testing the ALCL. poor cold start running

[Karl]

What are the pins and their location on the ALCL to test for trouble codes? I am referring to the paper clip method. If I remember correctly they are the slots in the upper right corner but I am may be wrong.

I started my z yesterday and not more than 100 feet later the car began to stumble and almost cut off. After warming up it went away and began to drive fine except for a slight bog in 2nd gear under load.

The car has about 68K on the clock and there seem to be a lot of original parts on the car. I have replaced the coils and wires. The prior owner installed new FIC injectors that are ethanol compliant.

Thanks ahead of time!

[-=Jeff=-]

Did you get a Set light? If not, you may not see any codes

[Karl]

No SES light.

[Roadster]

What are the pins and their location on the ALCL to test for trouble codes? I am referring to the paper clip method. If I remember correctly they are the slots in the upper right corner but I am may be wrong.

I started my z yesterday and not more than 100 feet later the car began to stumble and almost cut off. After warming up it went away and began to drive fine except for a slight bog in 2nd gear under load.

The car has about 68K on the clock and there seem to be a lot of original parts on the car. I have replaced the coils and wires. The prior owner installed new FIC injectors that are ethanol compliant.

Thanks ahead of time!

That's where they are on my 82, and I would imagine that they are the same for our Z's....
Not being too familiar with the LT5, I would assume that you start from the beginning. Such as, fuel delivery, spark (ignition), grounds, etc.,etc. If the engine doesn't have a code, you would need to go through each system to narrow down the source of the problem....JMO

[XfireZ51]

The ZR-1 is an OBD-1 car. Pins and pulling codes is the same across all vehicles.

[Karl]

I assume they are the top two right pin holes, pin A & B?

FEDCBA
G

[Karl]

Never mind, I just tested the ALCL and it threw no codes.

[Karl]

I am beginning to think I may have a fuel problem

Is there anything specific about the ZR-1 fuel system any care to share?

In particular how the fuel pumps work?

I just connected a fuel pressure gauge and it would not move past 20 psi at idle and it bounced maybe to 25 psi while driving the car.

I think either my fuel filter is clogged or the problem lies within the fuel pumps and or assembly.

I put the gauge on my daily driver Malibu and it held 30 psi so I know the gauge is working.

Is this normal fuel pressure for the LT-5?

[XfireZ51]

I am beginning to think I may have a fuel problem

Is there anything specific about the ZR-1 fuel system any care to share?

In particular how the fuel pumps work?

I just connected a fuel pressure gauge and it would not move past 20 psi at idle and it bounced maybe to 25 psi while driving the car.

I think either my fuel filter is clogged or the problem lies within the fuel pumps and or assembly.

I put the gauge on my daily driver Malibu and it held 30 psi so I know the gauge is working.

Is this normal fuel pressure for the LT-5?

Karl,

The FP should be in the 43+# range. If you haven't changed the filter, you should do it anyway. You may want to check the pumps. If they are original, it can also be an issue w the plastic clamps in the tank. They may be loose enough so that they lose pressure sort of like a leaky blood vessel. If not that, could be time to change the pumps

[Franke]

Karl,

The FP should be in the 43+# range. If you haven't changed the filter, you should do it anyway. You may want to check the pumps. If they are original, it can also be an issue w the plastic clamps in the tank. They may be loose enough so that they lose pressure sort of like a leaky blood vessel. If not that, could be time to change the pumps

What XfireZ51 said plus I am surprised that it runs with that low of a fuel pressure. Interesting.:confused:

[Karl]

What XfireZ51 said plus I am surprised that it runs with that low of a fuel pressure. Interesting.:confused:

What's really interesting is when I modified my old 85 with a new engine and such, first thing to go was the fuel pump.

Guess it's coincidence....

[Karl]

I just finished changing the fuel filter and the car now holds 22psi at idle.

Time to pull the fuel pumps.....

[XfireZ51]

I just finished changing the fuel filter and the car now holds 22psi at idle.

Time to pull the fuel pumps.....

Karl,

Check to see if you have the plastic clamps on the pumps. If so, I would replace w metal hose clamps and see what happens then before replacing pumps. Altho there's always the "while you're there" rule and the corollary which is "may as well". :dancing

[Karl]

Fuel pump assembly has been removed. All looks good. Before I replace the fuel pumps with ones from a suburban 454, is there a test I can do to confirm they are bad?

http://s5.postimg.org/wtgnw0rf7/20140517_095805.jpg (http://postimg.org/image/wtgnw0rf7/)


http://s5.postimg.org/d04k3be1f/20140517_095814.jpg (http://postimg.org/image/d04k3be1f/)

http://s5.postimg.org/dqxa93ger/20140517_095823.jpg (http://postimg.org/image/dqxa93ger/)

[XfireZ51]

Karl,

I would replace those black plastic clamps first then put pumps back in the tank. See what ur FP is. Its easy enough to pull the pumps again if u need to replace them.


Fuel pump assembly has been removed. All looks good. Before I replace the fuel pumps with ones grok a suburban 454, is there a test I can do to confirm they are bad?

http://s5.postimg.org/wtgnw0rf7/20140517_095805.jpg (http://postimg.org/image/wtgnw0rf7/)


http://s5.postimg.org/d04k3be1f/20140517_095814.jpg (http://postimg.org/image/d04k3be1f/)

http://s5.postimg.org/dqxa93ger/20140517_095823.jpg (http://postimg.org/image/dqxa93ger/)

[Karl]

Are you referring to the black clamps around the hoses?

[XfireZ51]

Are you referring to the black clamps around the hoses?

Yep, replace them w hose clamps. They get loose and fuel will squirt out lowering the FP.

[Karl]

One last question. How tight should the clamps be?

[Karl]

The ones I replace them with? Hand tight?

[XfireZ51]

The ones I replace them with? Hand tight?

Just don't have the rubber squeeze through like dough.

[Schrade]

Do you have air in the line?

What's your static pressure? Does it drop off quickly after priming?

[Franke]

I just finished changing the fuel filter and the car now holds 22psi at idle.

Time to pull the fuel pumps.....
Karl, do you have another fuel pump tester? Just to verify the first one is reading correctly before you replace the pumps. 22 PSI is really low.

[Karl]

I put the pressure gauge on my Malibu and it held 30psi.

Also the gauge will hold 23psi with the ignition on and turned off after the car has started.

I replaced the clamps with metal ones, all 6, and ignition on it jumps to 23psi, and the same when starting the car/idle. It holds pressure when I turn off the car.

I am pretty sure its the pumps. They are old and just before all this I rode around on reserve twice waiting to get gas since I was going to Indiana (i'm about 5 miles from the border, maybe less).

Do the suburban pumps drop in without any issues?

[XfireZ51]

Just don't have the rubber squeeze through like dough.

I put the pressure gauge on my Malibu and it held 30psi.

Also the gauge will hold 23psi with the ignition on and turned off after the car has started.

I replaced the clamps with metal ones, all 6, and ignition on it jumps to 23psi, and the same when starting the car/idle. It holds pressure when I turn off the car.

I am pretty sure its the pumps. They are old and just before all this I rode around on reserve twice waiting to get gas since I was going to Indiana (i'm about 5 miles from the border, maybe less).

Do the suburban pumps drop in without any issues?

Yes.

[Karl]

One last questions, are the strainers for this car available? If so anyone know the part number or an equal replacement part and or number?

Is it necessary to replace the strainers? I never have and I have changed plenty of fuel pumps.

Thanks!

[XfireZ51]

One last questions, are the strainers for this car available? If so anyone know the part number or an equal replacement part and or number?

Is it necessary to replace the strainers? I never have and I have changed plenty of fuel pumps.

Thanks!

For me, I would always change them out. Over time, they start to plug up making the pumps work harder. You can sometimes see this with filters collapsing in the middle.

[Karl]

New fuel pumps arrived last night and will be going in tomorrow!

[Schrade]

Did you ever do a static pressure test?

If you have leaking injectors, new pumps won't make any difference.

Getting a new bike pump won't patch a hole in the tire...

I think you should do static pressure, and then chart leakdown time.

[Karl]

Static pressure test?

With the ignition key on and the car not running the fuel pressure guage will hold 23psi and not move.

Is this what you are referring to?

I posted other test results in this thread too.

[Karl]

New fuel pumps and strainers are in and i'm back on the road. No more bog in second gear either.


:-)

[Schrade]

Cool.

All I noticed was 23# holding pressure @ idle (static FP test is primed FP only, motor off).

[-=Jeff=-]

That is on my list.. Along with auto down windows

[Karl]

Well my car still runs bad.

It worked fine for two trips. After changing the fuel pumps and strainers I assumed (yeah I know) all was good and did not check the fuel pressure.

Car started right up and no cold start issues. Went downtown and ran a few errands, sat in traffic, and had no problem passing on the expressway.

I let the car sit for a few hours and the symptoms came right back. Maybe they never went away.

New fuel pumps, strainers, and filters.

Here are 4 videos I made.

* Ignition on, no start.
* Ignition off after no start
* Start up
* Shut off

http://feed1.tinypic.com/rss.php?ua=WRrBnBQSlu068B0gbgs0BA%3D%3D

I am lost. Only thing I can think off is the fuel pressure regulator or maybe the ECM due to this thread with the same similar start up issues.

http://www.zr1.net/forum/showthread.php?t=4082&highlight=fuel+pressure

I see no leaks anywhere and all the lines are nice and tight.

Thanks for the help.

[XfireZ51]

MAP sensor hose? Pop off? Has oil?

[Schrade]

Alright - maybe let's do static pressure test, and leakdown time.

Plug in FP guage, turn on key to prime rails. If it's not @ 43+ PSI, turn the key off and on again.

If you don't get it then, GENTLY pinch the fuel return line, and prime the rails again (this will NOT yet rule out the FPR), but will tell a line leak, or leaking injector, or (not likely), a bad pump check valve.

Post back on that...

And cold starts and running like bats from Hades means NOTHING. (and do bats actually 'run'??? maybe they do, to V1, then roll flaps and go for V2?)

[Karl]

Where can I pinch the fuel return line?

Only place I can think of is the return line to the tank in the rear.

Also I will check the map sensor.

[Schrade]

Pinch at the P side line at the back of the motor on top at the passenger side. Follow the rail crossover to determine which is feed and which is return. The one coming from the FPR is return.

Some more snappics here. (http://www.zr1.net/forum/showthread.php?t=21439&page=25)

Start with a light pinch - you don't want to damage the line.


edit:
Front one is return line. Pinch THAT one.

https://lh4.googleusercontent.com/-HhBEWTJMr3A/UnfewvnietI/AAAAAAAACPo/_QCrLcG1ZIQ/s1280/IMG_6013c.JPG

[Karl]

I am pretty sure I just found the problem and will have it fixed in the morning. Will report in the morning. Thanks again!

[Schrade]

I am pretty sure I just found the problem and will have it fixed in the morning. Will report in the morning. Thanks again!

What was it there Karl?

You know what they say about minds that enquire, and the yen for knowledge...

[Dynomite]

What was it there Karl?

You know what they say about minds that enquire, and the yen for knowledge...

:happy1:

[Karl]

I over slept and was running late for work!

Will take care of it tonight when I get home and update everyone.

[-=Jeff=-]

What was it there Karl?

You know what they say about minds that enquire, and the yen for knowledge...

:happy1:

Loose nut behind the wheel :dancing

[Dynomite]

Loose nut behind the wheel :dancing

If only Karl would give us a clue :D

[Karl]

More like a loose nut on one end of my fuel filter.

The end nearest the engine (the outlet side) was about 1/2 a turn loose until it became truly tight.

It is a hard angle to get at, especially if the car is not very high off the ground.

Hopefully this is the problem. Last night I primed the fuel pump and heard a drip and smelled fuel. Low and behold there was fuel on the garage floor. I could see and feel it seeping out the filter.

I need a lift in my garage!

I will start her in the morning and see what happens.

[Schrade]

Well my car still runs bad.

It worked fine for two trips. After changing the fuel pumps and strainers I assumed (yeah I know) all was good and did not check the fuel pressure.

Car started right up and no cold start issues. Went downtown and ran a few errands, sat in traffic, and had no problem passing on the expressway.

I let the car sit for a few hours and the symptoms came right back. Maybe they never went away.

New fuel pumps, strainers, and filters.

Here are 4 videos I made.

* Ignition on, no start.
* Ignition off after no start
* Start up
* Shut off

http://feed1.tinypic.com/rss.php?ua=WRrBnBQSlu068B0gbgs0BA%3D%3D

I am lost. Only thing I can think off is the fuel pressure regulator or maybe the ECM due to this thread with the same similar start up issues.

http://www.zr1.net/forum/showthread.php?t=4082&highlight=fuel+pressure

I see no leaks anywhere and all the lines are nice and tight.

Thanks for the help.

What do you think made it start leaking between this time? Did you hit any bumps?

More like a loose nut on one end of my fuel filter.

The end nearest the engine (the outlet side) was about 1/2 a turn loose until it became truly tight.

It is a hard angle to get at, especially if the car is not very high off the ground.

Hopefully this is the problem. Last night I primed the fuel pump and heard a drip and smelled fuel. Low and behold there was fuel on the garage floor. I could see and feel it seeping out the filter.

I need a lift in my garage!

I will start her in the morning and see what happens.

I'm still thinking static fuel test is in HIGH order... Any Tuned Port Injection mill HAS TO HAVE AT LEAST 43 PSI - preferably 50+ for LT5 (although Marc H says 43 is sufficient). I don't know better to argue with him, OR FSM.

Do you have long crank time for hot motor?

And remember - cold start means nothing........................................... ...

[Karl]

I think it was leaking al the time and I never knew it. I replaced the fuel filter before the pumps. Me discovering the leaking filter and taking that video was is the same day. Car has not moved or been started since then.

Starting time seems to be the same weather cold or hot.

I am still somewhat puzzled since it ran fine for a short amount of time.

I still have the fuel pressure gauge connected so I will see what the pressure is when I start the car in the morning.

[Schrade]

I think it was leaking al the time and I never knew it. I replaced the fuel filter before the pumps. Me discovering the leaking filter and taking that video was is the same day. Car has not moved or been started since then.

Starting time seems to be the same weather cold or hot.

I am still somewhat puzzled since it ran fine for a short amount of time.

I still have the fuel pressure gauge connected so I will see what the pressure is when I start the car in the morning.

You can check pressure in about 3 minutes, if you take your time. ;) Motor off, + leakdown time.

Open Loop [cold] motor will run with a PLETHORA; a BEVY, of problems. You'll hear 'em say, "It runs like a bat leaving Hades". WOT performance doesn't mean squat either...

[Karl]

Car still has low fuel pressure. When I say the car ran fine for a short amount of time, I am referring to running errands around down, sitting in traffic, etc. A good 30 plus minutes of driving. The car got plenty warm, was on the expressway, bumper to bumper traffic, stop light driving, etc.

I started the car and fuel pressure is still at ~23 psi. Car fired right up, no leaks around the fuel filter either. I had it wrapped in toilet paper and all the toilet paper is dry.

I put the key in the ignition and turned it to the on position for 3 minutes without starting the car and the fuel pressure held about 26 and then fell to about 20 psi at the end of the three minutes. When the ignition first came on the fuel pressure gauge spiked to about 36 psi then settled down to about 26 psi.

EDIT: Will upload video later.


I am going to my friends shop and borrow his fuel pressure gauge to make sure mine is working correctly. I also disconnected the MAP and the connections were clean and free of oil any noticeable oil deposits.

[-=Jeff=-]

is the vacuum side of the fuel regulator wet? maybe the regulator is bad..

But diagnose it first, don't just swap parts

[Schrade]

is the vacuum side of the fuel regulator wet? maybe the regulator is bad..

But diagnose it first, don't just swap parts

Yup - forgot all about ruptured bladder in FPR.

Static FP test will show this too - pinch front stainless steel mesh line coming from FPR.

I put the key in the ignition and turned it to the on position for 3 minutes without starting the car and the fuel pressure held about 26 and then fell to about 20 psi at the end of the three minutes. You just now did this? (this is static FP test - good job; no need to even start the car right now then).

If the vacuum hose on FPR has no gas in it, you have either air in the line, or leaking injectors. Not likely a bad new pump. And the old pump was probably good too.

Put a jumper wire in the FP test socket on the firewall harness Driver's side.

https://lh6.googleusercontent.com/-91DRqAMXYlY/UnltMoOmLLI/AAAAAAAACWg/l4Bq7wiwuNg/s1280/HPIM7409.JPG

then run jumper cables across the motor, along with the jumper wire, so you can get at the guage bleed valve. Have the bleed hose going into a can or jug. HOLD THE GUAGE BLEEN OPEN, and see if air bubbles are coming out of the bleed line.

WHen bubbles stop, pull the 12V power.

Close the bleed line, and now hold the jumper wire to the 12V jumper cable until pressure pegs. Note what it pegs to.

Then pinch the fuel INLET line, remove the 12V jumper, and undo the pinch to the fuel INLET line. This apparently forced air BACK to the pump, and got it out of the line.

Then repeat the static FP test. Note initial pressure, and post up on it.

[Karl]

I don't plan on throwing parts at the car.

[Karl]

Gauge bleed valve? My fuel pressure gauge doesn't have one.

If there is air in the system won't it eventually burp out?

[Karl]

There is no visible sign of gas or any fluid in the vacuum line from the fpr. It smells like gas but after turning on and off the ignition I did not see any visible sign of any fluids. I will start the car with the line off and see if that makes a difference regarding the presence of gas or not in the line.

Also when pinching the braided fuel lines, are you pinching them with pliers or such? Are you wrapping the braided line with a towel or something to cushion the braided line?

[Karl]

I just came back from a 20 minute joy ride. Drove to my friends shop and he was not there yet. Wanted to use his fuel pressure gauge to double check mine.

Seems like my car is possessed. It drove fine. No bogging or poor running conditions. Plenty of pull power, etc.

Hopefully my old fuel pressure gauge and or air in the fuel line was the problem.

Going to work now and will see what happens tomorrow and during the weekend.

Its to nice outside to not drive the Z!

[Schrade]

Sounds like FPR is good, with no gas in FPR vac tube. Now you need only to check for injectors leaking...

Fuel pressure guage should have a button on the side that lets fuel drain, so you can remove it without fuel spraying. Maybe some don't have it.

I pinched the fuel line with Vise Grips. CAREFULLY. I always preached against this, because of damage to the line. But FSM suggests this. A rag might help insure against damage. Pinching does deform slightly the braided line, but you can squeeze it back with your fingers.

I don't know if air will 'burp out' or not. I had air after top end work, and I wanted it out before proceeding.

Did you save your old pumps? Sounds like they were good...

[Karl]

Yes I saved my old pumps.