Humm.. I am, once again getting a rough idle. Between the rough idle, and hard starts, I am starting to suspect leaky injectors. Would this cause a rough idle? (I know it can cause the hard starts). If so, is there any way to check my injectors, and see which are leaking? Or do I need to just replace them all in one shot?

 

1. GM service manual has procedures for checking injectors, but a thorough check on the car requires some specialized epuipment, don't know the total cost.

2. You can take the injectors out and have them checked and cleaned at a shop - LPE used to do this for less than $100.

3. You can replace them - TLD has GM injectors at about $600 for a set, or SVO injectors from Jegs are about $200. Note the SVO's are LOUD, and may require a PROM change on a 92 (not sure).

4. Original injectors on a 92 would have been running for almost 10 years - might be about time to replace.

5. Symptoms could also result from weak fuel pump, fuel filter, MAP sensor, O2 sensors, Temp sensor, plugs, wires, or any number of other things. You would really need to run some diagnostics to know what's going on. I use Diacom.

HTH

DrJ

 

I'd suggest you take the car to a tune up place and have them run 'on the car injector cleaning' service. I don't know what they charge but its should not be more than about 40 - 60 bucks. You may need new injectors but this is worth doing anyway. It supposed to clean the deposits on the valves as well. You can also do it yourself buy getting the hose etc from a place on the web.

I put in larger injectors in my car and about 3 months later they started bleeding down when hot. I doubted they went bad so quickly so I looked into the cleaning option. I got the cleaning solution but I haven't found a fitting for it locally. The problem appears to have gone away since then too.

 

Do a fuel pressure check first.
If the pressure is low when the car is running, Id suspect a weak fuel pump...happened to my cars as well..didnt have enough fuel supply and would idle rough, stall sometimes or etc.Sometimes a restricted fuel filter will do this as well.

If fuel pressure is good, turn off the car and watch to see if the pressure drops suddenly.
If it does, re prime the fuel rail pressure with the key on then off a few times and pinch off the return hose on the gas tank.
If pressure still drops a bit or the same as before right away,id suspect leaky injectors.FPR is possible leak internally but not often.

A book I have said another trick is to lift the fuel rail and injectors off the intake just high enough to see the bottom of the injectors.Do this on a cold engine and NOT running.
If any injectors form a drop of gas on them, theyre leaking.You may need to turn the key on and off a few times(not run) to prime the fuel rail with fuel and then see if they leak out there when the key is off.If they form wet droplets or drip, youve found them.

Im not sure how the fuel rail is held down on your engine where they connect to the lines,but be sure you can lift it while its still attached to the lines but DONT force it..if the lines are too short and must be disconnected to lift the fuel rail, then skip that"visual" test..dont want to damage the fuel lines and rail.

I always start simple...fuel pressure checks, adequate spark, good voltage and etc.
(hope its not the opti-crap)