Second dead injector?? What's going on?

[PhysicsSHO]

So I recently discovered that the SHO was running rough, the cylinder balance test showed zippo from cylinder #5, and I checked that the problem wasn't spark. On Saturday, we replaced the #5 fuel injector, and the car ran perfectly, driven hard all day long. That evening, the *exact same symptoms*, this time cylinder #4 has failed!!

How could *two* injectors fail back-to-back??!! What's going on here?

I replaced the fuel filter, the old one looked pretty new and wasn't clogged. Should I just order a complete set of injectors from SHOShop and replace them all? Do I need to flush the fuel rails? (how??)

 

[olympic]

A set of cleaned injectors from SHOshop is cheaper than one brand new one so that's probably the way to go. You can clean out the fuel rails once their off with some carb or brake cleaner. But they probably arn't dirty.

 

[luigisho]

That does seem odd but not impossible. I second/or third the sho shop cleaned injector idea. Best shot for the money.

I wonder if you have alot of particulates in the tank/fuel system.

<small>[ April 23, 2002, 11:41 PM: Message edited by: luigisho ]</small>

 

[PhysicsSHO]

The first reman Borg-Warner from O'Reilly's was about $75, much cheaper than $160 for 6 from SHOShop.

I'm willing to replace all 6 injectors, but what happens if I bust another because of some underlying cause?

Is there a way to flush the fuel system, or flush the tank without dropping it?

-Alex
'95 MTX 72k

 

[luigisho]

I can't imagine you could clean the tank very well without dropping it. You do have a point if you only want to replace 1 injector. The sho shop's are cheaper if you want to cover all 6 at once but there are no leftovers as I believe there is a core charge to get your old ones. Dropping the tank sure increases the labor factor. I'm not sure I would do it just to take a peek. If I'm dropping the tank I'd like to be reasonably sure it was warranted and I would probably replace the pump and return check valve if they had some years on them. This is just my opinion having already dropped my tank and not wanting to do it again if necessary. It's not difficult technically, I just didn't really enjoy it the last time.

<small>[ April 24, 2002, 12:03 PM: Message edited by: luigisho ]</small>

 

[jcostantino]

Don't forget to replace the fuel filter while the system is depressurized... something like $7 from autozone (standard part, even)..

Worth doing "just in case"

Jeff

 

[PhysicsSHO]

Jeff, as I said at the top, "I replaced the fuel filter, the old one looked pretty new and wasn't clogged."

Luigisho, it's true that one is cheaper, but for the cost of two I suppose one might as well have gotten all six. The O'Reillys have core as well. If I drop the tank I will replace the fuel pump and check valve as well (the pump is whining), but given how long it took me to do the fuel filter, and how much gas I breathed, I'm none too eager to tackle the tank unless someone thinks I *have* to.

 

[jcostantino]

I didn't see that at the top.. Is it possible that you have a tank of bad gas with something in it that contaminates the injector?

I forget if the mtx has pintle or disc type injectors but if I recall correctly, the pintle type can foul from bad gas evaporating from the tips when the engine shuts off.

Can you maybe spray some carb cleaner on the tips and reinstall the fouled injector?

Jeff

 

[PhysicsSHO]

According to alldata, it has pintle type. I've only had the car for 5-6 tanks of gas, but it's received only Exxon Premium since. The really funny thing (about bad gas or contamination) is that only one injector is affected, and goes from fine to nil while all its neighbors remain unaffected.

I'm sure willing to spray some cleaner on the tips, but reinstalling the injector means putting the whole intake back on, which is ugly.

 

[bigblksoul]

I got all of my injectors cleaned and balanced by Cruzin Performance. It cost me $65.00, they replaced all the o-rings, screens, and even painted the injectors flat black. The turn around time was 3 days. Check them out.

www.cruzinperformance.com

<small>[ April 25, 2002, 01:17 PM: Message edited by: bigblksoul ]</small>

 

[PhysicsSHO]

Thanks bigblksoul! A found a local Austin shop that can do it, but they charge like $25/each. The guy at Cruizinperformance was very friendly and helpful in explaining what could be wrong and what he can do. Unfortunately, there's not enough demand for SHO injectors to keep an inventory for flow-matching.

I guess I stand to lose either way: if the #5 and #4 injectors failed mechanically or electrically, then I have to replace the whole set from the SHOShop, and if the they failed due to clogging, then there's something really nasty in my fuel system. At least I'll know.

They got mailed off today...