OK My 'Vette starts fine when cold but after it is warm and sits for a while it will turn over for a long time and when it starts it is rough,the exhaust smells like gas. I believe that it is a leaky injector. When it sits long enough(overnight) the gas in the intake evaporates and it starts well. I also could smell gas inside the air delivery hose when I changed the air filter.

My question is how do I figure out which one(or2) are leaking without having to replace them all. Is there a way to rebuild or clean them? At around $60 a pop dont want to replace them all unless I have to. I did a leak down test and fuel pressure drops to 20lbs in about 10-15min.

 

Don't bother cleaning them, I just went through that-Pulled them out, took em in for rebuilding, car acted great for about 20 minutes! Couldn't figure out why it started stumbling all over itself! Wound up having a shop diagnose it and paid through the nose!!
There are some good injectors out there for a couple hundred bucks a set. Maybe someone will pipe in with a link. I wound up with 24 lb Bosch, after a set of Accels turned up defective.

 

Thanks cuisinart was looking a accels guess I will take them off my list. Would like some more info on the best set for the best price anybody?

 

First check for a vacuum leak; a friend had this problem and it acted just like leaking injectors.

If the injectors are leaking you can send them to Rich at Cruzin Performance (link on my site). For around $100 and 48hr shop time he cleans, reconditions, leak tests and flow tests them.

 

Will check the vacuum again but what is the definative test for leaking injector(besides smelling a lot of gas fumes) really feels like it is flooded when it finally starts will idle rough for about 30sec then will run just fine. When cold it fires up within 2 sec and idles fine.

 

To clear a flooded condition turn the key on, hold the accelerator to the floor for about 30sec, release the accelerator and start the engine.

If it then starts right up the problem is flooding.

 

Ok did the flood clear procedure it start a little easier but there is still a delay when warm so I guess injectors it is. Is it better to send them off the be cleaned and flow tested or buy new? If buy new where is the best price and brand at?

 

Key on pressure should be 42 psi and holding. Unusual to get a good cold start and have it go funky when warm, but you might want to ohm your injectors. Each should be about 16 ohms across the terminals both cold and hot. If so, scan and check your Coolant Temp signal. If it's not warming up it's going to increase injector pulse and flood it.

 

Will break out the VOM and check that.Pressure is 42-43lbs but bleed down to 20lbs takes about 10-15 min from what I read that is too short.

Anyone wanna suggest a Brand for replacement and where is the best price?

 

This seems to be my problem also. Starts GREAT with very little turnover if it's sat for a week or so. But if I've driven it for a little bit and if it even sits for a few minutes, it cranks hard and doesn't want to start. Sometimes when it does start, it will stall back out again. I've found injectors for $30 each at Advance Auto / Auto Zone, but the Chevy dealer wants to replace them with GM ones for $150 ea PLUS labor.

On a side note, is there any damage in the long run that can be caused by a leaky injector? Also, what about one of those fuel system cleaners where they run crap directly though your engine??? I'm guessing that won't do anything, but $60 would beat $500+

 

Already had the 3 stage cleaning done no help there. My guess is if enough leaks into manifold and drips into a cylinder it will mix with the oil probably not a good thing but someone here may have more intimate knowledge about this. That is why I am a little worried and am trying to fix it.

 

I might have got lucky on a Google search are these worth checking into?

http://store.yahoo.com/dpstore/322a0515.html

 

When my injectors started leaking I would get a thump sound in the exhaust from the excess fuel and when I parked it in the garage I would get a strong gas smell after I shut the motor off. Changed the injectors and no more problems.

 

http://www.fiveomotorsport.com/Injector_SetsTPI.asp

Here is where I've been linked to before. I'm just hesitant to take on the project on my own. I'm not very mechanically inclined.....But don't want to be raped by a dealer either.

 

We've been there. The stockers are Multecs, I believe. Not even worth rebuilding, or replacing with the same. A good set of aftermarket injectors will run you about 300+-. Removal looks intimidating, but its fairly straightforward. Takes notes, label hoses, start at the top (T.B.)and work your way down. Lots of help here. Might as well replace the EGR while your'e there. Two biggest culprits of rough idling in L98

 

This is an LT1 isn't it? If so, the task is a great deal less daunting. You might just want to check out a few other things first. The gas odor you smell can just as easily be caused by a malfunctioning evaporative emissions controls system - clamp off the hose and see if it goes away - and the skewed CTS I mentioned earlier would flood it when hot. Loss of pressure - and half in 20 minutes isn't that bad - can be caused by a bum regulator or defective check valve in the fuel pump assembly. Clamp the fuel return hose and see if the pressure holds. If you want, you can remove the rail with the injectors attached and then energize it. A paper towel underneath the injectors should pick up any leaks and from there, you can decide whether to replace all 8 or just the bad one(s). If you have a scanner, and given your year, you could see if one bank is running rich and then narrow down the possibilities. For what it's worth, I'm running Accels with 0 problems and I think whatever you use is a matter of personal choice.

As to potential problems, a leaking injector might contaminate the oil and the vapors would get sucked back into the engine through the PCV. The O2 would think it's running rich and the ECM would lean it out causing driveability problems. Frequent oil changes would minimize this. If an injector was stuck open, the excess fuel is going to go out through the exhaust valve and potentially, might cause a fire in the Cat. If it overwhelms the combustion chamber, it could blow the head gasket or do other damage. Your symptoms are no where near that.

 

Sun CR-You're right. My bad!

 

The CTS should show up on the guages shouldn't it my temp guages work fine as far as I can tell around 200deg when fully warm. I dont think it is stuck fully open just leaky( drip drip drip) and suspected the possible ramifications to the oil etc. Not sure how to check the regulator but as I said when it has sat overnight it fires right up. After warming up it will delay on start idle rough til I rev it a few times then run OK. I dont have a scanner nor access to one. When I changed the Air filter I could smell a distinct gas smell in the air delivery hose and right after a warm start I can smell the gas in the exhaust pretty easily I talked to summit racing about FMS injectors ( as mentioned in a different post) and they never heard of putting them in a 'Vett. I need a part# for FMS injectors that will fit my 93 LT1 the link87 ragtop left has the orange ones which is what summit has but they have a lot of different part #'s for them. I would think with 155k miles on this engine it would be a good time to replace the injectors any way.

 

No - Coolant Temp Sensor is below the water pump on the LT1 and another sensor (I believe on the right side of the block) controls the gage. I just went through a shorted sensor circuit on my Vette - it was stuck on 250 degrees, so cold starts were a bear (actually non-existent). Mine was the ECM, but that's one of the reasons I suggest you look at it. If it's reading below 100 degrees on a hot engine, it could easily flood it out. If you do find a problem, you will need to check for high circuit resistance, which given the mileage, is a possibility.

Of course, absent a scanner, that may be a bit of a task. If you know the pinout at the ECM, it should show 1.7 to 2.0 volts at operating temp - all GM's spec out at this #.

I'm not so sure that the fumes you smell aren't normal. A functioning evap system dumps tank fumes into the plenum once it's up to operating temp and above a certain speed. There is usually a check valve somewhere in the system too (to keep it from dumping fumes when it sits). If that's shot, you'll get the smell. Again, it's just something to consider, particularly since you've had the injectors cleaned.

There's an inlet and and outlet to the fuel rail with the outlet sometimes a tad smaller (but it's definitely not the one from the fuel filter). Somewhere there are rubber hoses and if you clamp the outlet shut, you can see if the pressure stays constant once you energize the rail. If it does, an injector isn't leaking. Otherwise, pulling the rail and putting a papertowel underneath it should reveal the culprit (I remember one member leaving it overnight to find the one that was dripping).

I'm pretty sure Accel makes a replacement for the LT1. Try Street & Performance - www.hotrodlane.cc - they sell a ton of stuff for any injected motor and should have anything from stock to an economical replacement.

 

Thanks a lot SunCr very good info will check all this out before I but the injectors. Summit has the Accels for around $220 a set but FMS was recommended by some other guys. Once again Thanks