error 41 injector circuit

[bling5tatus]

I have already searched about this problem and read quite a few posts. Most people have fixed it by replacing the plugs going to the injectors, my problem MAY or may not be fixed with that solution. I haven 't gotten new plugs yet so I will not know.

I do have a couple of other questions though, the car is running with a miss and I'm pretty sure it has something to do with the injector problem. I am getting spark on all four cylinders and all four cylinders are also getting 150psi of compression. The silly car smokes like crap and it smells like gas, I've already got my SAFC2 setup (partially). It has not been tuned so it's not exact, but it will probably need to be slightly tweaked. Another thing, if I'm getting an injector circuit error, why, then, when I disable each injector through my datalogger does the car bog (as if they are all working and then stopping them for a second makes the car behave badly).... so I'm a bit perturbed as to what's going on.

I do have a logger, I can log whatever (fishing for troubleshooting tips on what to log to pinpoint my running rich problems here), I haven't gotten to the point to where I can actually tune the thing yet because I still am having an issue with the clutch. The injectors are 550cc injectors and my fuel pump is a 255. I am going to take a stab in the dark and guess that my stock fuel pressure regulator is being overrun and I need to get an adjustable one.

So, to summarize a bit, here are my questions:

Is it possible for an injector to be dead completely before the other's have reached their demise?
Why does disabling the injectors through a logger cause the car to bog if one is supposedly not working right?
Wouldn't disabling a dead injector not cause the car to change how it's running?

Please let me know if you need more info to help me out here.

 

[steve]

Yes, it common for one to fail and the others be good. It also possible that one of the injector resistors has gone bad and as you mentioned the connector could be giving you problems.

It's the cylinder that doesn't make any difference whe you turn it off that is bad. Since it wasn't contributing turning it off has no impact. Turning off a good cylinder will be noticeable.

Steve

 

[bling5tatus]

Well, that's what I'm saying is that as I was disabling each injector with my logger, I could notice the car's performance drop and that's what really baffled me about it. Maybe it's an intermittent failure?

I have a voltmeter, maybe I'll check the injector resistor pack. I am not sure how, but I think my manual will probably have the answer....

Anyway, yeah it was odd that I could disable the injectors with the logger and each one caused the car to stumble.

 

[steve]

A couple of things.

When my injector died giving me 41 errors it opened up when it was hot. It would start running rough and then cool down run for a while and go open again. If you testes the injector when it was cold it looked good and ran good.

The ECU can be bad. It's been awhile since I looked at the code what triggers the CEL but it's possible that the problem is with the circuit to sense the injector function.

Try clearing the codes and see if it comes back

Steve

 

[bling5tatus]

Yeah I already cleared it and sometimes the car will run for a short while without throwing that code but it comes back.

The ecu is a known good ecu that has been recapped and socketed. I have already tested it in another car and it ran just fine as well as running just fine (intermittently) in my car.

So are you suggesting that I warm the car up and then shut it down and check the injector again.... I'm thinking I may try switching the injector into another cylinder along with the spark plug and see if it stays clean connected to another wiring harness in the injector loom.

 

[steve]

I guess I missed it, how did you decide which cylinder was bad?
If you do know that, then yes you could swap injectors to see if the problem moves.

 

[bling5tatus]

Well, I'm going off of assumption at this point, since only one connector for the injectors is a different color than the other (stock) three and the actual two wires with the metal "inserts" crimped on can actually be pulled out of the female plug side itself. I am not so sure that it's making a bad connection, although it's likely it could, because I can still press the wires in far enough to where they'd be making a connection. Also, one of the spark plugs looked completely clean when I did the compression test last week.... so I am going to go with that's the one having an issue. I will post more when I've tried switching the injector.

Do you know exactly what triggers that error code, or what host of problems can trigger that code? I know you mentioned the possibility of an ecu problem causing that code, but what other things? Does the ecu have the capability of knowing if an injector is dead, like is there any feedback from the injectors to the ecu, or is the ecu just saying "squirt, squirt, squirt" without checking to see if there's any problem?

All your help is greatly appreciated. Thanks.

 

[bling5tatus]

Ok, so I checked the resistance on all my injectors yesterday. Three of them held steady readings between 3 and 4... or whatever the spec was, I do not recall right now, but they were right according to the book. So, the other one, it would hold within spec, but every so often jump to some outrageous number that was WAY out of spec. My question now is, how feasible does this sound? When measuring the resistance of something that has no power applied to it, and no moving parts (since there's no power, such as an injector with no power having no moving parts)... is it possible for the resistance value to jump around if the part is bad? I mean, I assume so.... since the other three seemed to test fine and that one was giving funky readings. It seems to me that it's time to buy a set of injectors.

Can anyone confirm this? What are the characteristics of a dead injector when measuring the resistance?

Moving along, I believe, since I'm getting a coolant temp sensor code on my logger, that my coolant sensor was bad. I checked that with the multimeter as well, and it was out of spec. I also warmed the car up and watched the coolant temp on the logger and every so often it would bug out and say it was -14 degrees... which is incredibly cold and probably made the ecu think that the car was not warm, thus pushing it into running rich/lean (whichever it does during warmup) and throwing my afr out the window. I'm sure that sensor being bad was causing my car to run very crappy. It still has not left the driveway since the motor was installed.

Any insight that someone can add would be greatly appreciated, even if it's something dumb like, "well, sounds like you're on the right track, keep truckin with what you're doing/thinking." Even that would at least tell me that I'm not crazy/doing things wrong. Thanks in advance, and thank you for all the help thus far.

 

[steve]

Sounds like your injector was going open intermittently while you were measuring it.

So replace the injector and the sensor. Your diagnosis so far sounds in line with the problems your reporting.

Steve

 

[bling5tatus]

Thank you sir, I will keep this thread updated as I replace the parts and get the car running correctly.

Oh, it's worth mentioning, I went to pep boys, and I've learned the hard way to take the part you're trying to buy a replacement for with you when you go to one of these kinds of places, and I asked them to look up my coolant sensor, so the guy did... and he went to the back and came back with the coolant sensor, the dumb thing would not have worked with my sensor wiring harness, one of the connector blades was perpindicular to the other and the one came out of my car had two parallel blades...

So anyone reading this, I'm sure you're already smart enough to know, take a part with you when you go to one of those kinds of places, just so you can compare and save yourself another trip when they give you the wrong thing.

 

[bling5tatus]

Well I'm a dumbass for thinking that the ac cutoff switch was a coolant sensor.... long story short, I got a used coolant sensor, tested it using an ohmmeter and a torch.... works great. Pepboys was not wrong, the sensor they showed me was the coolant sensor I needed.

The one that came out of the car had no or infinite resistance, not sure which, but it was jacked. So the car is not throwing a code for the coolant sensor anymore, and I can also tell it's running a ton better right after start up. I've got an idle surge, but I can work that out without any help (I'm pretty sure anyway). Also, it's weird but the injector circuit code has not reappeared, so I'm a little bit confused about that. I did not change any fuel injection circuit parts, so who knows.

Anyway, I said I'd update, and I did. Also, I bought an Innovate LC-1 yesterday, it just needs to be wired... but I'm excited about that, and my next check I will use some of my "play money" for an egt gauge. My only issue is, I don't want the inside of my car to look like an airplane cockpit... so I'm trying to find a way to minimize on the amount of gauges I have. I don't have an a-pillar pod, and I will not get one... anyway, that's irrelevant.

Any comments are welcomed and appreciated.

 

[bling5tatus]

Grrr... my car is still throwing that injector circuit code intermittently. I need to pull the plugs again and make sure they're not all trashed and maybe check the gap again.