Exactly. Problem is the chip has been programmed to what he was told the specs were. If that is wrong, the program will be wrong and now we have more and more variables.

 

If things are systematically done and the guy is a diagnostician and not a parts replacer, I doubt it will be too bad. IOW, the mechanic needs to be able to understand why certain events are happening in the way they are and not just "This sensor reading is out".

 

Yes there are but that should not be your first point of attack on the problem. I understand that if you diagnose or guess it right in 2 minutes, you get paid an hour of diagnostic time in some places so as long as there aren't too many "come backs", life is good.

Again, I'm not against the idea of replacing parts to test. I'm against the idea that we use that as the first diagnostic strategy which is what many of the mechanics I see do instead of doing testing. Often, that leads to my buying parts that were fine to begin with because you were too lazy to follow through with the diagnosis charts and rather guess what the problem is.

 

LOL. What a strange discussion this has been. I mean your the one whos trying to dissuade the op from measuring the resistance of his cars injectors, and I'm the one trying to stop you, and now you are thinking this ???

 

10 to 1, most will Ohm it, find it good and declare "Mission Accomplished". He is dealing with a set of injectors that are supposed to be an upgrade but doesn't really know what is going on. If you are going to pull them all again, why not send it out so you know whether they are flowing what 24pph injectors are supposed to be flowing or whether they will need to be replaced with the right ones or the programming needs to compensate for it? Or like I said, ohm it and if it comes out right, declare the problem elsewhere and go chase that.

 

I don't see how you can make that conclusion based on his statements in post 10. I just don't see it, in fact it sounds to me like he knows exactly what he is dealing with.

 

He knows the car it came out of.

 

Oh come on that's is not what it says. Your starting to get pretty far away from an honest intellectual debate. Just say its a good idea for him to test the resistance of his injectors ... because it is.

 

As I alluded to before, if the idea is to call it good when the resistance comes out ok and avoid further testing, it is a decent way to call it "Mission Accomplished". As part of a more complete test, absolutely.

 

@ The OP - For the record it sounds to me like your car is running lean and not rich.

 

Which is why I questioned his fuel pressure way back on post #28. He didn't choose to pursue that.

 

I'm with Tom on this - I don't think pressure should drop at all, not even for a "second or so ish"....

 

@ The OP - The above quoted statement is 100% correct. There is no exception, and in the event your cars fuel pressure is not doing this exactly, then this very well may be the actual problem.

 

ok, so wow you guys kinda went crazy on me.. thank you all the discussions.

1.. the injectors were out of a known car, that ive had since original purchase.. i only pulled them because i built the engine and needed bigger injectors.. they were pulled one year ago, and ohmed out fine..

2.. thanks DT86, ive heard many people say the same thing about running these with no problems. and now the tune matches these injectors.

3. when i say the fuel pressure dropped when i gassed it, i should have corrected, it probable for like 1/8 a second.. that being said.. new fuel pump, and good adjustable regulator. however i did find a huge vacuum leak on my brake booster.. so that might have changed my adjustments, to not be at the pressure i originally set it at. please keep in mind .. this typically only occures under load.. but has occurred just after load as well.. and to the point of stalling the car sitting at like 1500 rpms for 30 seconds, then just dieing. ill recheck my pressure after i install the new booster.

4.. have had the car hooked up to a snap on scanner and the o2 sensor is toggling between rich and lean as it should all the time... no other blaring issues.. TP sensor is reading correctly. but a good thought.

5.. car has the daughter board from my recent tune, but i can go back anytime i want to the "original" tune, that was a hpyertech tune anyways.. i dont have the stock tune. as i baught the car 2 months ago and been trying to get it on the road since.

grounds look good.

everyone is so caugh up on injectors... can we assume they are good and move on to other potential issues?


as a side note... two of my friends who are both MDT's have come over a couple times to try and help, one who owns a c4 and built a bunch of vettes. neither think it has anything to do with injectors.

 

LOL. Yeah it happens. I can assure you its us and not you.

So I'm of the opinion your car is lean and not rich. I don't actually think you have an injector problem beyond the fact that your not using the original injectors, which shouldn't be a problem.

I think my next step would be to drive the car with your fuel pressure gage taped to the windshield so I could observe fuel pressure while driving. I would also be interested to know what long term and short term fuel trim numbers are while driving. Also, stick your finger in the tailpipe and wipe the inside. There should be almost nothing on your fingertip. Heavy black soot means its rich and not lean.

 

thats gonna be my plan...

i doubt this is it.. but want to make sure fuel pressure isnt dropping off with inertia forward , ie wiring or something like that with the newly installed fuel pump... etc.. i keep saying its a load problem.. but i wonder if it isnt an inertia problem.... that should rule that out.

exhaust im sure is a little rich now as i had to "modify" my clogged cat, but im guessing not much in the tips as it had a partially clogged cat for since i started driving this car again, all of 20 miles.

 

Ok then.

One way or the other you have to make the distinction between if its going rich or lean while its malfunctioning. Its worth mentioning that a cat converter wont self destruct in a lean situation but it will if its rich. We haven't taked about the history leanding up the the destruction of the converter but its something you may want to be thinking about.

 

i couldnt really say about the cat.. but it looks like one of the rear sections of the cat just physically broke off and then turned sideways, the rest of the cat was in surprisingly good condition.

aside from saying that i could only guess about the cat. remember this car sat for who knows how long before i purchased it.. hence why i had to redo the entire fuel system before it would run.. it was all varnish.

atom.. i see your from lansing... my car came from flint...

 

Think I got it figured out, uts kinda injectors but not really..They are just a contributing factor... To those so said lean amd lower fuel pressure you are right.... The engine bogging cut out was low fuel oressure... I filled up my tank which made a hige difference... But ultimately... fuel pump cant keep up...when I get on it in gear the fuel pressure drops . Any suggestions for a stronger fuel pump, I just bought a cheapo from rock auto the first time.. I dont mind spending to get a descent one..

 

Ok so the cat issue is probably just happenstance then.

I for one, am glad to hear you successfully rescued the car from Flint. There is basically nowhere in the United States that is as foul. Flint is a hundred times worse than Lansing, and Lansing was the 8th most dangerous city with a population under 200k again in 2015. For the record, I spend the majority of my time in Houston TX.