Long or hard starts rough idle and misfires

Here of late, I have seen several GA owners with long or hard starts rough idle and misfires. Last week I bought some remanufactured Injectors(6) for $230(shipping included and overnight). In this order they sent a few comments from a GM bulleti#99-06-04-005B. Also I hav the phone # and address for the place where I picked up the injectors for anyone interested.

Anyway I scaned the letter to show to anyone who has had the issues described above. You may hav to right click on the pic and save it, then open it in a paint shop program to read it all(limited to 250k through the link). Or I can email a larger size(Just ask) of the doc to whom ever would like to read this. It is a good article and I would recommed reading it to all.

http://i22.photobucket.com/albums/b346/roboticgod/GmMFI2.jpg

the pic didnt turn out for crap. heres one link refering to the article.
http://www.lindertech.com/pattern_failures.htm

I just done a google search for the bulletin #. This should clarify several issues.

I'm not saying that this is always the case with every similar symptom you may hav with the long starts and overall rough engine performance due to misfires(cloged injector). The more miles on the injectors and a combo of bad gasoline seems to contribute to bad mpg also.
If you bought these injectors individually they are around $75 each(6=#450).

Heres A quote;

"G.M. Stainless Stamped Spray Tip Injectors. We've been getting calls regarding fuel injector problems with G.M. Multec injectors with the Stamped (stainless) Spray Tip. General Motors introduced this version of the Multec injector in 1993. It is used on, for the most part, the 3100 engine (vin M & J), the 3400 (vin S & E) and the 3800 (vin K). Many of the complaints are related to a MIL on and/or a lean condition. In the last few months we've been hearing some new complaints. It seem as technicians are checking into these driveability problems, they find that one or more of these injectors doesn't seem to be working at all. However, with a few "taps" on the side of the injector, it comes back to life.
Let's try to explain what is going on.

The redesigned injector utilizes a larger discharge bore when compared to the original Multec and are slightly shorter (2.65mm). This was done to prevent fuel dripping from the discharge area and improve air/fuel mixing. This makes the injectors prone to carbon build up at the discharge end reducing the amount of fuel flow. This will cause a multitude of problems such as hard starting, hesitation, MIL on and a lean condition. G.M. has published a TSB regarding these particular problems: Bulletin# 99-06-04-005B. Below is an excerpt from the bulletin.

Condition
Some owners may comment on driveability symptoms of long or hard start, chuggle, rough idle and light or intermittent misfire. The MIL may also illuminate.

Cause
Due various factors, the fuel injectors may become restricted. At this point, no specific fuel or engine condition has been identified as causing the restriction. The restriction causes the engine to operate at a lean air/fuel ratio. This may either trigger the MIL to illuminate or the engine to develop various driveability symptoms.

So what's happening with these injectors? At some point these vehicles probably started with a symptom like the ones mentioned in the TSB. But, nothing was done about it. The carbon, dirt, rust or whatever was restricting the injector was not cleaned out. Now the problem has gotten worse and something has become lodged in the injector or it is so clogged that very little or no fuel is being discharged. A few "taps" on the side of the injector dislodges whatever happens to be stuck inside the injector and it seems to work fine again. This could be related to the use of fuels that do not contain certain detergents or fuel additives and the use of fuel with an improper octane rating. Driving patterns such as short trips with long cool down periods can also accelerate this condition.

So is tapping on the injector a fix? Absolutely not! In most cases the injector will stick again and/or other injector will develop the same problem.

What's the fix?
1. Take a fuel sample and test for fuel contaminates such as: water, sugar, rust, dirt, etc. This may mean you have to leave the sample sit overnight.
2. Flush the fuel rail, lines and tank as needed.
3. Perform an intake cleaning to remove carbon that could possibly clog the new injectors.
4. Replace all injectors with our flow-matched sets.
5. Educate your customer that regular maintenance can reduce their chances of having this problem reoccur in the future. This includes oil changes, PCV valves, fuel system service and intake cleaning to remove carbon. Not only will this make you shop money, but there is much less chance that this vehicle will come back with the problem again.


Doug Garriott
The Injector"Wizard"

Good read,

Only thing I can relate to this is when I start, it sometimes is a long start.. straight to rough idle then the rpms go back up to 650. I noticed this morning while in traffic that it was slightly being rough enough to shake the car... Ill keep this article in mind.

ya Gir, at first you may get the harder starts, then it will go to throwing misfire codes and even rougher of an idle and your mpg may drop down to 18mpg or less. The old injectors all had good readings upon electrical testing(were only 6-7 months old), except when I pulsed the injectors on the fuel rails they were all irregular in the patterns they sprayed. I am religious when it comes to maintenance and they still screwed up somehow.

Sometimes I hav gotten whatever was pluging them to blow out with some hard acceclerations but eventually i had replaced them 1 by 1($450).

I just thought it was a good idea to let others know that there are other options when purchasing these injectors you can find sets instead of buying them individually.

Thanks for the info. So, what fuel injectors do you recommend replacing them with? I've had the fuel system cleaned regularly and use Mobil, so if my problem is the fuel injectors I definitely don't want this same kind. I went to AutoZone to get the scanning done, but they said they only do it on '96 and newer vehicles (I have a '94 GT 3.1). If I had an oxygen sensor problem would I definitely get the Service Engine Soon light? It has been about 4.5 years/30,000 miles since I had that replaced.

Although that bulletin is a good read, its older that the crust in my grandmas underwear.
The problem with the information you have posted is it is outdated.
There have been several revisions and updates to the procedures regarding Multec 2 injectors.
The latest and greatest bulletin for this is #03-06-04-030A.
Here is some information about these injectors.
First off injectors fail one of 2 ways..electrically or hydraulically.
If they fail, the only repair is replacement.
On the Multec 2 injectors, carbon build up on the director plate causes the injector to flow lean..this is where you run into misfires and performance loss.
The correct procedure is to check the pressure drop of each injector to check its flow..if the drop difference is greater that 20kpa of each other, the proper repair procedure is to clean the injectors (using a mixture of 10% TEC to gas at 75psi) twice..then recheck the pressure drop if the difference is greater that 15 kpa, then the injector fails and should be replaced.
Use of aftermarket cleaners do not do the trick..also pour in injector cleaners do not do the trick either and may cause the injector to fail electrically because the fuel is used to cool the injector coil and the additive may attack the coil winding coating.

Here are some things you should know and usually I don't post GM Service information on the net, but car owners need to know this.
TOP TIER Detergent Gasoline (Deposits, Fuel Economy, No Start, Power, Performance, Stall Concerns) #04-06-04-047E - (Aug 17, 2005)
TOP TIER Detergent Gasoline (Deposits, Fuel Economy, No Start, Power, Performance, Stall Concerns)
2006 and Prior All General Motors Passenger Cars and Trucks (U.S. Only)

2006 and All Prior Saturn Vehicles (U.S. Only)

2003-2006 HUMMER H2 (U.S. Only)

2006 HUMMER H3 (U.S. Only)

2005-2006 Saab 9-7X (U.S. Only)

This bulletin is being revised to add the 2006 model year, include additional models and add additional marketers of TOP TIER Detergent Gasoline. Please discard Corporate Bulletin Number 04-06-04-047D (Section 06 - Engine/Propulsion System).

A new class of gasoline, called TOP TIER Detergent Gasoline, is appearing at retail stations of some fuel marketers. This gasoline meets detergency standards developed by four automotive companies. A description of the concept and benefits of TOP TIER is provided in the following question and answer section.


Gasoline Brands That Currently Meet TOP TIER Detergent Gasoline Standards
As of August 15, 2005, the following gasoline brands meet the TOP TIER Detergent Gasoline Standards:

• Chevron Chevron has markets in 29 states in the West, Southwest and South, as well as in Alaska and Hawaii. ALL grades of Chevron with Techron gasoline meet TOP TIER Detergent Gasoline Standards.

• QuikTrip (not to be confused with Kwik Trip) QuikTrip operates convenience stores and travel centers in a number of metropolitan areas:

- Tulsa, OK

- Springfield, MO

- Kansas City, MO and Kansas City, KS

- Wichita, KS

- Des Moines, IA

- Omaha, NE

- St. Louis, MO and St. Louis, IL

- Atlanta, GA

- Dallas-Ft. Worth, TX

- Phoenix, AZ

- Bartlesville, OK

- Miami, OK

- Vinita, OK

- Columbia, MO

• Conoco has over 4,000 stations located in 33 states.

• Phillips 66 has locations in 32 states across the nation.

• 76 has over 2,700 stations located throughout the country.

• Shell Shell Oil Products has a network of nearly 7,000 branded gasoline stations in the Western United States. Shell Oil Company markets branded products through more than 10,000 stations in the Eastern and Southern United States.

• Entec Stations offer gasoline through stations located in the greater Montgomery, Alabama area.

• MFA Oil Company offers gasoline at "Break Time" convenience stores located throughout Missouri.

• Kwik Trip, Inc. offers gasoline at Kwik Trip convenience stores in Minnesota and Wisconsin and Kwik Star convenience stores in Iowa.

• The Somerset Refinery, Inc. offers gasoline at Somerset Oil stations in Kentucky.


What is TOP TIER Detergent Gasoline?
TOP TIER Detergent Gasoline is a new class of gasoline with enhanced detergency. It meets new, voluntary deposit control standards developed by four automotive companies that exceed the detergent requirements imposed by the EPA.


Where Can TOP TIER Detergent Gasoline Be Purchased?
The TOP TIER program began on May 3, 2004. Some fuel marketers have already joined and have introduced TOP TIER Detergent Gasoline. This is a voluntary program and not all fuel marketers will offer this product. Once fuel marketers make public announcements, they will appear on a list of brands that meet the TOP TIER standards.


Who developed TOP TIER Detergent Gasoline standards?
TOP TIER Detergent Gasoline standards were developed by four automotive companies: BMW, General Motors, Honda and Toyota.


Why was TOP TIER Detergent Gasoline developed?
TOP TIER Detergent Gasoline was developed to increase the level of detergent additive in gasoline. The EPA requires that all gasoline sold in the U.S. contain a detergent additive. However, the requirement is minimal and in many cases, is not sufficient to keep engines clean. In order to meet TOP TIER Detergent Gasoline standards, a higher level of detergent is needed than what is required by the EPA. Also, TOP TIER was developed to give fuel marketers the opportunity to differentiate their product.


Why did the four automotive companies join together to develop TOP TIER?
All four corporations recognized the benefits to both the vehicle and the consumer. Also, joining together emphasized that low detergency is an issue of concern to several automotive companies.


What are the benefits of TOP TIER Detergent Gasoline?
TOP TIER Detergent Gasoline will help keep engines cleaner than gasoline containing the "Lowest Additive Concentration" set by the EPA. Clean engines help provide optimal fuel economy and performance and reduced emissions. Also, use of TOP TIER Detergent Gasoline will help reduce deposit related concerns.


Who should use TOP TIER Detergent Gasoline?
All vehicles will benefit from using TOP TIER Detergent Gasoline over gasoline containing the "Lowest Additive Concentration" set by the EPA. Those vehicles that have experienced deposit related concerns may especially benefit from use of TOP TIER Detergent Gasoline.

And this one here
Maintenance Cleaning of Fuel Injectors #04-06-04-051A - (Sep 3, 2004)
Maintenance Cleaning of Fuel Injectors
2005 and Prior All General Motors Passenger Cars and Trucks

2003-2005 HUMMER H2

General Motors is aware that some companies are marketing tools, equipment and programs to support fuel injector cleaning as a preventative maintenance procedure. General Motors does not endorse, support or acknowledge the need for fuel injector cleaning as a preventative maintenance procedure. Fuel injector cleaning is approved only when performed as directed by a published GM driveability or DTC diagnostic service procedure.

Due to variation in fuel quality in different areas of the country, the only preventative maintenance currently endorsed by GM regarding its gasoline engine fuel systems is the addition of GM Fuel System Treatment, P/N 12345104 (in Canada, 89020804), added to a tank of fuel at each oil change.
Important
The addition of GM Fuel System Treatment should not be necessary for those customers who exclusively use Top Tier Detergent Gasolines only. Refer to Corporate Bulletin Number 04-06-04-047A.

Look, I like Pontiac; I would buy a new Pontiac if they still made cars that looked like Pontiacs instead of Toyotas. But, I don't think every owner of a GM vehicle in the Chicago area should have to buy Shell V-power to not develop fuel injector problems, esp. since that was not invented yet when my car was made, and my owner's manual says to use 87 octane. If something is still wrong with my fuel injectors after I had them cleaned twice, unless it's normal to need new ones after 11 years, perhaps this is another GM design flaw, like these wonderful '94 Grand Am brakes.

In formation overload dude! The real point a was try to make is that there are trouble areas with in these fuel systems, and that when you purchase these Multec 2 injectors one by one ur getting ripped off, because you can buy an entire kit for half the price.
This carbon build up happens on several differnt automotive companies engines, why is it just GMs that I've seen, tend to be the ones disrupted by the littlest build up creating misfires and rough starts then burning up the coils in the injector...

Look, I like Pontiac; I would buy a new Pontiac if they still made cars that looked like Pontiacs instead of Toyotas. But, I don't think every owner of a GM vehicle in the Chicago area should have to buy Shell V-power to not develop fuel injector problems, esp. since that was not invented yet when my car was made, and my owner's manual says to use 87 octane. If something is still wrong with my fuel injectors after I had them cleaned twice, unless it's normal to need new ones after 11 years, perhaps this is another GM design flaw, like these wonderful '94 Grand Am brakes.

Did you ever think that the GAS companies product is getting worse?

In formation overload dude! The real point a was try to make is that there are trouble areas with in these fuel systems, and that when you purchase these Multec 2 injectors one by one ur getting ripped off, because you can buy an entire kit for half the price.
This carbon build up happens on several differnt automotive companies engines, why is it just GMs that I've seen, tend to be the ones disrupted by the littlest build up creating misfires and rough starts then burning up the coils in the injector...

If you properly maintain and clean the injectors, you won't have to replace them.
In GM warranty audits, GM found that over 60% of the "failed" injectors replaced under warranty were dirty and not failed electrically or mechanically.
This means good parts were being replaced and not cleaned.
This means you could be replacing a part that is dirty...do you replace your car when it gets dirty?
Probally not, you clean it and keep driving.
The gas companies product quality has diminished over the years (while the price goes higher). The effect of this is deposits being formed on componants and drivability issues popping up.
SO GM along with other car makers (who are having the same problems with fuel related concerns) developed a specification for fuel and challenged the GAS companies to change their fuel to meet the specifications.
So if you use TOP TIER gasoline (instead of that crap they pass off as gasoline) you shouldn't have any driveability problems.
One thing you will find in non top tier gasoline is ALCOHOL.
Alcohol absorbs water. Excessive alcohol (10% or more) causes corrosion inside the fuel system and can cause undesirable drivability concerns.
So don't blame GM for these problems..blame the GAS COMPANIES! They are the ones passing off this crap to us as gasoline :2cents:

i will agree with the gas being/going to crap. I stick with alcohol free fuel mostly BP Amoco, the blue colourd fuel no 10% ethanol(alcohol).

GMM You said, "If you properly maintain and clean the injectors, you won't have to replace them.
In GM warranty audits, GM found that over 60% of the "failed" injectors replaced under warranty were dirty and not failed electrically or mechanically.
This means good parts were being replaced and not cleaned."

So why is it that GM DEALERS replace these injectors that are "cloged" or "dirty" instead of cleaning them? Lazyness? Stupidity? Monopolizing on the public because they know no better and GM needs the bucks? Who does these audits, an outside third party source with no bias in the outcome? These audits, are all done by Gm themselves so they are biased facts.
Most vehicles I own are GM and the majority of the automobiles I service are GM, see the trend? A flaw in design that no one will ever admit too. Just pissin in the wind...

Oh I see now, everyone who owns a GM with Multitec 2 injectors should regularly bring their autos in, once everyother month, for one of those $250-300 fuel system cleanings that require a whole day to doo. Since after market cleaners are harmfull to the sysytem and over all are crap too.

A big source of revenue for General Motors is Mr. Goodwrench. They want you to bring your car to them for all your needs and will always look for ways to make more.

This isn't specific to GM. All automobile manufacturers today are using their after-sale service as revenue generators.

The solution, then, is to use high quality aftermarket parts whenever possible; generally, a higher quality aftermarket part will cost less than the original part from Mr. Goodwrench. Also, try to support your local independant mechanic if you can find a good, honest one.

So why is it that GM DEALERS replace these injectors that are "cloged" or "dirty" instead of cleaning them? Lazyness? Stupidity? Monopolizing on the public because they know no better and GM needs the bucks? Who does these audits, an outside third party source with no bias in the outcome? These audits, are all done by Gm themselves so they are biased facts.

Lets start at the beginning..first, when your vehicle comes in for a warranty repair, who pays the bill? (besides you in the purchase price)..GM pays the dealer for the repair.
GM warranty audits are done by GM themselves. The facts are not biased, this information is declassified GM internal information.
It doesn’t do GM (or any other car maker) good to have a high warranty expense on their vehicles.
When GM sees a trend in a repair, they take a closer look at the repair and do extensive research into what caused the failure.
The research into the root cause of the failure goes to the development of a TSB and any changes in the product to make it better.
What GM found is that the injectors were being replaced for incorrect pressure drop. The incorrect drop was caused by poor fuel quality. The fuel was clogging the holes in the director plate restricting the amount of fuel injected when the injector was energized. The lean condition from the clogged director plate is what causes the hard start, rough running and misfires.
This lead to the TSB on the procedures to check and clean the injectors and the development of the specifications for TOP TIER gasoline. (GM isn’t the only company having problems with poor gas quality and the Multec 2 injector is used in other vehicles).
Once the determination of the proper diagnostic and repair procedure was validated, a TSB was issued and the dealers should be following the repair procedure.
If an injector is returned under warranty, it better have failed mechanically or hydraulically..
This procedure should also be followed when the vehicle is out of warranty. Following the procedure will give the customer the best repair and save them money.
Oh I see now, everyone who owns a GM with Multitec 2 injectors should regularly bring their autos in, once everyother month, for one of those $250-300 fuel system cleanings that require a whole day to doo. Since after market cleaners are harmfull to the sysytem and over all are crap too.
You did not read the last TSB I posted. It states that “Maintenance cleaning” of injectors is not necessary.
One bottle of Fuel injector treatment (Tectron) added to the fuel tank after each oil change is sufficient for those who do not use TOP TIER gasoline.


A big source of revenue for General Motors is Mr. Goodwrench. They want you to bring your car to them for all your needs and will always look for ways to make more.
This isn't specific to GM. All automobile manufacturers today are using their after-sale service as revenue generators.
The solution, then, is to use high quality aftermarket parts whenever possible; generally, a higher quality aftermarket part will cost less than the original part from Mr. Goodwrench. Also, try to support your local independant mechanic if you can find a good, honest one.

This just shows your ignorance of how GM works.
GM makes money by selling cars and trucks. They also make money by selling parts to the dealer, but many GM family companies (Delphi, AC Delco ) have been spun off GM and they are their own corporations with no ties to GMs profitability.
Dealers are private franchise owners of licensed GM products and do receive specific product training and are allowed to sell GM labeled products.
This means that the dealer must purchase parts from GM and must meet standards set by GM (these standards have to do with everything all the way to the uniforms the techs wear)
After sales service is a big revenue generator for the automaker…Service sells cars and GM makes money on each car it sells..NOT from the service department.
The dealer has a service department to take care of their customers.
So your dealer is the local independent repair shop.
Any profits from the service department go to the dealer, not GM.
The dealer must meet requirements set forth by GM for the training level of the service technicians.
Unfortunately if the dealer has 20 techs and 1 is 100% trained, the dealer meets the standard. This means the dealer has 19 techs who are not trained.
A trained dealer tech has the training, tools and technical support to properly diagnose, service and repair your GM vehicle right the first time.
The trained dealer tech has an advantage over other mechanics because they have the specific product knowledge.
Trained dealer techs are specialists. They work on one product and know it well.
Do you want a guy who dabbles with everything (including farm tractors and lawn mowers) to work on your car or do you want a TRAINED SPECIALIST to fix your car?
Remember, a mechanic works on cars, a TECHNICIAN fixes them!
So anytime you go to the dealer, you are supporting your local independent TECHNICIAN.

wow, you do know ur stuff there mr. Goodwrench. Mr Gw, ur parts ..... i like it when you ramble.