injector issues after replacing connectors

[solaire]

So this is a continuation from my previous threads. I've got a 91 with a misfire on 1, 3 and 6. Cyl 2/4 are weak. It started after I pulled the plenum and replaced injector connectors. I've put new plugs in it, checked all my connections. I cleaned the CAS, PTU, even pushed the pins back in and closed them up. Everything seems to help a little then it goes back acting up.

I put contact cleaner in the injectors and cleaned out the corrosion and original dielectric grease buildup and blew it all out with a keyboard duster, the contacts on the injectors are super clean. After i did that, the car will run great at startup for about 5-10 secs then go to missing. I've swapped his ECU into my car and my car runs fine with it so it's not ECU related.

I'm starting to think this is an injector related issue. I've checked the injectors I can get to.
1: 17.1 ohms
2: 12.5 ohms
3: 12.1 ohms (this one fouls plugs, suspect it's mechanically stuck)
4: 15.1 ohms
5: can't get to so didn't check. it's the STRONGEST cylinder and unplugging it will make the car die almost instantly.
6: 14.0 ohms

I also checked these readings behind the electrical crimp and solder work I did to put in the new connectors and all readings are within 0.0-0.1 ohms. I bought the connectors on ebay but they're like the ones Z1 sells.. actually I payed more since I didn't check Z1 first so I don't think it's the connectors themselves mainly because of what i stated before, I get same readings at solder joints and injectors.

Is it possible this car had 3 injectors just "go bad" overnight? The car ran fine before the work, ran decent the day I finished (ran rough at cold start but smoothed out after a short test drive) but the next day started all this mess. I'm wondering if driving the car with the connectors fixed and working maybe "overworked" the injectors that had been corroded for at least the past 5+ years.

Owner can't believe these injectors just "went bad overnight" and wants is "running the way it was before he brought it to me" so would it be bad to recommend he replace all the injectors? Or should I keep looking elsewhere?

[nissanfreak12]

If it has the old style injectors, very possible. I had one go bad from morning to night. Went to newer style. Older style will have square connectors, newer style will have oval connectors.

Yes, replace all the injectors. When two to three go out at once, which you have 3, the others will follow shortly after.

[solaire]

Yea it looks like #3 and 5 have been replaced sometime in the past 5 years from what he told me but #1, 2, 4 and 6 are originals. Just hard to get him to understand that more than 1 has gone bad about the same time. I think driving it around the neighborhood with 1 bad one may have taken the others with it. Knowing they can go that quick makes me scared to take my Z to raleigh this weekend..

[t.mcginley.jr]

The ethanol in today's gas just destroys the old style injectors from the inside. Its really only a matter of time before they all crap out.

Not saying you should do this, but I bought the new style adapter kit from Z1 for ~$100 or whatever it is now, and a set of 6 reman'd new style injectors off of ebay (from TLFperformance, I think that was the seller/stores name) for like $130-140 and called it a day. I did mine with the plenum off though, but you can just do the dremel method. The new style injectors don't go bad nearly as fast and the reman'd ones are all sonic cleaned and flow tested, etc. I have about 1 year and 10k miles, no issues ever besides a pinched O-ring from not putting enough lube.

[solaire]

Did yours give you any signs or just go out overnight? I know this car sat in my yard for almost a month due to snow and bad weather before I started the work. Normally he drives it a few times a week. Could be the ethanol got to them while it sat.

[t.mcginley.jr]

Could be the ethanol got to them while it sat.

Yes, because the way the car is wired there is a measurable amount of voltage constantly going to the injectors even with the car off (there's a mod to fix this: Switchable injector voltage) Which leaves the injectors open to being corroded internally. I actually bought my Z with a bad misfire because the previous owner didn't know anything about cars so that was one of the first things I did. I never ohm checked the old injectors, but I can guarantee at least half of them were bad.

[solaire]

I think I'm going to tell him to suck it up and buy injectors from z1. I just want it running. When mine starts to act up ill convert but because of how this guy has been this whole time, its not my car and idc if a few years from now it starts acting up from ethanol. I only get an hour each afternoon to tinker with it and he rushes me and is on my butt every day saying "it was fine when i gave it to you. I want it running like it was" but doesn't want to spend money on injectors. Said he would have sold it if he knew injectors were going to fail..

It has to be a combination of the car sitting for a month and having correct voltages applied to them due to new connectors being installed. Only 2 were replaced before and now the rest seem to be acting up along with one of his new ones. If they don't fix this misfire idk what else could since 3 cylinders are fuel fouled and swapping ptu and coils has no effect

[solaire]

On another note how safe is my car to drive more than around town? It runs perfectly and It's got 85k miles, was garage kept and dealer maintained. It's even had a paint job recently. Someone took care of it. As for fuel quality idk but I always run 93 from the same station I put fuel in the rest of my cars. What's the chance mine could just go out like that? I drive it a lot but I only live about 2 miles from work so it maybe sees 5-7 miles a day (I usually drive It until it reaches operating temp then drive a few more miles after work)

If I was to replace mine I'd convert and do the coolant tube elimination and such while I'm in there to make my life easier.

[solaire]

This what you were talking about t.mcginley.jr?

http://www.ebay.com/itm/Nissan-1990-93- ... ad&vxp=mtr

They've gone up and pic shows brown but they say for Non-turbo models and come with connectors so that explains the price. Still half of what Z1 wants for originals.