P0505 and P0300 after Pulling Upper Intake

[MisterH]

Just finished up replacing all the injectors, miscellaneous hoses and valve cover gaskets on my '99 and was really pissed that upon startup it was idling badly and spewing what seemed to be unburned fuel out the tailpipe. Flashing CEL with P0505 and P0300. Oh joy!

In an earlier post I mentioned the horrible time I was having with some of the 23 year old harness connectors and I specifically remember how hard it was to both disconnect and then reconnect the IACV plug under the intake. Now I'm thinking the IACV plug never fully seated when I connected it up so it seems I'll be removing the intake again. This time I'll wire in a new IACV plug and hopefully that will take care of it, but I'm also wondering about the multiple random misfires present. Were they the result of the IACV being disconnected or should I be looking around for something else I screwed up?

Many thanks again!

[MisterH]

Update: reached around behind the intake and sure enough, the IACV connector is not fully seated - I can move it back and forth but can't seem to exert enough force to get that magic "click."

[VStar650CL]

Stick a mirror in there to look for a bent pin. When a connector won't seat without extreme force, that's usually the issue. If you do have a bent one, surgical forceps are usually the best straightening tool.

[MisterH]

Stick a mirror in there to look for a bent pin. When a connector won't seat without extreme force, that's usually the issue. If you do have a bent one, surgical forceps are usually the best straightening tool.

Great idea - will give it a try tomorrow morning. Do you think having my IACV disconnected could also be the cause of multiple random misfires?

[VStar650CL]

Do you think having my IACV disconnected could also be the cause of multiple random misfires?

Absolutely. The IACV's job is basically to be a metered vacuum leak, and when it becomes an uncontrolled one the ECM can't control lean-rich properly. Stuck wide open, it will almost certainly cause a lean misfire.

[MisterH]

And of course that explains the raw gas coming out of the tailpipe. Many thanks for your assist!

[MisterH]

Luckily the pins were not bent but this time I managed to exert enough force to finally get the connector firmly seated and now the IACV is active. However, other issues appeared and the tailpipe is still emitting raw gas: Got a cylinder 1 misfire and P1105 Map/Baro solenoid error. Note: During the disassembly process the original solenoid valve the plastic nozzle that connects to the vacuum line under the manifold just broke off so I had to replace it. I guess it's possible I routed the vacuum hoses incorrectly. I checked the vacuum routing diagram and it looks like port C on the solenoid connects to the same line that connects to the air intake box, is that right? ( The diagram that I have is pretty small and lo-res, so I may be wrong.

[VStar650CL]

The manual here has the vacuum diagrams, page EC-18. EC-355 has the MAP/BARO with a port drawing:
https://www.nicoclub.com/service-manual ... 9%2FEC.pdf

However, with the IACV hooked up, that raw gas has to be an injector issue. Nothing about a P1105 or the MAP/BARO can really cause a flood. Did you lube the injector o-rings during assembly? If not, there's a good chance you rolled one or more of them and they aren't sealing.

[MisterH]

I cleared the P1105 as I realized I had the port C vac line reversed. Now I have P0300 and raw fuel still exiting the tailpipe. I did lube the O rings prior to installation but it now seems logical that one of them must be squished out of position. Is there a way to isolate which injector it might be before I pull the intake again? if it's on bank one it'll save a lot of time. Is it usually the nozzle side little O ring or the upper, larger one that would cause a leak? Just for the heck of it I did a spray test around the intake to eliminate the possibility that it was sucking air from there and it wasn't.

Thanks so much for your help!

[VStar650CL]

The big rings are more prone to rolling up and the little rings are more prone to get dinged, but fuel flowing straight into a cylinder would indicate a small ring. Whichever cylinder(s) leak will have wet plugs, so that will be your best indication. If necessary, you can power up the pump with the plenum pulled and the plugs out to look for action with a flashlight. Rolled seal rings will leak anytime the rail is pressurized.

[MisterH]

Again, most thankful for your sage advice!

[MisterH]

Update: I pulled all the plugs for examination and number three was completely black - the rest were perfect. I pulled the injector and could not find any evidence that the O-rings had been distorted. Checked the bore in the fuel rail for any obstructions and it was clean. This had me really stumped. I then put my meter on the injector terminals and it read 159 ohms. So it appears that #3 must have been continually open.

[VStar650CL]

That injector must be mechanically screwed and not just electrically. By itself, high resistance in a coil will make the injector fail to open, not stick. Sounds like it's a QC reject with multiple problems, perhaps assembled incorrectly.

[MisterH]

To be transparent, I did buy a set of reman injectors from GB engineering. I just couldn't stomach paying $140 each for OEM. The weird thing is that I thought I tested the resistance on each one when I received them from Rock Auto.

[A1218]

When I changed my injectors last spring on my 97 Pathfinder I got a set of brand new Hitachi injectors on Rockauto for about 31 bucks a piece. So less than 200 for injectors in the end. And that is basically like buying original injectors.

No problems so far.

I don't see them on Rockauto anymore now that I check and they are super expensive on other sites now as compared to last year.

$62 for one on Partsgeek now and $105 for one on Carid where it was only $39 there last year.

Looks like everything got expensive...

[MisterH]

Yeah, I noticed the big jump in prices on some auto parts - I wish I could have nabbed the Hitachi's for that price. One thing that's odd is that the price for injectors jumps wildly even within R50's. For some reason the ones for my year were higher than earlier years.

[MisterH]

This is really getting out of hand. Yesterday I received my replacement fuel injector for cylinder 3 and installed it. Fired up the engine and within a minute the CEL is flashing and raw gas is still pouring out the tailpipe. Hooked up my scanner and it displays no error codes. Prior to replacing #3 injector it displayed P0300. Unplugged scanner, shut down engine and started again. Still flashing and no codes. Gas is dripping out of the seams in the muffler. I pulled #3 plug and it's clean. I'm at a loss to figure out what to do next other than take it to a bona fide professional.

[VStar650CL]

You sure it's fuel and not water with some gas in it? A flammability test might be in order, but one way or another, raw gas out the pipe means raw gas in the cylinders, so the offending jugs should be wet. The flashing CEL indicates a misfire whether there's a code or not, nothing else causes that.

[MisterH]

Yeah, nothing makes sense. I did pull the oil dipstick and it sure smells strongly of fuel, so I'm definitely flooding out. At this point I'm wondering if I should stop running the engine until I get this sorted out.

[VStar650CL]

If it's that severe, you could be washing out the rings. Yah, I think I'd run it sparingly until you figure out the problem.

[MisterH]

I guess I'd better play it safe. That said I've just found something that raises my curiosity and may be a clue. While cleaning up my work area I found an injector seal from one of the original injectors I removed. It's different than the ones that were supplied with my rebuilt injectors. The original has a slot cut into the seal that faces downwards towards the injector rail. The replacements on the new ones have no such slot on them. Is this significant?

[VStar650CL]

It could be. I know of at least one other member here who found his engine flooding because of aftermarket injectors that didn't seal right.

[MisterH]

Thanks for your help. I guess to be thorough I should pull the intake again and replace all those seals. What a project this turned out to be!

[MisterH]

Just to put a period at the end of this problem, it turned out that I had two issues that caused the extreme running rich condition:
1) Injector #1 defective.
2) I had stupidly switched the vacuum hose that runs to the MAP sensor so the ECM reacted as though I was at almost WOT while at idle.

The upside is that I didn't have to pull the intake again!

[VStar650CL]

[Niti QX4]

Just to put a period at the end of this problem, it turned out that I had two issues that caused the extreme running rich condition:
1) Injector #1 defective.
2) I had stupidly switched the vacuum hose that runs to the MAP sensor so the ECM reacted as though I was at almost WOT while at idle.

The upside is that I didn't have to pull the intake again!

Hey, mistakes happen. Glad you got it fixed!