How does one test for leaky or clogged fuel injectors????

 

leaky....

Pull upper plenium off. Pull fuel rail up and somehow support it so the tips of injectors are touching NOTHING. Lay clean papertowels down. Make fuel pump kick on tell its done cycling. If you see fuel on the tips, or spots on the paper towels, they are leaking.

Clogged/plugged, send them in is only way I know how.

 

Easier (but nobody here likes to do it)- Put a fuel pressure gauge on the fuel rail valve and make sure the pressure holds steady with key on & engine stopped. http://www.actron.com/product_detail.php?pid=16174

Clogged/plugged = injector balance test, but again, that requires a fuel pressure gauge, along with an injector tester. I bought mine for cheap from the Actron.com website's garage sale - but apparently they've redesigned their website, and there's no more garage sale.

 

wow great
I don't mind spending a little extra $$
if it'll save me time & time

thanks again

 

Not stealing this topic but, how hard is it to take that upper plenium off? Mine hasn't been off since I bought the car and I'm afraid to break something or strip a bolt. Will it come right off? Thanks

 

The bolts won't be stuck; they're steel bolts going into aluminum, they're only on there with 12-15 ft/lbs of torque.

Because of that, only put the bolts back with 12-15 foot pounds worth of torque!!! Steel bolts can strip out aluminum threads, OR crack the plenum bolt holes. For those of you without torque wrenches (why?? Buy a torque wrench!), 12-15 foot pounds is about "a little past snug".

For the upper-plenum-to-lower-plenum gaskets, try not to re-use them. They've flattened out, and re-using them can cause a vacuum leak. Instead of paying $30 for a full intake gasket set just to use 2 gaskets, buy a roll of thin, flat black gasket material for $3. Get an x-acto penknife and a hollow punch, and trace/cut your own new gaskets. Use the old ones as a template; they should come off in one piece. If only one comes off in one piece, guess what, both gaskets are the same dimension... so you can use one original old gasket to make two new ones.

When you put the new gaskets and the plenum back on, snug the bolts up in a cross-pattern (make a star pattern over the plenum, example, rear right bolt, then front left bolt, then middle right bolt, then rear left bolt, etc...). Then do the same pattern for bringing the bolts up to torque. This ensures even "clamping" over the whole plenum, and keeps the gaskets flat.

So as long as you don't overtighten those bolts when you put the plenum back on, you won't crack anything.

OH- same thing (with bolt torque) goes for the throttle-body-to-upper-plenum bolts, too. 12-15 ft/lbs torque. Same for the thermostat housing bolts. Same for the transmission pan bolts. Same for any steel bolt that goes into an aluminum hole!!!

Afterthought- it's a good idea to lay shop rags over the plenum openings when you remove the upper plenum; that way you don't drop anything into the holes! Plus it looks cool too.

 

Thanks TomP, I will be getting injectors in a couple months and this is great to know

 

I've got some 3.4 injectors that Rich as Cruzin Performance cleaned for me. I ran them for not even 100 miles before switching them out for the old 2.8 ones (I thought they were the cause of my high emission problem) and I'm a bit too lazy to swap them back. They've been sealed up since I took them out so if you want them let me know, I'm sure I could part with them for less than a parts store would .

 

Why did you take them out?

 

Like I said in my previous post, I thought they were the cause of my high emission problem. It turns out they weren't and I think TomP (IIRC he did the swap as well) could back me up on that they don't cause any emissions problems. They work fine, I had them cleaned and worked over so that they all put out within the given tolerances of each other. I don't have the paper from Cruzin Performance any more though.

 

I do think they would cuase the idle of the motor to run reach though. I buddy of mine did that and his ran a bit rich at idle, how much are you looking at? Thanks

 

I think Tom might be able to give some more definate answers to the rich problem. I thought he took the New Jersey emissions test with some in and passed. What do you say to $100 plus whatever shipping is.

 

If they caused me to run rich enough to smell it, I don't think I would've passed NJ emissions! (They throw us on the chassis dyno, like in California.)

Click on this for full details: https://www.thirdgen.org/techbb2/sho...hreadid=232064

Oh, one point, though- I put 3.1 injectors in. I don't know what 3.4 injectors would do!!