Leaking injector but no code?

[GseaQ]

Hi all,

Well, here we go again with our "new" '95 Q45t - formerly known as "Quella". She started idling rough intermittently a week ago. Then yesterday the roughness continued onto the freeway - enough to keep the rear view mirror vibrating at 60 mph. Obviously I had a seven cylinder.

I went right to my mechanics shop with it. About an hour after getting there it started right up and was smooth running while it drove inside. Today when he got to it his scanner showed a code 34 knock sensors, but no injector code. The code 34 returns at idle immediately after he clears it with his scanner. He did this repeatedly.

Next up was the power balance test. Number 8 makes no difference whether the injector is enabled or disabled. So, we know #8 is at fault, but injector or coil. I've had both issues in the past on our '92 Q and replaced an injector on it only to find a failed coil. But this time it feels EXACTLY like a bad injector, in that it's leaking into the cylinder. When it's acting up, starting the car requires 5 seconds or more of cranking as if it were flooded.

I pulled out #8 injector today - man they're hard to pull out! - the plastic on top was all chipped up. They were supposed to be Deatschwerks injectors (I have their test report), but this one was pretty ugly. Sept '06 was the test date. The little o-ring on the nozzle (bottom of injector) was absolutely shredded. How does that happen? So, maybe this o-ring caused the leaking and the injector is electrically OK so no code? What do you all think?

I had been wondering why I could only get a spec idle with the IAC valve set at 1 turn from seated. But it seemed a little lean or flat just off idle then. One and a half turns got 750-800 RPM. I wonder if it was being affected by this injector. When I got the car it was idling at 900 RPM. I double checked the cables and adjusted it down with the IAC valve.

Code 34 knock sensors - the car was advertised with new knock sensors. Would the JWT ECU cause a code 34?

Thanks for reading,Glenn

[goody90q45]

I didn't see you mention ohming the KS and injectors. You can do #8 directly on the two pins on the FI and the others from the connectors shown in the pic. Let us know the readings.

[qship96]

Didnt that car get a junkyard engine put in a few years ago?

[GseaQ]

Hi Mike,

I can't get to the car until Friday, but will check resistance then and let you guys know.

Thanks,Glenn

[GseaQ]

Yeah, it did in summer or fall '06. Actually, it was a JDM takeout, but the injectors are from Deatschwerks.

[Mint Q45A]

Welcome to the club...of the injector lower o-ring failures

In my case it all started with hard cold starts, then it progressed to a rough idle and finally turned into a no-start (hydroloc) situation - that's when I stopped the car. After running some leakdown tests I confirmed that #2 was leaking; looked at the O-rings and they were hardened and had lost their circular shape - looked more like a cylider. That's when I decided to pull the rails off - didn't want to run the risk and trouble of more O-rings failing in the future.... Now all my injectors have new O-rings....just in case...

Lots of work, but it is worth it >>>>> peace of mind.

NOTE: Ohming the injectors will not tell you anything about the condition of the O-rings....

[GseaQ]

Thanks Mint! I've already ordered a replacement injector because I know I'll need one someday. In the meantime I've got a perfectly good blue one for a '92 that I'll probably never use now. Oh well... So, I'll ohm this one and if it's in spec I'll put it back in with new o-rings and save the new one for later.

Cheers,Glenn

[Q451990]

The new o-rings should be lubricated with vasoline, dielectric grease, or some even suggest KY Jelly. Just make sure you lubricate it... not doing so is the most common reason for o-ring failure after replacing an injector.

Good luck!

Heath

[GseaQ]

Thanks Heath! You anticipated my next question. Actually, I was thinking of engine oil, but dielectric grease is likely better.

[Mint Q45A]

Besides adding the lubricant to the O-ring, make sure you put some on the rail itself. There is a very small angled surface on the edge of the opening that will help guide the o-ring. If it is properly lubricated, it should go in with minimun effort; if you are fighting it, it means the o-ring is catching on the edge and is probably already damaged....

[GseaQ]

Thanks Mint. I put a generous amount of Vaseline on the o-rings and it went in pretty easily. Good tip, though & I will put Vaseline on the lands for the next 7.

[GseaQ]

Hi Mike,

So, I ohmed #8 injector while I had it out - 11 ohms - PERFECT! New o-rings and back in it would go. The old bottom o-ring was torn up and I discovered the old upper one was actually really loose on the injector - maybe 2 mm larger diameter than the new one.

Then I ohmed all the others via the pins on the connector. They all ohmed at 22.0-22.8!!!!!!!!!! I thought WTF????? Then I plugged in the #8 that was 11 ohms on the bench and what do you know - now it's 22.0!

I put it back together and she started right up and ran nice and smooth. Then it warmed up and was not quite as smooth, so I thought I'd give the IAC valve another go. When I gripped the IAC plug I heard a whistle. Wouldn't you know it - the vacuum hose was off the Fuel Pressure Regulator! Plugged it in & did the adjustment - somewhere around 2 turns now if I was to count and idling at about 6oo-650 nice and smooth.

I don't understand why all the injectors check out at 22 ohms at the connector, but if they were really 22 ohms and working as perfectly as they seem to be, I'm sure I'd survive a lightning strike and win the lottery!

Now, over to the knock sensor thread...

Glenn

[goody90q45]

I don't understand why all the injectors check out at 22 ohms at the connector, but if they were really 22 ohms and working as perfectly as they seem to be, I'm sure I'd survive a lightning strike and win the lottery!

First thing this morning you should hedge your bets, take the Q out for a spin, and go buy that lottery ticket. While you're out, stop at Radio Shack and buy a 10 amp resistor (about $2) and a new battery for your voltmeter. Then use your voltmeter to check the resistance of the resistor- it should read 10.0. If it does go back and recheck the FI resistance.

Does the positive probe of your voltmeter have good contact with the battery/clamp? You can also check #1 and #2 FI pretty easily by removing the center plastic cover. Good luck.

[GseaQ]

Hi Mike,

I've been thinking about it. I didn't drive the car yesterday but I did run it for about an hour - off and on at 2000 RPM as per the FSM for setting the idle. I shut it off and restarted repeatedly. It all seemed normal and smooth. After all the settings, I let it idle for close to a half hour. I think if I had 7 injectors at 22 ohms I could not have done this.

I'm also thinking the #8 injector was 11 ohms at the bench with my multimeter and 22 ohms through the harness - exactly double. If I half the readings for the other seven, they're all exactly in spec. I just don't know why. Maybe you're right and the battery in my multimeter is old and tired like me. I'll put a new one in and do it again.

I'll see the car again on Tuesday and go for a drive.

Thanks,Glenn

[Dabizzo1]

When I replaced my injectors, I first considered whether to bite the bullet and buy new oem or get rebuilds from Deatchworks. After repeated viewing of post after post of bad luck stories with used injectors, I decided to get new purple tops from Joe in Scottsdale with new upper and lower o-rings for all. Dennis has pointed out in the past the there is no guarantee of the viability of used injectors, even if reconditioned. The pintles can be replaced, but the windings are still X number of years old with a history of electrical load and heat exposure. Given the absolute biotch the plenum job is, I didn't want to have to undo all of that stuff for the same thing twice. I'm also not thoroughly convinced of ohming through the harness. This process assumes the harness wont affect a reading through its own internal metal fatigue through the years. My harness readings were way off from direct injector ohm readings just like you..this was with a brand new multimeter and battery as well. If it isn't the knock sensors, you may want to consider new oem injectors. Peace of mind on the road is worth it to me even amidst $140 each. You'll be good for the next 100k or so with new injectors with a proper diet of iso heet and flushes. Also, you mentioned the knock sensors were new. Is the motor valley they are in free of standing goo or liquid, which could essentially cook them? The mechanics could have easily reinstalled the new knock sensors into a mucky mess...unfortunately, many don't care. Hope you find your culprit. Boris P.

[GseaQ]

Thanks Boris,

I'm confident the injectors from Deatschwerks are still ohming at between 11-12 ohms, but will confirm on Tuesday. From what I can see through the plenum runners, the valley is beautifully clean & dry. I'll keep everybody updated as things progress.

Glenn