WHALE RUNS FINE YESTERDAY-TODAY NO GO?

WHALE RAN FINE YESTERDAY, WENT OUT TODAY CRANKS SORT OF STARTS RUNS HORRIBLE MISSING CHUGGING STALLS WONT RESTART
AND I SMELL GAS. ANY IDEAS? THANKS STEVE

Check your Fuel Pressure, have some one turn the key on while you are at the back of the car listening for the fuel pump, also look for fuel leaks under the car. whens the last time you changed your fuel filter?

A fuel filter doesn'tl suddenly plug up over night,.

If it has a really strong odor of fuel,. best to determine where the leak is,..

er,. don't smoke while you do,.unless its over insured?

I would suspect if you can smell gas, then check the spark.
Got a  spare plug? Pull the #1 plu gwire, stick the spare plug into it and see if you get a good bright white spark coming off the plug when it is grounded to the header. (edit: read the next post first before you do the stupid thing i suggested of getting a nIce open spark when you smell gas)

If not, then it is an ignition issue. Mine doesn't fire up beneath a certain battery voltage either. Get to around 10V and fugedabowdit.

These cars are notorious for burned out Ignition modules due to the module being on top of the motor buried inside the distributor housing. They get fried in there.
Symptoms usually are you can start it and get to someplace nearby ( grocery shopping) and when you restart ... nada.. due to heat saturation.

A few good suggestions here. But they should be organized into a logical, orderly approach.

First thing I would do is verify where the smell of gas is coming from. You don't want to be checking spark in an explosive environment!!! A fuel leak of any substansive size -- large enough to drop the fuel pressure below the required level -- should show up pretty quickly as drips or a puddle under the car, or on the engine. Get an LED flashlight if necessary then get down on your hands and knees. Turning the key on for a few seconds will pressurize the system and if it's leaking, that should now show up -- er, down -- somewhere.

If there is no evidence of leakage from the supply, then it is entirely possible you are facing a spark issue, and that the odour is coming from the tailpipe. The test described by Lakeffect is useful to some extent, but unfortunately is not definitive. Certainly, if there is no spark it confirms the issue is spark, however the presence of spark does not rule out a spark issue.

Sufficient voltage to cause spark in open air is much lower than the voltage required to initiate a spark under a compression. Richer mixtures require even higher voltages. Google "spark quench effect" for more detailed information, but for now understand that the higher the sparkplug voltage requirement, the more likely cross-firing within a cap and/or wire leakage becomes.

Given that the car runs rough (albeit for a short period of time) it suggests there is some life left in the ignition system. Depending on whether this is an opti-spark car or the older HEI system, your troubleshooting will vary but checking the wires is always a good place to start.

Personally, before getting carried away with the ignition system, I'd verify the engine coolant temperature being reported to the PCM or ECM. If the computer thinks the engine is cold, it will richen the mixture. It may even flood the engine.

buickwagon wrote:

... Personally, before getting carried away with the ignition system, I'd verify the engine coolant temperature being reported to the PCM or ECM. If the computer thinks the engine is cold, it will richen the mixture. It may even flood the engine.

oooh, excellent advice. I plumb forgot about that important little bugger.

Good point!

Aside from the smell of gas, he describes the symptoms of a failing fuel pump. Add that gas smell and I agree on leak somewhere. Use the Mark I sniffer (located on your face) to isolate where the fumes are coming from and proceed accordingly.

Is it an LT1 car or TBI? From your avatar I see exhaust on the drivers side so I'll guess a 94 with the small mirrors

a flooded efi car can be started by full throttle application while cranking,.
full throttle while cranking shuts the injectors off.

nick

phantom 309 wrote:

a flooded efi car can be started by full throttle application while cranking,.
full throttle while cranking shuts the injectors off.

nick

More good info I dint know. Yeah, I know. That could fill an encyclopedia.

phantom 309 wrote:

a flooded efi car can be started by full throttle application while cranking,.
full throttle while cranking shuts the injectors off.

Correct. However, if the cause of the original flooding is a faulty temperature sensor (which hasn't been established -- it's just a guess at this point) then engine will simply flood and stall again as soon as the throttle is released. At some point, the plugs will become so carbon fouled they will no longer spark and nothing will happen.

Sprocket wrote:

Aside from the smell of gas, he describes the symptoms of a failing fuel pump. Add that gas smell and I agree on leak somewhere. Use the Mark I sniffer (located on your face) to isolate where the fumes are coming from and proceed accordingly.

The problem is the symptoms described could be attributed to a number of causes. For example, a mouse nest in the intake obstructing the airflow could cause similar signs and symptoms -- and even explain the smell of gas. It's like a person reporting they are having difficulty breathing -- the root cause could be anything from anaphylaxis to congestive heart failure to pneumonia. You would expect a doctor to rule out a few things before scheduling a lung transplant.

I think a more accurate way of looking at things right now is that these signs and symptoms are of incomplete combustion. A failing fuel pump is one possibility -- lack of fuel pressure results in extremely lean mixture, below the flammability range, so that what little fuel reaches the engine passes out the tailpipe unburnt, causing the odour. Occasionally, after several intake strokes, the concentration of fuel accumulated on the cylinder surfaces builds to the point of allowing one ignition event and the engine coughs or sputters briefly. Times 8. The same could occur if a significant leak is dumping fuel on the ground or if the fuel pressure regulator is stuck open.

At the opposite end of the mixture equation, the mouse nest mentioned above could be choking the engine, or the temperature sensor could be flooding the engine, etc. In this case, the mixture is generally richer than the flammability range, ignition is sporadic, and again, the exhaust pipe fills the air with the odour of unburned gas.

Finally, even if the mixture is correct, a problem with the ignition system or the cam timing can prevent combustion, excepting the occasional accident, and yet again those pesky unburned gasses exit the tailpipe.

My first rule of troubleshooting is to check the simplest and easiest things first because a) they don't take much time or cost much money and b) they are usually the problem anyway. What is the easiest thing to check in this case? Look for a puddle of fuel under the car. It wouldn't take much time to pop open the air filter housing and verify the intake is clear either.

Next, assuming a 94-up, the coolant temperature sensor through the climate control computer display. Put the CC into the diagnostic mode and then check the value of -24 (coolant sensor) against the actual ambient air temperature (remember, it's in °C, NOT °F). The question is answered in less than 2 minutes for a cost of $0. **While in there, one could check for any stored codes too (-00). I don't think that trick works for a pre-94 model. A scan tool or an ohmmeter and chart would be required for the older cars. More time, but still low cost.

A fuel pressure test will quickly verify that the pump can at least produce some pressure and the regulator is not stuck open. A volume delivery test is better to verify the filter and capability of the pump -- but that usually affects driving where the demand is high, not starting.

Once the atmosphere is made non-explosive (ventilation, etc.) spark can be investigated. The method described earlier, using a spare sparkplug, is not quite definitive. A better test is to use a spark checker with an adjustable gap. A wider gap requires higher voltage and better simulates the spark quenching conditions of compression and mixture. In free air, the relationship is approximately 30kv per centimeter of gap. So using a plug gapped to 0.050" in free air, the ignition system will develop less than 4kv. If the insulation is breaking down at 10kv, the spark plug test will not find it. Opening up the gap to 1cm (~3/8") will ensure the ignition system is capable of providing the 20 or 30 kv required to make a spark under compression. The tool is fairly cheap -- $10 or so -- and easy to use. (The old mechanic's trick of sticking a screwdriver in the boot and holding it near the block can lead to damage from over-voltage if the gap is too big, so use the tool!)

Quote :

Is it an LT1 car or TBI?

A critical question that has yet to be answered. The fuel and ignition systems are completely different and the OP would get much better advice if he would respond. For example, the original LT1 Opti-spark supplied with the 94 has a well-documented flaw making it susceptible to moisture. A TBI engine is susceptible to carbon arcing inside the cap. The injector spray pattern can be easily observed with a TBI engine, but not an LT1, but it's easier to measure the fuel pressure on an LT1. Until this question is answered, the responses must be somewhat generic.

**I have a professional scan tool with the appropriate software. So that's what I use. I read about the CC display on the Buick Roadmaster forum and was going by that reference. However, I just went out to my 95 RMW tow-pack (with HD cooling of course) and discovered that the instructions are wrong. I can't find an accurate temp sensor readout using the CC on my car. It may work on some cars, but not mine. The scan tool does provide an accurate readout.

Well there are no fuel leaks. When my buddy was in car to turn on key while I listened
for fuel pump to run, which it did. He hit the starter and it fired right up and runs fine.
Could I have depressed accelerator when I got in the other day and flooded it?
By the way, it is a 1994 LT-1, 59,000 mile car. Thanks for all the ideas. Steve

Pushing slightly on the accelerator might have confused the PCM. It reads the throttle position sensor when you first turn the key and takes that value as 0, so it would assume that the slightly depressed position was closed throttle and fueled accordingly -- lean, since the butterfly would be slightly open.

You would know better than us how likely that is.

It is also possible that there is an intermittent failure (which usually means something electrical). Do you know if your 94 has the original Opti-spark system? You might want to look into the modifications required to bring it up to the 95 standard.

The really good news is that this rules out any really serious mechanical issues like cam timing.

buickwagon wrote:

phantom 309 wrote:

a flooded efi car can be started by full throttle application while cranking,.
full throttle while cranking shuts the injectors off.

Correct. However, if the cause of the original flooding is a faulty temperature sensor (which hasn't been established -- it's just a guess at this point) then engine will simply flood and stall again as soon as the throttle is released. At some point, the plugs will become so carbon fouled they will no longer spark and nothing will happen.

bullshit,.

buickwagon wrote:

Pushing slightly on the accelerator might have confused the PCM. It reads the throttle position sensor when you first turn the key and takes that value as 0, so it would assume that the slightly depressed position was closed throttle and fueled accordingly -- lean, since the butterfly would be slightly open.

You would know better than us how likely that is.

It is also possible that there is an intermittent failure (which usually means something electrical). Do you know if your 94 has the original Opti-spark system? You might want to look into the modifications required to bring it up to the 95 standard.

The really good news is that this rules out any really serious mechanical issues like cam timing.

... Comments edited 08/18/12 for non topical contents .... DJB

i,ve seen small block chevys with the chain so loose they'll wear a hole in the timing cover,. and still DONT skip cam timing,.
has anyone of you internet gurus ever seen a cam jump timing ,. with chain drive??

... Comments edited 08/18/12 for non topical content...DJB

phantom 309 wrote:

i,ve been reading your long winded over explained load of twaddle,. and i,m pretty sure you get your experience from google,

While the internet is a great resource, it wasn't available in 1965 when I tore down my first engine -- a Chevy "Stovebolt" (with Dad's help). In 1992, when I bought my first Roadmaster, the closest thing I had was Fidonet over a 300 baud modem and I don't think I'd even heard of Google yet. Maybe Yahoo. Between those times, I had torn down hundreds of engines, and continue to this day (although I mostly rebuild motorcycles and antique outboards these days.)

I do keep current. I have a complete shop with everything but a lift. Complete meaning everything from scan tools, to a refrigerant recovery machine and everything in between for hand tools. I have a lathe and mill and make my own engine parts as required (mostly for the repair of the aforementioned antiques.)

I've seen many a skipped camchain (replaced one in a Dodge Stealth a month or two ago -- it's actually a belt on that interference engine, skipped means bent valves). What I have never, ever seen is a camchain fix itself. Once they skip, they stay skipped. His engine starts and runs fine now, therefore the chain has not skipped, therefore the problem is (or was) elsewhere. Even if you think it's BS.

Yes it is the original opti-spark. I have replaced the cap-rotor-and wires at one point.
I see Jegs has their house brand on sale for 200.00 and had thought about getting one
just to have, because I hear they are prone to problems. I have no clue what it would
take to upgrade to the 95-96 unit or why it would be an upgrade. I thought they were
all problematic.

The later years had a vacuum venting system to keep the insides dry. I've heard of two approaches: one to improve the venting system on the 94, the other to replace it with the later version, which requires some modifications. (I've never had a 94 so I've never done it personally. In this case, I plead guilty to the charge of being an "internet guru" -- what follows is just what I've read and assumes I'm remembering this right.) IIRC, the later version does not bolt right on, it may require a different timing cover, a new wiring harness connector and the vacuum harness.

However, some guys over at ISSF did some experimenting and worked out a way to vent the older one with inexpensive parts -- basically some tubing, a check valve and a restricted orifice to limit the flow. If yours does not yet suffer from corrosion damage, this might be the most economical solution.

There are also complete replacements that swap in a coil pack instead. I understand they can be a bit pricey.

New develpoment. Runs fine-drive 2 blocks stalls-restarts and drives fine. This morning
pulling into MickeyD's for coffee dies completely, I mean no power to anything, no lights,
dash goes black, all dead. Sits for five minuets and power comes back. Starts up and
stalls. Restart and finish the drive to work.WTF?

Ok, this definitely sounds electrical. First thing to check is the battery terminals. Second thing to check is the aux terminal on the passenger fender. Third thing to check is the body-to-engine grounds (I think rear of driver's side cylinder head) and the body ground near the battery. Something sounds loose or corroded.

buickwagon wrote:

Ok, this definitely sounds electrical. First thing to check is the battery terminals. Second thing to check is the aux terminal on the passenger fender. Third thing to check is the body-to-engine grounds (I think rear of driver's side head) and the body ground near the battery. Something sounds loose or corroded.

Check if your auxiliary battery post is brass-colored or silver-colored. The silver-colored ones can cause weird problems.

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Sounds like a electrical short is the best possibility!

Come on now, Jim. That's uncalled for. - Ray

Yes, I'm gonna start checking cables when and if I get home from work tonight.
Funny you add that link,because I was looking in the parts computer at work and I
ordered one of those and read the service bulletin.

I believe you guys have found the problem. The aux battery post is silver and has been
hot enough to melt a hole in the top of it. When the car loses power, you can wiggle the
cable at the post and it comes back momentarily. It is also very warm. Parts are ordered
and I will update when installed. Thanks to all and especially to Nick Danger for the link
on this. Thanks, you guys rock. Steve

1. The Opti Spark on a 1994 B boby IS VENTED FROM THE FACTORY. So there is no need to install a newer one has it is already on there.

2. Ray really needs to knock off this bullshit of editing and deleting peoples posts.

3. Things here have been just fine for years. No need to go all Nazi on the place.

94Woody wrote:

1. The Opti Spark on a 1994 B boby IS VENTED FROM THE FACTORY. So there is no need to install a newer one has it is already on there.

I don't have a 94, so maybe the B-bodies got the vacuum vented opti-spark system a year earlier than the other models. However, you might want to look at these:

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@6500steve54: Glad to hear you have found the problem. You can probably get away temporarily by removing the wires, cleaning things up with a wire brush and reassembling until your new one arrives. You should clean up the wires anyway so it's not wasted time.

buickwagon wrote:

The later years had a vacuum venting system to keep the insides dry. I've heard of two approaches: one to improve the venting system on the 94, the other to replace it with the later version, which requires some modifications. (I've never had a 94 so I've never done it personally. In this case, I plead guilty to the charge of being an "internet guru" -- what follows is just what I've read and assumes I'm remembering this right.) IIRC, the later version does not bolt right on, it may require a different timing cover, a new wiring harness connector and the vacuum harness.

However, some guys over at ISSF did some experimenting and worked out a way to vent the older one with inexpensive parts -- basically some tubing, a check valve and a restricted orifice to limit the flow. If yours does not yet suffer from corrosion damage, this might be the most economical solution.

There are also complete replacements that swap in a coil pack instead. I understand they can be a bit pricey.

Incorrect!!! All of the b-bodies got the vented opti spark. Only the f and y bodies got the non-vented version.

94Woody wrote:

1. The Opti Spark on a 1994 B boby IS VENTED FROM THE FACTORY. So there is no need to install a newer one has it is already on there.

What he said......

I stand corrected. I didn't realize the B-bodies got the redesigned opti right from the get-go.

I wonder why GM didn't install the improved version on the other models? Oh well, that's just one more thing GM did that leaves me shaking my head wondering "WHY?".

buickwagon wrote:

I stand corrected. I didn't realize the B-bodies got the redesigned opti right from the get-go.

I wonder why GM didn't install the improved version on the other models? Oh well, that's just one more thing GM did that leaves me shaking my head wondering "WHY?".

So they could get rid of old stock which had a possibility of failing before the warranty period was up; but willing to take that risk to save some dollars.

6500steve54 wrote:

I believe you guys have found the problem. The aux battery post is silver and has been
hot enough to melt a hole in the top of it. When the car loses power, you can wiggle the
cable at the post and it comes back momentarily. It is also very warm. Parts are ordered
and I will update when installed. Thanks to all and especially to Nick Danger for the link
on this. Thanks, you guys rock. Steve

I'm glad my write-up is still helping people.

Parts installed tonight after work. Running fine so far. Test cruise Sunday, I'm confident

you guys called it. WooHoo. Thanks Steve.