Strange Behavior/Injector Harness

[OLU40]

Two weeks ago my CEL went off and on and my independent mechanic pulled a code 51 (open/short circuit-harness). I had rough idle, slower acceleration and when going at neighborhood speed (3-5mph) the car chugged, shaking back and forth like there was a clogged injector. After a two week back order, the harness was replaced. Yesterday, when I accelerated from a stop, the engine missed completely as if I lost all power then it kicked right back in again. When slowing down on a corner to approach a bridge, she cut off. I threw it in N and when it restarted the idle was erratic and it cut off again. One more try and it started. It cut off a few more time like this and the power loss was felt at time when I accelerated. On top of this the CEL is back on and it's steady now. Also when I park in confined areas like an indoor garage I notice the light pops on. No codes came up but I will go to the dealer to get a more accurate reading. What the hell is going on? Maybe a wire from the harness was not properly attached? And why does the car chug along like that at idle and low speeds? Feels like a '65 Dodge shaking me back and forth. Any clues people?

[DougQ45]

It sounds like an individual injector failure. Check the injector at the injector pins (if possible without pulling plenum)---this will confirm. It is likely your mechanic replaced the entire harness when the injector itself was bad. Failure is intermittant--then absolute.

[OLU40]

Doug, I agree, but the thing that threw me off was that the code was a 51. Not a 45 indicating an injector leak or failure, so I was sure the code was sure fire. After replacing the harness now the car cuts off and acts crazier thatn before. I can't stand to see CEL lights:mad:. Loss of power and the chugging sound like injetor faults but I guess the code threw me off. Weird.

[elwesso]

I agree with doug.....

You can do an ohm test on the car... I will post details if you can DIY this.....

[OLU40]

Gracias senor. Shame on you for starving your Q and killing your fuel pump!:tisk:

[elwesso]

LOL... Gas comes tomorrow...

I wouldnt starve my Q if my wallet wasnt starved as well!

CULTIVATE AN ATTITUDE OF GRATITUDE. Paypal to [email protected]

[OLU40]

Seems a code 45 should have popped up instead of 51.

[hh11011]

Chugging sounds like might be mass air flow or CAS connections.

[Q451990]

That would be my guess too. One bad injector won't cause the car to cut off (at least in my experience)... it'll run rough, but that's about it.

Heath

[OLU40]

CAS? (Crank Angle Sensor) I didn't even know those went out. I wiggled the MAF but no noticeable change. I hit the gas tank with two bottles of Techron just to see if there would be improvement. This stuff is giving me some improvement in terms of smoothness but I'm still going to the dealer. Have you guys ever replaced a CAS on your Q's?

[elwesso]

Its not usually the CAS that goes out but the connection to it, like the MAF connector..

Does the engine speed not rise above like 2000-3000 rpm?

[OLU40]

Sad thing is, I just changed this MAF last year. I know they tend to weaken but damn it can't be ready to go yet. I'll check.

[Q45tech]

Use a current probe and oscilloscope to look [substitute clampable wire loop for injector fuse] at the combined sequential injector ramp currents..........that will show you each injector condition including the harness.

[hh11011]

OLU40,I wasn't too clear, like Heath mentioned, check and re-clean MAF and CAS connections first! hh11011

[OLU40]

Use a current probe and oscilloscope to look [substitute clampable wire loop for injector fuse] at the combined sequential injector ramp currents..........that will show you each injector condition including the harness.

Thanks guys. Went to the dealer today and I had alot of vacuum hose loose MAF connector pin slightly flex (outside mechanic) idle too high. But the major thing is the number 3 cylinder is misfiring and is only at 9 rpm. I had to leave but I will go back. They want to see if it is the coil or the injector. I haven't seen many members talk about the coil. I hope it is that because it's alot cheaper than an injector. What's your guess people? My CEL is still on even though the car runs alot better since they tightened those hoses and MAF connector pins. Also the valve cover was not on properly as it is pressurized. I'm going to the dealer and T3 when I move to atl from now on. I'm pissed. Will a misfiring cylinder keep the CEL on? No codes came up except for my air bag. I need to know if my car is safe to drive for awhile until I get this figured out. I have a heavy foot!

[hh11011]

Most likely an injector:)

[OLU40]

Most likely an injector:)

Even though no code came up?

[elwesso]

Yes. Codes are not definite, IE if theres no code that doesnt mean its not POSSIBLE something else happened......

[OLU40]

Yes. Codes are not definite, IE if theres no code that doesnt mean its not POSSIBLE something else happened......

So I have to put up with this CEL until I replace it? Does this mean I have to keep it under 85?

[elwesso]

Why would it be necessary to keep it under 95...

Email me off board, I wanna talk about something.....

[OLU40]

Why would it be necessary to keep it under 95...

Email me off board, I wanna talk about something.....

Okay. I'm at work so I'll hit you in about an 1hr and change my time.

[OLU40]

BG 3000K stopped the chugging and hesitation I had. Nomore CEL for almost two days until this evening. Maybe I should use the BG treatment a few times? I forgot how good this stuff is. #3 injector is still on the way. No other fuel cleaner gave me these results. I hope I didn't blow $140 for nothing.

[OLU40]

BG 3000K stopped the chugging and hesitation I had. Nomore CEL for almost two days until this evening. Maybe I should use the BG treatment a few times? I forgot how good this stuff is. #3 injector is still on the way. No other fuel cleaner gave me these results. I hope I didn't blow $140 for nothing.

[Q45tech]

BG 3000 is a milder version [designed to use every 1000-3,000 miles] of BG44k more like Techron.BG44k will clean up injectors but not as well as a full rail flush with BG injector cleaner and BG 44k in the tank afterwards

[texasoil]

I keep tellin gpeople buy good quality gas and oil, keep it clean with good filters. Hard parts are real expensive compared to theconsumables like fuel and oil (and antifreeze, brake fluid, ATF, PS fluid, etc.)

[OLU40]

I keep tellin gpeople buy good quality gas and oil, keep it clean with good filters. Hard parts are real expensive compared to theconsumables like fuel and oil (and antifreeze, brake fluid, ATF, PS fluid, etc.)

It's so hard to get good gasoline in NYC. I would love to try Chevron but it's non-existent out here.

[OLU40]

Changing the third injector definitely made the idle and low speed smooth out. No chugging. But before that. The mechanic said that the real problem was the platinum gasket on the 3rd cylinder. He said it was leaking which caused a misfire. He tried that first and it seemed fine until the CEL came on again and the idle was rough. So he did the injector for free. He changed my spark plugs on the driver side and all the gaskets. The CEL has come on a couple of times then goes off. I had a rich smell and realized my AFM wire had a little short in it. He adjusted that but he turned a screw in the back left by the passenger side that was supposed to adjust the fuel/air ratio. What screw is that? The rpm and engine light stopped showing for awhile after that. Weird. Thanks guys for everything. And Wes big thanks for that FSM!

[Q45tech]

That screw is the IAC bypass adds air around both computer controlled IAC and TB. Cheater to set up idle speed when TB/plenum is dirty.