Help with bogging, non drivability
Race Director
Joined: Oct 2008
Posts: 17,982
Likes: 1,074
From: Lansing MI
A segment of a test is a waste of time at best and misleading at worst. How many failed coils have you seen vs how many clogged injectors? How do you know that those injectors are really spraying what you think they are spraying? Are you SURE it is a 24pph injector? People have modified injectors before. I'd check the model first to see if it is what you think it is first. If I still suspect them, have them tested and see what they are doing. Go to a tech college that has a bench and beg, borrow or steal some time to check them out. Time spent KNOWING is better than GUESSING.
Team Owner
Joined: Jul 2004
Posts: 28,472
Likes: 3,290
From: Hartford WI
That device (or one like it) combined with a decent fuel pressure gage will function with much more precision than is required. We are not trying to find the Higgs Boson particle, we are just trying to make a car run right.
As far as GM top engine cleaner not being an effective product, well maybe you better try it sometime.
I can tell you with 100% certainty if top engine cleaner wont clear a restricted injector then nothing else will either, and you might as replace it (which is what I said earlier).
Also, when you say I'm some sort of slacker, it makes me think you feel like your on the wrong side of a losing debate.
Maybe you should just admit the implicit statement you made about the op wasting his time testing injector resistance .... was not very good advice.
As far as GM top engine cleaner not being an effective product, well maybe you better try it sometime.
I can tell you with 100% certainty if top engine cleaner wont clear a restricted injector then nothing else will either, and you might as replace it (which is what I said earlier).
Also, when you say I'm some sort of slacker, it makes me think you feel like your on the wrong side of a losing debate.
Maybe you should just admit the implicit statement you made about the op wasting his time testing injector resistance .... was not very good advice.
I have tried a lot of those "cheap" ideas before. As a rule, I can't afford them. I have spent my allotment of money on those kinds of things and fixing the damage they cause to trust another one of those kinds of "Mechanic in a can" things.
The "Mechanic in a can" won't clean a collapsed filter basket. Had one before. New basket did work. Try that 100% again.
Fair enough. What is the word for mechanics or people in the automotive world that think they are exempt from systematic work in diagnosis? PS: The word is "YOU'RE" and not "your". THIS might help.
When you can tell me how the resistance can show me what the injector is flowing at for volume and the spray pattern, I'll admit you have a point. Till then, as I said, it's one of those "Dr Feelgood" things. Gives you a sense of relief while you dart around at other things.
Team Owner
Joined: Jul 2004
Posts: 28,472
Likes: 3,290
From: Hartford WI
Yes it does. Again, you haven't told me of your injector experience from perfectly good to partially varnished up to FUBAR. How many bad coils have you had vs the others in this real world you are talking about?
PS: "In the real world" makes me think of someone trying to justify why their diagnosis failed when they were trying to beat book time by guessing instead of being thorough.
Last edited by aklim; Sep 7, 2016 at 01:50 AM.
Race Director
Joined: Oct 2008
Posts: 17,982
Likes: 1,074
From: Lansing MI
When you can tell me how the resistance can show me what the injector is flowing at for volume and the spray pattern, I'll admit you have a point. Till then, as I said, it's one of those "Dr Feelgood" things. Gives you a sense of relief while you dart around at other things.
Team Owner
Joined: Jul 2004
Posts: 28,472
Likes: 3,290
From: Hartford WI
Resistance wont tell you anything mechanical about the injector. The point of testing resistance is to determine of the injector is electrically sound. Call it whatever you want but a shorted injector can cause havoc with the ecm.
I am confident you wont be able to stop him no matter how hard you try.
I am confident you wont be able to stop him no matter how hard you try.
I agree. His pattern has shown that he is more attuned to throwing parts than doing a step by step check of a system. Of course, there is the hope that someone will come in with a more thorough mousetrap than what I suggested and I could benefit from it.
Last edited by aklim; Sep 7, 2016 at 01:57 AM.
Race Director
Joined: Oct 2008
Posts: 17,982
Likes: 1,074
From: Lansing MI
Please elaborate. How are things done "in the real world"? With guessing and throwing parts at it? I have had 2 clowns already tell me that years ago. Several hours later and several hundred dollars later, they were unable to diagnose the issue. Some crazy guy who went down the line did find the issue. If that is the real world, I'll take the other guy who doesn't live in that world. BTW, I have a module that I had to scrounge because the "real world" guy used a Ford dealership scanner and diagnosed it to be faulty. Needed the truck so we had to get a used one but it didn't fix it. I had him follow the FSM and we found out it was something else. IIRC, he gave me something along the lines of "in the field we sometimes...."
Yes it does. Again, you haven't told me of your injector experience from perfectly good to partially varnished up to FUBAR. How many bad coils have you had vs the others in this real world you are talking about?
PS: "In the real world" makes me think of someone trying to justify why their diagnosis failed when they were trying to beat book time by guessing instead of being thorough.
Yes it does. Again, you haven't told me of your injector experience from perfectly good to partially varnished up to FUBAR. How many bad coils have you had vs the others in this real world you are talking about?
PS: "In the real world" makes me think of someone trying to justify why their diagnosis failed when they were trying to beat book time by guessing instead of being thorough.
I don't know what your asking me regarding my injector experience. Ive cleaned hundreds and replaced dozens for many different reasons. I didn't bother to count them or keep a journal or anything.
Race Director
Joined: Oct 2008
Posts: 17,982
Likes: 1,074
From: Lansing MI
Minor ?? Not today. You may or may not realize it but a shorted injector makes the driver in the ecm the load in the circuit. This is never good and always bad.
Team Owner
Joined: Jul 2004
Posts: 28,472
Likes: 3,290
From: Hartford WI
In the real world of auto repair, no one tries to sneak into the community collage to use the flow bench like you suggested. I don't know how anyone is even supposed to take that seriously.
I don't know what your asking me regarding my injector experience. Ive cleaned hundreds and replaced dozens for many different reasons. I didn't bother to count them or keep a journal or anything.
I don't know what your asking me regarding my injector experience. Ive cleaned hundreds and replaced dozens for many different reasons. I didn't bother to count them or keep a journal or anything.
Surely you can roughly say something like "Of the last 100 injectors that were condemned, 20 were coil shorts and 80 were mechanical, give or take a few" without a journal. I don't keep a log either but I can say for example, "3/4 of my clients are white females", etc.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Team Owner
Joined: Jul 2004
Posts: 28,472
Likes: 3,290
From: Hartford WI
As I said, we don't really know, other than what he said he is dealing with. IMO, the more you KNOW, the less you have to GUESS. Once the injectors are a known quantity, we can go on to see if the fuel delivery, which, AFAIK, isn't really known. We know he has 43psi. Is that stock pressure? Does it hold for long? Does it deliver when demand is high. After which we can go further and further out. Perhaps systematic testing instead of jumping around isn't the best way but I certainly don't know of a more reliable way in general.
Race Director
Joined: Oct 2008
Posts: 17,982
Likes: 1,074
From: Lansing MI
When you don't have a flow bench and you want to verify the work, you got to buy someone who has access to one a few beers and they might help you. BTW, I know my friends who are mechanics have sometimes borrowed tools from one shop to another.
Surely you can roughly say something like "Of the last 100 injectors that were condemned, 20 were coil shorts and 80 were mechanical, give or take a few" without a journal. I don't keep a log either but I can say for example, "3/4 of my clients are white females", etc.
Surely you can roughly say something like "Of the last 100 injectors that were condemned, 20 were coil shorts and 80 were mechanical, give or take a few" without a journal. I don't keep a log either but I can say for example, "3/4 of my clients are white females", etc.
The overwhelming majority of injector problems are something mechanical, although the driveability symptoms are generally more extreme when when one fails electrically.
Race Director
Joined: Oct 2008
Posts: 17,982
Likes: 1,074
From: Lansing MI
Now you know.
Race Director
Joined: Mar 2015
Posts: 15,926
Likes: 579
I thought injectors too and he knows they are the wrong ones. I sent him to FIC they told him they were the wrong ones. He does not believe they are the problem and will not spend the $169 to put the right ones in.
Last edited by antfarmer2; Sep 7, 2016 at 08:06 AM.
Race Director
Joined: Oct 2008
Posts: 17,982
Likes: 1,074
From: Lansing MI
Maybe its an injector problem maybe its not. Personally I think the problem he described sounds like its lean under a load and not rich. I don't know how long he's been driving it this way but unless it just started then there will be heavy black soot in the tailpipe if its rich.
Race Director
Joined: Mar 2015
Posts: 15,926
Likes: 579
Maybe its an injector problem maybe its not. Personally I think the problem he described sounds like its lean under a load and not rich. I don't know how long he's been driving it this way but unless it just started then there will be heavy black soot in the tailpipe if its rich.
but hard to tell he has now had it reprogrammed just making it harder. If he can get the stock programming back along with the right injectors it would give him a solid starting point. Other than that you're just guessing and chasing your tail. 
Last edited by antfarmer2; Sep 7, 2016 at 09:32 AM.
Race Director
Joined: Oct 2008
Posts: 17,982
Likes: 1,074
From: Lansing MI
One thing is for sure; modifications wont make the diagnostic process easier.
Team Owner
Joined: Jul 2004
Posts: 28,472
Likes: 3,290
From: Hartford WI
Buying someone a beer or lunch every time you need to test something is not practical. The world of auto repair cant function that way. Imagine what would happen if every time someone had to test something, they first had to stop and go to the local bar for beers and lunch, or sneak into the local community college, or box up the suspect parts and ship them off to wherever. This is just not a good idea.
The overwhelming majority of injector problems are something mechanical, although the driveability symptoms are generally more extreme when when one fails electrically.
The overwhelming majority of injector problems are something mechanical, although the driveability symptoms are generally more extreme when when one fails electrically.
Another agreement there. Exactly why I said that all the ohm test will do is reassure the tester that the injector is fine when it might not be since odds are the problem is mechanical. As such, a better way is to test the entire thing to rule out issues.
Team Owner
Joined: Jul 2004
Posts: 28,472
Likes: 3,290
From: Hartford WI
IF the diagnostic chart leads you that way, I'm good EVEN IF THERE IS A MISTAKE and the part is good. OTOH, just replacing parts on a trial and error basis, no.
Last edited by aklim; Sep 7, 2016 at 12:37 PM.
Race Director
Joined: Oct 2008
Posts: 17,982
Likes: 1,074
From: Lansing MI
Think very carefully about what your saying here as it relates to the OP symptoms. Do you think a mechanical injector problem could be so severe on the OP car that it warrants skipping the electrical testing ?? Do you think it would run normally under the 2k rpm number ?? Would it rev clean in neutral ??
Race Director
Joined: Oct 2008
Posts: 17,982
Likes: 1,074
From: Lansing MI
Yes and some mechanics take that to be the way to fix cars. Keep throwing parts at it till it works. I'm fine with that as long as it is Other People's Money. I have a few on that list myself which is why I specify that people on the list I provide DO NOT touch my car when I have to bring it in for whatever reason. You wanna buy a couple of sensors left over from those people's hard work?
IF the diagnostic chart leads you that way, I'm good EVEN IF THERE IS A MISTAKE and the part is good. OTOH, just replacing parts on a trial and error basis, no.
IF the diagnostic chart leads you that way, I'm good EVEN IF THERE IS A MISTAKE and the part is good. OTOH, just replacing parts on a trial and error basis, no.
Team Owner
Joined: Jul 2004
Posts: 28,472
Likes: 3,290
From: Hartford WI
