the one or two vacuum lines that go to it and plug them.
Then if you had a vacuum leak there, it wont be there after you plug the lines.
I cant believe that would cause the three start problem.
It may have an affect if the advance plates are stuck in the full advance position when its cold...then it wont really start right..but it will eventually start...
If you look at the arm that sticks out of the canister it has a little c-clip that attaches to the advance plates.
Remove the c-clip and remove the canister so its not in the way...then see if you can EASILY move the top advance plate...should be really easy and simple to move.


Is this every single cold start time?
If so, put the fuel pressure gauge back inline and leave it overnight.
Turn key on ONCE...read gauge.
Does it show 30#?

It just sounds like you are not running a full fuel system.

Rich:

It is every single cold start...three attempts minumum for the car to stay running. To set the fuel pressure, I had a buddy crank the sarter while I made the adjustments. As soon as starter is not cranking the engine, fuel pressure drops to 20 PSI.

The advance plates in the distributor are free. They turn upon tightening the points in the distributor. I agree that the vacuum canister would not cause the three start problem.

I appreciate your experience in this matter.

Bob

It sound like its either a loose fuel line or a fuel pump.
I would suspect the pump if it wont hold the pressure.

Try putting the gauge back inline.
Turn key on three to five time to charge the system.
See if it holds the 30#

Prior to replacing the pump, I would first suspect the hose routing.
Ensure you are indeed sucking from the larger port on the tank, you have no kined fuel lines under the tank, and you have hooked up the hoses to the pump correctly..

all of the above hose issues we have all done..so go check again.
Especially the kink under the tank and the hoses going into the pump.

For the under the tank kink...a small digital camera stuffed into the access hole under the tank is an easy way to see what you cant see.

Rich

#7 suck it or blow it!! basically checking #1 it holds vaccum but #2 more importantly you can blow through it or suck through it..

since your idle i assume is up 1200 when first cold started then down to 950 after 10 minutes.. is in a way normal function of the AAR but is a litlle slow... the oscillation is not normal.. mine used to oscilate at idle when warm and I seriosly can't exactly tell you it was one thing but hows your wiring harnes? clean tight connnections (3 pole ground tab nice and clean tight everywhere ect.) cracks and to many repairs cause issues.. the ecu contol knob bascially at the age off these car should be set at rich, I tried to avoid setting too rich and that did not work as well and evry time I had it to a mechanic they turned it up rich too so. Every single component on my djet in NOS down to the harness and MPS ECu relay board all everything and still sets at rich.. it is like your car is trying to get some air.. when you set the idle on the bleed screw make sure your car is fully warmed up 10 minutues or so since tha is where you issue is..

Read until you dumb founed several time the Rennlist The Ecu documents fully noy just the trouble shoot, in there somewhere he expalins his 20 year idle chase in a personal matter that shows you what nuances there are after long freeway, after grocery shopping, in the morning, or when it cold and wet//; ect.. boring stuff but after 2 weeks of buring into it "bada Bing' it just ha[ppens to come clear and easy but never specific/..

How is it supposed to idle, anyway? (copied from the below link, not my car, I do not live in Pheanix and I can't spell)
I'm going to take you through a typical day of driving the car to work, going out for an errand, and driving home. What I describe below is how my car behaves, this is a real example.

Let's say it's spring and your garage temperature is about 60 degrees, and the car has been sitting overnight. This is a "cold" condition for the motor. If you're in the winter in New England and it's 0 degrees, this is called "cold-cold". We'll take the warmer case as our baseline for the scenario. Without pressing the accelerator (factory says to start the car with a wide-open throttle, I've personally never done that but sometime, I'll give it a try!), you turn the key, and the car starts. 99% of 914's in good condition will start up like a champ, but will need one or two light taps on the throttle to get the idle up after it drops a few seconds after starting. By the time you back out of the garage and stop to put the car in first, your idle should be about 1600 to 1800 rpm, as your auxiliary air regulator (AAR) is open and is providing air that bypasses the throttle plate, keeping the idle high to overcome internal friction while the engine warms up and the oil comes up to temperature.

By the time you get to the second or third stop light (about 5 to 10 minutes), the AAR is closed, and the idle drops to the spec setpoint, about 950 to 1000 rpm. You might note a slight instability of about 50 to 100 rpm, as the motor is still warming up and is probably a bit lean. As you approach the light and let off of the throttle, the engine speed should smoothly decrease to idle and slow as it approaches the idle level - not drop through it like a rock and bounce around. As you drive, on your 20 minute commute, the idle does not vary from the setpoint by more than 50 rpm any time you are sitting at a light. It gets smoother as the engine warms up, and by 10 to 15 minutes, the engine is fully warmed up and there is no change past this point in the way the idle behaves. You arrive at work and park the car. The air temperature is about 75 degrees (I live in Phoenix, that's how warm it is here in the spring in the morning...).

About an hour later, you need to make a 30 minute errand to go to the Post Office. You start the car, the idle comes to the setpoint or somewhat below, quickly. That's because the AAR is still hot and isn't open, and while the motor is warm, the heads have cooled considerably. Because the air-cooled D-Jetronic depends on head temp for setting the warm-up mixture, you're likely to have a bit of bogging and low idle for the first 5 minutes, until head temperatures come up. This is a well-known design issue with 914's, "warm start over-enrichment" is what we'll call it. There's not too much you can do about it. You may have to use an open throttle to get the car to start, as it's too rich and needs more air.

You go into the Post Office and it takes you less than 10 minutes to do your business. When you restart the car, it idles stably. That's because the head temp is still high and you have the correct mixture. Your car idles properly until you shut it off back at work.

It's now 5 pm and you're ready to go home. Let's also say this is early spring, and it's dark enough to use your headlights. When you start your car, it's very similar to the morning start. The AAR is active for 5 to 10 minutes, you have high idle, then it comes down. But your idle is now no more than 50 rpm lower than the setpoint, due to the power needed to drive the alternator to supply the headlights, so your idle is about 900 to 950 rpm. The car idles fine until you shut it off back home.

Idle Stability Trouble Shooting..

http://members.rennlist.com/pbanders/idle.htm

In the D-Jet system, the operating pressure is about 28.7 psi, measured with the car running. When shutoff, the pressure drops to about 20 psi and holds for a period of time for hot start situations.

The fuel pump, when running, should hit the 29 psi rapidly, as in a couple of seconds. If not, then the pump is either going south or you have a restriction somewhere in the supply lines.

On shutdown, if the system doesn't hold pressure (20 psi) for a fair amount of time, it is possible the the pressure relief valve on the pump is not holding.(on a 911, fuel pressure is held for 20 mins). This would also cause a slow rise in fuel pressure as the pump is bypassing fuel pressure to the return line. The pressure relief and checkvalve are one in the same on a teener pump. Two springs, seating a ball under one silver cap.

Food for testing the fuel system.

Re-connected the fuel pressure gauge. Fuel pressure jumped almost immediately to 30 PSI upon cranking the engine. Dropped to 20 PSI immediately after the starter dis-engaged. Leakdown from 20 PSI was as follows:

30 sec - 15
60 sec - 11
90 sec - 8
120 sec - 6
150 sec - 4
180 sec - 3
210 sec - 1
240 sec - 0

What are your thoughts? Fuel pressure drops to zero in about 4 minutes. Check valve?

Thanks,

Bob

Went another two clicks on the ECU after bumping the fuel pressure to 30 PSI. Now two taps of the throttle after it initially fires seems to do the trick.

I still have to check a few more things but it looks like things I am getting there - from reading "99% of 914's in good condition will start up like a champ, but will need one or two light taps on the throttle to get the idle up after it drops a few seconds after starting." - it sounds like my system is functioning pretty well.

Thanks,
Bob