OHM Fuel Injectors - My test results

[andbeyond]

Well just finished ohming my fuel injectors

what do you think of the results

Cyl #1 - 37.6Cyl #2 - 0Cyl #3 - 19.5Cyl #4 - 404 Cyl #5 - 0Cyl #6 - 402 Cyl #7 - 87.1Cyl #8 - 13.5

from what I've read 10-14 ohms is correct range

so obviously #2 and #5 are bad , but why the high readings from the other ones.

the only that looks normal is #8 @ 13.5 ohms

your input would be greatly appreciated, thanks

[3Q Jay]

i'd have to question your data. is '0' as you say truly '0' (short circuit), or are you saying infinite (open circuit).where are you measuring, what meter scale setting, what does meter read on a calibrated standard?

car would barely run if data is real.

[andbeyond]

you're right, it barely runs, feels like its running on about 6 cylinders

just resealed the valve covers and replaced plugs thought that was it, it helped and there was some oil leaking on some of the plug holes, but still runs / idles rough.

I'm using a Fluke meter, set it on ohm.

positive probe to + battery terminal

negative probe to pins in the injector harness connector

[goody90q45]

Check #1, #2 and #8 directly on the FI and see what the readings are. These 3 are easy to get to. I'm curious if you'll get something on #2. If the readings you posted are correct you're only running on 4 cylinders.

[andbeyond]

Update -

93 Q45

ok I have removed the plenum , (used the info on Q45.org., only regret is it stated to cut the 3 outlet IAC hose and thats not necessary, oh wel)

anyway I have searched,

but have not found a thread on removing the fuel rail, if someone could post a link or describe the steps to this, what to watch for, what to do first, etc.

I found a lot on injector removal (after the rail is removed) , but not fuel rail removal.

also, I have a 93 Q45, can I use the later injectors, 94 up

and finally where is the best place to buy new or rebuilt injectors

thanks and Happy New Year

[Q451990]

From what I recall, the rail is held in place by a couple of 10mm bolts on the right side. I would go ahead and cut the fuel line feeding it and replace with new OEM hose while you're in there. To my knowledge the 94+ injectors aren't compatible.

There are several injector rebuilders, but I had pretty bad bleed-down experiences with my try back in the late 90's. If you're looking for a "do it once and be done with it" solution, I would buy OEM injectors from Joe at Infiniti of Scottsdale. I would also check the knock sensors for cracking, ohm them, and repalce them if you see any signs of problems. Even if they're fine, I would replace their wiring harness. The harnesses seem to be a major weak point.

Good Luck!

Heath

[elwesso]

Update -

93 Q45

ok I have removed the plenum , (used the info on Q45.org., only regret is it stated to cut the 3 outlet IAC hose and thats not necessary, oh wel)

anyway I have searched,

but have not found a thread on removing the fuel rail, if someone could post a link or describe the steps to this, what to watch for, what to do first, etc.

I found a lot on injector removal (after the rail is removed) , but not fuel rail removal.

also, I have a 93 Q45, can I use the later injectors, 94 up

and finally where is the best place to buy new or rebuilt injectors

thanks and Happy New Year

The fuel rail is held in with 4 bolts on both sides... You simply undo those and a couple of fuel hoses back behind the plenum and your all good. Just pull it out of the runners

Then, send your injectors to deatsch works (find their contact info in the ADVERTISERS link in my sig) and send them your injectors. If you have bad ones, they will replace them for like $55 each and clean/rebuild the other to make them good as know. They KNOW their stuff about nissan fuel systems, and if they say an injector is good, I believe them! Great customer service, tell them your from NICO!

You send them the entire fuel rail they will install new O rings and pressure test it so all you have to do is install the rail onto the car with new fuel hoses and your done!

[andbeyond]

ok,

I have the fuel rail off and all boxed up to send out for injector service / replacement, (thanks elwesso)

couple of things I noticed on removing the fuel rail,

watch out for the spacers ( like a thick black plastic washer), between the fuel rail mounting tabs and the block. I dropped one down in the dark, wet, valley, and have to grab my super duty 4 battery mag lite to locate it, fish it out.

also check out the difference between my first test, @ the pin conn. plenum on,

and the 2nd test , plenum off , fuel rail off, and taking a reading at each injector,

Test #1 (at connector) - test #2 at each injector

Cyl - reading

1 - 37.6 1 - 27.32 - 0 2 - .9593 - 19.5 3 - 16.04 - 404 4 - 84.85 - 0 5 - 06 - 402 6 - 148.7 7 - 87.1 7 - 4..628 - 13.5 8 - 16.3

[goody90q45]

ok, I have the fuel rail off and all boxed up to send out for injector service / replacement, (thanks elwesso)

Hang on to that package. It looks to me like all 8 injectors are ohming way out of spec and if that's the case an injector cleaning/fuel rail flush is not going to bring them back to life. Before Deatschwerks does any cleaning they are going to ohm them, still in the rail, and Dave Deatsch (nice guy BTW) will be calling you to replace all 8 from their existing, refurbished stock. He won't let you spend your money cleaning unusable injectors.

I've got two Deatschwerk injectors in my Q (and 4 more ready to use) and they work great. What I am getting at is it might be cheaper to buy 8 refurbished injectors from PopPop and put them in the rail yourself. Good Luck.

[elwesso]

man those are some GOOFY readings.. You dont have one in spec. Mike, BTW, you might as well send them to deatschwerks because they sell replacement ones for like $50 and will install and pressure test them in the rail. No chance for a pinched lower O ring and all the other complications... Plus when you get them the $50 includes cleaning!

At this point, might as well send them to deatsch and see what they think.

[goody90q45]

At this point, might as well send them to deatsch and see what they think.

I'm not disagreeing with you. Gary needs to know that it's not going to be a cheap $15 per injector cleaning. With 8 refurbed injectors installed on the fuel rail the bill is going to be close to $500.

[maxnix]

With 8 refurbed injectors installed on the fuel rail the bill is going to be close to $500.

The point being is the injectors are wear items and no one replaces the windings. Refurbished injectors are used injectors. Once they are overheated because of soo much current draw, they are down the road to failure. Get new injecotrs from Joe or plan on replacing them again soon.

Double check your readings. I don't see how your car could have run at all with those readings.

[texasoil]

The real issue is WHY are the windings failing? I suspect the ETHANOL in gasoline today is attacking the potting compound of the injector body, causing it to swell and pull the wires in two internally.That's the 'post mortem' I did on 3 'original' ones off my '94--all wentprogressively HI ohms in 3 months of ethanol in gas. The other 5 had been replaced by P.O. just B4 I bought it 4 yrs/50K miles ago and have different potting compound.

[96Qowner]

Now, THAT makes some sense.

I've been reading the comments about ethanol attacking the windings, but the windings aren't exposed to the fuel. Add to that, the fact that I've been running ethanol in my Accord for 17 years without a single injector failure. Just didn't make any sense.

The potting compound used in the G50 injectors is vulnerable - THAT makes sense.

[Q45tech]

Tainted ethanol was to blame for shutting down pumps at nearly 50 Milwaukee service stations in 2001. The supplier, Archer Daniels Midland Co., had added 100 times the prescribed amount of rust inhibitor to the ethanol. The problem was detected by a state inspector performing a daily test.......................

Most surprising, Dankovich said, was that every injector, without exception, sent in by dealers as being faulty performed perfectly when tested by engineers in the company's national lab. He doubted dealers would knowingly send to the corporate lab properly functioning fuel injectors that they had replaced.

"What this tells me is that when they get out of the presence of the fuel, they run just how they are supposed to," he said.

And, he said, early indications point to problems with a particular gasoline company. Dankovich would not name the company; he stressed that results are very preliminary.

http://www.jsonline.com/story/index.aspx?id=281037

Something else that concerns me is the fuel pressure and fuel damper metal diaphrams and seals.

ALSO THE ACCURACY of the VOM used to measure

[Jeff Williams]

If this was my car, I would flush the fuel tank and lines, replace the fuel filter, and seriously consider replacing the fuel pump.

[Skibane]

The real issue is WHY are the windings failing? I suspect the ETHANOL in gasoline today is attacking the potting compound of the injector body, causing it to swell and pull the wires in two internally.That's the 'post mortem' I did on 3 'original' ones off my '94--all wentprogressively HI ohms in 3 months of ethanol in gas.

Hard to see how a break in a wire would cause a GRADUAL increase in resistance - Seems like it would cause an almost-instantaneous jump to near-infinite resistance.

IMO, a gradual resistance increase implies corrosion in a soldered or crimped connection (ie, at the solenoid winding/connector interface).

[rotorimp]

I just completed a swap and had all 8 cleaned/serviced with new O rings. After installation the car ran great for about 3 hours and developed a odd sound--it boiled down to the fact that I had 2 bad injectors (both Ohm'd out to 0.00) So sometimes it may be worth it to just buy at least 4 NEW injectors (the ones under the plenum) and get 4 cleaned/serviced in case they go T.U.

[texasoil]

Re: swelling and resistance: I took a 20 ohm original injector (not too bad but out of tolerance and not going back in), and put it in a jar of 20% ethanol in gasoline. In one day it went from 20 to >2K, and in 2 days went to infinity (open) Q.E.D. as they used to put in my Calculus books-the proof is complete. I do not know if later potting compounds are similarly damaged by ethanol--I suspect not since MTBE was in wide use by mid 90's. I did not see any fuel line deterioration though-would not expect it. Other plastic parts? case-by-case. fuel pump?looks like nylon or delrin--not likely to be affected.

Note--Volvo techs are reporting universal clogging of EGR systems since ethanol introduction. Crankcase chemistry can be drastically changed leading to copious varnish and gum formation if oil not changed frequently. They (Volvo techs) now always include (and charge extra for) EGR system cleaning every major service.

[Q45tech]

You might enjoy the test done in Australia on fuels with 20% Ethanolhttp://www.deh.gov.au/atmosphe....html

"At the test pressure, eight out of ten [fuel pressure]regulators demonstrated a decrease in bypass flow rate averaging 42%. Meanwhile, the remaining regulators AENHY09 (ULP) and AENFO07 (ULP) demonstrated increases of approximately 18% and 139%"

Fuel pumps: "the fuel pumps run on E20 on average had a slightly higher relative increase in electrical current draw after the mileage accumulation cycle. The typical trend was for current draw to increase as the pumps wear. The mechanism for this relative increase in E20 fuel pump current draw has not been identified, but could be suggestive of an increased level of wear.

Ring wear, exhaust valve recession, were increased with Ethanol

"Over mileage there will be a significant increase in the regulated tailpipe emissions for the Australian new passenger vehicle fleet if operated on a 20% ethanol blend fuel.

It is highly likely that certain vehicles will be above the legislated level for ADR37/01 at 80,000km, particularly those with lower engine capacities and engine control system that cannot compensate in all modes of operation for the extra oxygen introduced with 20% ethanol.

Due to deterioration of the exhaust catalyst over the accumulated mileage, vehicles operated with E20 will have significantly higher aldehyde emissions than the equivalent vehicle operated on gasoline.

There is also sufficient evidence to conclude that there was greater levels of wear observed on engines operated with E20 than for those operated with gasoline.

Similarly the levels of engine deposits observed were greater for the engines operated with E20 than for those operated with gasoline."http://www.deh.gov.au/atmosphe....html

Scarey isn't it! That your government would want to decrease the life of engines and cats with ethanol

[Q45tech]

Permeation of ethanolized fuel 65% higher than convention per CARB tests.http://www.arb.ca.gov/fuels/ga...n.ppt

[1990Q45'r]

Beyond the physical placement of the injectors on this engine, consider the cold/ hot cycling along with vibration of the injector coil windings. An increase ohmage of coil brought on by cold/ hot cycles, must be due to makeup/quality and the eventual degragation of the coil wire itself used in winding, including method and materials used in the winding connections. Can't see fuel has anything to do with it regardless of lack of problems by some in different areas of the country!

[Q45tech]

http://www.hawaii.gov/dbedt/er...l.pdf

226 pages of everything one should know about ethanol/ALCOHOL fuels and chemistry WITH POLICY ISSUES. Engine design parameters.......combustion, wear vs oil temp

The massive section on cleaning and corrosion effects of alcihols and blends

Comparison of wear with 3k vs 10k oil changes

These Consultants did their jobs well!

[Q45tech]

Just the implied FACT that injectors don't fail unless they are exposed to alcohols...............ethanol, MTBE, ETBE etc are all alcohols.

I have 311,000 miles on my as built injectors and we have multidozen [almost 100] Q customers with high mileage where injectors have never been changed in Atlanta............the only cars where injectors have failed were from out of state or spent a major portion of their lives in other states where MTBE and ethanol were used as oxygenates.

You can research the history of cars and see where they lived even if current owner doesn't know..............I make it a point to do so when any injector is replaced.

Why because I wanted to understand the potential for a sudden rash of problems in Atlanta environs as that would finally bury the old Q from a business perspective. At one point we used to keep $100,000 of Q inventory.........now we try to keep less than $10,000...........our Q business has declined by over 60%. We have 10 dead Q outback for parts just at 1 of 3 stores.

Not to mention my costs alone for 8 new injectors which might only have a limited life after spending $1500.

Just to reexcite my faith, a NC customer comes in for a Chain Guide job at 180k on a pristine 1991 he bought it brand new. He showed me records for 61 oil changes.................every 90 days no matter the mileage .

Inside of engine was pristine and there was zero wear on any plastic guide.

Fuels and lubes quality matter a great deal.

[Q45tech]

The 1.0 ampere ramp up [/!......../!.........../!] probably mitigates against the corrosion until the slow progressive increase in resitance significantly reduces the current flow.

It would be interesting to ADD a variable resistance in series wiyh a brand new injector to measure the fuel flow decrease as the resistance increases.Obviously since the flow is so low idle/cruise would show up first as a misfire.

Texasoil can you get hold of an inductance bridge..........this will tell you IF the turns in the coil are shorting [varnish attack] at the same time the connection resistance is increasing.

Cycle the injectors before they fail completely. The current may burn off corrosion. At idle the injectors are opening 1.35 times per second and 15 times per second at redline and still only staying open a max of 55% of the available time.

Another thing to try is higher than 13 volts [15-17 well regulated]........the insulation might fail so be careful...........a 2 amp fuse.

[maxnix]

Just to reexcite my faith, a NC customer comes in for a Chain Guide job at 180k on a pristine 1991 he bought it brand new. He showed me records for 61 oil changes.................every 90 days no matter the mileage .

Inside of engine was pristine and there was zero wear on any plastic guide.

Fuels and lubes quality matter a great deal.

There is a 1992 in my neighborhood that seems to have a TPS problem. Guy is religious about OCI and has about 220,000 on it. Wish I could help him with his non-start problem so I could see the chain guides.

For now, it just sits.
Modified by maxnix at 9:07 PM 1/12/2007

[Q45tech]

Checked mine yesterday 12.6-13.0 with 4@ 12.8 ohms at 50F ambient and ~~ 80F at the imjector body [IR gun] thats after passing 17,500 + gallons of fuel/8= 2200 gallons each...............way over 10,000 hours of use.

Just ordered another 12 cans of BG44k for personal use ..........

[pugstrip]

hi im having injector pulse problems with my j30 ...my dialup is so slow i was wondering if i could talk to you for a few my cell is 989 329 3654if you can call me i will call you right back so it doesnt cost you anything

thnx Harry

[andbeyond]

ok sent my complete fuel rail to Deatsch W E R K S

and I got a call stating 3 injectors were dead, and the other 5 could be revived but it would not be long term.

see above for my test results

bottom line, I purchased 8 of their injectors and they installed them in the rail rail and shipped em back.

great service, I have a good set for 1/3 of the price of a new set, and I don't have to worry about R & R ing the injectors from the rail.

thanks to the guys @ Deatsch W E R K S

now all I have to do is reinstall the fuel rail and the plenum (yea, all I have to do)

[texasoil]

On injector vs oxygenates:

The service history of cars operated in high MTBE regions (Arizona seemed worst) vs non-oxygentate areas (Atlanta) is conclusive in my mind. The injectors did not plug-up--they electrically failed. The only way this could happen is permeation of the oxygentate through the potting compound. and causing the electrical failures. There is a definite change between original '<95' injectors and those made after that date. In my particular case--I went from a perfectly smooth idle to dead miss is short order after ETHANOL (up to10%?) was added to premium fuel here in Houston. (By the way, ethanol is 'splash loaded' on top of gasoline already in the truck--so was it really 10% , or was it 6% +4% water? or was it 15%? .

The fuel HAS to have demonstrated keep clean injector performance in the EPA test before it could be sold. My situation affirmed it was NOT fouling--injector cleaners of all types had NO effect- even BG-44 was impotent. (the dead injectors WERE spotless on removal though.)

I am hoping ther later injectors are resistant to oxygenate related damage. So far-so good. The proof will be next summer when they again push up the ethanol content. If 'we' wisely remove the ridiculous $2/gal 'gift' aka 'payment' we, the people' make to ethanol blenders, they would minimize it. Our 'gift' to the poor oil companies encourages them to use as much as they can get--cause it works out to be 'free' after the subsidy--and they sell it as gasoline @ $1.70/gal or so-wholesale ex taxes.

Like I say--so far-so good. 3000 vehicle miles over the holidays on the Q-ships and both are rock solid and smooth.