Chevy

Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP

Ask an Expert,
Get an Answer ASAP!

Chevy
This answer was rated:

2000 Camaro Z28 LS1 engine, 6-sp manual transmission. Engine

has been modified. 2200-7200 Compcams...
2000 Camaro Z28 LS1 engine, 6-sp manual transmission. Engine has been modified. 2200-7200 Compcams cam, 60 lbs injectors, 80mm Edelbrock throttle body, ported heads, ported exhaust manifolds, 2 1/2" y-pipe to 3" pipe to Magniflow... Engine ran great 35,000 miles, until today. At idle, engine started to run very poorly, like misfiring cylinders. All ignition coils are working fine. At idle, on 4 cylinders, when the fuel injectors are unplugged, there is no change. With engine running, using a multimeter, on those cylinders, the connectors have 14.26V from (+) wire to ground, 8.91V when multimeter is connected between the 2 wires at each connector. So there is no electrical issue, injectors must be no good on those cylinders. Engine has been dynotuned to those 60lbs injectors. I plan on replacing all of those injectors with better quality ones. Are all 60lbs injectors the same? Will I have any issues by simply changing out those injectors with better quality ones?
Show More
Show Less
Ask Your Own Chevy Question
Answered in 55 minutes by:
1/2/2016
Gary
Gary, ASE Certified Technician
Category: Chevy
Satisfied Customers: 1,379
Experience: Senior Technician
Verified

Hi there,

Can you tell me which cylinders the engine is misfiring on?

Can I assume that your modified engine has a non-AFM camshaft?

I would always recommend to replace injectors with the same type from the same manufacturer.

If other injectors are also rated at 60lb, then they are probably ok, but there could be subtle differences.

Then the tuning will be off, some rich some lean etc.

Gary

Ask Your Own Chevy Question
Customer reply replied 2 years ago
Cam is Compcams K54-428-11 kit. Cylinders 3,5, 2,4. The current injectors are Siemens Deka, paid $229.00 for set of 8 of eBay. Ran great for 35,000 miles. I was considering going with a FAST 306008 60lb set. But if that is going to throw the tune of then I won't. Should I still stay with the Siemens Deka? If so, it shouldn't have to be re-tuned then right?

Hi again,

I am happy that you have used a kit from a cam manufacturer, especially Comp Cams, top marks.

Are you quite sure it is the injectors for those four cylinders, all failing at the same time?

The cylinders you have mentioned are adjacent to each other, 3 and 5 on bank 1, and 2 and 4 on bank 2.

Have you done a compression test with all spark plugs out?

Have you measured the injectors resistances, all 8 for comparison?

You should be able to stay with identical injectors and no further programming should be needed.

I would ask the programmer what the maximum duty cycle is at the moment, maybe you need larger injectors.

Gary

Ask Your Own Chevy Question
Customer reply replied 2 years ago
100% sure all 4 of those injectors failed at the same time. I did not see a reason to do a compression test. It does not burn any oil, no smoke in exhaust, not even an engine code. If compression was off, cylinder would still fire. If there were no compression, I'm sure there would be smoke in the exhaust. With engine running at idle, disconnecting the injectors involved has no impact on idle quality at all, not even a momentary drop in rpm. This happened at idle.

Hi Brian,

Ok, I would class it as extremely odd to have 4 fail at the same time, but if you are sure it is the injectors, then go ahead with replacing them.

Strange that is also does not have an engine code.

But maybe the program ignores misfires, since misfire detection is more important for emissions as far as OEM is concerned.

It is possible that the offending injectors have become blocked with fuel system debris etc, I would take the rail and injectors out for a flow test by an off-car injector specialist.

I have seen injectors block up or go open circuit (no fuel), and have seen injectors stick open, flood the engine and then bend rods. It only takes one to do that.

I bet your car goes well prior to this.

Gary

Ask Your Own Chevy Question
Customer reply replied 2 years ago
I agree with you that it is extremely odd. On the 4 that work, the idle changes when the injectors are unplugged. The 4 that I am referencing do not. Like I said this happened at idle. Can the fuel rail be cleaned without taking it to be tested? The injectors that are in it are out of warranty. I don't really have a lot of time, would rather just purchase a new set, and clean the fuel rail. Yes, my car is quick.

Ok, another test to do.

Have you had a noid light on the injector plugs to see if the pulse is there?

Another thought is the offending cylinders are 2,3,4,5.

Coincidence?

Is it a programming issue for antitheft or something?

You can remove the rail, remove the injectors, blast some carb cleaner through the rail, to make sure it is clean, fit the new injector set, etc. Replace your fuel filter.

I like to read the new injectors ohms first, just in case one is faulty out of the box.

Gary

Gary

Ask Your Own Chevy Question
Customer reply replied 2 years ago
I don't have a noid light, just know that there are no broken wires, no electrical issues. The system must have had debris in it some how. That is the only explanation I can fathom for 4 injectors failing at once, at idle. Fuel filter is prob has 12 months on it. I wil definitely changing it. Can the fuel pressure regulator in the fuel rail be cleaned with carb cleaner too? How is it cleaned? Would the regulator have any debris caught in it?

Hi Brian,

If your system is like ours, then you only have the feed line going to the fuel rail.

The regulator is in the tank pump assembly.

You may find nothing in the rail, but you need to take it off for inspection.

If you are really keen, I would swap the 4 injectors with the other 4 and see if the fault does go to the other 4 cylinders.

Gary

Ask Your Own Chevy Question
Customer reply replied 2 years ago
There is a valve in the fuel rail. What is that? Does it need to be cleaned? The fuel rail has to come off to change to change the injectors anyways.

It may have a damper within the rail.

It also has a schrader valve for fuel pressure measurement, and pressure relief prior to disassembly.

A blast of compressor air as a final check to make sure all is clear.

Blast into a rag etc, to check for what may have been in there.

Gary

Ask Your Own Chevy Question
Customer reply replied 2 years ago
The valve is part of the rail, does not separate from it. Should I blast it from all sides?

It really depends on what if any comes out of the rail.

The injectors have their own filters, so as you pull each one out, look into the top of the injector for debris.

That will give you idea of what might still be in the rail.

It could well be clean inside, a blast out of air in every direction should suffice.

Gary

Ask Your Own Chevy Question
Customer reply replied 2 years ago
Is it possible that the injectors involved just need to be cleaned? Or are they no good once debris get's in there?

Hi Brian,

I have seen many injectors come back from the dead after a clean.

Get them out for an off-car injector flow test and clean.

Could be worth your while prior to buying a new set.

Gary

Ask Your Own Chevy Question
Customer reply replied 2 years ago
Do they have to be taken somewheres or can I clean them myself with air compressor/carb cleaner?

Injectors are best cleaned by an ultrasonic cleaning machine, and then flowtested to ensure they flow within a tolerance of each other.

Normally the tech would flow them first to see the errors.

Gary

Ask Your Own Chevy Question
Customer reply replied 2 years ago
Where would I find a place that has 1 of those machines?

Hi Brian,

You need a service that comes to you like this:

http://electronicinjectorservices.com.au

Do you have anybody like this where you are?

It would cost you more to buy the necessary equipment than to buy many sets of injectors.

Gary

Ask Your Own Chevy Question
Customer reply replied 2 years ago
This was addressed in the other thread we had today. Thx.

Hi Brian,

I hope I have given you some guidance with your car.

Gary

Gary
Gary, ASE Certified Technician
Category: Chevy
Satisfied Customers: 1,379
Experience: Senior Technician
Verified
Gary and 87 other Chevy Specialists are ready to help you
Ask your own question now
Customer reply replied 2 years ago
Thanks you for your assistance.

Thanks very much Brian.

Hope you get your car running fast again.

Happy New Year to you and your family.

Regards

Gary

Ask Your Own Chevy Question
Ask Gary Your Own Question
Gary
Gary
Gary, ASE Certified Technician
Category: Chevy
Satisfied Customers: 1,379
1,379 Satisfied Customers
Experience: Senior Technician

Gary is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money.

Todd LRochester NY

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

< Previous | Next >

Meet the Experts:

GM Tech (Cam)

GM Tech (Cam)

Chevy Technician

15,289 satisfied customers

GM Grand Master Technician 2007. 14 years experience.

Gary

Gary

Chevy Technician

9,357 satisfied customers

15 years GM master tech

Tim&#039;s Auto Repair

Tim's Auto Repair

mechanic

8,866 satisfied customers

Have owned a repair shop for 25 yrs.

Dave Nova

Dave Nova

Chevrolet Technician

7,092 satisfied customers

ASE Master Certification. GM World Class Certification

John

John

Master A.S.E Automotive technician

4,071 satisfied customers

A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician

Don - Mo Lurch

Don - Mo Lurch

Auto Mech / Electronics

2,918 satisfied customers

Chevrolet Cert., Heavy Line Mech, Race Shop Owner, Mobile Electronics.

Ron Z.

Ron Z.

- Chevy Tech -

2,734 satisfied customers

18+yrs experience. State Inspector and Chevy Diagnostics

< Previous | Next >

Related Chevy Questions
Got an error code p0341 and p0342 relating to the camshaft
got an error code p0341 and p0342 relating to the camshaft position sensor. Been searching online for the right one but the ones that supposedly "fit" look nothing like the one presently on the vehicl… read more
Jared D
Jared D
Shop Supervisor
Bachelor\u0027s
3 satisfied customers
I already change the spark plugs and wires on a Malibu 2003
I already change the spark plugs and wires on a Malibu 2003 Chevy it won't start … read more
kalamykid
kalamykid
Pactor automotive
Vocational, Technical or Trade Scho
97 satisfied customers
My engine light went on yesterday The code is P0013. Exhaust
My engine light went on yesterday The code is P0013 … read more
fordguy4u
fordguy4u
Automotive Tech
Vocational, Technical or Trade Scho
70 satisfied customers
Engine light on" clean exhaust filter continue to dric. Ve
engine light on " clean exhaust filter continue to dric … read more
BOBBYSS
BOBBYSS
TECHNICIAN/ADVISOR
Associate Degree
8,343 satisfied customers
Won't start, get spark from the spark plugs, have put gas in
won't start, get spark from the spark plugs, have put gas in the intact still won't start. Starter is turning all the belts … read more
heavy_chevy_396
heavy_chevy_396
Vocational, Technical or Trade Scho
2,518 satisfied customers
O2 sensor and camshaft position sensor failed emissions.
o2 sensor and camshaft position sensor failed emissions … read more
Stephen, MBA
Stephen, MBA
Master's Degree
166 satisfied customers
2014 Chevy Silverado 4.3 cylinder two misfire a spark plug
2014 Chevy Silverado 4.3 cylinder two misfire a spark plug is looks like it's wet with gasolineAlso engine code P0106… read more
fordguy4u
fordguy4u
Automotive Tech
Vocational, Technical or Trade Scho
70 satisfied customers
P0017 Code. Crankshaft and camshaft position sensor for bank
crankshaft and camshaft position sensor for bank 1, and yes I have tried to reset it multiple times … read more
Matt
Matt
Engineer
Bachelor\u0027s Degree
5 satisfied customers
Pulled spark plug out and fuel came out with the plug.
pulled spark plug out and fuel came out with the plug. … read more
Dan
Dan
Automotive Technician
Vocational, Technical or Trade Scho
25 satisfied customers
Misfire code p0306 I️ changer distributor cap spark plug and
Misfire code p0306 I️ changer distributor cap spark plug and wires new fuel pump don't understand why code is appearing … read more
Gary
Gary
ASE Certified Technician
1,379 satisfied customers
Misfire in cylinder #1 replaced coil and spark plugs, engine
misfire in cylinder #1 replaced coil and spark plugs, engine light on and flashing. Put in injector cleaner also. … read more
eauto
eauto
self employed
High School or GED
74 satisfied customers
Crank ok but won't start when hot, fuel 55psi,spark plug
when it cold start up no problem,i even replace coolant temp sensor… read more
Michael Solis
Michael Solis
363 satisfied customers
1 cylinder Spark Plugs crack and misfire. Random at first
1 cylinder Spark Plugs crack and misfire JA: How many miles are on the car? Is it a steady misfire? Or random? Customer: Random at first 79000 mjiles JA: What is the model/year of your Chevy? Customer… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
We have changed the ignition coil and the fuel control
we have changed the ignition coil and the fuel control module and still have no fire. … read more
roy
roy
Associate Degree
3 satisfied customers
Crank, no start. fuel pump is working. spark plugs (I think)
crank, no start. fuel pump is working. spark plugs (I think) are firing. … read more
eric remington
eric remington
FORMER SHOP OWNER/TECHNICIAN/INSPECTOR
associates degree
293 satisfied customers
I'm trying to change the spark-plugs on my 2006 chevy
Hi,I'm trying to change the spark-plugs on my 2006 chevy Malibu,3.5 But I ran into a problem,a couple of the spark-plugs seem to be froze.they don't turn one bit.how can I get them out with out Breaki… read more
Eric
Eric
Auto Technician
589 satisfied customers
The check engine is on. I have changed all the spark plugs
Hi the check engine is on. I have changed all the spark plugs and core and ignition core. … read more
GM Tech (Cam)
GM Tech (Cam)
Chevy Technician
Vocational, Technical or Trade Scho
15,289 satisfied customers
Changed 1500 ignition coil connector and fuel pump was
changed 1500 ignition coil connector and fuel pump was perfect now dies after 20 sec seems like another wire somewhere is not giving juice to pump … read more
Gary
Gary
Chevy Technician
Vocational, Technical or Trade Scho
9,357 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x