Sputters on acceleration

[nullset]

First, a bit of history.

My daily driver lately has been stumbling under load. I worked out that, because I'd recently been in the fuel tank, it was probably something there.

I replaced the pickup hose, fuel pump, and fuel filter (the filter I already had. The pickup hose I both got from Sean and tried another one from the project car. The fuel pump was brand new and in the project car as well).

The whole time she would start up and idle just fine, but when you started giving gas it would sputter and die.

I worked out that I'd installed the baffle wrong. That's correct now and I'm 100% sure of the fuel side of the equation, up to the filter.

Today I discovered that if I pull the air filter box and push lightly down on the pressure plate while opening the throttle, it works fine. I think this means that my mixture is off, but I wanted confirmation.

My mixture has never been adjusted. What do I need to do? Drill out the plug (any particular size drill bit, or depth, or method I need to follow?)?

Does this sound like mixture or something else?

The only thing left on the fuel side is the mixture and the injectors. I have not tried replacing them with the brand new ones from the project car, but I can if it'll help, or I can pull them and check the spray pattern.

--buddy

[Bitsyncmaster]

The first thing I check is the mixture (dwell the FV). Is your FV even buzzing?

My mixture plug was already removed when I bought my car but you have to be real carfull when you drill the plug out. I myself would remove the mixture unit and pull it apart to make sure I do a good job drilling.

[David T]

First I have to assume you have the hesitation when the motor is warmed up. If it happens while cold you also could have a problem in one of the systems that is operating while the motor is warming up. Hesitation while warm-hot is most often caused by vacuum leaks and/or the mixture being off. Again, I am assuming the Lambda system is working (the FV is buzzing). Other things that can affect the mixture include bad/leaky injectors or a plugged up air filter. Do not begin by messing with the mixture screw. All too often it is where it should be. By adjusting it you are trying to compensate for vacuum leaks and you can't. They have to be fixed.
David Teitelbaum

[nullset]

First I have to assume you have the hesitation when the motor is warmed up. If it happens while cold you also could have a problem in one of the systems that is operating while the motor is warming up. Hesitation while warm-hot is most often caused by vacuum leaks and/or the mixture being off. Again, I am assuming the Lambda system is working (the FV is buzzing). Other things that can affect the mixture include bad/leaky injectors or a plugged up air filter. Do not begin by messing with the mixture screw. All too often it is where it should be. By adjusting it you are trying to compensate for vacuum leaks and you can't. They have to be fixed.
David Teitelbaum

It happens whether it's cold or warmed up. It does seem to get worse as the engine warms up, though.

Right now it barely moves.

--buddy

[nullset]

The first thing I check is the mixture (dwell the FV). Is your FV even buzzing?

My mixture plug was already removed when I bought my car but you have to be real carfull when you drill the plug out. I myself would remove the mixture unit and pull it apart to make sure I do a good job drilling.

What/where is the FV?

I'm going to go ahead and swap the injectors over from my project car to see if that helps. It can't hurt…..

--buddy

[deloumis]

First, a bit of history.

My daily driver lately has been stumbling under load. I worked out that, because I'd recently been in the fuel tank, it was probably something there.

I replaced the pickup hose, fuel pump, and fuel filter (the filter I already had. The pickup hose I both got from Sean and tried another one from the project car. The fuel pump was brand new and in the project car as well).

The whole time she would start up and idle just fine, but when you started giving gas it would sputter and die.

I worked out that I'd installed the baffle wrong. That's correct now and I'm 100% sure of the fuel side of the equation, up to the filter.

Today I discovered that if I pull the air filter box and push lightly down on the pressure plate while opening the throttle, it works fine. I think this means that my mixture is off, but I wanted confirmation.

My mixture has never been adjusted. What do I need to do? Drill out the plug (any particular size drill bit, or depth, or method I need to follow?)?

Does this sound like mixture or something else?

The only thing left on the fuel side is the mixture and the injectors. I have not tried replacing them with the brand new ones from the project car, but I can if it'll help, or I can pull them and check the spray pattern.

--buddy

I have the exact same problem. Check your injectors. Mine were clogged up due to my own mistake (mine are all new).

[deloumis]

What/where is the FV?

I'm going to go ahead and swap the injectors over from my project car to see if that helps. It can't hurt…..

--buddy

Its located on the passenger side valve cover. Has a plug on it with 2 hoses coming off of it going to the FD.

I would put the put the injectors in cups and jumper the relay to verify while they are out.

[WelmoedJ]

What/where is the FV?

I'm going to go ahead and swap the injectors over from my project car to see if that helps. It can't hurt…..

--buddy

FV = Frequency Valve; position already provided in a previous reply.

[sdg3205]

If the FV is not buzzing, check the relay socket before you adjust anything. If one of the pins on the lambda relay has back out your whole emissions system is not operating as it should.

[nullset]

Is it possible to pop the driver side injectors out without removing the intake manifold? I can't seem to get to the clips…..

If someone here has done it, please chime in. Otherwise I'm going to start removing it.

--buddy

[nullset]

If the FV is not buzzing, check the relay socket before you adjust anything. If one of the pins on the lambda relay has back out your whole emissions system is not operating as it should.

Is this needed even if the RPM relay is jumpered? Are they related?

Which relay do I need to check?

--buddy

[opethmike]

Is it possible to pop the driver side injectors out without removing the intake manifold? I can't seem to get to the clips…..

If someone here has done it, please chime in. Otherwise I'm going to start removing it.

--buddy

Perfectly possible, just a bit annoying. Use something like a pick with a curve on it, or even a coat hangar to pop the clips off.

[Bitsyncmaster]

If your lambda relay (main fuel) is the wrong type, your FV will not work. That relay is different from the other relays. I've also seen a few bad RPM relays cause the lambda to not work.

[nullset]

The fv appears to be buzzing.

It revs up just fine until I try to go anywhere, then it starts losing power

If i turn the key off and back on, it will act normally again

I've tried the rpm relays for both cars.

Any other ideas?

[Bitsyncmaster]

Turning the key off and on fixes it? Then you must have an electrical issue. My guess would be something is intermittent with the lambda unit. I would suggest you get a dwell meter and learn to use it. Then when it acts up you need to check the FV without turning the engine off.

[deloumis]

The fv appears to be buzzing.

It revs up just fine until I try to go anywhere, then it starts losing power

If i turn the key off and back on, it will act normally again

I've tried the rpm relays for both cars.

Any other ideas?

Make sure the ground behind the intake manifold on the pass anger side is grounded properly. IIRC that's the ground to the lambda system. Anyone correct me if I'm wrong.

[nullset]

I will pick up a dwell meter at Auto Zone tomorrow.

Is there a way to force the lambda to run open loop, or bypass it entirely?

(temporarily, to test my hypothesis)

--buddy

[Bitsyncmaster]

I will pick up a dwell meter at Auto Zone tomorrow.

Is there a way to force the lambda to run open loop, or bypass it entirely?

(temporarily, to test my hypothesis)

--buddy

If it's working, you can unplug the O2 sensor to force it to hold a fixed dwell on the FV.

[nullset]

I've decided to stop trying to fix this blind.

I have a set of Bosch fuel pressure gauges coming. As far as dwell goes, what do I need to check that?

Any one of these?

http://www.amazon.com/s/ref=sr_nr_n_0?rh=k%3Adwell%2Cn%3A15684181%2Cn%3A%2 115690151%2Cn%3A15706941&bbn=15690151&keywords=dwell&ie=UTF8&qid=1330438143&rnid=15690151

Or these?

http://www.autozone.com/autozone/accessories/Tools-Garage-and-Equipment/Multimeter/_/N-26lr?filterByKeyWord=dwell&fromString=search

Is there a particular brand to seek out or avoid?

Thanks all.

--buddy

[jawn101]

I've decided to stop trying to fix this blind.

I have a set of Bosch fuel pressure gauges coming. As far as dwell goes, what do I need to check that?

Any one of these?

http://www.amazon.com/s/ref=sr_nr_n_0?rh=k%3Adwell%2Cn%3A15684181%2Cn%3A%2 115690151%2Cn%3A15706941&bbn=15690151&keywords=dwell&ie=UTF8&qid=1330438143&rnid=15690151

Or these?

http://www.autozone.com/autozone/accessories/Tools-Garage-and-Equipment/Multimeter/_/N-26lr?filterByKeyWord=dwell&fromString=search

Is there a particular brand to seek out or avoid?

Thanks all.

--buddy

People seem fond of this one: http://www.amazon.com/Actron-CP7605-Tachometer-Voltmeter-Analyzer/dp/B00062YUUS/ref=sr_1_1?s=automotive&ie=UTF8&qid=1330444625&sr=1-1

I have heard that it is better to avoid the digital ones as the 'swings' can be hard to detect. Never used one so I don't know for sure.

[sean]

People seem fond of this one: http://www.amazon.com/Actron-CP7605-Tachometer-Voltmeter-Analyzer/dp/B00062YUUS/ref=sr_1_1?s=automotive&ie=UTF8&qid=1330444625&sr=1-1
.

It's the one I have. Been happy with it so far.

[nullset]

It's the one I have. Been happy with it so far.

Good, because that's the one I ordered!

It should be here tomorrow. The fuel pressure gauge should be here by the end of the week, I hope.

--buddy