1990 Q45 injector issues update....

[pito11213]

Ok guys for those keeping up..

I ohmed my injectors on my 90Q and found 2 definately bad and 1 reading open loop. Well today I tried taking off the MAF and thoroughly spraying with brake parts cleaner, cleaning throttle body using one can of cleaner. When I put back in the MAF I used dielectric grease on the connectors. I then removed the front plastic piece and looked at the number 1 injector which gave me an open loop reading. I then pulled the plug cleaned the contacts and replaced with dielectric grease. After everything was said and done I noticed a slight change and far as the bounce feel.

1. Noticed that when I played with the injector harness of one of the injectors I noticed a slight change in engine sound. 2. I also know for a fact I will be changing the injectors myself. It doesnt look beyond my expertise.

I would like to know if anyone has done the injectors with out completely removing the plenum. I know many will say just do it all the way but due to space problems I have to try to cut any corners I can. Remember all my work is done at an autozone parking lot. Again I am changing the number 1,3,6 injectors. 1 and 3 dont look that bad but 6 looks like an issue. Please all help would be appreciated.

[DAEDALUS]

I think Qdog was successful in replacing an under-plenum injector without removing the whole thing. Removed the bolts and just lifted it up enough to get enough clearance to replace it. I can see it happening for #3, not sure about #6. You'll need to replace all the plenum donuts, and be careful you don't cause a leak in one of the hoses by stressing it.So...the one that was OL, was it still OL when you measured it directly at the injector?

[pito11213]

Hey D....I put the probes on the two contacts on the injector was that correct? If so then yes the meter still said open loop.

As far as the plenum rings those are new from when I went in there a couple of months ago. I replaced the majority of the hoses under there just not all. I agree injector 3 looks ok but 6 looks a little difficult.

[DAEDALUS]

Yeah that's right--it's open for sure then. Don't forget to zero the pressure in the rail before doing the job, have a fire extinguisher handy, no open flame, etc. Be careful to not get too much fuel down in the cylinder, and change the oil when you're done. The hardest part for #6 will be getting enough room to get the bugger out, but at least it won't matter if you destroy it in the process. Be careful to not drop anything solid down the runner.

[pito11213]

Thanks D.

I will try to get this done within the next week. I believe number 6 will be the hardest one to do. When you say zero the rail you mean pull the fuel pump fuse and crank the motor right. And let it run till it dies.

[DAEDALUS]

Yeah. Remove the gas cap too. That'll zero the pressure, but the rail will still be full of gas. You could remove the hoses off the lines above the passenger valve cover to get out some (most?) of the fuel if you choose to.

[Q451990]

1,2,8, and maybe 7 are replaceable without removing the plenum.... forget about it with #6. I'd say this job is a bit beyond the Autozone parking lot. Would a self-storage place rent you a garage-sized place for a week? My two tips are to be sure to lubricate the o-rings with vasoline or di-electric grease (believe it or not there was a thread a few years ago with what the best lube would be - and some thought that KY jelly would be the best for the seals!) The second is to go ahead and get replacement screws for the injector rail caps... they're really easy to strip out. I recommend replacing them with a hex-head screw. Oh yeah, and a third.... OEM injectors only! I had a real problem (bleeding down) with aftermarket remans.

Heath

[pito11213]

Yo Heath.

Do you think I could get away with removing #6 by just taking off the plenum bolts and "manuvering" the plenum to pull the injector. I think with some finesse and trickery I could pull it off. (No pun intended)

[Q_SHIP]

I just removed all of the boltsand lifted it just enough to get in there. It was actually very easy. I could gett to all of them that way.

[pito11213]

Thank you for the confirmation. Any tricks or tips that I need to know.

[Jesda]

I just removed all of the boltsand lifted it just enough to get in there. It was actually very easy. I could gett to all of them that way.

Thats very encouraging! I guess I'll replace all the bad ones then.

[Q451990]

Actually, I've done it before too. Maybe it was #5, but it was one of the middle ones.... You said you just did plenum hoses, so they may be flexible enough to get in there. Hopefully there is no reason to keep the old injectors (e.g. rebuilding) because you'll probably destroy them in the process. Some folks say that a good penetrating oil (WD-40, PB Blaster) helps with injector removal too.

Didn't you say you have knock sensor codes too? I'd sure think about fixing everything at the same time. Between three bad injectors and the knock sensors I can see why you were thinking your engine is toast!

Heath

[Q451990]

One more thing... I would go ahead and get a pressurized rail flush when you're done. The others have to be pretty dirty by now. Also, on all of my injector failures - the associated spark plug was fouled to the extent that it wouldn't spark. You'll probably want to replace the plugs with new OEM or NGKs after the injector job.

Heath

[pito11213]

I know I need spark plugs as well Heath. I can say they have not been changed in 2.5 years minimum. So who knows how long it has been.

[Q451990]

As much as anything just be sure you wait until after you replace the injectors to change the plugs. My bad injectors would foul the plugs to the point of not firing in a mile or two.

Heath

[elwesso]

Pito.. I think its time for a decision...

If you engine smokes, i might consider driving this one till it dies then getting a new engine... 3 injectors, plus you really should replace the KS, thats a lot of money. Get a new engine, and do this stuff if you have to to make it worthwhile...

Honestly, I wouldnt do all this crap to the engine, because you really want to take the plenum off to do this all at once...... Id drive on the bad injectors and use the savings for a fresh engine (or maybe a fresh car entirely?)

[Q451990]

I've talked back-channel to Pito, and he says he's not really experiencing oil consumption. If it has noticeable smoke - it should be drinking oil like a Ford.

I wonder if it's not black smoke (running rich) from the bad injectors?

Heath

[pito11213]

Nope it is 100% blue smoke. Plus there is some oil residue in the exhaust tip. That is a sure tip off. Like I said I am still considering the engine replacement but I have to look at the cost of that plus all the goodies with it as opposed to getting another Q.

But to find another good Q that I wont have to dump money in RIGHT away is another issue. I understand that the Q is expensive but atleast give me some time to put up the funds to baby one.

[Q45tech]

Remember a newish JDM need lots of work before it can be swapped:That work is valve cover seals, 30 new hoses, new knock sensors and harness, chain guides, and the general cleaning of plenum tb etc plus new water pump and thermostat plus new spark plugs. Plus maybe some new injectors. [Parts cost $1500 +]

Of course easier to swap mix and match while both are out side by side but still 8-15 PROFESSIONAL hours...........combines to make 25 minimum Professional hours.

If someone gave you a JDM engine you still need to spend $1500 ++++ 25 hours [35-40 hours non professional time].........usually ends up costing $4,000-$6,000 to do it right, for a job that could last another 100,000 miles.

Why we don't see anyone getting a new engine for a 90-93 or even 94-96Q anymore............the cars are worth less than the engine job.

We are in the process of desludging a ES300 [horrible Toyota V6 if you don't change the oil] in only 82,000 miles..............$2,000 [26 hours plus some new head [+ other] gaskets.........we may save it so he can sell it to some unsuspecting person [a real smoker]. The dealer wanted $7,000 to swap a short block, we offered $4,300 for a newish engine or a $2,000 partial rehab [with few guarantees].......no rings no bearing just hours of disassembly and pressure washing.

Speaking to a friend who started up a [T3 minus 2 shop] near by. He gets all the jobs we won't take ---- the real rolling junk [and gets paid some in trade]. He is miserable concerning the jobs he has to take, the bottom of the food chain.........poor people with a worn out lux car or Honda.

As long as a car is worth $10,000 plus people seem somewhat willing to repair them?????????

Not $2,000-$4,000 Q or LS.

[pito11213]

Well I could get the labor for about $800.

And the motor for $1500 That is already at $2400. Then the parts come into play.

I know where I could get a complete replica of my car for $3000 that has been taken care off....wink....wink...

[elwesso]

Pito.. You really need to get Heath's Q.. Probably one of the better hi milers other than dennis' Q, as far as OCD maintenance...

[pito11213]

Yeah Wes that was the wink...wink

well like I said right now it is all about seeing what time will bring....

But I am very interested in it as I expressed to Heath himself....

[DAEDALUS]

I know I need spark plugs as well Heath. I can say they have not been changed in 2.5 years minimum. So who knows how long it has been.

Man I just can't share the enthusiasm for replacing things and being all swap-happy. Aren't you curious as to what's causing the burning oil? The plugs are constantly exposed to the cylinders' combustion. They're windows and records of the engine's operation, like arctic core samples. They often tell a lot about each cylinder.The oil could be from a valve stem seal. The seals on most engines can be replaced without removing the head. Not cheap, but maybe cheaper than a swapped engine or another car.

[pito11213]

So exactly what is your suggestion D

[DAEDALUS]

Admittedly I'll have a different view because it's a different situation where I'm at. I have a secure place to work and enough tools. If I didn't and had to pay someone to look at the plugs I might hesitate more. But I'd look at all the plugs first. Is just 1 cylinder blowing oil or all of them? Does one plug have a fouled side, indicating a bad valve stem seal? For that matter, is it possible the oil is running down the plug from the valve cover? Some disagree with that theory, but is anyone certain? What are the relative costs to fix each potential cause? A bad oil ring is probably not worth fixing. A bad stem seal might be. A leaking plug definitely. How's the leakdown, compression and oil pressure? Trying to make sure all the bases are covered for reasonable diagnosis before breaking out the hacksaw.