Fuel Injector Woes at TexasOil Garage

Post by **texasoil** » Mon Dec 11, 2006 7:51 pm

Well, my son was visiting from Germany, and we tackled BOTH Q45a's my 94 with TC, and wife's 92. Mine first--the TC stuff adds 50% to the effort IMHO. Lots of extra hoses and connectors. I had one DEAD cylinder and 2 weak--injectors OHMED bad--1 at 600, 1 at 65, one at 29. Others at 11.9-12.0. Replaced the bad ones. Replaced KS and harness also. Both had MELTED covers-from when radiator end cap had sprung leak on spouse as she was returning from Hobby Airport and saw 'smoke' and temp gauge at HOT. fortunately no other damage evident. LOTS of scratches and scrapes, but she runs better than ever. Completely silky smooth at 500 RPM no-load. Interestingly, all 3 high ohm injectors went to completely open after 2 days of sitting out. There were all original--other 5 had been previously replaced by P.O. Replaced both VC gaskets--were original and leaking badly. Not much varnish in engine. No sludge or deposits.

Wife's car had one dead at idle, good at 1500RPM up. Progresively worse. Ohmed 75. Had 2 others in 40 ohm, 1 @25ohm and 4 @12.1 Replaced them with a complete set from a low mileage '96. Now runs better than ever--absolutely buttery smooth.

I have no explanation for the rash of electrical side failures. Never before in over 26 years of FI cars had ANY injector problems. Fuel side was clean in all cases. Manifold was ugly though. Cleaned throttle bodies,etc. EGR were clean on both cars. ISC were cleaned. All fuel, vac and water hoses replaced.

Post by **Q45tech** » Tue Dec 12, 2006 4:17 am

Isn't the Texas water in the ethanol wonderful, so much for the 94 injectors being better than early design.

This was pointed out years ago in a Nissan letter to CARB concerning the proposed use of ethanol in CA to replace MTBE back in 1996.

It essentially said if you have gasoline/injector complaints now JUST wait until you switch to ethanol.

The unoffical response was good, because we want old injected cars to fail and get them out of our pool and everyone into OBD2.

Nissan pointed out that injector designs don't change with OBD2.

I use Isopropyl in every tankful now..............312k on injectors all still within 0.3 ohms........................how much longer can my luck hold?

I'm confused how did the 96 low mile injectors fit in 92 injector runner holes?

Post by **maxnix** » Tue Dec 12, 2006 5:57 am

Q45tech wrote:I'm confused how did the 96 low mile injectors fit in 92 injector runner holes?

Good question!

Post by **texasoil** » Wed Jan 10, 2007 3:26 pm

Actually, deleted the OEM hard black spacers under fuel rail bolt pads, shimmed to(lower) level height with steel washers so all square up with injectors fully seated. Injector tip sits +/- 1'8" deeper into intake runner. Car has never been so smooth at idle (Has JWT ECU, all other stock)

Post by **Q451990** » Wed Jan 10, 2007 6:33 pm

Very interesting! It's been a while (knock on wood) since I've had the injectors out of a Q. I seem to remember thinking that the plastic spacers also acted as seals... Is that not the case? In fact I really don't remember how the rails were attached to the runners. Might be time for a plenum job just to keep my DIY credentials up to snuff

Do the 94-96 injectors fit in the rail, or do you have to replace them as a set? Also, I undertand the connectors on the sub harness are different... is the other end that connects to the main harness the same?

Heath

Post by **Black stallion** » Tue Jan 16, 2007 7:03 am

What is the significance of using isopropyl in the tank? Is it geographical,maintenance, or some other reason. Also is that the same as rubbing alcohol?

Post by **maxnix** » Tue Jan 16, 2007 7:48 am

Isopropyl is more water soluble and doesn't attack injectors like methanol (HEET).

Post by **Q45tech** » Tue Jan 16, 2007 8:43 am

Pure Isoproyl [becomes 70% rubbing alcohol when 30% water is added].

All common alcohols [Me, Et, & IPA] form a suspension mixture [vodka, etc] with water. the 2 are miscibleGasoline can only contain about 0.02 % water by volume before the water will separate.When you mix gasoline, ethanol, and water you get a ternary solution as long as the water content is low enough. As the proportion of water increases it will reach a critical point at which time the ethanol and water will separate from the gasoline and form a new solution. A water/ethanol solution is heavier than gasoline or water, so it will drop to the bottom of the tank.Isoproyl is the best in that at cool temperatures it allows more water to stay in suspension in gasoline/ethanol.

Oxygenated gas already is 10% ethanol so more just makes the problem worse.............Isopropyl can hold up to half it's volume of water depending on temperature.............so 11 ounces can hold 3-5 ounces of water that has settled out from cold ethanol in gasoline.

Methanol attacks aluminum whereas the others don't, methanol is more agressive in melting certain rubber hoses.

Either way ethanol in gasoline is not great [for so many reasons] and absorbs water from the air so isopropyl is the only thing you can use.............not great just the only thing.

The gasoline and ethanol at the tank farm are 99.99% water free so at worst you get 0.28 ounces of water for each 22 gallons...........that is fine UNLESS your gasoline station tank has water or the tanker dumps in the rain or you fill up in cold weather or in the rain.

Eventually you can end up with water in the tank..........it rusts the fuel pump and injectors.

Brand new oem fuel filters can block a little water and all the rust so fuel filters should be changed frequently.

The filter pick up sock in tank is very low in the cup so there is Zero margin for error..............you could redesign tank so that the pickup is a few inches higher................look at the level of the 2.5 gallon remaining sensor for ideas.

Post by **texasoil** » Tue Jan 16, 2007 8:12 pm

Injector rails 90-mid 95?are the same I think--injector connections are different, so gotta have harness for the injectors, Wiring harness end is the same. At sometime in 95 they switched to a 'top feed' injector from the 'side-feed' used from start to then.

Post by **nadirgholi** » Wed Jan 17, 2007 7:51 am

I was wondering what you meant by "Doesn't ATTACK injectors like methanol(HEET)"

Can you expand on that? In a separate related topic I posted you recommended ISO-HEET though.

Post by **maxnix** » Wed Jan 17, 2007 9:30 am

nadirgholi wrote:I was wondering what you meant by "Doesn't ATTACK injectors like methanol(HEET)"

Can you expand on that? In a separate related topic I posted you recommended ISO-HEET though.

Q45tech wrote:Methanol attacks aluminum whereas the others don't, methanol is more agressive in melting certain rubber hoses.

And read Texasoil's post on submersing an injector in ethanol and gasoline and the resulting open circuit.

Post by **Q45denver** » Wed Jan 17, 2007 11:56 am

Texasoil, Could explain what you did a little better as I am in process of installing some of the latter top feed injectors in my 1990. I have the complete rail assemblies and wiring harness from a 1995 and also bought some new spacers which fit between the 1990's intake runners and the new fuel rails. Thanks

Post by **nadirgholi** » Wed Jan 17, 2007 8:15 pm

Where do you find pure (100%) Isoproyl? How much do you add to a tankfull?

Post by **maxnix** » Wed Jan 17, 2007 10:32 pm

ISO-HEET.

Depends how much water you think may be in gas. At least one bottle.

Post by **nadirgholi** » Thu Jan 18, 2007 9:24 pm

Is this the one in red bottle in the link bellow?http://www.goldeagle.com/heet/products.htm

At $1.30 for a 12oz bottle this is pretty cheep provided it is pure Isopropyl compared to $5.00 for a 16oz bottle of 99% Isoproply alcohal.

Post by **nadirgholi** » Sat Jan 20, 2007 8:10 am

Is Austin blend?

Post by **Q45tech** » Sun Jan 21, 2007 6:13 am

Google is your friend!http://www.austinchronicle.com...73280

http://www.cleanfuelsdc.org/info/images/Map.gif

You will have to check with the Austin blending terminal as it is not a mandatory RFG area........however HRB seems to be pushing it at their locations.

Post by **nadirgholi** » Sun Jan 21, 2007 11:24 am

Q45tech. Sir, Isopropyl is avai;able in 70%, 91% and 99%. Which one do you use in every tankful?

Post by **texasoil** » Sun Jan 21, 2007 1:07 pm

99% IPA is what you want to remove water from your gasoline system

Post by **Q45tech** » Sun Jan 21, 2007 4:29 pm

Hyundai vehicles equipped with Fuel Injection (petrol) manufactured after 31st October 2003 are equipped with fuel systems compatible with alcohol (Ethanol). These vehicles can operate on a maximum of 10% Ethanol / 90% unleaded petrol, however if drive-ability is affected, the use of 100% unleaded fuel is recommended. Ethanol blended fuel mixed at 10% is generally referred to as E10.Hyundai vehicles equipped with Fuel Injection (petrol) manufactured before October 2003 do not have fuel systems compatible with alcohol (Ethanol). If Ethanol is to be used in these vehicles, then a maximum of 10% Ethanol / 90% unleaded fuel (E10) can be used in conjunction with periodic use of a fuel corrosion inhibitor. (The Hyundai recommended inhibitor is available under part number AL009M0002)Hyundai vehicles equipped with carburettor fuel supply systems should not be run on Ethanol blended fuel of any ratio. This is due to both the incompatibility of the fuel lines with the moisture holding characteristics of Ethanol, and to the negative effect on vehicle performance due to the variation of vapour pressures between petrol and Ethanol. Q Can Ethanol damage my Hyundai? Hyundai vehicles equipped with carburettor fuel supply systems should not be run on Ethanol blended fuel of any ratio. This is due to both the incompatibility of the fuel lines with the moisture holding characteristics of Ethanol, and to the negative effect on vehicle performance due to the variation of vapour pressures between petrol and Ethanol.Ethanol is hygroscopic, (attracts and holds moisture) and can therefore accelerate corrosion. The use of E10 (Ethanol blended fuel) may result in negative effects to cold starting, as well as engine drive-ability (‘smoothness') at light to medium engine load conditions. It will also result in reduced fuel economy. Q Will it affect my Warranty? The use of Ethanol at E10 will not affect warranty simply by its use. However, failure caused by Ethanol such as corrosion of fuel injection due to Ethanol's' hygroscopic nature (attracts and holds moisture) will not be covered by warranty. .............................................

Fuels with unspecified quantities of alcohol, or alcohols other than ethanol, should not be used. customers choose to run with up to E10, HMCA recommends that 1 in 5 tank fills is with 100% petrol.

Post by **nadirgholi** » Sun Jan 21, 2007 7:10 pm

Dang. Seems like Aussies had a taste of this ahead of us. Didn't know they grow a lot of corn and alike there. May be they did us a favior trying it first for incentives.

Post by **Q45tech** » Mon Jan 22, 2007 2:15 am

I love Hyundai's honesty.................if you use Ethanol you are on your own without warranty coverage and we recommend at least 1 in 5 tanks be conventional gasoline to wash out the water and ethanol.

Please use additives in every tank to fix your decision to use ethanol.

Post by **96Qowner** » Mon Jan 22, 2007 8:15 am

Let me just repeat that my Accord has been fed 10% ethanol for 17 years and 385,000 miles with not a single fuel system or sensor failure, the majority of it from one Phillip 66 station, the rest from assorted stations scattered across the Midwest and South.

It's still running on the original fuel pump and injectors. I've put some Heet into it maybe three times in its life. I typically let the tank run down to 3 gallons before refilling. I've replaced the fuel filter maybe three times.

Not argumentative: just one man's real-life experience with one Honda Accord.

Post by **Q45tech** » Mon Jan 22, 2007 8:57 am

What do Honda's have to do with a 370cc side feed fuel injector designed in 1987?

Fuel problems are always design specific.

We are not condeming Ethanol for every application besides human consumption just pointing out that it seems problematic in this application.

Just as MTBE was in previous years

Just one of the EXTRA things to consider if you own or plan on buying a 90-96 Q or 300zx or Subaru flat 6 and others which might use this particular injector.

Just a warning that one should have another $1200 besides the normal $3,000 in reserve for problems.

Years ago I pointed out that certain used cars can cost as much as new ones to buy as they get OLD.

The reall question is with brand new injectors [old the old type plastic] how long do they last under 10% ethanol with proper maitenance [fuel filter changes and BG44k].

If they last 60k -4 years that might be ok as $2,000 every 60k is only 3.3 cents per mile extra.

Post by **pugstrip** » Thu Jan 25, 2007 8:07 am

hi do you know if the 93 j30 injector wiring is the same as the 94?

Post by **werepe** » Tue Nov 27, 2007 2:12 pm

TexasOil, please advice on how to install 1996 fuel injectors with rail and harness in a 1992 Q45. I just read your previous posts but couldn't quite get what I was looking for. Please advise on what to do.Thanks!

Post by **Q45tech** » Tue Nov 27, 2007 2:39 pm

The question is are brand new 94-96 injectors any better than brand new 90-93 injectors. It appears both suffer the same degradation from exposure to ethanol and water in gasoline.

Post by **texasoil** » Sun Dec 30, 2007 6:03 pm

I replaced the fuel rail and injectors. The new 2nd gen side feed injectors will not fit in the old(1st gen) rail. The only adaption needed was removing the black plastic spacers at the hold down bolts and replacing with a thinner stack of flat washers to allow the shorter injector+rail to seat squarely on the manifold. One could also grind the OEM plastic spacers thinner. 2nd gen wiring harness (>94) needed. The 92 (168K miles) has been silky and buttery smooth with these FI.

Post by **Denver90Q** » Mon Dec 31, 2007 11:17 am

If you were using metal washers how did you keep from getting vacuum leaks?

Post by **Haitian_King** » Wed Jan 02, 2008 7:32 pm

How long did this take you and your son? This was all done in one day was it?

Fuel Injector Woes at TexasOil Garage

Fuel Injector Woes at TexasOil Garage

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